MIT-GEM-DM-01
PFC/RR-91-15
GEM Magnet Options:
Preliminary Report
J.D. Sullivan, P.G. Marston, R.D. Pillsbury, Jr.
R.J. Thome, N. Diatchenko, H. Becker
M.I.T. Plasma Fusion Center
R.L. Myatt, P.H. Titus
Stone & Webster Engineering Corporation
November 25, 1991
Plasma Fusion Center
Massachusetts Institute of Technology
Cambridge, MA 02139
This work was supported in part by SSCL/DoE under contract P.O. #91-W-09962.
Reproduction, publication, use, and disposal, in whole or in part, by and for the
government of these United States is permitted.
MIT-GEM-DM-01
PFC/RR-91-15
GEM Magnet Options:
Preliminary Report
J.D. Sullivan, P.G. Marston, R.D. Pillsbury, Jr.
R.J. Thome, N. Diatchenko, H. Becker
M.I.T. Plasma Fusion Center
R.L. Myatt, P.H. Titus
Stone & Webster Engineering Corporation
November 25, 1991
Plasma Fusion Center
Massachusetts Institute of Technology
Cambridge, MA 02139
This work was supported in part by SSCL/DoE under contract P.O. #91-W-09962.
Reproduction, publication, use, and disposal, in whole or in part, by and for the
government of these United States is permitted.
Contents
i
List of Figures
1
1 Introduction
2
Basis for Design Evaluation
2
3
Overview
4
4
GEM Baseline
5
5 Fringe Field Shielding
11
6 Small Angle Resolution
15
19
References
A Options
A.1 Solenoids with field shaping ....
A.1.1 Solenoid without end poles .
A.1.2 EoI baseline: Solenoid with t hick end poles
A.1.3 Thin pole case 1 ......
A.1.4 Thin pole case 2 ........
A.1.5 Thin pole case 3 ........
A.1.6 Thin pole case 4 ........
A.1.7 Lol baseline: Thin pole case 5 .
A.1.8 Thin pole case 6 ........
A.2 Further shaping and shielding . . . . .
A.2.1 Compensation . . . . . . . . . .
A.2.2 Bottle Solenoids . . . . . . . . .
A.2.3 Complex pole pieces . . . . . .
A.2.4 Miscellaneous . . . . . . . . . .
A.3 Alternatives of some interest . . . . . .
A.3.1 Solid iron wedge . . . . . . . .
A.3.2 50% iron wedge . . . . . . . . .
A.3.3 Bottle with solid iron wedge
A.3.4 Bottle with 50% iron wedge .
A.3.5 Bottle with return and 50% iron wedge
A.4 Shielding . . . . . . . . . . . . . . . . .
A.4.1 Full iron return frames . . . . .
A.4.2
Superconducting return
. . . .
A.5 High Field Options . . . . . . . . . . .
20
20
20
25
36
41
46
52
57
65
71
71
97
107
127
136
136
141
146
151
156
163
163
166
171
178
B Pless's Analysis
i
List of Figures
1
. . . . . . . . . . . . . . . . . . . . . . . . . .
GEM schematic (EoI) . . . . . . . . . . . . . . . .
Reference curve: 0(27) . . . .
. . . . . .
. . . . . .
. . . . . .
GeV . . .
GeV . . .
. . . . . .
jZ] at intermediate angles for EoI . . . . . . . . . . .
1ZI at middle angles for EoI . . . . . . . . . . . . . .
IZI at large angles for EoI . . . . . . . . . . . . . . .
EoI surface field, 50 m . . . . . . . . . . . . . . . . .
Sketch of design with 1.3 m return frame . . .
|B| vs radius near surface . . . . . . . . . . . . . . .
Flux contours . . . . . . . . . . . . . . . . . . . . . .
Sketch of design with 2.0 m return frame . . .
IBI vs radius near surface . . . . . . . . . . . . . . .
Flux contours . . . . . . . . . . . . . . . . . . . . . .
Sketch of s.c. solenoid with s.c. return, bottle, and Fe wedge
1BI vs radius near surface . . . . . . . . . . . . . . .
Surface field, 50 m . . . . . . . . . . . . . . . . . . .
Flux lines . . . . . . . . . . . . . . . . . . . . . . . .
Resolution at P = 500 GeV . . . . . . . . . . . . . .
Schematic of simple solenoid . . . . . . . . . . .
Contours of 11 . . . . . . . . . . . . . . . . . . . . .
Flux contours . . . . . . . . . . . . . . . . . . . . . .
IBI vs radius in hall . . . . . . . . . . . . . . . . . . .
|I vs radius near surface . . . . . . . . . . . . . . .
Surface field, 50 m . . . . . . . . . . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . . . . . .
BI2 isopleths . . . . . . . . . . . . . . . . . . . . . .
Schematic of EoI baseline . . . . . . . . . . . . .
Contours of $1 . . . . . . . . . . . . . . . . . . . . .
Contours of B. . . . . . . . . . . . . . . . . . . . . .
Contours of B,. . . . . . . . . . . . . . . . . . . . . .
Flux contours . . . . . . . . . . . . . . . . . . . . . .
IBI vs radius in hall . . . . . . . . . . . . . . . . . . .
IA vs radius near surface . . . . . . . . . . . . . . .
Surface field, 50 m . . . . . . . . . . . . . . . . . . .
Surface field, IR site 1 . . . . . . . . . . . . . . . . .
Isopleths of BL2 for uniform field . . . . .
Design comparison: BL 2 versus n . . . . .
Design comparison: Ratio of BL 2 versus 77
Design comparison: Resolution at P = 500
Design comparison: Resolution at Pt = 500
|Z| at small angles for EoI . . . . . . . . .
Surface field, IR site 4 . . . . . . . . . . . . . . . . .
11
2
43
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53
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77
78
79
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81
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85
86
Surface field, IR site 5 . . . .
. .... ..
Surface field, IR site 8 .
. .... ..
Resolution for P = 500 GeV
. .. ....
GeV
500
=
Resolution for Pt
. .. ....
Resolution for P = 100 GeV
. .. ....
Resolution for Pt = 100 GeV
... ....
GeV.
=
50
P
Resolution for
... ... .
Resolution for Pt = 50 GeV
... ....
Resolution for P = 5 GeV
.. ....
.
Resolution for Pt = 5 GeV
2
... ... .
BL isopleths . . . . . . . . .
... ... .
Comparison of IRs at 10 G . .
thi
Schematic of solenoid with
n pole #1
. . . . . . .
Contours of RBI . . . . . . . .
. . . . . . .
Flux contours . . . . . . . . .
. . . . . . .
B-I vs radius in hall . . . . . .
. . . . . . .
B I vs radius near surface . .
. . . . . . .
Surface field, 50 m . . . . . .
. . . . . . .
Resolution for P = 500 GeV
. . . . . . .
Resolution for Pt = 500 GeV
BL 2 isopleths . . . . . . . . .
Schematic of solenoid with thin pole #2
. . . .. . Contours of BI . . . . . . . .
. . . . . . .
.
.
.
.
.
.
.
Flux contours . .
. . . . . . .
1.81 vs radius in hall . . . . . .
. . . . . . .
1RI vs radius near surface . .
.
. . . . . .
Surface field, 50 m . . . . . .
. . . . . . .
Resolution for P = 500 GeV
. . . . . . .
Resolution for Pt = 500 GeV
2
Br isopleths . . . . . . . . .
Schematic of solenoid with thi n pole #3
. . . . . . .
Contours of 1.1 . . . . . . . .
. . . . . . .
Contours of B . . . . . . . .
. . . . . .
.
.
.
Contours of B,. . . . . . .
. . . . . . .
Flux contours . . . . . . . . .
. . . . . . .
[El vs radius in hall . . . . . .
. . . . . . .
1 IIvs radius near surface . .
.
. . . . . .
.
.
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.
m
50
Surface field,
. . . . . . .
Resolution for P = 500 GeV
. . . . . . .
Resolution for Pt = 500 GeV
BL 2 isopleths . . . . . . . . .
Schematic of solenoid with thiin pole #4
Contours of IBI . . . . . . . .
Flux contours . . . . . . . . .
iii
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Intercomporison of Magnet Resolving Power
a Baseline
A Thin-pole
+ Uniform Field
x Simple Solenoid
40
30
x
20
-
10
I--
0F . . . . l . . . . 1 . .
0. 0
1.0
.5
2 .5
2.0
1.5
Pseudoropidity (r)
Integral paths start at Phlen s p-detector baseline
Figure 4: Comparison of various magnet designs: BL 2 versus 7. The curve for a uniform
field is marked with a +, that for a simple solenoid with x, for EoI baseline Q, and for the
LoI baseline A.
Intercomparison of Magnet Resolving Power
2.
I
.
. I
.
.
I
I
I
I
II
a Uniform Field / Thin-pole
A Thin-pole / Baseline
+ Uniform Field / Baseline
x Simple Solenoid / Base
1.5 0
1.0
Cal
aW
a
.5
n
0.
0
2.5
2.0
1.5
1.0
Pseudorapiditjy (,)
Integral paths start at Phlen s p-detector baseline
.5
Figure 5: Comparison of various magnet designs: ratio of BE 2 versus 7. The curve for a
uniform field/EoI baseline is marked with a +, that for a simple solenoid/EoI baseline with
x, for uniform field/Lol baseline Q, and for the LoI baseline/EoI baseline A.
6
. . . . . . . . . . .
ABI vs radius in hall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.61 vs radius near surface . . . . . . . . . . . . . . . . . . . . . . . . . . .
I.9l vs z on axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surface field, 50 m. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . . . . . . . . . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . . . . . . . . . . . . . . . . . .
BL 2 isopleths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Schematic of poleless, 2 m compensated solenoid . . . . . . . . . . .
Contours of Ji3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flux contours . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BI vs radius in hall . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . .
IAR vs radius near surface . . . . . . . . . . . . . . . . . . . . . . . . . . .
IAl vs z on axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surface field, 50 m. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . . . . . . . . . . . . . . . . . .
Resolution for Pt = 500 GeV . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . .
BL 2 isopleths . . . . . . . . . . . . . . . . . . . . . . .
Schematic of extended solenoid . . . . . . . . . . . . . . . . . . . . . .
Contours of AlI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flux contours . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IBI vs radius in hall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
$ vs radius near surface . . . . . . . . . . . . . . . . . . . . . . . . . . .
AB vs z on axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surface field, 50 m . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . . . . . . . . . . . . . . . . . .
Resolution for Pt = 500 GeV . . . . . . . . . . . . . . . . . . . . . . . . . .
BL 2 isopleths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Schematic of extended, compensated solenoid. . . . . . . . . . . . .
Contours of flI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flux contours . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.
IA vs radius in hall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IA vs radius near surface . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ijl vs z on axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surface field, 50 m . . . . . . . . . . . . . . . . . . . . - . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . . . . . . . . . . . . . . . . . .
Resolution for Pt = 500 GeV . . . . . . . . . . . . . . . . . . . . . . . . . .
BL 2 isopleths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Schematic of solenoid plus end solenoid, double c rrent . . . . . . .
Contours of ABl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.
... . . .
Flux contours . . . . . . . . . . . . . . . . . . . . . - IBI vs radius in hall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IA vs radius near surface . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . .. . .. I Surface field, 50 m . . . . . . . . . . . . . . . . .
131 Flux contours . . . .
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GEM Magnet Options:
Preliminary Report
A strawman muon detector geometry is used in the evaluation of various designs
for the GEM magnet. The muon track resolution for the EoI baseline magnet
(superconducting solenoid with thick iron end poles) is compared with an option
with modified end poles (the LoI baseline), and with a uniform field. Design magnet
options to improve muon resolution at small angles (1.5 < q
2.5) include the
replacement of the iron poles with a superconducting "bottle" solenoid and/or the
addition of conical shells (wedges) of iron for field shaping. Because of concern
about the far (surface) field, shielded variants which use either a superconducting
outer solenoid or an iron flux return are also presented.
1
Introduction
The designs for a GEM' magnet are based on satisfying the physics measurement requirements. The project goal is to develop designs for magnet systems which can be constructed
within schedule and within budget, which have adequate safety margin, and which meet all
environmental requirements. The possibility of staging of some magnet elements (e.g., small
angle toroids) may be considered because of the tight construction schedule.
The initial conceptual approach (following L* [1, 2]) used a uniform field with the requirements of
* an 0.8 T uniform field in the central tracker (vertex detector),
* 5% momentum resolution for 500 GeV muon at 90' assuming 100 pm errors, and
* reasonable muon resolution (for constant P) out to 7 = 2.5.
The EoI2 baseline design [3] sought to make a uniform field from a (superconducting) solenoid
with (field shaping) thick iron pole pieces. However, the GEM collaboration was cognizant
from the first of the lack of flux return and of the importance of muon resolution at fixed Pt
as a function of q, e.g., the resolution at low angles needed to be improved. Consequently,
in addition to cost and complexity, the magnet design options discussed below address the
following two questions which were drawbacks inherent in the basic concept
1. How is the magnetic flux returned? and
2. What can be done about the rapid loss of resolution at forward angles?
'yep detector
EoI - Expression of Interest (in proposing an experiment)
2
1
To. summarize the results of comparing these four options:
1. An ideal uniform field is better than either baseline.
2. At lower angles the LoI baseline is better than the EoI baseline because the iron pole
extends further.
3. The surface field for the Lol baseline is slightly smaller than that for the EoI baseline
because of less iron.
4. At intermediate angles the resolution for the LoI baseline is somewhat worse than that
for the EoI baseline.
Although there is a loss of resolution at intermediate angles (where resolution is a maximum),
the LoI baseline uses less iron (costs less) and gives better access than the EoI baseline design
(which is why the change).
Finally, there has been some discussion of the possibility of adding muon detectors outside
the superconducting windings (of the EoI baseline). For 7 = 0, a gain in achievable resolution
seems feasible (depending on other errors); however, for 77 >- 1 the total ifI decreases and
no gain would appear to be possible. This is shown in Figures 8-11 where the dependence
on angle is explicitly shown. The abscissa is the path (arc) length so that the turnover
comes at different values depending on the angle of the path. Where the curves are straight,
BL 2 can be easily estimated as the product of the height difference and the length. The
corresponding curves for the LoI baseline would be, for all practical purposes, identical.
GEM 1 --Path
* Path
+ Path
x Poth
*
S
40
at
at
at
at
Baseline with Full Pole
5.0
7.5
10.0
12.5
degrees
degrees
degrees
degrees
32x
24
16
8
n
0
10 5,
5
m
S, In
15
20
25
Integral paths start at geometric center
Figure 8: Plot of Ill for the EoI baseline magnet versus path length from the interaction
point for tracks at 5, 7.5, 10, and 12.50 (from the beam line).
8
219
220
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223
224
225
226
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123
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124
124
125
125
Resolution for P = 500 GeV . . . .
126
Resolution for Pt = 500 GeV . . . .
2
126
BL isopleths . . . . . . . . . . . .
127
Schematic of MIT case "5d" . .
127
Flux contours . . . . . . . . . . . .
128
Surface field, 50 m . . . . . . . . .
129
Schematic of solenoid with s.c. cusps
129
Contours of BIA . . . . . . . . . . .
130
Flux contours . . . . . . . . . . . .
130
IBI vs radius in hall . . . . . . . . .
131
IB! vs radius near surface . . . . .
131
IBj vs z on axis . . . . . . . . . . .
132
Surface field, 50 m . . . . . . . . .
132
III at small angles . . . . . . . . .
133
IfZ at intermediate angles . . . . .
133
IIZ at middle angles . . . . . . . . .
134
1Zl at large angles . . . . . . . . . .
134
Resolution for P = 500 GeV . . . .
135
Resolution for Pt = 500 GeV . . . .
2
135
BL isopleths . . . . . . . . . . . .
136
Schematic of solenoid with Fe wredge
136
Contours of B!3 . . . . . . . . . . .
137
Flux contours . . . . . . . . . . . .
137
fBI vs radius in hall . . . . . . . . .
138
IA vs radius near surface . . . . .
138
Surface field, 50 m . . . . . . . . .
139
.
Resolution for P = 500 GeV . . .
139
Resolution for Pt = 500 GeV . . . .
140
BL2 isopleths . . . . . . . . . . . .
141
Schematic of solenoid with 50% Fe FHC
141
Contours of JBl . . . . . . . . . . .
142
Flux contours . . . . . . . . . . . .
142
IJI vs radius in hall . . . . . . . . .
143
IF31 vs radius near surface . . . . .
143
Surface field, 50 m . . . . . . . . .
144
Resolution for P = 500 GeV . . . .
144
Resolution for P = 500 GeV . . . .
2
145
.
BE isopleths
Schematic of bottle and iron wedge . . . . . . . . . . . . . . . . . . . . 146
Flux contours . . . . . .
IBI vs radius in hall . . .
B vs radius near surface
IAB vs z on axis . . . . .
Surface field, 50 m . . .
A
. . .
. . .
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vii
For multiple scattering [5, 6, 7], the central superlayer is assumed to have
csc 9 or sec9 for the barrel or endcap, so that
incidence, but
y
11.0 + 0.1111 log XO) ,
-
MS
2 V3 pcO
=
0.2 at normal
(4)
where D is the distance between superlayers. Finally, the systematic error is assumed to be
-= 25 gm.
,,
(5)
Occasionally, the outer edge of the central detectors and the inner edge of the magnet cryostat
are used as the defining dimensions but graphs in which this is assumed are always so labeled.
16
e
14
0
N
*
N
0
12
0 Fe pole
~
Central detectors
Barrel muon chambers
Endcop muon chambers
Cruostat
10
(A
0
L
2
0
2
6
4
Scom
8
10
12
14
16
oxis, M
Figure 2: Quadrant side view (based on the EoI) of GEM showing: the central detectors,
strawman muon chamber layout, magnet cryostat, and thick iron pole piece. The size of
the central detector is dictated by calorimetry resolution and the vertex detector; the muon
resolution determines the overall volume and the magnet cryostat must be outside that.
To obtain a resolving power measure4 , we consider the Lorentz force,
=-
,
c
dt
(6)
and assume that the particle rigidity R is high enough that p > L where p is the radius of
curvature (= R/Bi) and L is the length scale of interest (e.g., the size of the experiment).
Under this assumption, the osculating plane is fixed and (small) higher order corrections to
the path are ignored. The first integral of the force equation is the impulse I:
qf
4
ax
d
(7)
A complementary analysis by Prof. Pless of M.I.T. with the same result is reproduced in Appendix B.
3
GEM 1 ---
200
I
-
&q
Baseline with Full Pole
o Path at
60.0 degrees
A Path at
+ Path at
x Path at
70.0 degrees
80.0 degrees
90.0 degrees
-T
I
r
100-
0
5
15
10
20
25
5, m
Integral paths start at geometr c center
Figure 11: Plot of Z for the EoI baseline magnet versus path length from the interaction
point for tracks at 60, 70, 80, and 900 (from the beam line).
10
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
IBI vs radius in hall . . . . . . . 87.vs.radus.in.hal.......
vs radius near surface . . . . . . . . . . . . . . . .
Surface field, 50 m . . . . . . . . . . . . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . . . . . . .
BL 2 isopleths . . . . . . . . . . . . . . . . . . . . . . . .
Schematic of solenoid with thin pole #5 . . . . .
.
. . .
. . .
. . ..
. . .
. .
. . .
.
.
.
.
Contours of IF1 . . . . . . . . . . . .. . . . . . . . .. . ...
Contours of B. . . . . . . . . . . . . . . . . . . . . . . . . . ..
Contours of B,. . . . . . . . . . . . . . . . . . . . . . . . . ..
Flux contours . . . . . . . . . . . .
IBI vs radius in hall . . . . . . . . .
IBI vs radius near surface . . . . .
Surface field, 50 m . . . . . . . . .
IZI at small angles for Lol . . . . .
III at intermediate angles for LoI .
1Zf at middle angles for LoI . . . .
1.1 at large angles for LoI . . . . .
Resolution for P = 500 GeV . . . .
Resolution for Pt = 500 GeV . . . .
BL 2 isopleths . . . . . . . . . . . .
Schematic of solenoid with thin
Contours of IB1 . . . . . . . . . . .
. .. . .
. . . . .
. . . . .
. . . . .
. . . . .
. . . . .
. . . . .
. . . . .
. . . . .
. . . . .
. . . . .
pole #6
. . . . .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
. .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
. .
. .
. .
. .
. .
. .
. .
.. .
. .
. .
.. .
. .
. .
..
. . .
. . ..
. . .
. . .
. . .
. . ..
. .
. . .
. . .
. . .
. . .
. . .
.
.
.
.
.
.
.
.
.
.
Contours of B . . . . . . . . . . . . . . . . . . . . . . . . . ..
Contours of B,. . . . . . . . . . . . . . . . . . . . . . . . . ..
Flux contours . . . . . . . .
IA vs radius in hall . . . . .
IBI vs radius near surface .
Surface field, 50 m . . . . .
Resolution for P = 500 GeV
Resolution for Pt = 500 GeV
BL2 isopleths . . . . . . . .
Schematic of thin-pole, 1
Contours of
IBI
.
. . . . . . . . . . . . . . .. .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
. . . . .
. . . . . . . . . . . . . . . . . ..
. . .
. . . . . . . . . . . .. .
