.
JLAB-TN-07-024
12 GeV Accelerator Upgrade, 2007 Dipole and Corrector Magnet Design Summary
R. Wines, R. Michaud
Abstract:
The CEBAF beam transport magnets were designed to support 6 GeV operation of the accelerator. Design
studies have been done to determine the changes required to facilitate operation of the five pass machine at 11
GeV and the addition of a sixth-pass for 12 GeV beam delivery to Hall D. Magnetic measurement and FEA
modeling have been used to determine the performance of the accelerator magnets at the required specifications
for 12 GEV. The accelerator dipole magnets are catagorized into regions : Arc, Hall Transport, Spreader and
Recombiner, Extraction, Injection/Reinjection Chicanes, Arc10 and Hall D.
Requirements
Budget limitations of the upgrade project require the approach of reusing as many of the existing magnets in the
accelerator as feasible. Engineering and design time is also minimized by use of existing designs and design
principles for fabrication of new magnets. The beam transport magnets are to facilitate operation of the
machine from 12 GeV settings down to 50% of this range. To reuse the power supply and control scenario the
spreader and recombiner magnets will be powered by the Arc magnet power supplies, with their current settings
within the use of 20A shunts. The upgrade to 12 GeV will require using existing magnets at 4x the power, thus
hotter temperatures. For engineering purposes the temperature limit of dT < 40C has been set for magnets with
water cooled conductors. This limit was determined from temperature and life cycle studies conducted on
existing magnets. At the time of required evaluation of the upgrade magnets only the field quality specification
for Arc 10 had been defined. Since this is the region with the largest beam, this specification was applied to all
other regions as a conservative approach. The field quality aperture limits are defined by the size of the
upstream/downstream quadrupole magnet apertures. The Arc 10 field quality specification is defined by
evaluation of dB’L/BL along the curved beam trajectory with limits as defined in Figure 1.
12 GeV Dipole Specification
0.300%
0.200%
d (B'L)/BL
0.100%
0.000%
-0.100%
-0.200%
-0.300%
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
X (cm ) x=0 center of beam trajectory
Figure 1. Arc 10 Dipole Field Quality Specification
Arc Dipoles
The existing Arcs consist of four lines of magnets in the West and 5 lines in the East. This sums to 256
dipole magnets. The existing Arc dipole magnets use the same core cross-section and conductor size in their
design, except for the BR magnet. All Arc dipoles utilize a 40 turn count coil with the magnets varying only in
length. The Arcs are comprised of 1, 2 and 3 meter dipoles.
Evaluation of the existing dipoles was done by modeling the dipoles with the Vector Fields 2d and 3d FEA
software. These results were then verified through measurement of prototype dipoles. The analysis results in the
capability of reusing all the Arc dipole magnets with some modification. Arcs 3 through 9 will require the
addition of return leg H-steel (Figure 2.) to reduce affects of saturation and allowing operation at scalable
currents as exemplified in Figure 3.
Current
Bbase
AmpFac
AmpFac
base
w/H
B w/H
(A)
Gauss
Gauss
%
%
100
1969.70
1973.90
0.038
0.002
200
3936.80
3947.60
0.104
0.002
300
5890.70
5919.20
0.350
0.002
400
7713.20
7885.20
2.186
0.01
500
8879.20
9833.20
10.958
0.193
600
9711.70
11666.00
21.736
1.343
Figure 2. Prototype with H-steel
Figure 3. Measured reduction in
Saturation affects with H-steel
Other modifications to the existing magnets resulted from inspection of the present condition of the magnet
fabrication materials and the results of a life cycle test. These modifications are shown in Figure 4.
Material
Issue
Solution
Hoses
beyond manufacturer's recommended use replace as part of CEBAF maintenance
Support Wedges
become loose and coil allowed to move
flexibility decreases with extended use at
elevated temperature, may result in crack
Epoxy
Leads
modify center wedge to lock in place
Low Risk, Reviewed 11/06, new magnets
will have modified epoxy formulation
silver polish degraded
need stored energy device to prevent
Belleville washers loosening of connections
Silver polish leads during rebuild
Mylar tape
check and replace as needed
loose in spots
washers added during rebuild
Urethane spacers failed at elevated temperatures
replace during rebuild with EPDM
Klixons
replace during rebuild as needed
operating at higher temperatures
Figure 4. Modifications to Existing Dipoles for Upgrade
The design and operating parameters for the upgrade of the Arc dipoles are summarize in Figure 5.
