Difference between revisions of "CH PAS He3 BorAl Attenuation Study"

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Experimental Setup

Attenuation Measurements Setup
Poly box to contain Cf-252 source for attenuation measurements
He3 tube mounting for attenuation measurements
He3 tube mounted on 2" of virgin poly for attenuation measurements
Full poly box with lid pulled back for easy insertion of Cf-252 source
Top down view of Cf-252 source in place, ready to be covered by top sheet of virgin poly
Full setup with 8.5" of purple borated poly in place

The He3 detector is shrouded in BorAl, in a triangular configuration with +1250V to the pre-amp (this voltage is based on previous work by Jeff Burggraf and David Friant).

The thermalizing box is designed as regular poly surrounding the Cf-252 source on all sides except the side in the direction of the He3 tube.

The thermalizer is considered a regular poly sheet that can be slid in and out of the experimental setup.

The detector is ~30cm from the Cf-252 source. This allows for enough distance to insert 8" (20.32cm) of green borated poly, a 1" (2.54cm) thermalizing sheet, and still have the BorAl in the correct position.

No lead was included in the setup as it was not necessary.

The discriminator threshold was not changed during this experiment as it is in the center of the plateau work done by David Friant. See plot below.

Credit: David Friant. This plot is source in and source out He3 tube plateau measurements which were used to base discriminator and bias voltages for attenuation measurements.

Measurements

Background Measurements

I will be performing background runs overnight due to the low amount of background counts. This is necessary to get an acceptable level of uncertainty in the measurements as the count rate looks to be on the order of .5Hz.

The first run background run is taking place the evening of 6/25/21 and will end the following day.

Background run lasted for 60000 seconds and took place overnight. Run ended at approximately 11:45am 6/26/21

1250V Source Out Data
Run Number Configuration Discriminator Threshold (mV) Cf-252 Button Source Counts Run Time (Sec) Count Rate (Hz) Uncertainty
1 Detector surrounded by BorAl at +1250V 255 No 722 60000 0.0120 0.000448

Source In

No borated poly, just BorAl shielding around detector

1250V Source In Data
Run Number Configuration Discriminator Threshold (mV) Cf-252 Source Counts Run Time (Sec) Count Rate (Hz) Uncertainty
1 Detector on BorAl at +1250V 255 Yes 236 300 0.787 0.0512
2 Detector on BorAl at +1250V 255 Yes 263 300 0.877 0.0541
3 Detector on BorAl at +1250V 255 Yes 251 300 0.837 0.0528
4 Detector on BorAl at +1250V 255 Yes 203 300 0.677 0.0475
5 Detector on BorAl at +1250V 255 Yes 218 300 0.727 0.0492

Green Poly

1" Green poly (one sheet)

1250V source in
Run Number Configuration Discriminator Threshold (mV) Cf-252 Source Counts Run Time (Sec) Count Rate (Hz) Uncertainty
1 Detector on poly at +1250V 255 Yes 165 300 0.55 0.0428
2 Detector on poly at +1250V 255 Yes 219 300 0.73 0.0493
3 Detector on poly at +1250V 255 Yes 197 300 0.657 0.0468
4 Detector on poly at +1250V 255 Yes 220 300 0.733 0.0494
5 Detector on poly at +1250V 255 Yes 199 300 0.663 0.0470

2" Green poly (one brick)

1250V source in
Run Number Configuration Discriminator Threshold (mV) Cf-252 Source Counts Run Time (Sec) Count Rate (Hz) Uncertainty
1 Detector on poly at +1250V 255 Yes 154 300 0.513 0.0414
2 Detector on poly at +1250V 255 Yes 163 300 0.543 0.0426
3 Detector on poly at +1250V 255 Yes 150 300 0.5 0.0408
4 Detector on poly at +1250V 255 Yes 125 300 0.417 0.0373
5 Detector on poly at +1250V 255 Yes 154 300 0.513 0.0414

3" Green poly (one brick & sheet)

1250V source in
Run Number Configuration Discriminator Threshold (mV) Cf-252 Source Counts Run Time (Sec) Count Rate (Hz) Uncertainty
1 Detector on poly at +1250V 255 Yes 220 600
2 Detector on poly at +1250V 255 Yes 177 600
3 Detector on poly at +1250V 255 Yes 195 600
4 Detector on poly at +1250V 255 Yes 215 600
5 Detector on poly at +1250V 255 Yes 188 600

4" Green poly (two bricks)

1250V source in
Run Number Configuration Discriminator Threshold (mV) Cf-252 Source Counts Run Time (Sec) Count Rate (Hz) Uncertainty
1 Detector on poly at +1250V 255 Yes 153 600 0.255 0.0412
2 Detector on poly at +1250V 255 Yes 134 600 0.223 0.0386
3 Detector on poly at +1250V 255 Yes 124 600 0.207 0.0371
4 Detector on poly at +1250V 255 Yes 145 600 0.242 0.0401
5 Detector on poly at +1250V 255 Yes 133 600 0.222 0.0384