. . . . . . . . . . . . . . . . . ..
. . . . . . . . . . . . . . . . . ..
. . . . . . . . . . . . . .. .. .
m end-compensated solenoid
. . . . . . . . . . . . . . . . . . . . ... . ..
Flux contours . . . . . . . .
[$A vs radius in hall . . . . .
II vs radius near surface .
RIB vs z on axis . . . . . . .
Surface field, 50 m . . . . .
Resolution for P = 500 GeV
Resolution for P = 500 GeV
BL 2 isopleths . . . . . . . .
Schematic of thin-pole, 2
. . . . . . . . . . . ..
. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . . . . . .
. . . . . . . . .. . .
m end-compensated
Contours of 1.I . . . . . . . . . . . . .
iv
. .. .
. . . .
. . .. . .
. . . . . .
. . .. . .
. . . . .
. . . . ..
. . . . ..
.. . . . .
solenoid
.. . .
..
.
53
..........................
307 Schematic of "Ko" option ......
308 Contours of I . . ..................................
171
172
309 Flux contours . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
172
310
311
312
313
314
315
316
317
B I vs radius in hall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
RI1 vs radius near surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
Surface field, 50 n . . . . . . . . . . . . . . . .
Schematic of "Kycia" option . . . . . . . .
Contours of 1.9 . . . . . . . . . . . . . . . . . .
...................................
Flux contours ........
1BI vs radius in hall . . . . . . . . . . . . . . . .
RBI vs radius near surface . . . . . . . . . . . .
318 Surface field, 50 m
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .
174
174
175
175
176
176
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
ix
4
GEM Baseline
For the uniform field (where most results are analytic), isopleths of constant B1 2 are shown
in Figure 3; the 10 T m 2 isopleth is approximately the 5% resolution level (for fixed P).
However, the questions: "How well does the baseline design (cf. Figure 2) meet the conUniform Field (B = 0.8 T)
Contours oF Fixed
f if
Isopleths at 6, 8.
Ja x SLuds
10. and 12 T m2
10-
5
0
0
5
10
15
Z. m
Intogral paths start at Ahlon's W-detector boselire
Figure 3: Isopleths of constant BL 2 for a uniform field superposed on a sketch of GEM;
isopleths increase in value with distance from the origin.
ceptual design goals?" and "Is it possible to reduce cost, to improve access, etc. of the
baseline?" must be answered. We do this by considering (and comparing)
1. a uniform field,
2. a simple solenoid (cf. Appendix A.1.1),
3. the EoI baseline, a solenoid with a thick iron pole (cf. Appendix A.1.2), and
4. the LoI9 baseline, a solenoid with a thin iron pole extending to only 7 m (cf. Appendix A.1.7).
The resolving power as a function of pseudorapidity is shown in Figure 4 for these four
cases. The kink in all the curves is simply an artifact of the muon detector geometry. The
uniform field has larger resolving power at all values of q and the curve for the thin pole
crosses that for the baseline because the thin pole extends closer to the beamline. The
differences in resolving power can be seen in a plot of their ratios (cf. Figure 5).
The resolution (f) for a constant P of 500 GeV is shown in Figure 6 and for a constant
Pt of 500 GeV in Figure 7. Clearly for 77 > 1.5, the fixed Pt resolution deteriorates rapidly
and this is a major drawback to both baseline magnet options.
'LoI - Letter of Intent (to propose an experiment); due November 30, 1991 for GEM.
5
15
GEM
Thin Pole Opt ions:
I
1
I
I
Contours oF Fixed if
I
f
*
Case 4
I
I
x .dj-ds
Isopleths at 6, 8, 10, and 12 T m2
10
E
51
I
-
0
0
5
10
Z,
15
m
Integral paths start at Ahlen's p-detector baseline
Figure 92: Isopleths of constant BL 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
56
A.1.4
Thin pole case 2
Thin Pole Options.
GEM --
Case 2
MITMAP VI.A 11/13/91
12:13
1.6-
1.41.2-
U
.8
.6.4-
.2103
0.
.2
10
.4A
.5
.6
A I dN
i
1.0
EL.EMENTS
Figure 64: Side view of a superconducting solenoid with a thin pole, case #2. Note that the
beam axis (the z axis) is vertical on the page and the transverse (radial) axis is horizontal.
GEN --
Thin Pole Options.
Cosa 2
MITMAP VI.0 11/15/91
10:27
VNr
".IsintOn
fnCeOantg.
I.e
U
4.
3.
a
-
I
i'J
2.U
1.-
10
0.
0
.
I0
Figure 65: Contours of constant
labeled in gauss.
5.
1.
4.
3.
A ( m)
CONTOURS OF CONSTANT B
BI
superposed on a side view of the magnet; isopleths are
2.
41
A.1.5
Thin pole case 3
GEM ---
Case 3
Thin Pole Options,
14: 1
M[TMAP VI.A 11/13/91
1.6-
1.41.21.0U
.8-
"4
.6
.27
10
a
10o
.
.2
1.0
.8
.6
R (m)
ELEHENTS
Figure 73: Side view of a superconducting solenoid with a thin pole, case #3. Note that the
beam axis (the z axis) is vertical on the page and the transverse (radial) axis is horizontal.
GEN
---
Case
Thin Pole Options.
MITHAP V1.0
1
r//91
S
10:27
5.
4.-
S.
a
"4
2.
1.-
10
0.
.
11.
2.
4.
5.
CONTOURS OF CONSTANT B
Figure 74: Contours of constant JBj superposed on a side view of the magnet; isopleths are
labeled in gauss.
46
GEM --:D
I
I
Case 8
Thtn Pole Opttions:
I
III I
I
I
I
Contours of fixed if
I
I
I
U x .dards
f
Isopleths at 6, 8, 10, and 12 1 m 2
10Ea
5-
01
0
I
I
5
I
I
10
Z,
15
m
Integral paths start at ARlen's p-detector baseline
Figure 83: Isopleths of constant BI 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
51
GEM ---
Thin Pole Option4s
MITHAP V1.9 11/2/91
Case S
Mt34
3.0
2.52.0a
1.61
NJ
S-
-2.
1.5-
.-
0.
i1
1.9
.5
2.5
1.5
2.0
R m)
3.8
CONTOURS OF CONSTANT Bz
Figure 95: Contours of constant B. superposed on a side view of the magnet; isopleths are
labeled in gauss.
GEN
---
Case 6
Thin Pole Op+ onst
MITMAP VI.0 11/29/91
14:35
2.5
2.0
"
1.5
1.0
.5
10
-r-
8.
0.
.5
18
1.0
1.5
2.0
R 1 m)
2.5
CONTOURS OF CONSTANT Br
Figure 96: Contours of constant B,. superposed on a side view of the magnet; isopleths are
labeled in gauss.
58
GEN
Thin Pate Optioni
---
Coze 2
MITHAP V1.0 11/13/91
13s57
-------------\-----------..............
--------------
1.4'
J., . ..... ...................
...... ...... . ............ t-
-
--
-.-
---
-- - - ------- 4-
3.
2.
5.
4.
is
6.
7.
(m.,
Figure 68: JBj versus radius near the surface.
i I,
GEM --
Thin Pole Options:
.4
Feld (G)
S
on
Cose 2
50-m surface
.4
2.2
1.6
so
2.0
U
a
4-
3.2
s.e
0
0
0
L
I)
0
C
a
L
I-
-50
-
-
_ inn
-100
-50
0
Z-oxis (beamline),
so
100
In
CONTOUB LEVELS (101 3
Figure 69: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
43
GEN
Thin Pole Optionst
---
MITHAP V1.0 11/13/91
Cwdtmir I *
LU.N+ 0
t,1.
Case 3
14:29
. 87K.9
2. 0.
1.8
LI
1.
1.
1.2
U
0
.9
.
S.
0. 10
1.0
.S
R I m)
1.5
2.0
CONTOURS OF CONSTANT FLUX
Figure 77: Flux lines superposed on a side view of the magnet design.
GEM
---
Thin Pole Gotion:
NITNAP V1.0 11/13/91
Cost 3
14t 30
8.
7.
6.
G.
~
4.
2.
.
-- +---+---+---+------
--
to2
-
-
--
.4
.2
-
+-------+ ---
.6
.8
R al
Figure 78: JB| versus radius in the hall.
48
1.0
GEM ---
Thin Pole Op+aonas
Case 4I
MITHAP V1.0 11/13/91
Coatawr
I
*
£.m.8a
Omit.
15t11
5.375+.U
*
2.0
1.8
i-4
1.2
.
...
1.0
le
0
1.2
1.
-5
I VA///
.8
.6
CONTOilURSOFCOSANFU
.2
'It
0.
CN TOURIm
Figure 86: Flux lines superposed on a side view of the magnet design.
GEN --- Thin Pole Gotionsa
MITHAP VM.0 11/13/91
Case '4
15:12
8.
7.
-
------
-
-
-----
-
6.
S.
Li.
3.
- --
2.
101
0-
2
ive
-2
- ---
.4
- ---
at .1
.6
.8
1.0
Figure 87: JBj versus radius in the hall.
53
GEM --MITMAP
Than Pate
Ootionsi
VI.A It/ 4/91
Cosa 6
12129
8.
-------- ......------1. 6
........
...................... .
I.
2
9 ........- - - - 8 -- - ---
to
- - - - --
2.
I
3.
5.
q.
6.
7.
Figure 99: BI versus radius near the surface.
lUU
GEM ---
Thin Pole Options:
.
Case 5
.8
ield (G)on 50-m surface
1.2
50
2.
82
0
L
0
L
-50
-.-
-in
-100
-50
0
50
Z-oxis (beomline), m
CONT0UR LEVELS (101
100
Figure 100: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
60
15
GEM ---
Th'kn Pole Opttons:
Contours o
4ixed if f
.
Case 2
x .dIds
Isopleths at 6, 8, 10, and 12 T m2
10
a5'.
0
0
5
10
Z,
15
m
Integral poths start o Ahlen's p-detector boseline
Figure 72: Isopleths of constant BL' superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
45
08
-
GEM
--
Thin Pole Options:
. .
I
. .I
- - I
Mognet Resolution for P
500.0
e'~to
0*
Case 3
I
. .
06
C,)
N.
en
~0
04
-mon'
o
02-
0 . 00 ,
0.0
.5
I
2.0
1.5
1.0
2.5
Pseudoropidi ty (W)
Integral paths start at Ahlen s p-detector baseline
Figure 81: Resolution for constant P as a function of r7.
GEM ---
Thin Pole Options:
Magnet Resolution for Pt =
Case 3
500.0
. 3-<n
. 2 --
0 .0
. . . . I
0.0
.5
.
.
I
1.0
.
.
. .
.
1.5
I .
2.0
j
.
2.5
Pseudoropidkty (T)
Integral paths start at Ahlen s p-detector baseline
Figure 82: Resolution for constant Pt as a function of 17.
50
08
GEM --1
1
. I
Thin Pole Options:
I I
I I
Mognet Resolution for P
.06
-
ge
a
Case 4
I
I
500.0
O.
-eoui
(n
.04
.02 -
0 .00 1 . . . . I , , , , I . , , . I , .
0.0
, I , .
.5
1.0
1.5
2.0
2.5
Pseudoropidkty (n>
Integral paths start at Ahlen s p-detector baseline
Figure 90: Resolution for constant P as a function of 77.
GEM ---
Thin Pole Options:
Magnet Resolution For Pt
Case 4
500.0
.3
(n)
.2
1
0.01
0.0
.5
1.0
1.5
2.0
2.5
Pseudoropidity (T)
Integral paths start at Ahlen s p-detector baseline
Figure 91: Resolution for constant Pt as a function of 7.
55
15
GEM
Base and "Bottle 2b" Solenods
I
I
I
f
I
I
Contours oF f xed If f
Isopleths at 6,
8,
10,
I
I I
B x .cl-ids
and 12 T m2
101-
a.
5
0
I
C
I
I
5
I
I
10
I
15
Z, m
Integral poths stort ot Ahlen's p-detector baseline
Figure 186: Isopleths of constant BL 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
106
Thin Pole Cose 3 Extended
GEM ---
Magnet Resolution For Pt
500.0
.40
.32
(I,
N.
(f~
.24
16
.081
0. 001
0. 0
.5
1.0
1.5
2.0
.5
Pseudoropkdity (W
Integral paths start at Rhlen a p-detector boseline
Figure 157: Resolution for constant Pt as a function of q.
GEM
-
Thin Pole Case 3 Extended
Contours of
.
Fixed i
f fix zids'
Isopleths at 6. 8. 10, and 12 T
m2
10k
E
5j
77
0
0
, I , , , -
5
Z. M
10
15
Intogf-ol poths start at Aen's p-detector baselin.
Figure 158: Isopleths of constant BL' superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
91
GEM ---
Thin Pole Case 3 Extended with Im Compensotion
Magnet Resolution for Pt
500.0
.2-
t(n
.1-
0.0 ..
, .
.I
,.1
.5
0.0
.
.
,
1.0
.,
1.5
, ,
p
2.0
2.5
Pseudoropidity (-,)
Integral paths start at Ahlen s p-detector baseline
Figure 167: Resolution for constant Pt as a function of q.
OEM
-
Thin Pole Case S Extended with to CompAsation
Contours of fixed i
f ax dalds'
Isopleths at 6, 8, 10, and 12 T m2
10-
5--
0.
0
Integral
1 . .
5
paths stcrt at
. .
to
15
Ahlen's p-dateotor baseline
Figure 168: Isopleths of constant BL 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
96
151
GEM --I
I
Base and "Bottle 2a" Solenoids
I
1
1
1
1I
Contours oF 4'xed If f
Isopleths at 6,
8,
Q x dsI.ds'
and 12 T m2
10,
10 E
a.
5-
0
0
i
i
t
L
I
1
I
I
I
I
I
~
I
I
I
I
I
II
10
5
Z,
t
I
I II
,
I
15
m
Integral paths stOrt at Ahlen's p-detector baseline
Figure 177: Isopleths of constant BL 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
101
GEM --
Thin Pole Case 3 with Cold Iron
MITHAP V1.0 11/18/91
.SE.
Delt*a
Conto.u I
11: 4
C..
2.0
1.8
1.2
U
1.0
.8
.2
0.
1.0
.5
10
R Im)
I.S
2.0
CONTOURS OF CONSTANT FLUX
Figure 189: Flux lines superposed on a side view of the magnet design.
GEM --
Thin Pole Cone 3 with Cold Iron
HITMAP VI.0 11/18/91
111 6
8.
7.
.........-----
..... ....
J
----
6.
S.
4.
...... ....... ...............
........
3.
2.
-------------- ------ +---------- ---- --
2
a . L0
2
LI
2
F1
m)
.
.R
Figure 190: 1.6 versus radius in the hall.
108
.0
GEM
--
3 Extended vith Is Compensation
Thin Pole Ceo
MITRAP VI.0 11/18/91
contour
I
+
1. M
Dolts-
4E
10:59
5.262E+.
1.6
1.4
1.2
a
1.0
.8
.6
.2
10
0.
0.
10
5
i
1.5
1.0
I a)
2.0
CONTOURS OF CONSTANT FLUX
Figure 161: Flux lines superposed on a side view of the magnet design.
GEN ---
Thin Pole Coae 3 Extended with I1 Coapenoetion
111 0
MITHAP VI.A 11/18/91
a.
7.
.....
4......
........
6.
r--
*I
..
---
3.
2.
4~ ~-
~ o2
0-
.2
.4
t
-yY~-r-
.6
1
1.0
Figure 162: JBI versus radius in the hall.
93
GEM
0Se and
---
Sottle 2e* Solertohds
MITNAP V1.A 11/16/91
2
Contou
O8ti
I.UN.M1
.
17:17
6.DEet
2.0
I.e
1.5
1.2
-
1.0
.8
is
.
.2
9.
9.
2.0
3.5
1.0
CONTOURS OF CONSTANT FLUX
.5
CNU
R ICA)
Figure 171: Flux lines superposed on a side view of the magnet design.
SEM
---
Bon
nd Bo91tle 2a* Solenoids
MITHAP VI.0 11/16/91
-----
. ....-
.
.... 2
37' IS
- - -
6.
B.
4.
3.
2.
29e
. ...
...
0.
Figure 172:
.4 0
1.9
2
2
IBI
versus radius in the hall.
98
6EM
Base and "Bottle 2b- Solenoids
---
17:46
MITNAP V1.0 11/16/91
COnto.
I -
Delia
I.atUaI
-
2.0
I.ViI-.80
1.4
1.2
*
.6
.2
181
0.
.5
1.
.C
A I a)
CONTOURS
OF CONSTANT
2 .0
FLUX
Figure 180: Flux lines superposed on a side view of the magnet design.
GEM
---
Base 8nd '8ottle 2b* Solenoids
17t 8
MITMAP VI.0 11/16/91
a.
7.
--------
ro
4.
.......... .
3.
. .......
2.
10
.
Figure 181:
R(
m)
.BI versus
103
0
radius in the hall.
GEM ---
inn~
Thin Pole Case 3 with Cold Iron
/ eld (G) on
E
50 rn surfoce
1.2
50
1.8
2.0
C
0
3.2
3.6
41
0
L(A
L
-50
-100
-100
.4
.
.4
-so
0
50
100
Z-oxis (beamline), m
CONTOUR LEVELS (101
Figure 193: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
GEM ---
Thin Pole Cose 3 with Cold Iron
for P
Magnet Resolution
7-
06
(i-I
500.0
.04
021
o . nn
0.0
i
i
.5
1.0
1.5
2.0
2 .5
Pseudoropidity (v7)
Integral paths stort at Ahlen 9 i-detector baseline
Figure 194: Resolution for constant P as a function of -r.
110
GEM
100
Thin Pale Case 3 Extended with 1. Caspensation
I .
--
,
,
Field (G) an
0-g s
rface
1.2
-.
so
2.0
0-
C
0
-
-50-4.)
L
-100
-100
.
,
'
-50
0
50
Z-oxis (beamline), m
CONTOUR LEVELS (10' 1
100
Figure 165: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the bearnline (centerline).
.06 4
GEM --- Thin Pole Case 3 Extended with im Compensation
I . . ,
I .
. I I . . I I
. . I I I
.
Magnet Resolution For P
500.0
.056
.048
.040-
.032.024
.018
,
0.0
,
I
.5
*
I
,
,
,
1.0
1.5
,
I
2.0
,
,
,
2.5
Pseudoropidity (n)
Integral paths start at Ahlen s p-detector baseline
Figure 166: Resolution for constant P as a function of r7.
95
GEM ---
Bose and "Bottle 2o" Solenoids
net Resolut ion for P
500.0
.04
U,
.03
U,
.02
.01
0 .00 1 . . . . I - .
0.0
.5
-I. .. .I .
1.0
1.5
Pseudoropidity (,7)
. , I. .
2.0
2.5
Integral paths start at Rhlen s p-detector baseline
Figure 175: Resolution for constant P as a function of 77.
GEM ---
Bose and "Bottle 2o" Solenoids
Magnet Resolution for Pt =
500.0
.101
U,
-7
U,
.05
n nni
.
SI
0.0
.5
1.0
I
1.5
Pseudoropidity (C,)
I
2.0
2.5
Integral paths start at Ahlen s p-detector baseline
Figure 176: Resolution for constant Pt as a function of 7.
100
GEM ---
Bose and "Bottle 2b" Solenoids
t Resolution
or P
500.0
.04
.03
.02
-
-
.01
0.00
0.0
2.5
1.0
1.5
2.0
Pseudoropidity (,)
Integral paths start at Rhlen s p-detector baseline
.5
Figure 184: Resolution for constant P as a function of 17.
GEM
Bose and "Bottle 2b" Solenoids
---
Magnet Resolution For Pt
=
500.0
Cn
.0
.1
0.01 -
II
I , a , ,I
, . , , I I , I ,
I ., , _
2.5
2.0
1.5
1.0
Pseudorapidity ()
Integral paths start at Ahlen s p-detector baseline
0.0
.5
Figure 185: Resolution for constant P as a function of q.
105
GEM
---
Gase. Bot) 2a.
end
Atrn Sol.
+
Forw. NC
MITHAP V1.8 11/16/91
Contow I
...
2.0
-
21:35
Ouit* - 5.61W."
.LWK4I9
...
1.
1.0
a
1.4
1.2
10 .2
0.
10
CONTOURS OF CONSTANT FLUX
Figure 282: Flux lines superposed on a side view of the magnet design.
GEM --
Bose.
Botl 2. end Rtrn
Sol.
MITHAP V1.0 11/16/91
+
Forv. HC
2137
8.
7.
----- --- - -~
------~~
----
-
6.
5.
3.
---------- - -----
2.
-
LO
-2
Figure 283:
. 4 A( 1 . 6
fBI
.a
-----
10. 0
versus radius in the hall.
157
502
Fe wedge (FHC)
HITHAP VI.A 11/16/91
Gontaur i
-
2.0-
I
Dit
6.UKE.IM
*
19:33
. *
1.9'ffE.
4.
1~
1.8
1.0
1.11
1.2
U
1.0.8
.6-
.2
is
"1
0.
0.
1010
.5
CONTOURS
OF
2.0
1.5
1.
R I a)
CONSTANT FLUX
Figure 255: Flux lines superposed on a side view of the magnet design.
60?