ARC Magnet
L
#/Arc
(m)
1A
2A
3A
4A
5A
6A
7A
8A
9A
BE
BR
BEH
BBH
BBH
BBH
BAH
BAH
BAH
1
2
1
2
2
2
3
3
3
16
16
32
32
32
32
32
32
32
BdL
BdL
Nominal
TOSCA AmpFac Current
VOLTAGE Resistance
#
cooling
Power circuits
kG-cm
kG-cm
%
(A)
(V)
(ohm)
(kW)
794.5
1508.4
1111.1
1468.1
1825.0
2182.0
2538.9
2895.9
3252.8
799.0
1512.6
1122.1
1471.1
1822.7
2182.6
2532.4
2899.9
3256.4
2.8%
5.4%
0.7%
1.0%
1.0%
1.0%
0.7%
1.0%
1.3%
411
405
570
368
457
552
432
495
560
16.3
26.4
23.4
21.5
27.4
31.9
37.4
43.3
49.7
0.04
0.065
0.041
0.058
0.06
0.058
0.087
0.088
0.089
6.70
10.69
13.34
7.91
12.52
17.61
16.16
21.45
27.83
Figure 5. Arc Dipole Upgrade Parameters
dT
o
2
2
2
2
2
4
4
4
4
Water Water
Flow Velocity
( C)
(GPM)
(ft/sec)
16.9
34.1
33.6
24
38
18.9
17.7
23.7
31.2
1.5
1.2
1.5
1.2
1.2
3.5
2.9
2.9
2.9
6.6
5.2
6.6
5.5
5.5
7.7
6.3
6.3
6.3
The field quality specification defined for Arc 10 dipoles was applied to all Arc dipoles and evaluated through
the use of the 3d simulations. With the limits of the quadrupole aperture applied, the Arc dipoles meet the
requirements of this specification.
ARC1 BE 427A
0.300%
0.300%
spec
0.300%
0.200%
0.100%
dB'L/BL
dB'L/BL
0.000%
0.000%
-0.100%
-0.100%
-0.200%
-0.200%
-0.200%
-0.300%
-2.5
-0.300%
-1
-0.5
0
0.5
1
1.5
2
-2.5
2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
-0.300%
-2.5
2.5
0.000%
-0.100%
-0.200%
-0.200%
-0.200%
-0.300%
-0.300%
1.5
2
-2
-1.5
-1
-0.5
ARC7 BAH 434A
0
0.5
1
1.5
2
2.5
-2.5
0.000%
0.000%
-0.100%
-0.200%
-0.200%
-0.200%
-0.300%
-0.300%
2.5
-0.300%
-2.5
-2
-1.5
-1
-0.5
X (cm)
0
0.5
1
1.5
2
-2.5
2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
X (cm)
X (cm)
Figure 6. Field quality specification evaluated for Arcs 1 through 9
A sample evaluation of the field quality specification for an Arc 5 dipole at 50% activation for the upgrade
requirement is shown in Figure 7.
ARC5 BBH 182A
0.300%
spec
0.200%
0.0cm
dB'L/BL
0.100%
0.000%
-0.100%
-0.200%
-0.300%
-2.5
-2
-1.5
2.5
0.0cm
-0.100%
2
2
0.100%
dB'L/BL
dB'L/BL
0.000%
1.5
1.5
spec
-0.100%
1
1
0.200%
0.100%
0.5
0.5
0.0cm
0.100%
0
0
spec
0.200%
-0.5
-0.5
ARC9 BAH 560A
0.0cm
-1
-1
0.300%
spec
-1.5
-1.5
ARC8 BAH 495A
0.200%
-2
-2
X (cm)
0.300%
-2.5
0.0cm
X (cm )
X (cm )
0.300%
2.5
-0.300%
-2.5
2.5
2
0.000%
-0.100%
1
1.5
0.100%
dB'L/BL
dB'L/BL
0.000%
0.5
1
spec
-0.100%
0
0.5
0.200%
0.0cm
0.100%
-0.5
0
ARC6 BBH 563A
0.200%
0.100%
-1
-0.5
spec
0.0cm
-1.5
-1
0.300%
spec
0.200%
-2
-1.5
X (cm )
0.300%
-2.5
-2
ARC5 BBH 468A
ARC4 BBH 376A
0.300%
dB'L/BL
2
X (cm)
X (cm )
dB'L/BL
0.000%
-0.100%
-1.5
0.0cm
0.200%
0.0cm
0.100%
0.100%
-2
spec
spec
0.0cm
0.200%
dB'L/BL
ARC3 BEH 582A
ARC2 BR 407A
-1
-0.5
0
0.5
1
1.5
2
2.5
X (cm )
Figure 7. Field quality specification for Arc 5 dipole at half field
2.5
Hall Transport Dipoles
The transport lines to Experimental Halls A, B and C require the use of 24 Arc style dipoles and an
additional 2 BN dipoles. The Arc style dipoles again use the same core cross-section and conductor size. With
the addition of H-steel these magnets will meet the requirements of the upgrade and be reused. Preliminary
analysis indicates the BN magnets will have to be replaced with a new dipole design. Figure 8 summarizes the
upgrade parameters of the transport line dipoles. Since Hall A through C can take any pass beam these dipoles
have to operate from 1 to 11 GeV.
