CH He3 Attenuation Measurements

• Build poly box to house source and help thermalize neutron flux

• Get Cf source

• Measure rates in He3 tube with differing amounts of poly (and different types) -> get to background levels
  • Thermalize neutron flux from Cf with virgin poly for all measurements
  • Build virgin poly box around Cf source
    • Pretty quick and dirty measurement to figure out which poly is best

Experimental Setup

Attenuation Measurements Setup
File:PAS Cf-252 Poly Box2.jpg 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

He3 tube is mounted on 2" of virgin poly to put it at rough center of californium source

Cf252 source is enclosed in thermalizing virgin poly box

He3 tube is 8.5" from outside face of thermalizer

Cf252 is mounted approximately .5" behind thermalizing poly plate

Thermalizing poly plate is 1" thick

Will upload pictures and attached comments to each picture

Measurements

Background Measurements

1250V Source Out Data
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	No	32	300	0.107	0.019
2	Detector on poly at +1250V	255	No	44	300	0.147	0.022
3	Detector on poly at +1250V	255	No	55	300	0.183	0.025
4	Detector on poly at +1250V	255	No	34	300	0.113	0.019
5	Detector on poly at +1250V	255	No	20	300	0.067	0.015

Source In

1250V Source In
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	11255	300
2	Detector on poly at +1250V	255	Yes	10996	300
3	Detector on poly at +1250V	255	Yes	10750	300
4	Detector on poly at +1250V	255	Yes	10815	300
5	Detector on poly at +1250V	255	Yes	10696	300

Purple Poly without Thermalizer

For some reason, the purple poly bricks are 1 1/8" thick

1" Purple poly, no thermalizer

1250V source in
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	2816	300	9.39	0.177
2	Detector on poly at +1250V	255	Yes	2809	300	9.36	0.177
3	Detector on poly at +1250V	255	Yes	2774	300	9.25	0.176
4	Detector on poly at +1250V	255	Yes	2790	300	9.30	0.176
5	Detector on poly at +1250V	255	Yes	2875	300	9.58	0.179

2 1/8" Purple poly (one brick) no thermalizer

1250V source in
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	2118	300	7.06	0.153
2	Detector on poly at +1250V	255	Yes	2012	300	6.71	0.150
3	Detector on poly at +1250V	255	Yes	2092	300	6.97	0.152
4	Detector on poly at +1250V	255	Yes	2025	300	6.75	0.150
5	Detector on poly at +1250V	255	Yes	2092	300	6.97	0.152

3 1/8" Purple poly (one brick & sheet) no thermalizer

1250V source in
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	1434	300	4.78	0.126
2	Detector on poly at +1250V	255	Yes	1348	300	4.49	0.122
3	Detector on poly at +1250V	255	Yes	1489	300	4.96	0.129
4	Detector on poly at +1250V	255	Yes	1393	300	4.64	0.124
5	Detector on poly at +1250V	255	Yes	1372	300	4.57	0.124

4 1/4" Purple poly (two bricks) no thermalizer

1250V source in
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	1093	300	3.64	0.110
2	Detector on poly at +1250V	255	Yes	1068	300	3.56	0.109
3	Detector on poly at +1250V	255	Yes	1116	300	3.72	0.111
4	Detector on poly at +1250V	255	Yes	1031	300	3.44	0.107
5	Detector on poly at +1250V	255	Yes	1142	300	3.81	0.113

6 3/8" Purple poly (two bricks) no thermalizer

1250V source in
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	743	300	2.48	0.091
2	Detector on poly at +1250V	255	Yes	694	300	2.31	0.088
3	Detector on poly at +1250V	255	Yes	756	300	2.52	0.092
4	Detector on poly at +1250V	255	Yes	735	300	2.45	0.090
5	Detector on poly at +1250V	255	Yes	745	300	2.48	0.091

8 1/2" Purple poly (two bricks) no thermalizer

1250V source in
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	662	300	2.21	0.086
2	Detector on poly at +1250V	255	Yes	586	300	1.95	0.081
3	Detector on poly at +1250V	255	Yes	613	300	2.04	0.083
4	Detector on poly at +1250V	255	Yes	560	300	1.87	0.079
5	Detector on poly at +1250V	255	Yes	622	300	2.07	0.083

Purple poly with Thermalizer

2 1/8" Purple poly (one brick) with thermalizer

1250V Thermalized source
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes, thermalized	2117	300	7.06	0.153
2	Detector on poly at +1250V	255	Yes, thermalized	1869	300	6.23	0.144
3	Detector on poly at +1250V	255	Yes, thermalized	1836	300	6.12	0.143
4	Detector on poly at +1250V	255	Yes, thermalized	1893	300	6.31	0.145
5	Detector on poly at +1250V	255	Yes, thermalized	1886	300	6.29	0.145

Green Poly without Thermalizer

1" Green poly, no thermalizer

1250V source in
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	2566	300	8.55	0.169
2	Detector on poly at +1250V	255	Yes	2627	300	8.76	0.171
3	Detector on poly at +1250V	255	Yes	2559	300	8.53	0.169
4	Detector on poly at +1250V	255	Yes	2562	300	8.54	0.169
5	Detector on poly at +1250V	255	Yes	2660	300	8.87	0.172