Fe uede (FHCI
MITNAP VI.A 11/16/91
1943
S.
'4.
3.
2.
--
-
.-.
a. 12
2.
.
a
8)
. -
.
-.
Figure 256: 1BI versus radius in the hall.
142
.0
GEM:
Bace and "Bottle 2c" Solenoids
MITMAP V1.0 11/16/91
.m
.
Oetl*
Co..to.r I
*
plus Iron
FC
20t 2
7.M6E.UD
2.0
1.8
1.4
1.2
£
1.0
.8
.6
*4
.2
I0~
0.
0.
1.5
1.0
1Rim)
.5
10
2.0
CONTOURS OF CONSTANT FLUX
Figure 264: Flux lines superposed on a side view of the magnet design.
Bose end *Bottle 2a" Solenoid* clu3 Iron FC
6EMi
MITHAP V1.0 11/16/91
. ...
_ .....
.. .
.. .. . .
.. .
20* 4
.
.. . . .. . .. ..
7.
6.
------
......
..T
3.
2.
0.
2
10
.2
Figure 265:
.4
IBI
.6
.8
1.0
versus radius in the hall.
147
Base end
OEM --
"Bottle
2e Solenoids olu3 Forward MC
MITHAP VI.A 11/16/91
18160
Deita * 4.8M.0
B.USGE41
Contou, I
. . . . .
2.0 . . . . . . . . . . .
1.-
1.25
1.L0
.4
1.2
10
S.0.
01
to
5
2.0
1.5
1.0
RI 4)
CONTOURS OF CONSTANT FLUX
Figure 273: Flux lines superposed on a side view of the magnet design.
GEN --
Bose and *Bot+e 2e Solenoids plus Forward HC
MITNAP VI.A 11/16/93
18:62
9.
s.
-
- -------- - -
8.
. ------...
-
-
-
+------
---- ------------ ------
...
-
-
- - + - -----
- - - -
--- -
3.
2.
.
. 2 ..
1.
L9o
.8
S. .2..
.... .
1.0
RI 0)
Figure 274: BI versus radius in the hall.
152
Bose, Botl 2o, and Rtrn Sol. + Forw. HC
GEM ---
o Path at
A Path at
+ Path at
x Path at
5.0
7.5
10.0
12.5
degrees
degrees
degrees
degrees
4 x
.. ........
.
2
5
0
10
S. M
15
20
.
25
Integral paths start at geometric center
Figure 286: Plot of fZ versus path length from the interaction point for tracks at 5, 7.5, 10,
and 12.50 (from the beam line).
GEM ---
Base, Botl 2a,
and Rtrn
Sol. + Forw.
HC
1L
o Path at
8"
x
A Path at
+ Path at
x Path at
15.0 degrees
17.5 degrees
20.0 degrees
25.0 degrees
6
-I--.........
G)
5
10
15
20
25
S. M
Integral paths start at geometric center
Figure 287: Plot of IIZ versus path length from the interaction point for tracks at 15, 17.5,
20, and 25' (from the beam line).
159
.07
50\% Fe wedge (FHC)
I
2
Magnet Resolution For P
I
500.0
.064
.056
.048
.040
.032
n.)A t
0.0
I
2 .5
2.0
1.5
1.0
Pseudorapidi ty (W)
Integral paths start at Ahlen s p-detector baseline
.5
Figure 259: Resolution for constant P as a function of 7.
50\x Fe wedge (FHC)
'a A
Magnet Resolution For Pt
500.0
.24
cn.
.19
.14
.09
.04
0. 0
.5
1.0
1.5
2.0
2 .5
Pseudoropidty (W)
Integral paths start at Ahlen s p-deteator baseline
Figure 260: Resolution for constant Pt as a function of 77.
144
.05
GEM:
Bose and "Bottle 2o* Solenoids plus Iron FC
. 1 1. 1
1 1. . .
1
. I I . .
500.0
ognet Resolution for P
.04-
.03LO
.02-
.01-
I...
....
0.00
I
.
.
2.5
2.0
1.5
1.0
)
Pseudorop dity (1o
Integral paths start at Ahlen s p-detector baseline
0.0
.5
Figure 268: Resolution for constant P as a function of 77.
GEM:
Base and "Bottle 2o" Solenoids plus Iron FC
Magnet Resolution for Pt
500.0
.06-
(I)
.04
-
.02-
.
, .
2.5
2.0
1.5
1.0
Pseudoropidity (n>
Integral paths start at Phlen s p-detector baseline
, ,
0.00 . . . ,
.5
0.0
Figure 269: Resolution for constant Pt as a function of 7.
149
GEM ---
a
Bose and 'Bottle 2o" Solenoids plus Forword HC
net Resolutton
For P = 500.0
.04-
.03-
.02-
.01-
0.00[ . . . . i . . . . 1 . .
2.5
2.0
1.5
1.0
Pseudoropiditp ()
Integral paths start at Ahlen a p-detector baseline
.5
0.0
Figure 277: Resolution for constant P as a function of 77.
.12
GEM --1
Bose and "Bottle 2a" Solenoids plus Forword HC
. . . I . .
Magnet Resolution For Pt
500.0
.08(f)
.04
.
.
2.5
2.0
1.5
Pseudoropidity (y)
Integral paths start at Ahlen a p-detector baseline
0.001 . . . . ,
.5
0.0
.
. .
1.0
Figure 278: Resolution for constant Pt as a function of 77.
154
GEM --,
.06
Base, Botl 2o, and Rtrn Sol.
Magnet Resolution for P
+
Forw. HC
500.0
.04-
.02--
0.00 , , , ,. 1 ., , ,,1
0.0
.5
1.0
,
1.5
2.0
2.5
Pseudoropidity (N)
Integral paths stort at Phlen s p-detector baseline
Figure 290: Resolution for constant P as a function of rj.
.15
GEM ---
Base, Botl 2a, and Rtrn Sol.
Magnet Resolution for Pt
+ Forw.
HC
500.0
.10-
.05-
0.001 . . . .
0.0
.5
1.0
1.5
2.0
2.5
Pseudorapidity (N)
Integral paths start at Ahlen s p-detector baseline
Figure 291: Resolution for constant Pt as a function of 77.
161
A.3.3
Bottle with solid iron wedge
CEMs
Be* end
MITHAP
'c*
Ie 26" Solenoode plus lIon
V1.I 11/16/91
FC
20: 2
2.0
I~.
1.
E
F=FR
1.6
1.2a
1.0
.8
0.
.5
0.
1.0
A I ml
ELEMENTS
2.0
1.5
Figure 262: Side view of a superconducting solenoid with the end pole replaced by a superconducting bottle coil and with a solid iron wedge. Note that the beam axis (the z axis) is
vertical on the page and the transverse (radial) axis is horizontal.
GEN*
Base and
"Botle
2s" SoIenoids plus Iron FC
NITMAP V1.8 11/16/91
20: 2
T
Va e. C ..... e...nts
5.
23*
4.
3.
U
p.'
2. -
1.
10
0.
10
Figure 263: Contours of constant
labeled in gauss.
IBI
1.
4.
3
A I C;
CONTOURS OF CONSTANT B
2.
5.
superposed on a side view of the magnet; isopleths are
146
A.3.4
Bottle with 50% iron wedge
GEM
ease and "Bottte 2a" Solenoids Plus Forward HC
--
MITMAP V1.0 11/16/91
18f9q
2.0.
1.4-
I.5-
1.2B
A..57
.1
8.I
.5
10
1.5
1.0
R I M)
ELEMENTS
2.0
Figure 271: Side view of a superconducting solenoid with the end pole replaced by a superconducting coil and with a 50% iron wedge (calorimeter). Note that the beam axis (the z
axis) is vertical on the page and the transverse (radial) axis is horizontal.
EM
--
Bace end 'Bottle 2e Solenoitds
IUs Forward MC
18:49
MITHAP V1.0 11/16/91
5.
am
2.
a
I
21
NJ
2.-
1.
i I.
0.
]
2.
1
3.
q.
5.
A I Wi
CONTOURS OF CONSTANT 8
Figure 272: Contours of constant
labeled in gauss.
IBI
superposed on a side view of the magnet; isopleths are
151
A.3.5
Bottle with return and 50% iron wedge
GEN
---
Bete. BotI
2..
and Aten bol.
MITMAP V1.0 11/16/91
21:35
I,
i
2.6
- Forv.
HC
.i
1.61.'41.2a
1.6.8.6-
.2li
0.
0.
.
.5
.
I
.
.
I
1.5
1.6
.
2.0
ELEMENTS
Figure 280: Side view of a superconducting solenoid with a superconducting return, with
the end pole replaced by a superconducting coil, and with a 50% iron wedge (calorimeter).
Note that the beam axis (the z axis) is vertical on the page and the transverse (radial) axis
is horizontal.
GEN ---
Base. Botl 2e. *nd Aten Sol. - Forv. HC
NITMAP V1.8 11/16/91
21:35
Y~
becetow. Incm...nl
5. .. .
. . . ..
B
4I.-
a
3. -
if )m/
N
2.
-
1.1
0.
1.
2.
4.
3.
R
S.
CONTOURS OF ICONSTANT
B
N
N
Figure 281: Contours of constant A$ superposed on a side view of the magnet; isopleths are
labeled in gauss.
156
.10
Magnet Resolution Intercomparison For P
.
. . .
. .
.
500.0
=
.
o Basel ine
A Thin-poIe
UntForm Field
x Simple Solenotd
+
.08-
(n
.06-
. 04-
.02-
2.5
2.0
1.5
1.0
Pseudorapidity (T)
Integral paths start at Ahlen 9 p-detector baseline
0.0
.5
Figure 6: Comparison of the resolution of various magnet designs for constant P (500 GeV)
as a function of 77. The curve for a uniform field is marked with a +, that for a simple
solenoid with x, for EoI baseline 0, and for the LoI baseline A.
Magnet Resolution Intercomparison for P=
500.0
o Baseline
a Thin-pole
+ Uniform Field
4-
x Simple Solenoid
.3-
.2-
.1-
0 .0 . . . . . .
.5
0.0
.
. .
,
1.5
1.0
. . .
.
2.5
Pseudorapidity (r)
Integral paths start at Ahlen s p-detector baseline
2.0
Figure 7: Comparison of the resolution of various magnet designs for constant Pt (500 GeV)
as a function of 77. The curve for a uniform field is marked with a +, that for a simple
solenoid with x, for EoI baseline 0, and for the LoI baseline A.
7
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
Resolution for P = 500 GeV . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . .
BL 2 isopleths . . . . . . . . . . . . . . . . . .
Schematic of solenoid plus end solenoid.
Contours of 1B. . . . . . . . . . . . . . . . . .
Flux contours . . . . . . . . . . . . . . . . . .
JBf vs radius in hall . . . . . . . . . . . . . . .
JBI vs radius near surface . . . . . . . . . . .
Surface field, 50 m . . . . . . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . .
Resolution for Pt = 500 GeV . . . . . . . . . .
BL 2 isopleths . . . . . . . . . . . . . . . . . .
Schematic of solenoid with cold Fe . . . .
Contours of BI . . . . . . . . . . . . . . . . .
Flux contours . . . . . . . . . . . . . . . . . .
1BI vs radius in hall . . . . . . . . . . . . . . .
fBf vs radius near surface . . . . . . . . . . .
JBI vs z on axis . . . . . . . . . . . . . . . . .
Surface field, 50 m . . . . . . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . .
BL 2 isopleths . . . . . . . . . . . . . . . . ..
Schematic of "wing" solenoid with pole.
Contours of . . . . . . . . . . . . . . . . . .
Flux contours . . . . . . . . . . . . . . . . . .
Ifi vs radius in hall . . . . . . . . . . . . . . .
JBf vs radius near surface . . . . . . . . . . .
JBf vs z on axis . . . . . . . . . . . . . . . . .
Surface field, 50 m . . . . . . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . .
Resolution for Pt 500 GeV . . . . . . . . . .
BL 2 isopleths . . . . . . . . . . . . . . . . . .
Schematic of "split-wing" solenoid with ?ole
Contours of 1.6 . . . . . . . . . . . . . . . . .
Flux contours . . . . . . . . . . . . . . . . . .
IBI vs radius in hall . . . . . . . . . . . . . . .
fBf vs radius near surface . . . . . . . . . . .
fB vs z on axis . . . . . . . . . . . . . . . . .
Surface field, 50 m . . . . . . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . .
BL 2 isopleths . . . . . . . . . . . . . . . . . .
Schematic of poleless "wing" solenoid. .
Contours of JBI . . . . . . . . . . . . . . . . .
vi
100
100
101
102
102
103
103
104
104
105
105
106
107
107
108
108
109
109
110
110
111
111
112
112
113
113
114
114
115
115
116
116
117
117
118
118
119
119
120
120
121
121
122
122
Basis for Design Evaluation
2
In order to compare magnet designs fairly, the (momentum p) resolution [4, 5],
Ap
Apt =AS
S
pt
p
where p = Ipr,pt = Ip sin 9, and 9 is the angle from the beam line, is computed as a
function of angle (pseudorapidity') given p. S(p) is the sagitta given in eq. 9 and AS is the
total uncertainty including measurement error Omea, (cf. eq. 3), multiple scattering aMs (cf.
eq. 4), and systematic error -,,, (cf. eq. 5), e.g.,
S2 =as, + aM2S
+
(2)
2
The uncertainty in the resolution depends on the actual track (because the path length varies
and the angle relative to the magnetic field changes). Thus, to compute S and AS a muon
detector geometry must be defined, a suitable measure of the resolving power agreed upon,
and adequate computer codes (software tools) made available.
a0
Rngle versus Pseudorapidty_
80
70
4'
*3
B)
60
4)
40
0)
C
30
20
10
0.0
.5
1.5
1.0
Pseudoropidity
2.0
2.5
3.0
Wd
Figure 1: Reference curve: angle from the beamline versus pseudorapidity.
In general, for the results presented herein, the muon detector geometry is that shown in
Figure 2 (given by S. Ahlen). The muon detectors are assumed to have a resolution -j ,.
of 100 /Lm per layer, a thickness of 5 um per layer, and a chamber layout of 8, 16, and 8
layers for the inner, central, and outer detector superlayers. Whence assuming equal spacing
) where ( is the position on a given
- (Cer* "
between superlayers and that S = Cvai
superlayer,
(3)
=i,, 1w
+1
+ 1 (1 .
=-2'a
3
the symbol 1 is used for the pseudorapidity; 17
beamline (cf. Figure 1 for a plot of 0(77)).
-
2
In arctan(0/2) where 8 is the (polar) angle from the
100
N
, Path at
* Path at
* Path at
+Path at
C
I.-
GEM 1 ---
80
Boseline with Full Pole
15.0
17.5
20.0
25.0
degrees
degrees
degrees
degrees
60
x
40
20
n
-
0
;
5
t
15
10
20
25
S, M
Integral paths start at geometric center
Figure 9: Plot of IZI for the EoI baseline magnet versus path length from the interaction
point for tracks at 15, 17.5, 20, and 250 (from the beam line).
GEM 1 --
150
N
, Path at
* Path at
* Path at
+ Path at
C
I-
Baseline with Full Pole
30.0
35.0
40.0
50.0
degrees
degrees
degrees
degrees
100
x
50
n'-
0
5
15
10
20
25
S, m
Integral paths
start at geometric center
Figure 10: Plot of IIZ for the EoI baseline magnet versus path length from the interaction
point for tracks at 30, 35, 40, and 50* (from the beam line).
9
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287/
Contours of I . . . . . . . . . . . . . .
Flux contours . . . . . . . .
A$I vs radius in hall . . . . .
I vs radius near surface .
Surface field, 50 m . . . . .
Resolution for P = 500 GeV
Resolution for P = 500 GeV
BL 2 isopleths . . . . . . . .
Schematic of bottle with calorimeter
Contours of 1.9 . . . . . . .
Flux contours . . . . . . . .
IBI vs radius in hall . . . . .
IA vs radius near surface .
Surface field, 50 m . . . . .
Resolution for P = 500 GeV
Resolution for Pt = 500 GeV
BL 2 isopleths . . . . . . . .
Schematic of bottle with return and calorimeter
Contours of I$l . . . . . . .
Flux contours . . . . . . . .
IBI vs radius in hall . . . . .
A vs radius near surface .
Surface field, 50 m . . . . .
IZI at small angles . . . . .
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
IfZI at middle angles . . . . . . . . . . . . . . .
1Z1 at large angles . . . . . . . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . .
Resolution for Pt = 500 GeV . . . . . . . . . .
BEL 2 isopleths . . . . . . . . . . . . . . . . . .
Surface field, 1.3 m frame . . . . . . . . . . .
Surface field, 2.0 m frame . . . . . . . . . . .
Resolution at P = 500 GeV, 2.0 m frame . . .
Resolution at P = 500 GeV, 2.0 m frame . . .
BL 2 isopleths, 2.0 m frame . . . . . . . . . . .
Schematic of thin pole solenoid with s.c. return
Contours of IBI . . . . . . . . . . . . . . . . .
Flux contours . . . . . . . . . . . . . . . . . .
jBI vs radius in hall . . . . . . . . . . . . . . .
IBI vs radius near surface . . . . . . . . . . .
Surface field, 50 m. . . . . . . . . . . . . . . .
Resolution for P = 500 GeV . . . . . . . . . .
Resolution for Pt= 500 GeV . . . . . . . . . .
BEL2 isopleths . . . . . . . . . . . . . . . . . .
Zrl
t
-it
date+a'n les
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The impulse between two points is a good figure of merit when considering angular change,
e.g., Nier type mass spectrometer as Ap-= I or Api = 1.71. Further, the second integral
which we call BI 2 is given by':
~_
rs=2f~f
dtdS .(8)
BC 2 is a good figure of merit for linear displacements, e.g., radius of curvature or sagitta S
S
0.3
8|PI
=
0. 38 sin
pt
(9)
Both |I|, sometimes referred to as BL, and BL 2 are used as the situation dictates for
comparing magnet designs.8
Over the years, an extensive software toolbox has been brought together at the PFC.
This analysis toolbox includes
" Magnet codes [8, 9]
" Trajectory following codes upgraded from Astromag 7 , SIAM 8 , and L* [1]
" Error analysis codes including measurement, systematic, and multiple scattering uncertainties and the possibility of arbitrary physical structures, e.g., calorimeters, can
be handled.
" Graphical [10] and/or tabular output
In addition, various commercial codes (e.g., ANSYS [11] for finite element analysis) are
readily available but these are not used for most of what is reported herein.
Overview
3
Detailed plots for each design option are presented in subsections of Appendix A.
principal design options are discussed in the following sections
" GEM baseline and design options varying the pole pieces " Fringe field shielding (Safety/Environmental) " Small angle options -
The
Section 4
Section 5
Section 6
A separate report on fringe field shielding for operations is in preparation; it includes analysis
of forces and torques [12], of quadrupole shielding (need for current sheet), of counting room
shield, etc.
5
The factor of 2 in the definition of BL2 is included to agree with the naive results for a uniform field.
that in general BL2 0 B±L 2 and Jil # B±L.
7
Astromag was a magnet facility planned for Space Station Freedom and intended principally for cosmic
ray studies
'A balloon-borne cosmic ray isotope experiment
6 Note
4
A.1.7
LoI baseline: Thin pole case 5
GEM ---
MITHAP VI.A 11/
I.6~
_
_
C.so 6
Thin Pole Optionst
31:5q
4/91
mesuammmsmeI
_
_
_
_
_
_
1.0a
.8
N
-
.6 -
.2
a0
.
-
0.
.2
10
.4
-- - , . -
.
.6
-
.8
,
1.0
A Ida
ELEKENTS
Figure 93: Side view of a superconducting solenoid with a thin pole, case #5. Note that the
beam axis (the z axis) is vertical on the page and the transverse (radial) axis is horizontal.
GEN ---
Thin Pole Options.
MITHAP VI.0 11/15/91
Oeib.CA'ie
Incemenits
Cose 5
10:28
5.-
LOS
U
3.-
400
N
2.
1.
10~
0.
2.
3.
4.
A I .3
CONTOURS OF CONSTANT B
10
Figure 94: Contours of constant
labeled in gauss.
IBI
5.
superposed on a side view of the magnet; isopleths are
57
GEN
Thin Pole Optionss
--
Coss 2
MITMAP VI.0 11/13/91
Conito.r I
*
*.UUE4I
0.1$t.
13:56
*
.4162+.
2. 0
1.
I.
41.2
U
I.
1.
It
10
0
0.
A1.0 1)
R I m)
CONTOURS OF CONSTANT
.s
10
10
.5
2.0
FLUX
Figure 66: Flux lines superposed on a side view of the magnet design.
GEN
--
Thin Pole Optionst
MITNAP V1.0 11/13/91
Case 2
13i67
8.
-- - -- -
7.
.
*
-- -. - -
....
-----
6.
5.
------ -
3.
---------- ---
2.
0.
102
.......
.6
.4
.2
-------
.8
R( 0l
Figure 67: 1§1 versus radius in the hall.
42
1.0
-
GEM ---
Thin Pole Opthonis
Case 3
MITMAP V1.0 11/28/91
3.0
.
.v
. . . . ....
ai
M:30
$~e
2.5
2.0
a
JOB
1.5
-211
1.0
.5
1,
0.