6" Green poly (three bricks)

1250V source in
Run Number Configuration Discriminator Threshold (mV) Cf-252 Source Counts Run Time (Sec) Count Rate (Hz) Uncertainty
1 Detector on poly at +1250V 255 Yes 115 900 0.128 0.0119
2 Detector on poly at +1250V 255 Yes 137 900 0.152 0.0130
3 Detector on poly at +1250V 255 Yes 149 900 0.166 0.0136
4 Detector on poly at +1250V 255 Yes 151 900 0.168 0.0137
5 Detector on poly at +1250V 255 Yes 116 900 0.129 0.0120

8" Green poly (four bricks)

1250V source in
Run Number Configuration Discriminator Threshold (mV) Cf-252 Source Counts Run Time (Sec) Count Rate (Hz) Uncertainty
1 Detector on poly at +1250V 255 Yes 143 1200 0.119 0.00997
2 Detector on poly at +1250V 255 Yes 133 1200 0.111 0.00961
3 Detector on poly at +1250V 255 Yes 152 1200 0.127 0.0102
4 Detector on poly at +1250V 255 Yes 154 1200 0.128 0.0103
5 Detector on poly at +1250V 255 Yes 149 1200 0.124 0.0102

Regular Poly

1" Regular Poly

1250V source in
Run Number Configuration Discriminator Threshold (mV) Cf-252 Source Counts Run Time (Sec) Count Rate (Hz) Uncertainty
1 Detector on poly at +1250V 255 Yes 247 300 0.823 0.0524
2 Detector on poly at +1250V 255 Yes 189 300 0.63 0.0458
3 Detector on poly at +1250V 255 Yes 218 300 0.727 0.0492
4 Detector on poly at +1250V 255 Yes 220 300 0.733 0.0494
5 Detector on poly at +1250V 255 Yes 243 300 0.81 0.0520

2" Regular Poly (one brick)

1250V source in
Run Number Configuration Discriminator Threshold (mV) Cf-252 Source Counts Run Time (Sec) Count Rate (Hz) Uncertainty
1 Detector on poly at +1250V 255 Yes 192 300 0.64 0.0462
2 Detector on poly at +1250V 255 Yes 158 300 0.527 0.0419
3 Detector on poly at +1250V 255 Yes 189 300 0.63 0.0458
4 Detector on poly at +1250V 255 Yes 174 300 0.58 0.0440
5 Detector on poly at +1250V 255 Yes 177 300 0.59 0.0443

3" Regular Poly (one brick & sheet)

1250V source in
Run Number Configuration Discriminator Threshold (mV) Cf-252 Source Counts Run Time (Sec) Count Rate (Hz) Uncertainty
1 Detector on poly at +1250V 255 Yes 125 300 0.417 0.0373
2 Detector on poly at +1250V 255 Yes 142 300 0.473 0.0397
3 Detector on poly at +1250V 255 Yes 96 300 0.32 0.0327
4 Detector on poly at +1250V 255 Yes 117 300 0.39 0.0361
5 Detector on poly at +1250V 255 Yes 143 300 0.477 0.0399

4" Regular Poly (two bricks)

1250V source in
Run Number Configuration Discriminator Threshold (mV) Cf-252 Source Counts Run Time (Sec) Count Rate (Hz) Uncertainty
1 Detector on poly at +1250V 255 Yes 142 600 0.237 0.0199
2 Detector on poly at +1250V 255 Yes 150 600 0.25 0.0204
3 Detector on poly at +1250V 255 Yes 165 600 0.275 0.0214
4 Detector on poly at +1250V 255 Yes 194 600
5 Detector on poly at +1250V 255 Yes 160 600

6" Regular Poly (three bricks)

1250V source in
Run Number Configuration Discriminator Threshold (mV) Cf-252 Source Counts Run Time (Sec) Count Rate (Hz) Uncertainty
1 Detector on poly at +1250V 255 Yes 131 900
2 Detector on poly at +1250V 255 Yes 139 900
3 Detector on poly at +1250V 255 Yes 129 900
4 Detector on poly at +1250V 255 Yes 140 900
5 Detector on poly at +1250V 255 Yes 145 900

8" Regular Poly (four bricks)

1250V source in
Run Number Configuration Discriminator Threshold (mV) Cf-252 Source Counts Run Time (Sec) Count Rate (Hz) Uncertainty
1 Detector on poly at +1250V 255 Yes 162 1200
2 Detector on poly at +1250V 255 Yes 142 1200
3 Detector on poly at +1250V 255 Yes 183 1200
4 Detector on poly at +1250V 255 Yes 165 1200
5 Detector on poly at +1250V 255 Yes 152 1200

Results

Completed attenuation measurements with differing thicknesses of Borated Poly vs unborated poly with the He3 detector shielded by BorAl.

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CH He3 Attenuation Measurements

PAS Experiment Attenuation Measurements

PAS_He3_Detector

PAS_Experiment