Line Magnet
L
#/Arc
(m)
BAH
BAH
BEH
(kG-cm) (kG-cm)
3
3
1
8
8
8
(%)
(A)
VOLTAGE Resistance
(V)
(ohm)
#
Power cooling
(kW)
2752.0 2758.2 1.0% 469
40.8 0.087 19.1
2752.0 2758.2 1.0% 469
40.8 0.087 19.1
1133.0 1137.0 1.0% 578
23.8 0.041 13.8
Figure 8. Transport Line Dipole Upgrade Parameters
Water Water
Flow Velocity
dT
o
circuits
( C)
(GPM)
(ft/sec)
4
4
2
21.1
21.1
34.6
2.9
2.9
1.5
6.3
6.3
6.6
The Arc 10 field quality specification was evaluated for the simulation of the transport line dipoles with passing
results.
Hall B BEH 594A
Hall A& C BAH 469A
0.300%
0.300%
spec
spec
0.200%
0.0cm
0.200%
0.0cm
0.100%
0.100%
dB'L/BL
B'L/BL
A
C
B
BdL
TOSCA AmpFac Current
BdL
0.000%
0.000%
-0.100%
-0.100%
-0.200%
-0.200%
-0.300%
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
X (cm )
Figure 9. Hall A & C dipole specification results
-0.300%
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
X (cm )
Figure 10. Hall B dipole specification results
Synchrotron Radiation Compensation Coils
Energy loss is found to occur in the simulation of the higher energy Arcs and Hall Transport Lines due to
synchrotron radiation. To keep the beam on magnetic center of the magnet through these regions compensation
coils are required to trim the field. The conceptual design consists of two 8 turn, #14 AWG wire, coils wound
around the poles of each dipole in Arcs 8, 9 , 10 and the transport lines. The turns of the coils will be energized
such that the magnitude of the field is increased or decreased as needed to center the beam through the
trajectory of the magnets. All compensation coils in each Arc will be powered in series to give an adjustment
“knob” for each Arc.
Spreader and Recombiner Dipoles
The Spreader and Recombiner magnets carry the beam to and from the Linac regions. These 4 regions
are dominated by space restrictions resulting in the use of primarily 1 meter C-style dipoles. The existing 1
meter dipoles utilize 2 core designs; a 4” pole width and a 5” pole width. Their coils are configured from the use
of 2 coil designs; an 8 turn count and a 10 turn count. Various modifications to the existing 1 meter dipoles
were simulated and tested to achieve the upgrade requirements. The 1 meter dipoles will be modified by adding
H-steel, changing the turn count to match power supply requirements and adding shims to the pole ends to
achieve the field quality specifications. The Spreader and Recombiner dipole magnets are powered by the Arc
string power supplies. Shunts are used to reduce the Arc current settings to the corresponding pass Prototype
testing results of these modifications is compared with the Arc 10 field quality specification in Figure 11.
Unshimmed
AIH prototype end shim
Single shim
Symmetric shims
0.25%
spec
0.20%
spec
d(B'L/BL) (1/cm)
0.15%
0.10%
0.05%
0.00%
-0.05%
-0.10%
-0.15%
-0.20%
-0.25%
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
Transverse position (cm)
Figure 11. 1 meter prototype field quality comparison with modifications
The 1 meter dipoles for the upgrade requirements are summarized in Figure 12. The turn counts have been
changed such that no new coils will need to be purchased with the use of existing spare coils.