1.8
0
I.5
RS I
2.0
2.5
3.0
A)
CONTOURS OF CONSTANT 8z
Figure 75: Contours of constant B, superposed on a side view of the magnet; isopleths are
labeled in gauss.
GEM ---
Then Pole Oatonea
Case
MITHAP VI.9 11/20/91
S
M'1130
3.0
2.5
2.0
a
N
ZN
1.5
'.4
1.0
.5
19'
m
.
.5
1.
1.5
2.0
2.S
3.0
CONTOURS OF CONSTANT Br
Figure 76: Contours of constant B,. superposed on a side view of the magnet; isopleths are
labeled in gauss.
47
A.1.6
Thin pole case 4
GEM --
Thin Pole Options:
MITHAP
Case 4
14:32
11/13/91
VI.0
1.6-
1.2-
a
1.8.8
.2181
--
p
o.
.4
.2
t.
1.0
.8
.6
ELEMENTS
Figure 84: Side view of a superconducting solenoid with a thin pole, case #4. Note that the
beam axis (the z axis) is vertical on the page and the transverse (radial) axis is horizontal.
GEN
---
Cssa 4
Thin Pole Options:
MITMAP V1.0 11/15/91
18:28
VrIoif Cotur, 1ocrrinnt!
5.
Lee
4.
6WU
a
3.-
2.
1.0.
1.
2.
3
14.
5.
CONTOURS OF CONSTANT B
Figure 85: Contours of constant 1-I superposed on a side view of the magnet; isopleths are
labeled in gauss.
52
GEM
--
Thin Pole Options:
MITHAP V1.0 11/
4/91
Case S
12:28
2.
I. 8
1.8
0
I.
I.
-
0.
4.
IS'
S
s
e.,
10
1.0
1 0)
CONTOURS
OF CONSTANT
I.s
2.0
FLUX
Figure 97: Flux lines superposed on a side view of the magnet design.
GEM
--
Thin Pole Optiones
MITHAP V1.0 11/ 4/91
Cose 6
12:29
8.
.
6.
S.
3.
2.
u.
2
10~
.2
Figure 98:
.6
.4
.8
1.
R mI
IBI
versus radius in the hall.
59
GEM ---
Thin Pole Options:
Magnet Resolution for P
Case 2
500.0
.061
(n
.04
.021-
0.001 . . . . I . I I I I I , I . I I I I . I , , . I
0.0
.5
1.0
1.5
2.0
2.5
Pseudoropidity 61)
Integral paths start at Rhlen s p-detector baseline
Figure 70: Resolution for constant P as a function of q.
GEM ---
Thin Pole Options:
Case 2
Magnet Resolution for Pt = 500.0
3
<n
.2
.1
nn
0.0
.5
1.0
1.5
2.0
2.5
Pseudoropidity n)
Integral paths start at Ahlen s p-detector baseline
Figure 71: Resolution for constant Pt as a function of 7.
44
6E
---
Thin Pole Options:
Coase 3
14130
MITMAP VI.A 11/13/91
I
+-
.------- ..----.M
I
-
-
.6
.8
. .. . . .f
.. . ..
.. . . . . . . .
.4
.
I
I
4.
S.
6.
I.
t
4-,---.-
-~
2.
7.
10,
Figure 79: RBI versus radius near the surface.
GEM ---
Thin Pole Options:
.4
7eld (G)on
SO-m
Cose 3
.4
surfoce
1.2
1.6
2.0
3.2
L
L)
1,
0
-50
-D
-
-100
.
-100
A4.
-50
0I
-A-f, 1
50
1
1
100
Z-oxis (beomline), m
CONTOUR LEVELS (101
Figure 80: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
49
GEM
1,
Thin Pole 00tionso
---
Cogie 4
ITMAP VI.A 11/13/91
16:12
----
1.24
1.2
10
.4 . .........
..
I
.
-
2.
3.
1
....
..
.
14.
5.
7.
6.
RI ml
Figure 88: 1BI versus radius near the surface.
I
GEM ---
-
Thkn Pole Optkons:
.
-r~r
.4
ield IG) on 50-m surface
I
I
--'
T
r
Case 4
T-i
T
.
1.2
50
2.0
2.4
U
0
3.2
36
0
~0
L
lw1
-50
-100
-100
.4
- _i
.
i
-50
0
50
100
Z-oxis (beomline), II
CONTOUR LEVELS (101
Figure 89: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
54
A.2.3
Complex pole pieces
GEM ---
Thin Pole Cote 9 with Cold Iron
MITMAP V1.8 11/18/91
It.
3
2.07
-1.8
a
.4-
1.2
1.5
1.8
.5
8.
2.6
Al.
ELEMENT8
Figure 187: Side view of a superconducting solenoid with a block of iron within the cryostat.
Note that the beam axis (the z axis) is vertical on the page and the transverse (radial) axis
is horizontal.
GEM ---
Thin Pole Cost
MITNAP V1.
S with
Cold Iron
11/18/91
/
It: 3
5.
10
S
a
3.
1.
9.
9.
1.
2.
A I
3
i3
II.
S.
CONTOU8 OF CONSTANT 0
Figure 188: Contours of constant
labeled in gauss.
IBI
superposed on a side view of the magnet; isopleths are
107
6EM
Thin Pole Cease 3 Extended with Is Comoenietion
--
10158
MITMAP Vt.@ 11/18/91
2.0
1.81.6
1.4
.
.2
10
0.
-
1.5
1.9
.5
10
R I 4)
2.0
ELEMENTS
Figure 159: Side view of a superconducting solenoid with the conductor extended over the
pole piece and with the current doubled in the last 1 m. Note that the beam axis (the z
axis) is vertical on the page and the transverse (radial) axis is horizontal.
SEN
Thin Pole Case 3 Extended with In Compensaetion
---
MITHAP VI.0 11/18/91
vwravsi Conftw Incrants
10:58
5.-
S
3.
N
2.
I
1.
10
0.-
,I
S
0.
.
2.
10
OF
CONTOURS OF
3
5.
N)
4.
5.
CONSTANT B
Figure 160: Contours of constant IB3 superposed on a side view of the magnet; isopleths are
labeled in gauss.
92
A.2.2
Bottle Solenoids
The "bottle" solenoid for Figures 169-177 has a larger current than that in Figures 178-186.
GEM
Bose end "Botfle 2.* Solenoids
---
MITHAP VI.0 11/16/91
17:16
1.8
1.6
1.2
a
.s
.6
.4 "
.20.
.5
10
1.5
E.E
2.0
R I ml
ELEMENTS
Figure 169: Side view of a superconducting solenoid with the end pole replaced by a superconducting solenoid. The "bottle" current is 133% of that for the case in Figures 178-186.
Note that the beam axis (the z axis) is vertical on the page and the transverse (radial) axis
is horizontal.
GEM
---
Base and "Sottle 2.* Solenoids
HITHAP V1.. 11/16/91
I VMsbI@
17:16
I* ontow swowIt5
5-
4.
-
a
'.4
2.
-
I
1.
U.
1~
a.
I1.
3
q.
2.
R
CONTOURS OF CONSTANT 8
5.
Figure 170: Contours of constant jjf superposed on a side view of the magnet design.
97
GEM
Base and
---
"Sottle
2bI Solenoids
MITMAP VI.A 11/16/91
2.0
17:45
-
1.8
1.4
1.61.2
1.0-
.4
1
10*.2
0. -
0.
10 1
.5
1.5
1.0
A I a)
ELENENTS
2.8
Figure 178: Side view of a superconducting solenoid with the end pole replaced by a superconducting solenoid. The "bottle" current is 75% of that for the case in Figures 169-177.
Note that the beam axis (the z axis) is vertical on the page and the transverse (radial) axis
is horizontal.
GEM ---
ese and
D1ottle 2b* Solenoids
MITHAP VIA 11/+
1.............. ..
....-
17:45
r/g1
I
-
I
5.
-7
72
4.
B
3.
I ....
..
2.
1.
10~
0.
0.
10
I
2.
CONTOUA8
3.
C T mI
4.
5.
OF CONSTANT B
Figure 179: Contours of constant JB superposed on a side view of the magnet design.
102
GEM
Thin Pole Coze 3 with Cold Iron
--
NITHAP VI.A 11/18/91
6
- - - --
------
11: 6
---
1.1
6
.. .. .
........
-
-
2.10 1
3.
S.
4.
6.
7.
A( m)
Figure 191: BII versus radius near the surface.
GEM --
Thin Pole Cse 3 with Cold Iron
MITHAP VI.A 11/18/91
111 6
8.
------ ..-----.
6.
2.
10e
.. .
.2
10~
..
.6
.
Z( a)
.8
0
Figure 192: IBI versus z on axis in the hall.
109
GEN
-- Thin Pole Ceea
3 Extended with Is Cosoensotion
111 0
MITMAP VI.0 11/18/91
2
-6
. .......-.......
.6
'.
.4 ...-..... .....-
-------- I-- -- -
--
--
1
...
.....
.6
.-
2.
..
2.
.
IBI
Figure 163:
. .
. .
6.
4.
3.
1o
.
..
..
7.
R( ml
versus radius near the surface.
GEH -- Then Pole Cee
3 Extended vith tIn Compenation
111 0
MITHAP VI.A 11/18/91
............ .
........ ...........
-----------
------ - -----
.....
...
-------- ------------ 8. .....
---------............ -4.---
- ------------
2.
190
9'.
Figure 164:
12
IBI
.2
V 0)
.6*
.
versus z on axis in the hall.
94
6.
GEM
86se and *Bottle 2o* Solenoids
--
MITMAP VI.A 11/16/91
17118
2.
2.
8.....
.....
-- - - ----
2.
3.
i.
--
5.
6.
---
7.
fl( ml
Figure 173:
-
GEM
inn~
.6
JI
versus radius near the surface.
Base and "Bottle 2o" Solenoids
Field (G) on
507xsuraoe
.s5
1.s5
2.0
50
C
4.S
(4
0
IL
-50
1.0
-100
-I 00
.5
.
-50
0
50
Z-oxis (beamline). m
CONTOUR LEVELS (101
.
100
Figure 174: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
99
GEM ---
Rose and *Bottle 2b- Solenoids
MITHAP V1.0 11/16/91
17:48
...........
---
....-
1.20
10
-
2.
L-
3.
5.
4.
6.
7.
ft .1
Figure 182: 1BI versus radius near the surface.
100
GEM --4 -
Bose and 'Bottle 2b" Solenoids
.4
Field (
0-S
e
1.2
50.0
0
L
01
0-
L
-50.8
-100
50
0
-50
Z-oxis (beamline, m
CONTOUR LEVELS (10 1 )
100
Figure 183: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
104
6EM
Base. 8o1 2s. and ARtn Sol.
-
MITMAP VI.A 11/16/91
......
...
Forv. HC
*
2137
. .... ...-.
-----
1.00
ra9
--
2.
--
-----
5.
'A.
3.
7.
6.
Al ml
Figure 284: R$I versus radius near the surface.
100
GEM
-
Bfose. Boti 2a. and Htrn
0-
Field
e
Sol.
+
Form. KC
r
50
0
0
L
I.-
-50
.2
-inn
-100
-50
0
50
Z-oxis (beamline). m
CONTOUR LEVELS (101
100
Figure 285: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
158
66Z Fe wedge (FHCI
HITMAP
VI.A 11/16/91
19:34
2. .2 .4 .. . .. .. .. . ....
2.
I'
I,
-
I,
.2'
I.
.2 ------.....
---
..
......
8....
..........
......
...
........
10
3.
2.
4.
5.
7.
6.
fi<.m
Figure 257: 1Bj versus radius near the surface.
5O\x Fe wedge (FHIC)
..4
ield (G)on
a
-<
1
50-m surface
.4
-
-
.8
1.2
so
1.6
2.0
4;
3.2
L
0
L
-50
-1 Af
-100
50
0
-50
Z-oxis (beaml ine). m
CONTOUR LEVELS (101 1
100
Figure 258: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
143
Baae and *Bottte 2e Goienoids plus Iran FC
GEMs
MITMAP V1.8 11/16/91
20: 4
2.4'
2.2
2.0
1.8
1.6
1.
1.2
1.0
.8
-
-
- ----
.4
2.
3.
10
5.
q.
7.
6.
R( M
Figure 266: JBI versus radius near the surface.
1nn
GEM:
.
Sae and *Bottle 2o* Solenolda plus Iron FC
!
.s
Field (G) on
S
01 % s
rooe
2.0
2.5
50
4)
0
C
so
4,5
a
.4-,
Ill
4)
(4
C4)
n M
.5
0
C
a
IA-.
-50
'N
_inn
-100
1.0
'a
. . .
-50
.
.
.
0
.
. 1
.
50
100
Z-oxis (beamline), m
CONTOUR LEVELS (101 3
Figure 267: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
148
GEN
---
Bse tend
"Bottie
2o' Solenoids plus Forward HC
18:52
MITHAP VI.A 11/16/91
2.
2.
48 ..
2.
4 ...........
2,--....
-....
..
2.
6.
5.
4.
3.
101
7.
Rl N)
Figure 275: jiB versus radius near the surface.
1in.
GEM
I
Bas. and 'Bottle 2o" Solenoids plus Forward hC
--
. . .
. .
.5
.5
Field (G) on
501 surface
1.5
2.0
-
50
2.5
C
4.0
_0
0
L
-50
1.0
-ifnn
-100
.5
.5
50
0
-50
Z-oxis (beamline). Is
CONTOUR LEVELS (101 )
100
Figure 276: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
153
Bose, Botl 2o, and Rtrn Sol. + Forw. HC
GEM
o Path at 30.0 degr s
a Path at 35.0 deg s
at
x Path at
+ Path
6-
40.0 de
50.0
e
gr
x
4
2
n-2
'U
15
20
S. m
Integral paths start at geometric center
10
5
0
25
Figure 288: Plot of IZ versus path length from the interaction point for tracks at 30, 35, 40,
and 50* (from the beam line).
- GEM
---
Base, Botl 2a, and Rtrn Sol.
o Path at 60.0 de
Path at
+ Path at
x Path at
-A
6-
+ Forw.
HC
rees
ees
es
70.0
80.
90
s
x
4-
2-
0
5
10
i
e
S, m
Integral paths start a t geometric
20
25
center
Figure 289: Plot of 1Zj versus path length from the interaction point for tracks at 60, 70, 80,
and 90* (from the beam line).
160
15
50\% Fe wedge
Contours oF ftxed if
(FHC)
f
3 x dIds
Isopleths at 6. 8, 10, and 12 T m2
101
2
a.
a
5
n
0
a
I
a
I
a
I
I-
i
10
5
Z,
15
m
Integral paths start at Ahlen's p-detector baseline
Figure 261: Isopleths of constant B2 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
145
GEM:
Base and "Bottle 2a" Solenoids plus Iron FC
15
Contours oF
if
'ixed
f
Q x
ialds
Isopleths at 6, 8, 10, and 12 T m2
10
E
5
-
0
II
5
10
Z,
Integral paths start at
15
m
Ahlen's p-detector boseline
Figure 270: Isopleths of constant BL 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
150
GEM ---
Bose and "Bottle 2a" Solenoids plus Forward HC
15
Contours of fixed If
f
x
dI ds
Isopleths at 6, 8, 10, and 12 T m2
10
E~
5
0
0
-
10
5
Z,
15
m
Integral paths start at Ahlen's p-detector baseline
Figure 279: Isopleths of constant BL 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
155
GEMI 1 I---
1 a
-1
with Full Pole
Boseline
1 a m
4
Magnet Resolution for P
500.0
.08
Cn
.06
04
02
0.001
0. 0
.5
1.0
1.5
2.0
2.5
Pseudoropidity (y,)
Integral paths start at Ahlen s p-detector baseline
Figure 45: Resolution for constant P as a function of 77.
GEM I ---
.
Boseline with Full Pole
Magnet Resolution for Pt
500.0
4
a
2
1
nn
. ,
0. 0
I
i i
i
.5
1.0
i
1.5
A
2.0
2 .5
Pseudorpidity (yv)
Integral paths start at Ahlen s p-detector baseline
Figure 46: Resolution for constant Pt as a function of 77.
31
A.1.3
Thin pole case 1
GEM ---
Then Pole Ohiaonst
Case I
11/13/91
10:20
MITHAP VI.A
1.5-
1.2-
U
P.4
.2
101
0.-I
0.
10
.2
1.0
.8
.6
.4
ELME)
ELENENTS
Figure 55: Side view of a superconducting solenoid with a thin pole, case #1. Note that the
beam axis (the z axis) is vertical on the page and the transverse (radial) axis is horizontal.
GEN ---
Then Pole Opteonst
HITHAP VI.0 11/15/91
VtP aooe
C
Case I
10:26
Ie..nt.
iii
4.
ggU
a
1.
IS'
0.
Figure 56: Contours of constant
labeled in gauss.
IBI
1.
2.
3.
4.
A I a)
CONTOURS OF CONSTANT B
5.
superposed on a side view of the magnet; isopleths are
36
SEM
---
Baseline Solenoid
MITHAP V1.0 11/15/91
Va
Obia tiantows ]-a,~**
10:29
5.
4.
.
101
0.
0.
10
L
1
2.
S.
4.
R I m)
CONTOURS OF CONSTANT 8
5.
Figure 25: Contours of constant IBI superposed on a side view of the magnet; isopleths are
labeled in gauss.
GEM --HITIAP VI*.
Ca~
3
Besleine Solenoid
10/25/91
1.111M.190
colts
18:31
&.am-".
2.0
1.8
1.8
1.4
1.2
1.0
.8
.2
0.
10
.5
1
10
I.5
2.0
iM)
CONTOURS OF CONSTANT FLUX
Figure 26: Flux lines superposed on a side view of the magnet design.
21
GEN I ---
Baseline wi+h Full Pole
MITHAP V1.0 11/20/91
I,
- - w-
MI27
Ig lt
l.,
*!
2.0
-10
O
1.5
2H
I.s
1.0
.
0. 1
.S
1.0
2.0
1.5
2.5
3.0
R I 0)
CONTOURS OF CONSTANT Or
Figure 35: Contours of constant B, superposed on a side view of the magnet; isopleths are
labeled in gauss.
GEM I
---
Seselne v
th
Full Pole
MI THRP V1.O 11/20/91
14:28
V0 ! ble Co,+au, Inc...e.ts
4.
2.5-
Ti II
_
5..
2.07
-/
U
U
1.5S
"A
1.0-
S
N
as
IU
10'
0. 11
.5
1.0
R
1 5
2.0
I M)
CONTOURS OF CONSTANT
2.5
3.0
Br
Figure 36: Contours of constant B, superposed on a side view of the magnet; isopleths are
labeled in gauss.
26
5
Fringe Field Shielding
As the surface field (cf. Figure 12) for the unshielded baseline magnet (either EoI or Lol) is
measured in 10s of gauss, various options to reduce the surface field below 10 G or 5 or ...
have been investigated to address both safety and environmental concerns. Basically, there
100
GEM 1 --.
Boseline with Full Pole
r
.
. .
eld (G) on
a
50-m surface
1.2
50
1.6
2.0
a
0
5.2
-. 8
0
4.0
4.0
L
L
5
.4
.4
-100
-50
0
50
Z-oxks (beomline). a
CONTOUR LEVELS (10'
100
Figure 12: Isogauss contours of the field on a surface at a nominal elevation of 50 m from
above the center (beam) line of the EoI baseline magnet. Note the peak field at an elevation
of 50 m does not occur on the midplane and is about 40 G.
are four approaches:
1. Full iron return frame (in the hall) cf. Appendix A.4.1,
2. Superconducting shield (second coil) cf. Appendix A.4.2,
3. Local shielding with an iron plate at the surface (or at some intermediate elevation),
and
4. Construct an earthen mound (hill) to physically exclude access to the increased fields.
Shown in Figure 13 is a side view of a full iron return frame with a thickness of 1.3 m
which is sufficient to reduce the surface (50 m) field to < 10 G (cf. Figure 14). The flux lines
for this case are essentially identical to the unshielded case and the resolution is unaffected
(cf. Figure 15). A 1.6 m thick return frame will reduce the surface field to 5 G. Shown in
Figure 16 is a side view of a full iron return frame with a thickness of 2.0 m which is sufficient
to reduce the surface (50 m) field to - 1 G (cf. Figure 17). The flux lines for this case are
essentially identical to the unshielded case and the resolution is unaffected (cf. Figure 18).
Of course the resolution at small angles is still a problem but at least the surface field is
negligible. A superconducting coil to return the flux adds some complexity but also suffices
to limit the surface field (cf. Section 6 and Appendix A.4.2). Either method of returning
11
GEM
Base. Botl
---
2e. and Rtrn Sol.
MITMAP V1.0 11/16/91
+
Forw.
HC
21:47
2.0
1.81.6
1.4
1.2PI
1.0
.8
.6
.2
1
0.
10
1
1.0
R ( a)
ELEMENTS
.5
2.0
1.5
Figure 19: Side view (one quadrant) of superconducting solenoid with superconducting return, with the end poles replaced with a solenoid, and with a conical iron wedge (forward
calorimeter) to draw flux towards the axis; the figure is rotationally symmetric.
GEM
---
Base. BotI 2a. and Rtrn Sol.
MITMAP V1.0 11/16/91
1.00
HC
21:48
-
- -------------
- Forv.