2" Green poly (one brick) no thermalizer

1250V source in
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	2176	300	7.25	0.155
2	Detector on poly at +1250V	255	Yes	2070	300	6.90	0.152
3	Detector on poly at +1250V	255	Yes	2055	300	6.85	0.151
4	Detector on poly at +1250V	255	Yes	2131	300	7.10	0.154
5	Detector on poly at +1250V	255	Yes	1957	300	6.52	0.147

3" Green poly (one brick & sheet) no thermalizer

1250V source in
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	1345	300	4.48	0.122
2	Detector on poly at +1250V	255	Yes	1335	300	4.45	0.122
3	Detector on poly at +1250V	255	Yes	1295	300	4.32	0.120
4	Detector on poly at +1250V	255	Yes	1384	300	4.61	0.124
5	Detector on poly at +1250V	255	Yes	1297	300	4.32	0.120

4" Green poly (two bricks) no thermalizer

1250V source in
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	1056	300	3.52	0.108
2	Detector on poly at +1250V	255	Yes	1085	300	3.62	0.110
3	Detector on poly at +1250V	255	Yes	1151	300	3.84	0.113
4	Detector on poly at +1250V	255	Yes	1064	300	3.55	0.109
5	Detector on poly at +1250V	255	Yes	1059	300	3.53	0.108

6" Green poly (three bricks) no thermalizer

1250V source in
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	728	300	2.43	0.090
2	Detector on poly at +1250V	255	Yes	737	300	2.46	0.090
3	Detector on poly at +1250V	255	Yes	759	300	2.53	0.092
4	Detector on poly at +1250V	255	Yes	717	300	2.39	0.089
5	Detector on poly at +1250V	255	Yes	764	300	2.55	0.092

8" Green poly (four bricks) no thermalizer

1250V source in
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	612	300	2.04	0.082
2	Detector on poly at +1250V	255	Yes	606	300	2.02	0.082
3	Detector on poly at +1250V	255	Yes	582	300	1.94	0.080
4	Detector on poly at +1250V	255	Yes	606	300	2.04	0.082
5	Detector on poly at +1250V	255	Yes	597	300	1.99	0.081

Green Poly with Thermalizer

2 1/8" Green poly (one brick) with thermalizer

1250V Thermalized source
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes, thermalized	1904	300	6.35	0.145
2	Detector on poly at +1250V	255	Yes, thermalized	1829	300	6.10	0.143
3	Detector on poly at +1250V	255	Yes, thermalized	1851	300	6.17	0.143
4	Detector on poly at +1250V	255	Yes, thermalized	1887	300	6.29	0.145
5	Detector on poly at +1250V	255	Yes, thermalized	1914	300	6.38	0.146

Virgin Poly

1" Virgin Poly (one sheet)

1250V Source In
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	12743	300	42.47	0.376
2	Detector on poly at +1250V	255	Yes	13109	300	43.69	0.382
3	Detector on poly at +1250V	255	Yes	13052	300	43.51	0.381
4	Detector on poly at +1250V	255	Yes	13136	300	43.79	0.382
5	Detector on poly at +1250V	255	Yes	13064	300	43.55	0.381

2" Virgin Poly (one brick)

1250V Source In
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	11950	300
2	Detector on poly at +1250V	255	Yes	12088	300
3	Detector on poly at +1250V	255	Yes	12068	300
4	Detector on poly at +1250V	255	Yes	12163	300
5	Detector on poly at +1250V	255	Yes	12183	300

3" Virgin Poly (one sheet & one brick)

1250V Source In
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	9185	300
2	Detector on poly at +1250V	255	Yes	9091	300
3	Detector on poly at +1250V	255	Yes	9040	300
4	Detector on poly at +1250V	255	Yes	9211	300
5	Detector on poly at +1250V	255	Yes	9035	300

4" Virgin Poly (two bricks)

1250V Source In
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	5924	300
2	Detector on poly at +1250V	255	Yes	6232	300
3	Detector on poly at +1250V	255	Yes	6006	300
4	Detector on poly at +1250V	255	Yes	5978	300
5	Detector on poly at +1250V	255	Yes	6222	300

6" Virgin Poly (3 bricks)

1250V Source In
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	2837	300
2	Detector on poly at +1250V	255	Yes	2985	300
3	Detector on poly at +1250V	255	Yes	3019	300
4	Detector on poly at +1250V	255	Yes	2912	300
5	Detector on poly at +1250V	255	Yes	3009	300

8" Virgin Poly (four bricks)

1250V Source In
Run Number	Configuration	Discriminator Threshold (mV)	Cf-252 Button Source	Counts	Run Time (Sec)	Count Rate (Hz)	Uncertainty
1	Detector on poly at +1250V	255	Yes	1974	300
2	Detector on poly at +1250V	255	Yes	2006	300
3	Detector on poly at +1250V	255	Yes	1975	300
4	Detector on poly at +1250V	255	Yes	2069	300
5	Detector on poly at +1250V	255	Yes	1990	300

Results

Posted 6/22/21

Completed attenuation measurements with differing thicknesses of Borated Poly vs unborated poly.

The purple and green poly definitely have some boron concentration in them. The fitted curves are the same within uncertainty, so it should not matter which type of borated poly is used in our experimental setup.

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PAS Experiment Attenuation Measurements

PAS_He3_Detector

PAS_Experiment