Magnet
Location
AI
AA
AC
AC
AG
AI
AF
AB
AE
1S
3S
5S
7S
9S
2S
4S
6S
8S
BdL
(kG-cm)
1312
1060
894
707
984
1272
1244
1332
1241
Arc Current
(A)
411
570
457
432
560
405
368
552
495
Shunt
(A)
3
2
2
2
5
6
2
15
2
Voltage
(V)
29.9
23.9
18.5
15.5
23.2
29.4
29.1
30.7
28
# Cooling
Circuits
4
2
2
2
2
4
2
3
3
dT
(deg C)
15
34.6
21.6
16.2
33.1
14.5
37.7
27.1
22.7
Water
Flow
(GPM)
3.1
1.5
1.5
1.6
1.5
3.1
1.1
2.3
2.3
Figure 12. 1 meter Spreader and Recombiner upgrade parameters
Water
Velocity
(ft/sec)
6.8
6.5
6.5
6.9
6.5
6.8
4.7
6.7
6.8
TURNS
72
40
40
36
40
72
76
56
56
The entrance/exit to the Spreader and Recombiner regions utilizes 2 H-style magnets, referred to as
BCOM magnets. Simulation of these dipoles indicates only the trapezoid dipole in these regions will need to be
modified for the upgrade. The 2d analysis resulted in the addition of 6” of steel to the return leg of the trapezoid
magnet to reduce the affects of saturation from the upgrade requirements as shown in Figure 13. The field
uniformity is shown to be within 10-4 range over 12 cm which encompasses the affected trajectories.
AX w ith 6" ad d ed
0.00E+ 00
dB /B
-2.00E-05
-4.00E-05
m id
-6.00E-05
-8.00E-05
-1.00E-04
40
42
44
46
48
50
52
54
56
58
60
X position across pole (cm)
Figure 13. BCOM dipole layout with 6” steel addition and field uniformity
The 3d simulation results for the rectangular BCOMS using the most stringent beam trajectory requirements are
shown in Figures 14 and 15 as compared to the Arc 10 field quality specification.
AWH 405A
10.801 Bend Angle
Line 2
AQH 411A
18.578 Bend Angle
Line 1
0.3%
0.3%
spec
0.2%
spec
0.2%
0.0cm
B'L/BL
B'L/BL
0.0cm
0.1%
0.1%
0.0%
0.0%
-0.1%
-0.1%
-0.2%
-0.2%
-0.3%
-0.3%
-2
-1.5
-1
-0.5
0
0.5
1
1.5
-2
2
-1.5
-1
-0.5
Figure 14. AQ field quality specification
(rectangular BCOM)
AQ
AS
AW
AX
1S
3S
2S
4S
0.5
1
1.5
2
Figure 15. AW field quality specification
(rectangular BCOM)
The upgrade parameters of the BCOM magnets are summarized in Figure 16.
Magnet location
0
R (cm)
R (cm)
#
cooling
VOLTAGE circuits
BdL
Arc
Current
Shunt
kG-cm
(A)
(A)
(V)
1312.0
1207.0
1448.0
1193.0
411
570
405
368
4
4
1
1
38.8
64.1
49.4
53.6
Water
Flow
Water
Velocity
( C)
(GPM)
(ft/sec)
22.0
38.2
30.7
36.5
2.8
3.6
2.4
2.0
6.0
6.3
5.3
4.4
dT
o
4
5
4
4
Figure 16. BCOM dipole upgrade parameters
The Spreader and Recombiner Septa magnet parameters are summarized in Figure 17. The 2d
simulations indicate 3 of 2 meter Septas can be reused with modification. The 2 meter septas will need new
coils to accommodate beam clearance through these magnets. A new 3 meter septa design will be used in all
other required locations. The new design utilizes the existing 2 meter design with the addition of a wider pole.
Figure 18 depicts the field uniformity of the 3 meter septa.