-
--------------
.90
S.80
----------
.70
10-3
.60
2.
Figure 20:
IBI
3.
I'.
RI ml
.I
5.
I
.
-
6.
7.
versus radius near the surface for the magnet design shown in Figure 19.
16
GEM I --,
Baseline with Full Pole
.
. , . .. .. , , , ,
, , , ,
Magnet Resolution for P
50.0
.05
.
.
.04-
(0
.03-
.02
.01
0.00 . . . .
0.0
.5
1.0
1.5
Pseudoropidty
(n)
2.0
2.5
Integral paths start at Ahlen s p-detector baseline
Figure 49: Resolution for constant P as a function of 1.
.07
.
GEM I ---
Baseline with Full Pole
Magnet Resolution for Pt
50.0
06
.05-
(n
.04
-
.03.02-
.0 1F . . . . l . . . . l . .
0.0
.5
1.0
1.5
2.0
2.5
Pseudoropidity ()
Integral paths start at Ahlen s p-detector baseline
Figure 50: Resolution for constant P as a function of 77.
33
GD -- Thin Pole Ootionia
MITHAP V1.0 11/13/91
Cone 1
12a11
-. ----
.6
...... \ -------- --------
. ....
-----
-
I.
.2
.4
10-
2.
5.
4.
6.
7.
fil ml
Figure 59: IJI versus radius near the surface.
GEM ---
Thin Pole Options:
ield (G) on
Cose 1
50--m surface
50
2.0
2 4
3.2
L
0
l1-
--
-50
.4.4
-1fl
-100
50
0
-50
Z-oxis (beamline), m
CONTOUR LEVELS (101
100
Figure 60: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
38
GEM ---
inn I
Baseline Solenoid
.4~
eld (G) on 50-m surface
SC
1.2
i.e
-
2.0
3.2
3.6
L
0
0
L
I-
-50
-inn
*
.4
-100
.4
-50
so
0
-
100
Z-oxis (beomline), m
CONTOUR LEVELS (101
Figure 29: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
GEM
Baseline Solenoid
Magnet Resolution for P
500.0
.08
n,
.06
n,
.04
.021-
000 . . . .
0.0
.5
1.0
1.5
2.0
2 .5
Pseudoropidkty (,))
Integral paths start ot Ahlen s p-detector baseline
Figure 30: Resolution for constant P as a function of 17.
23
GENl I --
Baseline with Full Pole
HITI4AP VIAU It/ 4/91
17s28
I.
4
.
. ..........
-- -. - ---
.
&.
.....
I.
1.
I.
1.
2u
10-s
2.
3.
10
4.
5.
7.
6.
RI M)
Figure 39: 1.9 versus radius near the surface.
GEM 1 ---
Isi
Boseline with Full Pole
ied(G) on
50-mn surroce
.8K
S
1.2
50
2.0
~2.
U
3.2
5.8
.4
0
,U
4.0
4.0
.-
.1..
-50
4,
-i n
-100
-50
0
50
Z-oxis (beolaline), m
100
CONTOUR LEVELS (101
Figure 40: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
28
GEM
-
Beaeline w/ Full Pole end 1.3m Return
MITHAP VI.0 10/10/91
Contour
1
-
Dbits
4.U9E
18,21
-
'i9.I-IlE
2.0-
/
1.6
1.4
1.2-
--------------
fr
1.0
N4.
.8
.67
10 1.
.5
1.0
A ( 8)
1.5
2.0
CONTOURS OF CONSTANT FLUX
Figure 15: Flux lines superposed on a side view of a superconducting solenoid with a 1.3 m
iron return frame. Note that the beam axis (the z axis) is vertical on the page and the
transverse (radial) axis is horizontal.
GEM - Baseline v/ Thick Pole end 2.6a
HITHAP V1.0 10/11/91
Return
9: 8
*1~
2.0x
1.0-
1.61.4
1.2S
1.0
l'J
.8
101
0. I
0.
101
.5
1.0
R ( m)
ELEMENTS
1.5
2.0
Figure 16: Side view of superconducting solenoid with a 2.0 m full iron return frame (the
figure is rotationally symmetric about the z-axis). Note that the beam axis (the z axis) is
vertical on the page and the transverse (radial) axis is horizontal.
13
.151
Base, Botl 2a, and Rtrn Sol. + Forw. HC
I I I I I
I I I I
GEM ---
500.0
Magnet Resolutkon For Pt =
101
U)
U)
.05
0.001
0.0
I
I
I
I
.5
I
I
I
I
1.0
i
i
I
1.5
i
I
2.0
2.5
Pseudorapiditp (n)
Integral paths start at Rhlen s p-detector baseline
Figure 23: Resolution for constant Pt (500 GeV) as a function of -r for the design shown in
Figure 19.
18
GEM 1 ---
Baseline with Full Pole
Contours of fixed i
f f.
x dalds
2
Isopleths at 6. 8, 10, and 12 T m
10
2
5
. . . . .. . .
eri i i i i
i i i i
0
5
i i i i
10
15
Z. m
Integral paths stert at Ahlen's V-detector boseline
Figure 53: Isopleths of constant BL 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
GEM 1 --inn..............
Baseline with Full Pole
50
0
.41
L
0
L
-50
-inn
I,.
.1
.
.
,
100
0
50
-50
Z-oxis (beamline), m
10 G Isopleths at IR sites 1, 4. 5, and 8
-100
Figure 54: Superposed 10 G contours of the field on the surface for nominal interaction
regions.
35
GEM ---
1I-
Thin Pole Optkions:
Contours oF Fixed
1ff
.
Case 1
x .Ids
Isopleths at 6. 8. 10, and 12 T m 2
1
E
a-
5-
5-
J
0
5
10
Z,
15
m
Integral paths start at Ahlen's p-detector boseline
Figure 63: Isopleths of constant BL 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
40
A.1.2
EoI baseline: Solenoid with thick end poles
GEN 1 -
Baseline with Full Pole
MITMAP VI.0 11/ 4/91
17121
1.81.41.2
1.0
a
.8
.6 .4 .2 10
0.
0.
1.6
.8
S
.
.4
I
.)
ELEMENTS
Figure 33: Side view of a superconducting solenoid with thick end poles (EoI baseline). Note
that the beam axis (the z axis) is vertical on the page and the transverse (radial) axis is
horizontal.
Basel ine with Full Polo
GEM I --
MITHAP VI.0 11/15/91
V.eI
it..
...
10:29
t
2.-
1.0
0.
1.
2.
3.
4.
5.
R I al
CONTOURS OF CONSTANT B
Figure 34: Contours of constant BI superposed on a side view of the magnet; isopleths are
labeled in gauss.
25
100
GEM1 I --1
G)
Fi~.
a
Baseline with Full Pole
on
1fg-foot
surf
1R
sl te 5
50
2.0
2s5
C
0
C
0
L0
.S
-50
-inn
-100
-50
0
50
Z-oxis (beamlinel, M
CONTOUR LEVELS (10)
100
Figure 43: Isogauss contours of the field on a surface at the nominal elevation of IR site 5.
GEM 1 --F
Baseline with Full Pole
(G)on 158-foot surfoc
50
1.Isk te 8
2.0-
C
a
41
0
f.-
.s
-50
-inn
-100
aw
' A
I
I i ,I
-50
0
50
Z-axis (beamlkne), m
CONTOUR LEVELS (101
100
Figure 44: Isogauss contours of the field on a surface at the nominal elevation of IR site 8.
30
the flux reduces the field in the experiment hall; the other two methods, e.g., local shielding
and surface mound, do not. Local shielding is discussed in a separate report [13]; a surface
mound would need to extend either to ~ 80 m to reduce the field to 10 G or to ~ 100 m
for 5 G; the corresponding volumes are ~ 3 x 10' m' and
-
5 x 10' m 3 assuming 100 m
radius and 50 m surface. The Earth's field of - 0.57 G has been neglected and the surface is
assumed to be at a nominal elevation of 50 m although explicit curves corresponding to the
different interaction regions have been generated for several of the options and are included
in the appendices. Essentially, any of the approaches can be made to work and it becomes
a question of cost, schedule, (and taste).
6
Small Angle Resolution
Several options have been generated in the effort to solve the resolution problem below 200
for fixed Pt. The most interesting are
1. Addition of solid iron conical wedge (cf. Appendix A.3.1),
2. Addition of 50% iron wedge, e.g., forward hadron calorimeter (cf. Appendix A.3.2),
3. Replacement of pole with "bottle" solenoid plus solid iron wedge (cf. Appendix A.3.3),
4. Replacement of pole with "bottle" solenoid with 50% iron wedge (cf. Appendix A.3.4),
and
5. Replacement of pole with "bottle" solenoid with 50% iron wedge and a superconducting
return coil (cf. Appendix A.3.5);
these are discussed here with more details'" in Appendix A.3. Clearly, the approach is
twofold. First, conical iron wedges are added to further shape the field by drawing the flux
towards the axis and, second, the iron pole piece is replaced with a small superconducting
solenoid (the "bottle"). It should be noted that if a forward hadron calorimeter is planned
and its absorber is chosen to be iron, then it will also serve as a wedge (these are the 50% iron
options). Both approaches have the beneficial effect of inducing field curvature orthogonal to
the particle trajectories at low and intermediate angles. That is, BL 2 is increased. Finally, a
superconducting return coil can be added to address the fringe field problems (cf. Section 5);
a side view for this option is shown in Figure 19. With the return solenoid chosen, the surface
(50 m) field is reduced to ~ 10 G (cf. Figure 20); an isogauss field map at the surface is shown
in Figure 21. The flux lines (lines of force) are shown in Figure 22 where they can be seen
to differ significantly from those of the baseline (cf. Appendix A.1.2). Finally, the resolution
can be seen in Figure 23 which should be compared with Figure 7 - the improvement is
obvious!
10 A number of other options are included in Appendix A.2, options with either end winding compensation or an extended solenoid or additional solenoids or complex pole pieces to further shape the field.
Miscellaneous alternatives to improve the small angle resolution including toroids are discussed briefly in
Appendix B.
15
A
Options
Except for the high field designs shown in Appendix A.5, the central field is 0.8 T, and the
following summary graphs are normally shown:
1. basic geometry
2. contours of
RI1
3. flux contours (lines of force)
4. plots of 1.9 1 vs p or z
5. surface field plot (at either a nominal 50 m and/or the elevations of the various IRs)
6. plots of (s)
,
7. isopleths of BL 2 at 6, 8, 10, and 12 T m 2
A.1
Solenoids with field shaping
A.1.1
Solenoid without end poles
SEH --- Basel-ne Solenoid
MITHAP V1.
10/25/91
18 23
1.4
1.2
1.8
.6
.6
.4
.210
0.
.2
.1 R I a)
ELEMENTS
Figure 24: Side view of a simple superconducting solenoid. Note that the beam axis (the z
axis) is vertical on the page and the transverse (radial) axis is horizontal.
20
Thin Pole Case 3 with 2m End Compensotion
GEM ---
Magnet Resolution for Pt
500.0
.2-
.1-
0.0
.
,
0.0
, I
I
,
,
,
1.5
1.0
.5
I
.
2.0
2.5
Pseudaraptd ity bvi)
Integral
paths
start at Ahlen s
p-detector
baseline
Figure 137: Resolution for constant Pe as a function of
GEH --
Thun Pole Cose
Contours of
S witIh
2*
ij.
End Comjensation
fixed if f A
x
lds
2
Isopleths at 6. 8, 10. and 12 T en
10E
5-
5
0
10
Irntegral pothu stort at mtale&, I--detector-
15
baseline
Figure 138: Isopleths of constant BL 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
81
GEM ---
Solenoid with
2
Mognet Resolution For Pt
m End Compensation
500.0
.3
(n
.2
.1
n-n
0.0
.5
1.0
1.5
2.0
2.5
Pseudorapiditty (n)
Integral paths start at Ahlen 9 p-detector baseline
Figure 147: Resolution for constant P as a function of 77.
GEM ---
Solenoid with 2m End Compensation
Contours of f ixed If
Isopleths at 6, 8,
f B
x dAl ds
10, and 12 T m2
10
S
a.
5
0
5
Integral
paths
start
Z, m
8*
10
15
Ahens ideteatar b@..eli
Figure 148: Isopleths of constant BL2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
86
A.2
Further shaping and shielding
A wide range of possible options has been considered. The options discussed in Section 4
did not include end winding compensation as a method to approximate more closely a
uniform field (in the desired detector volume). Using the option in Appendix A.1.5 as a
basis, alternatives with the current increased in the last 1 m (cf. Figures 119-128) or 2 m
(cf. Figures 129-138) of the solenoid have been run along with cases where the solenoid
is extended (cf. Figures 149-158) over the pole piece or extended and compensated (cf.
Figures 159-168). While simple end compensation (cf. Appendix A.2.1) better approximates
a uniform field, the replacement of the end poles with a "bottle" solenoid has the beneficial
effect of inducing field curvature orthogonal to the particle trajectories; that is, BL' is
increased (cf. Appendix A.2.2). Another way to induce field curvature (i.e., draw the flux
lines toward the axis) is to use complex pole pieces including conical iron wedges; several
variants are presented in Appendix A.2.3 where current sheets (solenoids) are frequently
used to model the iron wedges. If a forward hadron calorimeter is planned and its absorber
is chosen to be iron, then it will also be an iron wedge. Finally, a few other options are
presented in Appendix A.2.4.
A.2.1
Compensation
GEM
--
Thon Pole Cosa 3 vith End Compensation
MITMAP V1.I
11/18/91
10:53
2.2
1.0
1.6
1.2
1.0
1.4
.8
0.
.5
1.)
2.5
2.0
ELEMENTS
Figure 119: Side view of a superconducting solenoid with the current doubled in the last
1 m. Note that the beam axis (the z axis) is vertical on the page and the transverse (radial)
axis is horizontal.
71
GEM ---
Thin Pole Case 3 with End Compensation
,
,
1
15
Contours of fkxed if
-U x jid
f
ds
Isopleths at 6, 8, 10, and 12 T m2
10E
a.
5-
0
_
_
_
_
_
_
0
_
_
f
_i
5
10
i
l
l
15
, M
Integral paths start at Ahlen's p-detector boseline
Figure 128: Isopleths of constant BL
2
superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
76
GEM ---
Thin Pole Options:
o Path at
5.0 degrees
7.5 degrees
10.0 degrees
12.5 degre
A Path at
-
2.0
Ix
+ Path
at
x Path at
Case 5
1.5
1.0
.5
0
5
10
15
S, m
20
25
Integral paths start at geometric center
Figure 101: Plot of 21 for the LoI baseline magnet versus path length from the interaction
point for tracks at 5, 7.5, 10, and 12.50 (from the beam line).
E
x
4
GEM --
Thin Pole Options:
LA
15.0
Path at
Path at
+ Path at
x Path at
Case 5
degrees
17.5 degrees
20.0 degrees
25.0 degree
3
Ta
9 -6 -0-6..
2
1
0
5
10
15
S, m
20
25
Integral paths start at geometric center
Figure 102: Plot of IZI for the LoI baseline magnet versus path length from the interaction
point for tracks at 15, 17.5, 20, and 250 (from the beam line).
61
GEM
---
Thin Pole Optionss
Case 6
MITHAP V1.0 11/29/91
14:32
3.0
2.6
.e.
2.0
a
1.6
'.4
U-
1.9
.5
19
9.
9.
is
1.6
1.0
.s
2.9
2.5
3.9
A I N)
CONTOURS OF CONSTANT Bz
Figure 110: Contours of constant B, superposed on a side view of the magnet; isopleths are
labeled in gauss.
GEM ---
Thin Pole Optsont
MITHAP V1.0 11/20/91
Case 6
IM33
..
!
3.t
2.5-
2.9-
ea
(681
It
a
-J
in
101
.539
0
-- - --
.
1
.s
1.0
1.5
i
2.0
2.S
3.9
CONTOURS OF CONSTANT Br
Figure 111: Contours of constant B,. superposed on a side view of the magnet; isopleths are
labeled in gauss.
66
GEM
Solenoid with 2v End Cogenosaion
--
MITMAP V1.0 11/19/91
oei.
* .in.as43
Centiew
9:39
*
B.241E.U
2.0
1.8
1.4
1.2
.
1.0
.8
.6
S.
0.
.5
10
R
1.5
1.0
2.0
a)
CONTOURS OF CONSTANT FLUX
Figure 141: Flux lines superposed on a side view of the magnet design.
Solenoid with 2a End Coalensat ion
GEM ---
MITHAP VI.0 11/19/91
9140
6.
......---
....
....-
'-l
...
..
.
.
.
.
.
.........
.....
3.
2.
~
-~
---
0.
O
~
-' -
.2
Figure 142: 1
....
-
- - - - ......
.8
.4
1.0
R( 8)
versus radius in the hall.
83
GEM ---
Thin Pole Case 3 Extended
11: 1
MITHAP VIA. 11/18/91
coo
2.
..
I.DeE.a
B.
E
4
.
.1
2
10
0.
10
1
.
1.
R I m)
CONTOURS OF CONSTANT FLUX
5
2.0
Figure 151: Flux lines superposed on a side view of the magnet design.
GEM ---
Thin Pole
Cese 3 Extended
111 2
11/18/91
MITNAP V1.I
8.
7.
6.
.....
- + -----+
-
-
-
+--..............
4-
2.
1.
. .2 .
to, 2
.8
1.
R( al
Figure 152: |$I versus radius in the hall.
88
Thin Pole Case 3 vith End Compensation
OEM --
MITHAP V1.0 11/18/91
19166
- --- --- ++
8.
-
-
--
- -------- -
--
7.
6.
----.. --...----
-
-------
2.
18'
.
to
2
.4
.2
.8
.6
1.
A( a)
Figure 122: 1BI versus radius in the hall.
Thin Pole Case 3 with End Compensation
SEH -
MITMAP VI.A 11/18/91
10165
2.0
-
-
1.8
1.6
1.4
-1.2
1.8
-
-
------------
- -
.... ..... ..--- r
2. t
3.
4.
5.
---
--
- --------- -
6.
7.
Al:.l
Figure 123:
|BI
versus radius near the surface.
73
Thin Pole Case 9 with 2m End Copensat ion
GEM --
MITMAP V1.0 11/18/91
Comta
I * *.iniE4B0
Ows.
10:56
*
5.57M.U
2.0
1.8
1.8
1.2
a
L.0
.8
.2
190
9.
1.5
1.0
; .5
R I m)
CONTOURS OF CONSTANT FLUX
10
2.0
Figure 131: Flux lines superposed on a side view of the magnet design.
GEM --
Thin Pole Case 3 vith 2u End Comensation
10:57
MITMAP V1.0 11/18/91
-
6.
.
5.
4.
------------
2.
0
.6
.4
.2
--
+-- -------
.8
1.0
R( a)
Figure 132: 1BI versus radius in the hall.
78
GEM ---
Thin Pole Options:
Magnet Resolution for P
-
=
ge
Case 5
500.0
0*
-eouinPa
.06
(A
N.
.04
(A
.02F
n0 A ,
0.0
-
, , , ,,0
i
1.0
1.5
2.0
2.5
Pseudoropidity ()
Integral paths start at Ahlen s p-detector baseline
.5
Figure 105: Resolution for constant P as a function of q.
GEM ---
Thin Pole Options:
Cose 5
A
Magnet Resolution
for Pt
=
500.0
.3
F-.21
I
0.0
0.0
.5
1.0
1.5
2.0
2 .5
Pseudoropidity (7)
Integral paths start at Ahlen s p-detector baseline
Figure 106: Resolution for constant Pt as a function of 11.
63
Thin Pole Optiones
6EH ---
MITMAP VI.A 11/18/91
Coac 6
15846
......... .. ...... . ....... ...
. ......
1.8
1.6
--------- -
............. ........ ........ .......
..
............ .
-------------
-------- ---
1.4 --------------1.2
------ ------- --------
---------- -
..
.........
1.0
. ........... .
---- --- ----
. . . ....... .
.4
-----------
.......
. . . .......
. . . . I . . . . I .
3.
2.
5.
'.
6.
7.
R( m
Figure 114: JBI versus radius near the surface.
GEM ---
100
S
Thin Pole Options:
.4
ield WG
on
Cose 6
50-m surfoce
.6
1.2
50
2.0
C
3.2
3.6
0
0
0
L
i,
-50
7
-inn
-100
-50
0
50
100
Z-oxis (beomline), m
CONTOUR LEVELS (101
Figure 115: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
68
GEM ---
Solenoid with 2m End Compensction
Field (G) on
0-1s s rface
1.2
50
2.0
2
4.0
L
C
0
a
I
-50
-inn
-100
-50
0
50
Z-oxis (beamline), m
CONTOUR LEVELS (101
100
Figure 145: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
GEM ---
8E
Solenoid with 2m End Compensation
Magnet Resolution for P
500.0
06C
04-
02-
0.0.00 , . ,.
2 .5
1.5
2.0
1.0
Pseudoropidity (y))
Integral paths start at Ahlen s p-detector baseline
0
.5
Figure 146: Resolution for constant P as a function of -7.
85
GEM ---
in.
.
5 !.
Thin Pole Case 3 Extended
.
ield (G) on
-
.
.
I
.
50-m surface
1.2
1.6
2.0
24
3.2
3.6
50
0
-0
I.-
0
-50
.4
-100
-100
.4
.
