FINAL CRIA DESIGN
Grounding grid, x= 155 (reference number) (x = axial direction)
Distance between grounding grid and detector: 47mm.
Ring 1:
Ring 2:
Ring 3:
Ring 4:
Ring 5:
Ring 6:
Ring 7:
Ring 8:
Ring 9:
1117.5174
x = 158 to 172
1806.5000
x = 174 to 188
2392.4981
x = 190 to 204
2920.2609
x = 206 to 220
3408.5573
x = 222 to 252
4303.5090
x = 254 to 284
5122.1102
x = 286 to 316
5886.2035
x = 318 to 344 <note: could be 346>>
6252.0000 <<technically does not exist>> x = 349
Plane of annuli at x = 349
Annuli 1:
Annuli 2:
Annuli 3:
Annuli 4:
Annuli 5:
Annuli 6:
5411.1802
r = 0 to 21
5439.5947
r = 23 to 65
5515.3689
r = 67 to 109
5661.1548
r = 111 to 153
5899.3146
r = 155 to 197 <could be up to 198>
6252.0000 <<technically does not exist>> r = 200
Note: The following plots are for an energy distribution of
P(E) ~ Exp[-(E/Eth,1)2 – (E/Eth,2)]; Eth,1= 300eV, Eth,2= 25eV
P(θ) ~ Exp[-θ2/2σ2]
Distributions Taken from [insert reference later] and seemed to match experimental
results for a laser at least somewhat, though it’s likely that the distribution is much worse
than what will actually occur. This matches my theory of optimizing things by ‘worstcast’ scenarios.
Relative Voltage
Relative Voltage vs. Time, for m = 1, impact radius of
120mm
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0.845
0.85
0.855
0.86
0.865
0.87
Time of Flight (usec)
Relative Voltage
Relative Voltage vs. Time, for m = 30, impact radius of
120mm
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
4.64
4.66
4.68
4.7
4.72
Time of Flight (usec)
4.74
4.76
4.78
Relative Voltage
Relative Voltage vs. Time, m = 100, impact radius of
120mm
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
8.45
8.5
8.55
8.6
8.65
8.7
8.75
Time of Flight
Mass Resolution
Mass Resolution vs. Impact Radius, 'worst-case ions' up
to 50eV
200
180
160
140
120
100
80
60
40
20
0
0
50
100
150
200
Impact Radius (mm)
Note: worst case ions P(E) = const, up to 50eV. Isometric angular spread.
The following are Contour plots that show the radius at which an ion hits a detector given
an initial energy and angle for a variety of impact positions.
Note that for impact radii less than 130mm, zero-energy ions WILL NOT HIT a detector
smaller than 10mm in radius. This isn’t a huge problem, because the device is optimized
for impacts between 130 and 170mm of radius.
However, this gives me concerns about a small ion detector.
Ion Detection Radius vs. Initial Ion Energy and Angle, for Im pact
Radius = 90m m
S25
S22
S19
S16
70
30
-10
-50
-90
S13
Initial Ion Angle (-90 =
radially in. 0 = axial.
+90 = radially out)
Ion Energy
(eV)
60-70
50-60
S10
40-50
S7
30-40
S4
20-30
0
10-20
0-10
Ion Detection Radius vs. Initial Ion Energy and
Angle, for Impact Radius = 110mm
50
60-70
Ion Energy
(eV)
50-60
40-50
30-40
20-30
10-20
0-10
-90
-30
0
90
30
Initial Ion Angle (-90 =
radially in. 0 = axial. +90
= radially out)
Ion Detection Radius vs. Initial Ion Energy and Angle,
for Impact Radius = 130mm
50
Ion Energy
(eV)
40-50
30-40
20-30
10-20
0-10
-90
-30
30
0
90
Initial Ion Angle (-90 =
radially in. 0 = axial. +90 =
radially out)
Ion Detection Radius vs. Initial Ion Angle and Energy,
for Impact Radius r = 150mm
50
Initial Ion
Energy
30-40
20-30
10-20
0-10
-90
-30
0
90
30
Initial Ion Angle (-90 =
radially in. 0 = axial. +90 =
radially out)
Ion Detection Radius vs. Initial Ion Energy and Angle,
for Impact Radius = 170mm
50
Ion Energy
(eV)
40-50
30-40
20-30
10-20
0-10
-90
-30
30
0
90
Initial Ion Angle (-90 =
radially in. 0 = axial. +90 =
radially out)
Percentage of Ions Collected
Percentage of Ions Collected vs. Detector
Radius. For y = 120 mm
100
90
80
70
60
50
40
30
20
10
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85
Radius of Ion Detector (mm)
The apparent time resolution does not change (for impact radius = 120mm) for detectors
of radius > 5 mm.
To compare the 1mm vs. the 2mm gap versions.
Comparison of CRIA Voltage Models with 1mm and 2mm
Gaps
400
350
Time Resolution
300
250
1mm Gaps
2mm Gaps
200
150
100
50
0
0
50
100
150
200
Impact Radius
Note: this is not a strict comparison, because I intentionally tried to get better
performance for large impact radii for the 2mm gap design, at the (slight) expense of
smaller impact radii.
FOR 1mm GAPS the design *would be*
Grounding grid, x= 155
Distance between grounding grid and detector: 47mm.
Ring 1:
Ring 2:
Ring 3:
Ring 4:
Ring 5:
Ring 6:
Ring 7:
Ring 8:
Ring 9:
1118.2516
x = 157 to 172
1806.2954
x = 173 to 188
2391.1490
x = 189 to 204
2917.6823
x = 205 to 220
3404.7034
x = 221 to 252
4297.0360
x = 253 to 284
5112.9789
x = 285 to 316
5876.4002
x = 317 to 348
6238.0000 <<technically does not exist>> x = 349
Plane of annuli at x = 349
Annuli 1:
5389.5613
r = 0 to 21
Annuli 2:
5419.0092
r = 22 to 65
Annuli 3:
5496.5850
r = 66 to 109
Annuli 4:
5644.5936
r = 110 to 153
Annuli 5:
5884.5893
r = 156 to 199
Annuli 6:
6252.0000 <<technically does not exist>> r = 200