Magnet
YR7S,YR7R
YR9S,YR9R
YRBS
YR8S,YR8R
YRAS,YRAR
L
(meter)
3
2
2
3
3
BdL
(kG-cm)
2483
984
1127
2625
2625
Current
(A)
746
432
495
789
789
Voltage
(V)
79
32
37
84
84
# cooling
circuits
dT
24
24
24
24
24
35
12.7
16.8
39
39
Water
Flow
(GPM)
6.6
4.2
4.2
6.6
6.6
Water
Velocity
(ft/sec)
11.6
7.5
7.5
11.6
11.6
Figure 17. Septa magnet upgrade parameters
Figure 18. Field uniformity of the 3 meter septa
Due to space limitations the Spreader and Recombiner regions require the use of curved dipoles in some
portions of the beam transport. The curved dipoles are configured with the coils wound around the return leg of
the core rather than the pole. Analysis results indicate these magnets cannot be modified for reuse in the
upgrade. The design of the new curved dipoles is based on adding 1” of steel to the core of the existing design,
widening the pole by ½”, changing the curvature to match the beam path and changing the turn count of the
coils. Figures 19 and 20 show the 2d simulation results to be within 10-4 range over 3 cm for these
modifications.
AU modified at549A
0.00E+00
dB/B
-1.00E-04
-2.00E-04
-3.00E-04
-4.00E-04
-5.00E-04
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
X position along pole (cm)
Figure 19. AU modified
Figure 20. Field uniformity for AU modified
The upgrade parameters for the curved dipoles is summarized in Figure 21.
Magnet
location
AM
AN
AV
AU
3S
5S
4S
6S
BdL
(kG-cm)
2499
2487
2635
2628
Current
(A)
570
457
368
552
Shunt
Voltage
(A)
(V)
10
42
5
42.2
1
45
3
47.2
# cooling
circuits
Water
Water
Flow
Velocity
(GPM)
(ft/sec)
3.1
6.8
2.8
6.1
2.4
5.3
2.9
6.4
dT
4
4
4
4
28.7
26
25.8
33.7
Turns
48
60
76
52
Figure 21. Upgrade parameters of the curved dipoles
The 5th pass line to Arc 10 and the line to Hall D require additional 2 meter magnets (XH, XK) not
present in the current machine. The design of these dipoles uses the same conductor and turn count coils as the
existing Arc magnets. The core is similar to the Arc BR magnet with a 5.125” pole width. The 3d analysis gives
the field quality specification results as shown in Figure 22 and 23 compared to the Arc 10 dipole specification.
XK at 550A
XH at 480A
0.300%
0.3%
spec
spec
0.2%
0.200%
0.0cm
0.0cm
0.100%
d(B'L)/BL
d(B'L)/BL
0.1%
0.0%
-0.1%
-0.200%
-0.2%
-0.300%
-0.3%
-2.5
0.000%
-0.100%
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
transverse position (cm)
transverse position (cm)
Figure 22. XH 2meter field quality specification
Figure 23. XK 2 meter field quality specification
The XH and XK 2 meter magnets use the same core cross-section and conductor differing only in total turn
count. The parameters of the new 2 meters are summarized in Figure 24.
Magnet
XH
XK
location
BdL
Current
(kG-cm)
(A)
AS,AR,AT
2624
495
BS
2111
560
# cooling
Shunt
Voltage circuits
(A)
(V)
15
41.2
6
10
31.8
4
Water
Water
dT
Flow
Velocity
(GPM)
(ft/sec)
14.2
5.3
7.7
18.8
3.5
7.7
Figure 24. New 2 meter XH and XK upgrade parameters.
Turns
60
40
2.5
The 1st pass of these regions utilizes a 1 meter dipole with the coils configured around the return leg of
the core. Simulation shows this magnet design will meet the requirements of the upgrade by lengthening it to a
1.5 meter magnet, referenced as the XL. The 2d analysis shows the field uniformity to be within 10 -4 over 5 cm
for the geometry of this magnet as shown in Figure 25.
1.5 meter AL at 385A
0.00E+00
dB/B
-5.00E-05
-1.00E-04
-1.50E-04
-2.00E-04
-2.50E-04
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
X position along pole (cm)
Figure 25. XL 1.5 meter cross-section and field uniformity
Figure 26 summarizes the upgrade parameters for the 1.5 meter XL dipole.
Magnet
XL
location
2S
BdL
1448
Current
405
# cooling
Shunt
Voltage
circuits
20
33.2
4
dT
16.9
Water
Water
Flow
Velocity
2.9
6.3
Turns
60
Figure 26. XL dipole upgrade parameters
Extraction Dipoles
The upgrade of the Extraction region will reuse existing magnets. Additional BP and YA magnets will
be added to the lines to meet the upgrade requirements. Two meter YR magnets will be relocated from other
regions of the machine to be reused in the Extraction upgrade. The upgrade Extraction region configuration is
shown in Figure 27.