100
-50
0
50
Z-oxis (beamline), m
CONTOUR LEVELS (101
Figure 155: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
GEM
--
Thin Pole Case 3 Extended
Magnet Resolution for P
=
500.0
.06
u-i
u-i
.04
.02
n nn
0.0
I
I
I
1.0
1.5
2.0
2 .5
Pseudoropidty (n>
Integral paths start at Phlen s p-detector baseline
.5
Figure 156: Resolution for constant P as a function of 77.
90
GEM --- Thin Pole Case 3 with End Compensation
Magnet Resolution for P
500.0
.060
.052
U,
.044
U,
.036
.028
0. 0
.5
1.0
1.5
2.0
2.5
Pseudorapidity (N)
Integral paths start at Ahlen s p-detector baseline
Figure 126: Resolution for constant P as a function of 7.
GEM --
Thin Pole Case 3 with End Compensation
Magnet Resolution for Pt
500.0
.28
.23
U,
18
U,
13
.08
0.0
.5
1.0
1.5
2.0
2.5
Pseudoropidity G,)
Integral paths start at Ahlen 9 p-detector baseline
Figure 127: Resolution for constant Pt as a function of q.
75
GEM
nr'.I
-
Thin Pole Case 3 with 2m End Coapensotion
-.4
,
Field
(G)
.4
,
.
-
0-g s rface
1.2
E
50
2.0
4;
0
C
2.4
4.0
0
C
-50
-
-100
*.
-I00
.
I
. .
. 1 .
. 1
..
-50
0
50
Z-oxis (beamline), m
CONTOUR LEVELS (101
.
.
.
100
Figure 135: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
.U04
GEM ---
Thin Pole Case 3 with 2m End Compensation
Magnet Resolution for P
500.0
.056
.048
cn.
.040
.032
.024
fl18
0.0
I
I
.5
1.0
1.5
2.0
2 .5
Pseudoropidi ty (?)
Integral paths start at Ahlen s p-detector baseline
Figure 136: Resolution for constant P as a function of 77.
80
A.1.8
Thin pole case 6
GEM
Thn Pole Options
---
MITHAP V1.
Come 6
11/18/91
15:37
1.6
1.47
1.27
a
.6.4-
to
0.
1.5
1.0
R I of
.5
to
2.0
ELEMENTS
Figure 108: Side view of a superconducting solenoid with a thin pole (cf. Appendix A.1.5)
but with an 0.7 m center gap in the solenoid. Note that the beam axis (the z axis) is vertical
on the page and the transverse (radial) axis is horizontal.
GEN ---
Thin Pole Optionst
MITNAP VA
Case 6
11/20/91
14:32
5..
too
a
,CNN=
2.
1. ill
I
0.
1.
1A
2.
S.
soi
)
4.
5.
CONTOURS OF CONSTANT 8
Figure 109: Contours of constant IBI superposed on a side view of the magnet; isopleths are
labeled in gauss.
65
GEM
151
---
Thtn Pole Options:
Case 6
1
II
Contours oF f xed If
Isopleths at 6, 8,
f
-
J x .ds
10, and 12 T m2
-
10OE
6-
5-
.701
0
a-
10
5
Z,
15
m
Integral paths start at Ahlen's p-detector baseline
Figure 118: Isopleths of constant B 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
70
Baseline pIus Cuop
GEM I --
1:34
MITMAP VI.A 11/16/91
2.
2 -------------
------- ------ -
-
---
2.1
-
------------
- - -------
4 .. .....
--------- --- -------- ---
-- -- -- --- -- -
.2
2. 1
3.
4.
5.
Rl
6.
7.
ml
Figure 234: 1B versus radius near the surface.
GEH I
---
Sbei me DIus CuSS
HITHAP VI.A 11/16/91
14134
. ..
..
9.
8.
--
- ------- - - -
...
-- ---
5.
.
.
2....
4.
192
.
Z( 0)
.
.
Figure 235: 1.I versus z on axis in the hall.
131
GEM.
HITHAP
Solid Iron Wedge
18:56
VI.0 11/16/91
2.
2
U
1.
10
0
s
10
2.0
R 1 m)
CONTOURS OF CONSTANT FLUX
Figure 246: Flux lines superposed on a side view of the magnet design.
GEM.
Solid Iron Wedge
MITHAP V1.0 11/16/91
18s8
8.
..
6.
...... .
3.
...
. . ....
.
.
......2
- - - - -. .....
--- .
......
2.
...
8.
10
R( al
.....0
Figure 247: IF81 versus radius in the hall.
137
.2
Thinpole 3 with Split Wing Solenoid
'
GEM --. . I
Magnet Resolution
for Pt = 500.0
(I,
U.)
0.0
0.0
.S
1.5
1.0
2.5
2.0
Pseudorapidity (n)
Integral paths start at Ahlen
s p-detector baseline
Figure 215: Resolution for constant P as a function of -r.
I5
GEM ---
Thinpole 3 with Split Wing Solenoid
Contours o
fixed if f B x ds.ilds
Isopleths at 6. 8. 10. and 12 T m2
10 C
a.
10
5
0
15
Z, M
Integra) paths start at Ahnlen's p-detector baseline
Figure 216: Isopleths of constant BL2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
121
GEM
I
ne -
Solenoid
Double
T
.
0 A v
I
R i
.
.
Magnet Resolution for P = 500.0
.06
0,
aS
.04
.02
n nn
I
2.5
2.0
1.5
1.0
Pseudoropidity (0
Integral paths start at Rhlen s p-detector baseline
.5
0.0
Figure 225: Resolution for constant Pt as a function of 77.
GEM ---
Double Solenoid
Contours of fixed if f
D x
.dlds
2
Isopleths at 6. 8. 10, and 12 T m
10
C
a.
5
-7
n
0
10
5
Iot4Gal poth* start
at
15
%Ion's W-dtector baseline
Figure 226: Isopleths of constant B 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
126
.4
GEM ---
Thin Pole Case 3 with Cold Iron
. , . I I I I I I
. . , I , I , ,
I,
I,
500.0
Magnet Resolution for Pt
.3-
.2-
.0
0.0
.5
1.0
1.5
2.0
2.5
Pseudoropkdkty Wr)
Integral paths stort at Ahlen s p-detector baseline
Figure 195: Resolution for constant Pt as a function of il.
GEM ---
Thin Pole Case 3 with Cold Iron
Contours of fixed
i f B
Isopleths at 6, 8,
x dailds
10, and 12
T m2
10
0
5
10
Z, m
1
Intogr-al paths start at Ahlon's p-detoctor baseltie
Figure 196: Isopleths of constant BL 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
111
Thinpole 3 with Wing Solenoid
GEM ---
Magnet Resolution for Pt
500.0
072
064(n
(n
056
.048
040
.032
0.0
1.0
1.5
2.0
2 .5
Pseudorapiditp (v)
Integral paths start at Phlen s p-detector baseline
.5
Figure 205: Resolution for constant Pt as a function of r7.
GEM ---
Thinpole 3 with Wing Solenoid
Contours of fixed i ff
.
2
x
s Ids'
Isopleths at 6. 8, 10, and 12 T m2
10-
5
-7
01
0
5
10
15
Z. m
ItgrO) poths stort at Ahler's w-detector boseliMe
Figure 206: Isopleths of constant BL2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
116
BasehIne plus Cusp
GEM 1 --10
E
8
x
-r
G Path
A Path
+ Path
x Path
ot
at
at
at
60.0
70.0
80.0
90.0
degrees
degrees
degrees
degrees
r
TOM
6
4
-7
2
-.
n
0
20
15
S, m
Integral paths start at geometric center
25
10
5
Figure 240: Plot of 11Z versus path length from the interaction point for tracks at 60, 70, 80,
and 90' (from the beam line).
GEM 1
Basel ne plus Cusp
--
' '
1
' ' ' '
.06 1 1 1 1 1
a net Resolution For P
'
=
1
'
' ' 1
1
500.0
.041
u-i
.02
An flA ,n
0.0
, ,I
i
.5
i
1.0
i
1.5
2.0
2.5
Pseudoropidty (0
Integral paths start at Ahlen s p-detector baseline
Figure 241: Resolution for constant P as a function of r7.
134
GEM:
Mogn
-
Solid Iron Wedge
Resolution for P
=
500.0
.04
(n)
.03
Cr)
.021-
0.00
. .2.5
2.0
1.5
1.0
Pseudoropkdity (n)
Integral paths start at Rhlen 9 p-detector baseline
0.0
.5
Figure 250: Resolution for constant P as a function of 11.
GEM:
Solid Iron Wedge
Magnet Resolution for Pt
500.0
.10
in
.05
n nnl
I
2.5
2.0
1.5
1.0
Pseudorop i d k ty (y)
Integral paths start at Rhlen s i-detector baseline
0.0
.5
Figure 251: Resolution for constant Pt as a function of
139
i.
Double Solenoid
GEN -
MITMAP VI.A 11/18/91
0.t*.
C.n.+v I *I.S.U-
11:11
S.Y1u-m
-
2.9
1.8-
U
I'.'
1.2
A- 1.0
0.
CONTOURS
OF
2.0
1.5
1.0
CONSTANT FLUX
Figure 219: Flux lines superposed on a side view of the magnet design.
GE
-- Double Solenoid
MITHAP V1.0 11/18/91
1112
....
.-.......
7.
6.
-
2--
I-
--
-
2.
. 10 2
.
Figure 220:
.8
-4
1.
A( m)
IBI
versus radius in the hall.
123
GEM
-
CRSE 5d
1001
F-keld (G) on
50-m surface
.1
50
.32
C
L
C
a
0
L
V
-50
-1001.L
-100
II
I
I I
0
-50
I
50
Z-oxts (beamline), m
CONTOUR LEVELS (100
I
100
)
Figure 229: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
128
Thinpole 3 with Uing Solenoid
GEM ---
111 9
MITHAP VI.A 11/18/91
I
Contu
.
Omit
S.43.6
.W'iE.US
. *
2.0
1.8
1.0
2.4
2.8
1.2
.6.
1.5
1.0
0.
2.0
CONTOURS OF CONSTANT FLUX
Figure 199: Flux lines superposed on a side view of the magnet design.
GEM ---
Thinoole 3 with Wing Solenoid
MITHAP V1.0 11/18/91
S.
.
4.
. ...
1.29
......
......
8.
7.
8.
.. .....--
-- ----
4.
3.
2. -- ----------
--------
-------- ---------
-----
1.-
2.
to2
.2
S
.4
.8
1.0
Figure 200: JBI versus radius in the hall.
113
GEN
Thinpole 3 vith Split Ulng Solenoid
--
MITMAP VI.@ 11/18/91
Cotur I
Delta
41.Se.m-0
11: 6
*
6.31E.M
2. 0.
U
"'I
1. 2
1.
.
I.
8
1.
6-
2
16
I.
OO
F
S
L
CONTOURS OF CON37ANT FLUX
10
Figure 209: Flux lines superposed on a side view of the magnet design.
6EM
--
Thinpole 3 with $pili
MITHAP
V1.
11/18/91
L. .
J-
Ming Solenoid
111 8
.
. .........
.......
;.....
........
-----------;
--------J
6.
4.
I.
3
2.
I -, -+----
0.
t,2
.8
.2
1.0
A( 0)
Figure 210: fBi versus radius in the hall.
118
A.3
Alternatives of some interest
A.3.1
Solid iron wedge
GEM-
Solid Iron Wedge
MITMAP VI.A 11/16/91
18:56
2.0
1.81.6-
1.4-
1.2
.. 1.07
.6.4
12
0.
10
.5
2.0
1.5
1.8
I ml
ELENENTS
R
Figure 244: Side view of a superconducting solenoid with a solid iron wedge. Note that the
beam axis (the z axis) is vertical on the page and the transverse (radial) axis is horizontal.
GENH
Solid Iron Wedge
MITHAP VI
11/16/91
/
18:56
5. -
2s.
288
3.
-
a4
2.
1
is
I.
1,.
2.
CONTOURS
O
OF
S
CONSTANT
4.
S.
B
Figure 245: Contours of constant IBI superposed on a side view of the magnet; isopleths are
labeled in gauss.
136
A.3.2
50% iron wedge
537 Fe wedge (FHCI
19:33
MITMAP VI.A 11/16/91
7 01
1
1.01.6
1.27
-
1.07
.8.67
.2
:
10
0
0 I.
1.0
RI )
ELEMENTS
.5
10
1.5
2.
Figure 253: Side view of a superconducting solenoid with a 50% iron forward hadron
calorimeter (half iron wedge). Note that the beam axis (the z axis) is vertical on the page
and the transverse (radial) axis is horizontal.
601
Fe
wedge
tFHCI
MITMAP V1.0 11/16/91
19:33
5. -
251
3.-
2
2.
1.
10
0.
0.
1R
2
3.
'.
CONTOURS OF CONSTANT 0
5.
Figure 254: Contours of constant IBI superposed on a side view of the magnet; isopleths are
labeled in gauss.
141
GEM ---
I
-
.4
Field
.
Double Solenoid
(G)on 50m surface
-
1.2
1.6
50
2,0
a
3.2H
-
.4
3.5
01
,a
4.04
-50
.
-100
- 0
- I 00
so50
Z-oxis (beomline), m
CONTOUR LEVELS (101
100
Figure 223: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
0 , . . . ..
GEM ---
Double Solenoid
net Resolution for P = 500.0
-
.04
(<
.03
(A
.02
.01A AA ,
0.0
,nn
I
, , . ,
2 .5
2.0
1.5
1.0
Pseudoropidity (y)
Integral poths start at Rhlen x p-detector basel ine
.5
Figure 224: Resolution for constant P as a function of t7.
125
GEN I
--
Baseline plus Cuso
MITMAP VI.0 11/15/91
Delta
A , -A-705E+2
Coatueu
.
14:33
I.O2W.41
2.0
1.e
N2CJ ~
1.2
1.2U
1.0
.8
.6-
10'
0.
I.
-+-
2.0
.5
1.0
1.5
A I 4)
CONTOURS OF CONSTANT FLUX
*
10
Figure 232: Flux lines superposed on a side view of the magnet design.
GEM I --
Besel mne plus W$O
HITHAP VI.0 11/16/91
14134
7.
. -...-- -
- --------------- -----------------.......
......
3.
- - -----
1.
0-.
t
- ------- - -----
0.
2
.2
.C
. .5
I
1.0
Figure 233: JBI versus radius in the hall.
130
GEM ---
Thinpole 3 with Wing Solenoid
.4
Field (G) on
501m
.
ur'oce
1.2
5
1.6
0-
2.0
4.0
41
0
(L)
(A
L
-5 0
o
-10
-100
-
-. 4
_
_
-50
_
0
50
,_e_
100
Z-oxis (beamline), m
CONTOUR LEVELS (101
Figure 203: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
GEM ---
Thinpole 3 with Wing Solenoid
not Resolution For
P =
500.0
04
(n
03
.02
1
.01}0.001 , . . , , , , , ,
0.0
.5
I , , , ,
1.0
I
1.5
I
... , , ,.
.
2.0
2.5
Pseudoropiditty (v))
Integral paths stort at Ahlen s p-detector baseline
Figure 204: Resolution for constant P as a function of 77.
115
GEM --
1 n0.*,..
I
Feld
S
Thinpole 3 with Split Wing Solenoid
'~
..
(G)
.
on
i
.4
50-m surface
1.2
1.6
50
2.0
0
3.2
3.8
L,
0
C
a
LA
-50
.4
.4
-100n
50
0
-50
-100
Z-axis
100
(beamline), m
CONTOUR LEVELS (101
Figure 213: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
GEM
--
Ma
.04
Thinpole 3 with Split Wing Solenoid
Resolution For P
500.0
0,
-ol,
-eouino
.03
CrC
.02
.01|nn
A .fi
0.0
II
I
I
2.5
2.0
1.5
1.0
Pseudoropidity G?)
Integral paths start at Phlen s p-detector baseline
I
-
.5
Figure 214: Resolution for constant P as a function of -r.
120
4
stops) for a 500 GeV track:
S = .3 / 8(500) (.823) [4.93]2 / sinO = 1.48 x 10-3 meters / sine
1.48 mm / sine
=
The Sagitta grows from 1.48 mm to 2.85 mm. From 900 down to 31.3*.
Since the NDC magnet has a finite length of 14.5 - 6 = 8.5 meters, we
have for angles below 31.3 (which is the angle where the solenoid stops):
L = L(0*) / cose = 8.5 / coso
S = (.3 / (8 IP)) 1BI sine (L (0o))2 / cos 2 e =
(.3 / (8(500))) (.823) tan 0 (8.5)2 / cose
S = (.3 / (8(500)) (.823) (.176) (8.5)2 /.99 = 7.93 x 10-4 meters or about
.793 mm
Even in this case, BI. L2 is a useful figure of merit. If we assume an
overall resolution of 35 microns then the resolution of a 500 GeV/c track
at 100 is - 35 / 793 ~ 5%, which is an often quoted design parameter. If
we wished to keep the Sagitta at 100, equal to 1.48 mm, we would have to
increase the coil length to = 35.2 meter, which is clearly practical.
Hence it seems the baseline magnet will provide resolution of at
least 5% at a momentum of 500 GeV down to an angle of about 100. It
seems reasonable to consider an outside toroid for angles smaller than
about 100
Figure 2 shows the basic concept.
182
GEN ---
High Field Design
MITHAP VI.0 11/ 6/91
18:53
2.0
1.8
1.41.2
.1.0
.8.
10
0.
0.
10
1
1-.0
.5
R( m)
1 .5
2.0
CONTOURS OF CONSTANT 0
Figure 308: Contours of constant IBj superposed on a side view of the "Ko" option.
SEM
---
High
MITHAP VI.0 I1/
Field
6/91
Design
18:55
1.4
1.3
1.2
1.11.0
.9.8
.1
.3
.2
1-
R Im)
CONSTANT FLUX
10
CONTOURS OF
Figure 309: Flux lines superposed on a side view of the "Ko" option.
172
100
GEM ---
High Field Magnet Design fKycia)
eld (G) on
50-
sur'ace
2.
50
1.4
2.0
2.4
2.8
3.2
C
a
j-A
3.6(A~
0
C
a
L
-50
-100
-100
I
1
1
1,4 1
1
-50
0
50
Z-oxts (beamline), m
100
CONTOUR LEVELS (100
Figure 318: Isogauss contours of the field from the "Kycia" option on a surface at a nominal
elevation of 50 m above the beamline (centerline). Note the peak field at an elevation of
50 m is less than 4 G.
177
GEM ---I Bose, Botl 2o, and Rtrn Sol. + Forw. HC
1
1
I
I
S
I
I
I
Contours oF fPxed
If f
Isopleths at 6,
10, and 12 T m2
8,
Q x .ai ds
l0hE
0.
-7
T
5
0
0
,
5
,
,
10
,
,
15
Z, m
Integral poths start at Ablen's p-detector baseline
Figure 292: Isopleths of constant BV2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
162
GEN
Thin Pole Options
---
MITNAP V1.
Case S with SC return
11/ s/91
D.i.
Wid .-
I...* -2.121*141
con'tow, I - -2.41K.43
2.I
1323
.* ..
6.0M."
1.8
1.B
I.
,...
1.
1.
12
.s
1.0
.s
.
CONTOURS
OF
CONSTANT
2.
FLUX
Figure 300: Flux lines superposed on a side view of the magnet design.
6EM
---
Thin Pole 00ionos
Cooe S with SC
MITMAP VI.A 11/ 6/91
return
19.23
a.
----------
+-
7.
2.
10-j1
0.
.
2.
Is
.
.6
..
1.
At a
Figure 301: |fi versus radius in the hall.
167
5
We will show that:
S
=
(.3 / (2P)) BL 2 / cose
=
(.3 / (2P)) B t2 / cos3
F Ia 3
=
L / p = .3 BL / P
S'=OL/2=(.3B/2P) L2
L = t / coso
S = S' / coso
S=(.3/(2P)) B t2 /cos
30
Let us choose the following parameters:
t=3
B =1
0 = 100, 20
P = 500
S
=
(.3 / ((2)(500))) (3)2 / cos 3 (1 0) = 3 x 10-3
S
=
(.3 / ((2) (500))) (3)2 / cos 3 (2) = 2.7 mm for 20
2.8 mm for 100
At both angles the toroid has as good or better resolution than the
solenoid at the same momentum.
184
GEM ---
High Field Design
Field (G)
a
0-8
ace
1.2
so
1.5
.
'0
3.3
L
0
3.6
L
l'1
-50
-1001
-I 0
, i.8 , , , ,
,.
,
-50
100
0
50
Z-oxis (beamline). m
CONTOUR LEVELS (100 1
Figure 312: Isogauss contours of the field from the "Ko" option on a surface at a nominal
elevation of 50 m above the beamline (centerline). Note the peak field at an elevation of
50 m is less than 4 G.
GEM
---
High Field Magnet Design (Kyciel
MITMAP V1.8 11/12/91
1.2
10:57
............................................
1.1
.0
11 1111 1
MIMI
I
8
.6"
[if
.5-
.3
.2
U. I
0.
.8
.2
1.0
1.2
ELEMENTS
Figure 313: Side view of one quadrant of the "Kycia" option; the high field superconducting
solenoid and iron return frame are shown.
174
DRAFT
MAGNETIC FIELDS AND MOMENTUM MEASUREMENT
AND ERROR ANALYSIS FOR FRESHMEN
Irwin A. Pless
16 July 1991
Charged particles bend in magnetic fields. It is the measurement of
this bend and the error on the measurement of this bend that leads to the
evaluation of the momentum of charged particles and the error on that
momentum.
For the New Detector Collaboration (NDC) a resolution parameter,
B I- L2 (T - M2 ), is used to compare various magnetic field geometries
and the utility of a given magnetic field geometry for various particle
trajectories inside that geometry. Bi is the component of the field
perpendicular to the trajectory and L is the length of the trajectory.
The following is a simplified explanation and derivation of that
parameter.
As a starting point we use the familiar Lorentz force equation
(neglecting units):
F=K PxB
F is the force on the particle
P is the three momentum
B is the magnetic field
From this one easily derives, for a particle of unit charge, the
following:
iPI = 0.3 p IB sinO
(1)
p = P /.3 B sine
Again JPI is the magnitude of the momentum in GeV/c.
1BI is the magnitude of the magnetic field in tesla.
Sine is the sine of the angle between P and B.
p is the instantaneous radius of curvature in meters of the
particle trajectory in the osculating (kissing) plane. The
osculating plane at a point on a track contains the tangent to
the track at that point and the Lorenz force vector. The
Sagittas calculated in this note are also contained in the
osculating plane. For the small Sagittas and turning angles
considered in this note one can assume, without loss of
179
.10
GEM
-
Baseline w/ Thick Pole and 2.Om Return
Magnet Resolution For P
500.0
.08. 06-
.04-
.02
0.00 . . . ,.
0.0
.5
1.0
1.5
2.0
2.5
Pseudoropidity (4)
Integral paths start at Rhlen s p-detector baseline
Figure 295: Resolution for constant P as a function of 1;.
GEM - Baseline w/
Thick Pole and 2.Om Return
Magnet Resolution For Pt
500.0
.3-
.2--
.1-
0.0 , ,
0.0
,
I
1.0
1.5
2.0
2.5
Pseudoropidity (W)
Integral paths start at Rhlen s p-detector baseline
.5
Figure 296: Resolution for constant Pt as a function of r7.
164
Thin Pole Options:
GEM ---
Magnet Resolution for P
Case 3 with SC return
500.0
.06
ir~
-
.04
ge
trr
U~
-"oUCo
.021-
n n
i
I
2.5
2.0
1.5
1.0
Pseudorapidity In)
Integral paths start at Ahlen 9 p-detector baseline
.5
0.0
Figure 304: Resolution for constant P as a function of 77.
GEM
Thin Pole Options:
---
Mognet Resolution for Pt
Case 3 with SC return
500.0
.3-
.2-
to
.1
A
.0
0.0
.
,
I
.5
,
.
.
.
.
. .
JII
1.5
1.0
Pseudorapiditp
.
.l
A
2.0
.
.
1
2.5
(v)
Integral paths start at Phlen a p-detector baseline
Figure 305: Resolution for constant P as a function of 77.
169
GEM --
High Field Magnet Design
MITHAP V1.0 11/12/91
Kyciel
12166
S.
3.
I-
.-----
2.
--- --------
----- -
--.
1.0
A( ml
1.5
--.....
1.
0.
0.
0
1
.5
2.0
Figure 316: |JB versus radius in the hall for the "Kycia" option.
GEM
--
High Field Magnet Design (Kyciel
MITHAP VI.A 11/12/91
------I ...
2.2.
..
. . .......
-
1.A.6-
0
.2
12:66
2
- ----
---
..... . .....
1
2. II
Figure 317:
IBI
3.
'I.
5.
Al ml
6.
7.
versus radius near the surface for the "Kycia" option.
176
3
To derive formula (2) we start with:
dO= Idli / p(L) = .3 lB x dli / IPI
.3/PI JIBxdll
$=
S =p(l -cos(/2))=p/2(0 2 /4)=(p/8) (.3/P)2
[1B x dll ] 2
Using the mean value theorem we have:
S
= (p / 8) (.3 / IPI )2 (< IBI > < sin 0 > L) 2
S
=.3/(8
PI)<B><sinO>L 2
(3)
Note B sine = B±
Setting sin 0 = 1 recovers formula 2.
As an example of the use of formula (3) let us consider the base line
magnet for the NDC. We restrict our study, as always, to small Sagittas,
or high IPI.
Ro
=
8.830 meters
Ri
=
3.900 meters
For muon detection
L (90) = 8.830 - 3.900 = 4.93 meters
Length of magnet short 6 meters
Length of magnet long 14.5 meters
L (0) = 14.5 - 6 = 8.8 meters
For muon detection
1BI = .823 tesla
Let us calculate at the Sagitta for a 500 GeV particle between angles
of 90* and 100.
First we will look at angles from 900 to 31.30 (where the solenoid
stops).
S
= (.3 / (8P)) B sinG L2 (90) / sin 2 0 = (.3 / 8P)) B (L (90))2 / sino
Hence for angles down to about 31.3* (which is where the solenoid
181
A.4.2
Superconducting return
GEM
Cage
Thin Pole Dptsons:
---
S vth SC
MITMAP VI.0 11/ 5/91
11:24
1.0
1.5
return
1.
1.21.0a
.4 -
.2
ti'
0~
L.
t
0.
.5
ELEMENTS
Figure 298: Side view of a superconducting solenoid with a thin end pole (cf. Appendix A.1.5) and with a superconducting return coil. Note that the beam axis (the z
axis) is vertical on the page and the transverse (radial) axis is horizontal.
GEM
Thmn Pole 0ot ions:
---
MITHAP VI.A 11/
Ce0eiWr I -
I.IUC-11
Case 3 with SC return
5/91
13:22
Gse+*
5.
2.0
4
I.
1.8
1.14
1. 2
... 1.80
.8
.6
.2
I
9.
1 I
.5
L.I
I a)
1.5
CONTOURS OF CONSTANT 8
Figure 299: Contours of constant JBf superposed on a side view of the magnet design.
166
A.5
High Field Options
A fundamentally different approach, the "high field" approach, has been proposed by part
of the collaboration. The design concept is to have a much higher uniform field (5 T) in
a smaller volume with an iron return frame and use external toroids for measurements at
small angles. In initial support of this work two cases were run (without toroids):
1. the original concept called the "Ko" option here (Figures 307-312), and
2. a revised approach called "Kycia" (Figures 313-318).
As the first "Ko" option was not iterated, its field is high by about 12% (cf. Figure 310 and
Figure 316).
GEM
---
High Field Design
MITNAP V1.0 11/ 6/91
17:11
I.5
1.3I.21.11.0-
I IfIII
a
.8
I
-
----------
1
9.
LLJI I U 111
I I I L.LLl 1.11
, 9
.2
.4
6
totm)
.8
1.0
ELEHENTS
Figure 307: Side view of one quadrant of the "Ko" option; the high field superconducting
solenoid and iron return frame are shown.
171
GEM I ---
Baseline with Full Pole
Magnet Resolution for P =
100.0
.04-
.n
.03-
.02-
.01
0.00
,,
.
0.0
I
.5
1.0
1.5
2.0
2.5
Pseudoropidity (,)
Integral paths start at Ahlen s p-detector baseline
Figure 47: Resolution for constant P as a function of 77.
.10
GEM I ---
Boseline with Full Pole
Magnet Resolution For Pt
100.0
.08-
.06-
.04-
.02
0.00 . . . .
0.0
.5
1.0
1.5
2.0
2.5
Pseudoropidito (7>
Integral paths start at Ahlen s p-detector baseline
Figure 48: Resolution for constant Pt as a function of 7.
32
GEM I --.
100
Baseline plus Cusp
.
.
Field (G) on
,
.
,-
50-m surface
.2
50-
.4
C
L
0
L
I-
-50-
-100
.
.
I
50
-50
0
Z-oxis (beamline), m
CONTOUR LEVELS (101
-100
100
Figure 236: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
GEM I --0 Path at
-a Path at
.+ Path at
x Path
at
Baseline plus Cusp
5.0 degrees
7.5 degrees-
10.0
degr
I
0
x
-5|
--i
0
5
15
20
S, m
Integral paths stort at geometric center
10
25
Figure 237: Plot of III versus path length from the interaction point for tracks at 5, 7.5, 10,
and 12.50 (from the beam line).
132
GEN --
Thin Pole Ootions:
MITHAP V1.0 11/13/9
Omt.
Ce.,tmu 2 * S.UIE+.U
2.0
Case I
12:11
5.U'It+U
SA.
*
1.81.6
4
1.
2
U
1.
2
10
0.
10
15
10
5
,
AId
2.0
CONTOURS OF CONSTANT FLUX
Figure 57: Flux lines superposed on a side view of the magnet design.
GEN -
Thin Pole 0otionsi
MITNAP V1.0 11/13/91
Case I
12.11
8.
7.
--...---.-..--..
6.
- - - -- ----
+
-
. --...
-----
---------- --- - - ---
3.
2.
t0o
1.
0.
to-
2
.4
A(
l
.6
.8
1.0
Figure 58: JBI versus radius in the hall.
37
6EM
---
Beseline solenoid
MITMAP VI.A 10/25/91
18131
a.
7.
-
---
-
6
8
......
3.
i
2.
-
12
.
.
1
.
R( al
0
Figure 27: BIi versus radius in the hall.
SEM --- Buliane Solenoid
MITMAP VI.A 10/25/91
18131
1.6
1.4
-
--- -----
--
,
1.2
82
.4
- 2-
Figure 28:
A. m 9.
10
IBI
0.
versus radius near the surface.
22
GEN
---
Boseline with Full Pole
NITHAP V1.0 11/ 4/91
*.
st.E..
Del.ta
o's.
17:27
Co.*u
2.9
1.8
I.e
1.4
1.2
-
1.0
.6
.6
.2
19'
0.
0.
10
10
S
1.5
1.0
2.0
R Im)
CONTOURS OF CONSTANT FLUX
Figure 37: Flux lines superposed on a side view of the magnet design.
GEM I
---
Bose lm
with Full Pole
MITNAP V1.0 11/ 4/91
8.
17:28
-
7.
L.........
.---.---------..
...- .-------- C- .
....
....
-l.---
4.
3.
2.
- -- ---- - -- - - -- --- -- --
0.
t
.2
--
-- --
1.0
A( 3)
Figure 38: 1,f versus radius in the hall.
27
GEM - Baseline w/ Full Pole and 1.3a Return
MITMAP VI.A 10/10/91
18: 6
2.6
1.8-
999"
1.6
1.4
1.2
E
107
.8
.6
160
i
.
0.
.E
16
R Im)
.t
.
..
E.5
1.T
1.5
2.0
ELEMENTS
Figure 13: Side view of superconducting solenoid with a 1.3 m full iron return frame (the
figure is rotationally symmetric about the z-axis). Note that this figure is rotated 90* relative
to earlier figures; that is, the beam axis (the z axis) is vertical on the page and the transverse
(radial) axis is horizontal.
GEM
-
Baseline w/ Full Pole and l.Sm Return
MITMAP VIA6 10/10/91
18:22
.7.
8.
............... .........................-.
-"-.-----
... ..........
S-------
3.
.......
.~~.T.....
.
2.
2.
101
5.
3.
B.
7.
R[ m)
Figure 14: BI versus radius near the surface for 1.3 m return frame.
12
GEM ---
100
Base, Botl 2a. and Rtrn Sol.
+ Form. HC
(C-.pct-rn
Field
.3
.4
50
.95
C
0
_0
0
~0
L
C
0
L
-50
.2
-in
A1 . . . l . . . . l
-100
. . . . l . . . a
100
-50
0
50
Z-oxis (beomline), m
CONTOUR LEVELS (101
Figure 21: Isogauss contours of the field on a surface at an elevation of 50 m above the center
(beam) line of the design shown in Figure 19.
GEM
---
Base, Botl 2a, and Rtrn Sot.
MITCAP V1.0 11/16/91
Contour I
2.9UIE*82
Delta
+
Forw. HC
2148
.LEB
2.0
1.8
1.2
E
1.01
4~.l
.8
.8-
101
0.
0.
,
10
.5
1.0
1.5
2.0
R I m)
CONTOURS OF CONSTA NT FLUX
Figure 22: Flux lines superposed on a side view of superconducting solenoid with superconducting return (cf. Figure 19).
17
GEM 1
.05
.
Boseline with Full Pole
,
. .
.
Magnet Resolution for P
, , . ,
5.0
.04-
.03-
.02-
.01-
.
0.00
.
.
.I
1.0
1.5
2.0
2.5
Pseudoropidit (,)
Integral paths start at Rhlen s p-detector baseline
0.0
.5
Figure 51: Resolution for constant P as a function of -q.
GEM 1 --. . . . 1.
.05
Baseline with Full Pole
. .
1 1. I.
Magnet Resolution for Pt
5.0
.04-
.03in
.02-
.01
0.00
. .
0.0
.
.
.5
1.0
I
1.5
.
2.0
2.5
Pseudoropidkity (n)
Integral paths start at Rhlen s p-detector baseline
Figure 52: Resolution for constant P as a function of 77.
34
GEM ---
.08
Case 1
Thin Pole Options:
Magnet Resolution For P
=
500.0
.06-
.04-
.02--
,f
0.00
2.5
2.0
1.0
1.5
Pseudoropidity (n)
Integral paths stort at Ahlen a p-detector baseline
0.0
.5
Figure 61: Resolution for constant P as a function of 7.
-
.48
GEM --- , I
Thin Pole Options: Case 1
II . I. I . . I I
I
v .
Magnet Resolution for Pt
500.0
.40-
.32.24-
.16-
.08-
I
0.001
0.0
.5
.
1.5
1.0
.
2.0
.
.
2.5
Pseudoropidity (y)
Integral paths start ot Ahlen 9 p-detector baseline
Figure 62: Resolution for constant Pt as a function of 7.
39
GEM ---
Baseline Solenoid
Magnet Hesolution for Pt
500.0
.4
(In
.3
.2
.1
0.0
0.0
.5
1.0
1.5
2.0
2.5
Pseudoropidktj (,o)
Integral paths start at Ahlen 9 p-detector baseline
Figure 31: Resolution for constant P as a function of 17.
GEM
Baseline Solenoid
Contours of
fixed Iff I
Isopleths at 6. 8.
.
x
sids
10. and 12 T m2
10
C
a.
5
0
0
5
Imtegral paths starst
10
Z, M
0t ilien'
15
W-detector- boswlh.'
Figure 32: Isopleths of constant B2 for a simple solenoid superposed on a sketch of the
GEM concept; isopleths increase with distance from the origin.
24
GEM 1 ---
Baseline with Full Pole
F(0) on- 154-foot surface, IR site 1
S
50-
2.0
U
C
0
-4-
0
4,
L
I,
C
a
CI.-
-50 --
- inn1.
-100
-50
0
50
Z-axis (beomline), m
CONTOUR LEVELS (10)
100
Figure 41: Isogauss contours of the field on a surface at the nominal elevation of IR site 1.
GEM I --*
50
Basel ine with Full Pole
.5
eld (G) on 117-iF'ot surface
te 4
20
L
0
I--
-50
-100
-100
-50
0
50
Z-oxis (beamline), m
CONTOUR LEVELS (101
100
Figure 42: Isogauss contours of the field on a surface at the nominal elevation of IR site 4.
29
GEN
BaselIne
-
it/
Thick Pole and 2.9. Return
MITMAP VIA0 10/11/81
9t 9
.7.
3.
2.
10-4' . ..........
... . .
..
1.
....... .1
-
2.
4.
10 1
R( m)
6.
5.
7.
Figure 17: J.B versus radius near the surface for 2.0 m return frame.
GEN
-
Baseline v/ Thick Pole and 2.9m Return
MITMAP V1.0 10/11/91
Contour I *.UE48
I1
2.0
Delta -
9: 9
5. 32SE-
1.81.67
I.4
1.2
,..
1.0
.8
.210
0.
0.
10
10
1.0
1.5
R ( A)
CONTOURS OF CONSTRNT FLUX
.5
2.0
Figure 18: Flux lines superposed on a side view of a superconducting solenoid with a 2.0 m
iron return frame. Note that the beam axis (the z axis) is vertical on the page and the
transverse (radial) axis is horizontal.
14
References
[1] The L* Collaboration. Letter of intent to the SSC laboratory, November 1990.
[2] The L* Collaboration. Expression of interest to the SSC laboratory, May 1990.
[3] Second Detector Collaboration (GEM). Expression of interest to construct a major SSC
detector, July 1991.
[4]
U. Becker, J. Branson, M. White, B. Wyslouch, et al. Accurate measurements of high
momenta. Nuclear Instruments and Methods, A263:14-19, 1988.
[5] S. Ahlen. private communication.
[6] V.L. Highland. Nuclear Instruments and Methods, 129:49, 1975.
[7] V.L. Highland. Nuclear Instruments and Methods, 161:171, 1979.
[8] R.D. Pillsbury, Jr. Soldesign user's manual. Technical Report PFC/RR-91-3, MIT
Plasma Fusion Center, Cambridge MA, February 1991.
[9] R.D. Pillsbury, Jr. MAP user's manual. Technical Report PFC/RR-91-4, MIT Plasma
Fusion Center, Cambridge MA, February 1991.
[10] J.D. Sullivan. Graphics package version 4: User's reference manual. Technical Report
PFC/RR-84-4, MIT Plasma Fusion Center, Cambridge, 1984.
[11] Swanson Analysis Systems, Inc., Houston, PA. ANSYS revision 4.4a.
[12] R.D. Pillsbury, Jr. Fringe field dipole-dipole force interaction. Internal Memorandum
MIT-GEM-EM-01, MIT Plasma Fusion Center, Cambridge MA, November 1991.
[13] R.D. Pillsbury, Jr., L. Myatt, and J.D. Sullivan. Shielding of the magnetic fields from the
GEM magnet. Internal Memorandum MIT-GEM-EM-02, MIT Plasma Fusion Center,
Cambridge MA, November 1991.
19
GEN --
Solenoid
vith 2. End Compenset ion
MITMAP VI.A 11/19/91
9:38
2.01.8-
1.2
1.0-
1.2
1.0
.8
.6
.2
0.
'.9.
0.
iE.5
1.5
EM.N
ELEMENTS
2.0
Figure 139: Side view of a superconducting solenoid without iron pole pieces and with the
current doubled in the last 2 m. Note that the beam axis (the z axis) is vertical on the page
and the transverse (radial) axis is horizontal.
GEN
--
Solenoid vith 2& End Compensat ion
MITMAP VI.
)1/19/91
938
5.
tin
280
I
a
3.
U
2.7
N
I.-
I
101
0.
2.
3.
4.
A I .3
CONTOURS OF CONSTANT 8
5.
Figure 140: Contours of constant IBI superposed on a side view of the magnet; isopleths are
labeled in gauss.
82
GEM --
Thin Pole Coe 9 Extended
MITMAP V1.0 11/18/91
It*
I
2.0.
1.61.4
1.2a
'.4
.8
.6.4,
.2
101
0.
0.
.5
2.0
1.5
1.0E
R I .1
ELEKENTS
I0
Figure 149: Side view of a superconducting solenoid with the conductor extended over the
pole piece. Note that the beam axis (the z axis) is vertical on the page and the transverse
(radial) axis is horizontal.
GEM ---
Thin Pole Case
IMITMAP V1.0 11/18/91
S
Extended
It: I
Los
4.-
a
SIM
2.
101
0.
I
101
1,
2.
5.
4.
R I a)
S.
CONTOURS OF CONSTANT 8
Figure 150: Contours of constant ABI superposed on a side view of the magnet; isopleths are
labeled in gauss.
87
EN ---
Thin Pole Case S with End Compnsetion
MITAP V.A 11/18/91
10:53
5.
1'U
a
1.
1
0
0.
OF
ON2.
TA3.4.
s.
CONTOURS 0F CONSTANT 8
Figure 120: Contours of constant B I superposed on a side view of the magnet; isopleths are
labeled in gauss.
SEH
---
Thin Pole Case S with End Comoensation
MITHAP VI.
i /18/91
""'Cur. I
2.
,
19:53
i
I
-
9
.2
1.
0
B-
1010
- is
CONTOURS
1.0
R I m)
OF
CONSTANT
1.5
2.0
FLUX
Figure 121: Flux lines superposed on a side view of the magnet design.
72
GEM ---
S eWith 2. End Coootnsateon
Then Pole Ca
MITHAP VI.A 11/18/91
10:55
2.0.
1.8 -1.8 -
1.2-
1.0 .8.8-
.2 101
9.0.
to
1.5
1.0
.5
2.0
A a)
(
ELEMENTS
Figure 129: Side view of a superconducting solenoid with the current doubled in the last
2 m. Note that the beam axis (the z axis) is vertical on the page and the transverse (radial)
axis is horizontal.
GEN
---
Then Pole Case
S with
2. End Coenasation
MITHAP V1.0 11/18/91
10:55
5.-
U
uis
'-4
1. 19
9.
19
2.
CONTOUAS
3.
A IC
OF
4.
5.
A
CONSTANT B
Figure 130: Contours of constant IBI superposed on a side view of the magnet; isopleths are
labeled in gauss.