Figure 27. Upgrade Extraction region configuration
The 1st and 2nd passes are unchanged from the existing machine. The operating parameters of the extraction
magnets are within the tested limits of the existing magnets, except for the 5th pass BP. Simulation of the BP
indicates the field integral can be achieved with this higher current. Energy requirements of the Extraction
region are summarized in Figure 28.
Pass
1
2
3
4
5
Proposed Element
MYA2T01
MYB2T02
MBP2T03
MBQ2T04
MYA4T01
MYB4T02
MBP4T03
MBQ4T04
MYA6T01 & MYA6T01A
MYR6T02
MBP6T03 & MBP6T03A
MBP6T04
MYA8T01 & MYA8T01A
MYR8T02
MBP8T03 & MBP8T03A
MBP8T04
MYAAT01 & MYAAT01A
MYRAT02
MBPAT03 & MBPAT03A
MBPAT04
Energy (MeV)
2281.21
2281.21
2281.21
2281.21
4440.94
4440.94
4440.94
4440.94
6600.67
6600.67
6600.67
6600.67
8760.40
8760.40
8760.40
8760.40
10920.13
10920.13
10920.13
10920.13
BdL (kG-cm)
-10.120
-257.115
564.272
-284.888
-19.702
-500.507
1098.463
-554.591
-14.642
-743.319
816.211
-824.284
-19.432
-986.531
1083.273
-1093.989
-24.223
-1229.744
1350.336
-1363.693
Required Current Max Current Upgrade
(Amps)
Tested
dT degC
20.1
60
219
475
221
475
223
475
39.1
60
427
475
429
475
433
475
29.1 & 29.1
60
324
640
319 & 319
475
322
475
38.6 & 38.6
60
439
640
423 & 423
475
427
475
48.1 & 48.1
60
547
640
528
475
30.2
533
475
30.9
Figure 28. Extraction region upgrade requirements
The Extraction region requires a 3 channel septa magnet for extraction of beam to the 3 experimental halls.
The 3 channel septa, Lambertson, bends 2 beams with the center beam unaffected. Thermal analysis results in
the recommendation of replacing the existing coils in this magnet with a new 24 turn/coil to lower the dT below
40C. The additional turns will require the core to be machined out. The magnetic performance of B = 4.9 kG
has been verified by 2d simulations.
Injection and Reinjection Chicane Dipoles
The Injection/Reinjection region consists of chicane and mini-chicane regions. The upgrade of the
chicane will reuse the existing 3 BL magnets plus a new fourth one. Figure 29. compares the parameters of the
existing to the upgrade BL magnet requirements.
Existing MBL(max)
Upgrade MBL
Length
30.5 cm
30.5 cm
Turns (10AWG)
330
330
BdL
36.62 kG-cm
39.399 kG-cm
Current
10 A
12.9 A (20A supply)
Voltage
22V
29V
Power
220W
374W
Coil dT
6C
10 C
Current Density
1.33 A/mm 2
1.71 A/mm2
•Solution: use existing MBLs with 20 A trim cards
Figure 29. BL magnet comparison
•Replace MDK with MBL, higher energy will be sufficient for synchrotron radiation
Themonitoring
upgrade mini-chicane requirements are achieved by replacing the existing magnets with 3 new CB
magnets and
use the
Chicane
BL
magnet,
as shown
in Figure 30. The CB magnet design is based on
•MBL
designed
with
indirect
water
cooling
lengthening the existing BK magnet design and using a 20A supply with a dT in the coil of 8C. The mini•Currentsare
verified
by 2D TOSCA
modelling
chicane parameters
summarized
in Figure
31.
Figure 30. Mini-Chicane Upgrade layout
Magnet
MBD2R07
MBK2R09
MBK2R10
MBL0R04
Length
(cm)
16.2
15.2
15.2
30.5
Current
(A)
10
10
10
10
BdL
BdL needed 12 GeV Magnet Current
(kG-cm) (kG-cm)
(A)
18.456
39.399
CB
14.6
17.85
39.399
CB
14.6
17.85
39.399
CB
14.6
36.62
39.399
BL
12.9
Current Density
(A/mm2)
2.73
2.73
2.73
1.71
Length
(cm)
30
30
30
30.5
Turns
152
152
152
330
Figure 31. Mini-Chicane magnet parameter comparison
Arc 10 and Hall D Dipoles
The addition of Arc 10 requires 32 new 4 meter dipoles. Simulation results achieve the specification
requirements of field integral of 3600 kG-cm with a H-style dipole, as depicted in Figure 32. The coil is
configured as four 10 turn pancakes operating at 460A and a dT of 38C. The transport line to Hall D utilizes
two more of this design to bend the beam up to Hall D. Figure 33 shows the field quality specification of the 4
meter dipole.
Curved Integral H-ARC10 @ 460 amps
0.30%
B'L/BL (1/cm)
0.20%
0.10%
Integral
0.00%
Specification
-0.10%
-0.20%
-0.30%
-3 -2.5 -2 -1.5 -1 -0.5 0
0.5
1
1.5
2
2.5
3
Position (cm)
Figure 32. 4 meter dipole simulation
Figure. 33 4 meter dipole field quality
Correctors
Given the upgrade field integral and location requirements for corrector magnets, existing corrector
capabilities is evaluated. Figure 34 and 35 summarize the upgrade requirements and existing corrector designs.
Family
Existing Max
Currents
12 GeV Max
Current
Max BdL
Issues
MAT
3.0 amps (poly)
4.0 amps (poly)
7.0 amps (aluminum)
1000 G-cm (poly)
1686 G-cm (aluminum)
MAT8S10H upgraded to
aluminu m holder, and wire
mesh cover added for
safety.
MBT
3.5 amps
8.5 amps
5500 G-cm
MBT1S08V will use shunts
to correct
MBC
3.5 amps
8.5 amps
22000 G-cm
Limited to 16000 G-cm.
Water cool MBC’s going to
22000 G-cm. 4T09DV
compensated using AV
dipole
MBM
3.0 amps
7.0 amps
16175 G-cm
MBD
9.5 amps
9.5 amps
18500 G-cm
Issues at 6T09V, 8T07V,
and 8T09V.
Figure 34. Corrector upgrade parameters.
From the evaluation three complications exist with the corrector solution in the transport recombiner
region; MBD 6T09V, 8T07V and 8T09V. The 6T09V solution is to replace the BD magnet with a new CB
magnet as used in the mini-chicane. The 8T07V solution is to add a 2nd BD magnet in series. The 8T09V
solution is to replace the BD with a new CB magnet.
The upgrade requires the addition of 4 girders in the Injection region and 5 new girders in each of the
North and South Linacs. 19 new FEL style horizontal and vertical correctors will be used in these region.
Arc 10 and Hall D will utilize 136 new BD correctors to meet the requirements of the upgrade.
Summary
Figure 35. summarizes the modifications and requirements for new dipole magnets to meet the
specifications of the 12 GeV upgrade.
New Magnets
Magnet and Location
1
2
3
4
5
6
7
8
9
10
11
12
XK
XH
XL
XU
XV
XM
XN
4 meter
3 meter Septa
CB
YA septa
BP dipole
BS06
AR, AS, AT
2S,2R,2T
6S,6R,6T
4S,4R,4T
3S,3R
5S,5R
Arc10,Hall D
S/R
Chicane
Extraction
Extraction
Modified Magnets
13 1 meter dipoles
S/R
14 2 meter YR septa
BS05
15 Lambertson
Extraction
16 1meter dipoles
Arcs, Line B
17 2 meter dipoles
Arcs
18 3 meter dipoles
Arcs,Line A & C
Total Needed
Description
1
3
3
3
3
2
2
37
8
3
2
7
2 meter dipole, existing coil design
2 meter dipole, existing coil design, same core as XK, replaces 2 magnets
existing design lengthened
curved dipole
curved dipole
curved dipole
curved dipole
H-style dipole
extend existing septa design
existing design lengthened
existing design
existing design
45
1
1
40
96
112
add H-steel, change turn count, add end shim, rebuild
new coils, modify core
new coils, modify core
add H-steel, rebuild
add H-steel, rebuild
add H-steel, rebuild
Figure 35. Summary of new and modified dipole upgrade magnet
References
1. Leigh Harwood and Ken Baggett, Analysis of field quality specification and magnet measurement data
spreadsheet data.
2. Mike Spata, Scope of Extraction region for 12GeV upgrade.
3. 2006 and 2007 Beam Transport 12GeV Upgrade design reviews of each region, powerpoint
presentations.