77
6
GEM ---
Thin Pole Options;
o Path at
30.0 degrees
35.0 degr
40.0 de eces
50.0 d ree
A Path at
+ Path at
x Path at
Case 5
x
4
2
11
5
15
20
S, M
Integral paths start at geometric center
U
10
25
Figure 103: Plot of II for the LoI baseline magnet versus path length from the interaction
point for tracks at 30, 35, 40, and 500 (from the beam line).
GEM ---
Thin Pole Options:
o Path at 60.0
6
A Path at
+ Path at
x Path at
Case 5
ees
70.
80
9
egresdegrees
x
4-
2/-
.
,
p
I
,
10
5
S, m
,
15
20
25
Integral paths start at geometric center
Figure 104: Plot of IIZ for the LoI baseline magnet versus path length from the interaction
point for tracks at 60, 70, 80, and 90* (from the beam line).
62
GEN ---
Thin Pole Option:
Case 6
MITMAP VI.6 11/18/91
Cont@.,r
I
15:38
Ost.
.ME48
-
-
LU.U+0
2.8
'.4
1.2U
.6
.4
.
Ri
.
1
.e
.
CONTOURS OF CONSTANT FLUX
Figure 112: Flux lines superposed on a side view of the magnet design.
GEM ---
Thin Pole Ootions.
MITMAP VI.0 11/18/91
Cose 6
15'40
7.
6.
5.
1.
4
3.
2.
~ ~-----
----
0.
1022
.2
-y
--
.4
----
3
1.0
RI .3
Figure 113: IBi versus radius in the hall.
67
GEM --
Solenoid with 2. End Compensataon
MITHAP VI.A 11/19/91
9:11
2.0
1.4-
1.2---
-
--+
-----
102
---
.
-+
-+--
+
5.
6.
----
.4.
|BI
Figure 143:
4.
3.
2. t
A( m.
7.
versus radius near the surface.
Solenoid vith 2m End Cowpensation
GEM -
HITHAP VI.0 11/19/91
9:40
8.
...----* ...
.
.7.
.. ...
..
- ------..
.
t
---------- ------ --------. .----------------
3.
2.
8.
Figure 144:
2
IBI
.6
.
to
8
1.0
I( a)
versus z on axis in the hall.
84
6EM -- Thin Pole Case 3 Extended
M[THAP V1.0
.......
1.8-
.
-
- -
.-
-
---
. . . .. ...
...... .. . . ..
... ..... ..6.
. .... ..
.29
-------.
.0
*....
3
11:
11/18/9
.......
....
....
......
-. ----- - ----
1
2.
4.
3.
to
RI.1
5.
7.
6.
1I versus radius near the surface.
Figure 153:
GEM
--
Thin Pole Case 3 Extended
NITHAP VI.A
Ill 2
11/18/91
.......
- ---. ......
6.
-t..-
5.
7
... ..
......
.
...
-
to2
------
- ------
--------.
.4
1.81
-...-
,------- ------- 4.
. .------------
.2
Figure 154:
- -
-.
6
.8
..........
....
.-
. . ....... --
1.
9.
....
-. -
.....
...
....
I
1.0
versus z on axis in the hall.
89
6EM
Thin PoIe Case 3 vith End Gompensation
--
MITMAP V1.0
11/18/91
.. .
...........--
1816
6.
......
..
.
....-..
-------.
...........
...
---------............
...........
.
....
.. . ......... -------- .
........... .
.
.......... .
2.
1.
----------- - -------- ------------
a.
.2
.6
.4
.8
1.9
!( .1
Figure 124: fBI versus z on axis in the hall.
,
MGH
--- ThLn Pole Case 3 with End Compensation
, . .
. . .. ..... .
4
Field (G) on
5O? surface
1.2
1.6
2.0
50
al
L
-
0
L
C::
-50
-100
-100
S4
.0
0
-50
50
100
Z-oxis (beomline). m
CONTOUR LEVELS (101
Figure 125: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
74
GEM
Thin Pole Case 3 with 2m End Coa2Cnsation
-
10157
HITMAP VI.A 11/18/91
-
2. -
- --- - - ----
-
1.8- ... ...
-
1.
---
- --
--
-
----
-
------------- 7
------ .. ...
10-2
... ....
--------
5.
2.
6.
7.
RE Ml
Figure 133: JBI versus radius near the surface.
GEM
Thin Pole Cose 3 with 2m End COmO~n$StIOn
---
10I67
HITHAP VI.A 11/18/91
S.
.7.
4.
-
3.*
.
2.
------------
.-
r-
...
2
.2
.4
i
I -
.8
I
.9
I
a
Figure 134: 1BI versus z on axis in the hall.
79
GEM ---
1"
Case 5
Thkin Pole Options:
Contours oF Fixed If f
2 x .Lakids
Isopleths at 6, 8, 10, and 12 T n2
10
E
51
-
II
-7
01 I
0
I
I
I
I
I
I
5
I
fill
I
I
10
Z,
15
M
Integral paths start at Ahlen's p-detector baseline
Figure 107: Isopleths of constant B 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
64
GEM ---
I
Thin Pole Options:
Magnet Resolution
-
for P
ge
Case 6
500.0
0,
-eouinFo
.06$
N.
04
C,.)
.02F
n- nf
0.0
.5
1.0
1.5
2.0
2.5
Pseudoropidity (v)
Integral paths start at Ahlen s p-detector boaseline
Figure 116: Resolution for constant P as a function of 7.
4
GEM ---
Thin Pole Options:
Magnet Resolution
Case 6
For Pt = 500.0
3
(n
2
cn
.1
0 .0 1 . . . . I , . , . I . , .
0.0
.5
1.0
I . .
1.5
, ,
2.0
. .
2.5
Pseudoropid t ()
Integral paths start at Rhlen s p-detector baseline
Figure 117: Resolution for constant Pt as a function of 77.
69
Baseline plus Cusp
GEM 1
10
.
, .
I
.
'..
.
a Path
Path
at 15.0 degrees
at 17.5 degrees
+
at 20.0 degrees
Path
x Path at
.
.
25.0 degrees
x
0
.
-10
0
I I .
. I I I
I . I
10
5
SIM
15
i- i i i i
20
25
Integra I paths start at geometric center
Figure 238: Plot of 121 versus pat h length from the interaction point for tracks at 15, 17.5,
20, and 25' (from the beam line).
GEM I --61
-
o Path at
A Path at
+ Path at
x Path at
Baseline plus Cusp
30.0 degr
35.0 de ces
40.d r e
50.0 egr 9
4
x
2
0
0
5
Integral
1iS
10
paths
St a
start at
geometric
20
25
center
Figure 239: Plot of IIZ versus path length from the interaction point for tracks at 30, 35, 40,
and 500 (from the beam line).
133
Solid Iron lledoe
GEPi:
18168
IIITHAP VIA H1/16/91
2 .2
----------......
---- -------
-
... .
1.4
---
..... ...--
1.2
1.0
I
.4---------
2.
10
IBI
Figure 248:
E
4.
3.
6.
.
7.
RI amI
versus radius near the surface.
GEM:
Solid Iron Wedge
keld (G)
on
50-m surface
1.2
1.6
2.0
so
4;
3.2
3. B
L
(A
L
0
-50
-100
,
-100
4, '
I
-
-
..
50
0
Z-oxis (beamline). m
CONTOUR LEVELS (101
-50
100
Figure 249: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
138
GEM --
Double Solenoid
11:10
MITHAP VI.A 11/18/91
2.0-
1.2'
I
1.-
1.2U
1.t
.8.6-
.2-
103
+
.5
0. t
19
2.0
1.5
1.0
R I ml
ELEMENTS
Figure 217: Side view of a superconducting solenoid without an iron end pole but with a
separate superconducting "wing" coil to model an iron cone (cf. Figures 244-252). Note
that the beam, z, axis is vertical on the page and the transverse axis is horizontal.
GEN
--
Double Solenoid
IITMAP V1.0 11/18/91
11:10
5.
4.
288
U
IZ
1.
10o
I.
iSO
1.
2.
3.
4.
5.
CONTOURS OF CONSTANT 8
Figure 218: Contours of constant IBI superposed on a side view of the magnet; isopleths are
labeled in gauss.
122
A.2.4
Miscellaneous
Figures 227-229 are from an early attempt to both cancel the field and shape it; the central
field is x2 too large in this example (i.e., 1.6 T). Figures 230-243 tried to simultaneously
satisfy the far (surface) field requirement and improve small angle response by replacing the
end poles with superconducting cusp coils (cf. Appendix A.4.2); thus the far field is no
longer dipolar (or at least the dipole moment is reduced.)
GEN - CASE 6d
MITMAP VI.A 11/15/91
12: 2
2.0
1.0
1.61.47
1.2
-1.0-
.87
.4
101
0.
.5
0.
R(m
1~
1.$
2.0
ELEMENTS
Figure 227: Side view of a superconducting solenoid with a superconducting return and an
iron wedge. Note that the beam axis (the z axis) is vertical on the page and the transverse
(radial) axis is horizontal.
GEM - CASE 6d
NITNAP V .0 11/15/91
12s22
2.0
1.0
1
1.2-1.0
.e
.8
.6
12
CONTOURS OF CONSTANT FLUX
Figure 228: Flux lines superposed on a side view of the magnet design.
127
GEN
Thinoole S with Wing Solenoid
---
11
MITHRP V1.A 11/18/91
8
2.0
1.0
1.a
r
.6-
-03:
0.
0.
t
1t
.s
l.0
R 0.)
ELEMENTS
1.5
2.0
Figure 197: Side view of a superconducting solenoid with an iron pole and with a separate
superconducting "wing" coil to model an iron flux shaping wedge. (cf. Figures 262-270).
Note that the beam, z, axis is vertical on the page and the transverse axis is horizontal.
GEM ---
5.
-
Thinpole 9 with Usng Solenoid
MITHAP V1.0 11/18/91
V
11: 8
b a £.nt
.nc,~..
'4.
a
*.1
-I
1.B.0.
Figure 198: Contours of constant
labeled in gauss.
IBI
4.
1.
2.
3.
. I I II
B
CON8TANT
OF
CONTOURS
S.
superposed on a side view of the magnet; isopleths are
112
GEN
Thinpole 9 uth Split Uing Solenoid
--
MITMAP VI.A 11/18/91
11: 6
2.01.51.61.4-
1.2-
1.0-
.8.6 -
7
10~
~4.
-
*1
0.
10 1
1.5
1.0
R I mI
ELEMENTS
.5
2.0
Figure 207: Side view of a superconducting solenoid with an iron end pole and with a separate
split superconducting "wing" coil to model a 50% iron calorimeter and an additional iron
cone. (cf. Figures 271-279). Note that the beam, z, axis is vertical on the page and the
transverse axis is horizontal.
GEN
Thinoole 3 with Split Uing Solenoid
--
MITMAP VIA.
.V.I.
4.
11: 6
11/18/91
.
.si.ln. . .n..ts
...
-
We
a
10
0
I
0
10
Figure 208: Contours of constant
labeled in gauss.
.
2.
3.
4.
R I 4)
CONTOURS OF CONOTANT B
IBI
5.
superposed on a side view of the magnet; isopleths are
117
Baseline plus Cusp
GEM 1 ---
.2
Magnet Resolution For Pt
500.0
0.0 . . . .,.
.5
0.0
2.5
2.0
1.5
1.0
Pseudoropidity ()
Integral paths start at Ahlen s p-detector baseline
Figure 242: Resolution for constant P as a function of 77.
GEM 1
Baseline plus Cusp
--
Contours of Fixed if
f 1 x .'ds
2
Isopleths at 6, 8, 10. and 12 T m
10-
5
0
5
Z. m
10
Integral paths start at Ahlef's P-dtector
15
ba"stpe
Figure 243: Isopleths of constant B 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
135
GEM:
1
Sol1d Iron Wedge
Contours of 4 txed If
f
x
a ds
Isopleths at 6, 8, 10, and 12 T m 2
10 -
-
E
0.
5-
5-7I
I
I
I
0
a
I
A A
5
Z,
Integr-l
poths
I
10
--. L
------ L ------L-
-
15
m
stort ot Ahlen's p-detector boseline
Figure 252: Isopleths of constant BL 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
140
GEM --
Double Solenoid
1I1s12
MITMAP V1.8 11/18/91
2.0
1.8
1.8
------..1.4
....- +- --- --- +-- ----- +--.........
g: 1.2
1.0
------------------- +--.8 ...-
-+
.8
. ....
s
2
19
0.
R. m
.
.
Figure 221: JBI versus radius near the surface.
GEM --
Double Solenoid
HITHAP VIA. 11/18/91
11'12
5.
Li.
.....
--- ----
I
2. q...
... .........
------------- -
II....
. .f
..
..---1.....
9.
1O2
.8
.2
1.9
Z( a)
Figure 222: 1BI versus z on axis in the hall.
124
GEM I --
Bosel ino plus Cusp
MITHAP VI.A 11/15/91
14:32
2
.8-
I
I
.6-
-
1.2-
.2-
a.
0.
.5
2.0
1.5
1.0
ELEMENTS
Figure 230: Side view of a superconducting solenoid with the end poles replaced with superconducting cusps. Note that the beam axis (the z axis) is vertical on the page and the
transverse (radial) axis is horizontal.
GEN 1
---
Besel ne plus Cusp
MITHAP V1A 11/15/91
5.
14:32
-
290
1
d.-
a
Soo
2.
1.-191
9.
-t
1.
4.
2.
S.
CONTOURS OF CONSTANT 8
Figure 231: Contours of constant JBI superposed on a side view of the magnet; isopleths are
labeled in gauss.
129
SEM
Thinpole 3 vith Wing Solenoid
---
MITAP V1.0 11/18/91
2.
0
1.4
-
.
-...-
. . -
---
----------
-
11110
----
-...
-
-
I.e.----+---------- ;--
1.2
10
....
--
-2
- -I .
2.
I I
IBI
Figure 201:
3.
4.
R( a.
s.
6.
.7
versus radius near the surface.
6EM
---
Thinoole 3 with lina Solenoid
MITHAP VI.A 11/18/91
11110
-
---------- ----------
5.
2.
1.
0.
Figure 202:
.2
IBI
.4
Z( Nil
.8
1.0
versus z on axis in the hall.
114
EM
-- Thir'ole
3 vith Solit Iling Solenoid
11/18/91
MITHAP VI.
2.
2
11: 8
V
02.
...
---+--
+
+--- -
1.8'
1 2.-
~2~2
-
3.
2.
5.
4.
6.
7.
M( m)
IBI
Figure 211:
SEN
versus radius near the surface.
Thinoole 3 with Split Mina Solenoid
--
111 7
MITHAP V1.0 11/18/91
. ..
. -..
---
,.
2. 2
--
. ---
-------------.-----..---..-..-- -
.
-..
-----
+----
2.
-
2 -
-
- ----
I.
4.
- - - -
. .
2 ....
i-
2
.2
.11
.6
......
1.0
Z( III
Figure 212: 1.I versus z on axis in the hall.
119
C-4
Y,
w
44
4
D
I-yf
'S
0
V4)
Lu
I
-.- 1
4
-e(
. r
J4
-
183
-I
GEM
High Field Design
-
MITHAP V1.0 11/ 6/91
1SISS
S.
-
-- -
-
-
-+-----
------------
-
2.
3.
------
- -- -- -
-----
.......
-- ---- - --
2.
---------
- -
- - -
1.
-.T......
.5
0.
.....
..
----
1.5
I .11
AC .1
2.0
Figure 310: |$i versus radius in the hail for the "Ko" option.
High Field Design
GEM --
MITHAP VI.A 11/
6/91
18:55
2
2
.2
.2--+
.8
.6
-
--
-
-
--
-+
--
-
-
---
--
+--+-
-.
--
10
2.
t
3.
4.
6.
S.
7.
Al ml
Figure 311: 1BI versus radius near the surface for the "Ko" option.
173
B
Pless's Analysis
Stimulated by the following analysis, preliminary designs and cost estimates have been run
for various toroids at small angles. A separate report on these options is in preparation.
178
A.4
Shielding
A.4.1
Full iron return frames
See Figures 13-18 in Section 5; also see Appendix A.5 where iron return frames are used for
much higher fields (5 T).
GEM
Baseline w/ Full Pole and 1.3m Return
-
.a
Field
(G)
59-e
on
-
.8
urface
2.4
50
32
(A
.2
_0
4)
8.0
0
In
I.-
-<
-50
-inn s
-100
.0.8
i i hi
i i i i
i
i i i i
-50
0
50
Z-oxis (beamline). m
CONTOUR LEVELS (100
100
Figure 293: Isogauss contours of the field (1.3 m return frame) on a surface at a nominal
elevation of 50 m above the beamline (centerline). Note that the peak field is less than 10 G.
GEM
-
Baseline w/ Thick Pole and 2.Om fleturn
.1
Field (G) on
50-m surface
.1
-
"N
.
.4
50
0
c
a
L1
0
-A
L0
-50
-inn,
-100
-50
0
50
Z-oxis (beamline), M
CONTOUR LEVELS (100
100
Figure 294: Isogauss contours of the field (2.0 m return frame) on a surface at a nominal
elevation of 50 m above the beamline (centerline). Note that the peak field is ~ 1 G.
163
Ceac 3 with SC rectur'n
GEN -- Thin Pole Opt~oi,
MITMAP V1.8 it/ 6/91
.. .
2.
13:23
....... ..
4
I.
---...
I. '.6...........- -it7
I.
I.
~
I.
1
19
-i
-
-
- -- ---
3.
2.
Figure 302:
S.
4.
Atml
6.
'.
|.8
versus radius near the surface.
GEM
-
I0 f,
Thin Pole Options:
,
Case 3 with SC return
N.I
Field
(G) on
502n
-.
r-Fce-
.4
50
L
2.0
2.2
(A
C
a
0
L0
---
-50
0.0 -
00
-inn
-100
-50
0
50
Z-oxis (beomline). m
CONTOUR LEVELS (100
100
Figure 303: Isogauss contours of the field on a surface at a nominal elevation of 50 m above
the beamline (centerline).
168
6
We can look at the stored energy of the toroid compared to the
solenoid.
stored energy of toroid / stored energy of solenoid
=
(diameter (T) /diameter (S)) 2 - length (T) / length (T) / length (S)(B (T) / B (S))2
= (6.4 / 19.2)2 - 3 / 30 . (1 / .8)2 = .017
Hence the toroid has about 1.7% the stored energy of the solenoid. The
cost of this toroid should be of the order of $ 1 x 106 or less.
The three tracking planes are in air and can be of conventional
construction. They are not large by current standards.
The addition of the toroid system allows a resolution of 500 GeV
tracks from 10* to 20 of about 2.5%. This is a very useful region for the
study of asymmetries of muon production.
185
Nigh Field Magnet Design (Kycie)
GEM ---
MITMAP VI.0 11/12/91
Conar I * i.3"I243 , D.Ite
12s55
.28E-gI
.
1.8
1.5-
1.2
E
1.0
.2
l.
0.
.
2.0
1.5
1.0
.5
1
10
O C
N)
CONTOURS OF CONSTANT 8
Figure 314: Contours of constant IBj superposed on a side view of the "Kycia" option.
GEM ---
High Field Magnet Design (Kyciel
MITMAP V1.0 11/12/91
C0ito* 1 . 6.4148I
1.2
1.1
asl.
12:56
6I.41E.U1
.
9
.8
1.0
1.0
.9
V/
.8
.7.
U
I..'
.4.6
.24
19
S. le
.2
.4
.6
R I m)
1.2
CONTOURS OF CONSTANT FLUX
Figure 315: Flux lines superposed on a side view of the "Kycia" option.
175
2
accuracy, that the complete trajectory of the track is
contained in the osculating plane.
For simplicity, we will discuss a uniform solenoidal magnetic field
parallel to the beam of the SSC. There are three important parameters for
this magnet.
1.1B = The magnitude of the field.
2. R = Radius of the magnet.
3. L = The length of the magnet.
The philosophy of the New Detector Collaboration (NDC) design is to
have all measuring components inside the magnetic field.
In this case the momentum is measured by using the Sagitta
technique. Again, for simplicity, assume the charged particle leaves the
interaction region at 900, along a radius of the solenoid. Figure 1 shows
the trajectory and the relevant variables. Note the SSC beam (and
magnetic field) is coming out of the plane of the drawing.
fl
We will show that for this case:
S = (.3 / (8P)) (B) L2
(2)
For this case B = BI.
This leads to considering BL L2 as the resolution parameter since for
large Bi L2 one has large S.
180
GEM
-
Baseline w/ Thick Pole and 2.Om Return
Contours of 4>xed
if
f
B x dalds
Isopleths at 6, 8, 10, and 12 T m 2
10E
5 --
0
5
10
15
Z, m
Integral paths start at Ahlen's p-detector boseline
Figure 297: Isopleths of constant BL 2 superposed on a sketch of the magnet concept.
165
GEM ---
Thin Pole Options:
1
Case 3 with SC return
Contours oF 4ixed if
f
_ x kIds
Isopleths at 6, 8, 10, and 12 T m 2
1
a-
E
I
-
I-I
0
0
5
10
Z,
15
m
Integral paths start at Ahlen's p-detector boseline
Figure 306: Isopleths of constant BC 2 superposed on a sketch of the GEM concept; isopleths
increase with distance from the origin.
170