He3Tube Equipment

2nCor_44#Equipment

Analog Signals

He3 Tube neutron detectors are 52 cm long and 1.5 cm radius cylinders, 1200 Volts with EG&G (ortec) pre amp Model 142PC (Serial #787)

Although 1200 Volts is applied to the Ortec Preamp, only 350 Volts is established on the "input" port where the Tube is plugged in. If 1250 Volts is applied, then 366 Volts is observed.

For the TENNELEC you need to apply 1650 Volts to get 362 applied to the Tube

The TENNELEC signal output at 1550 Volts has less noise with signal at about 30 mV compared to the output of the ortec. There is a230 mV DC offset on the output

Output measured by CAEN V785N Peaks sensing ADC

Using a Cf-252 source positions on a shelf below the He-3 tube covered by 2" thick virgin Poly and set to 1250 Volts. Using Ortec pre-amp 142PC serial # 787.

The Timing output of the preamp was sent to an Ortec Timing filter amplifier to be inverted. The Gain was set to x10 and the integrate set to 20 ns.

The Energy output was sent to an Ortec Spectroscopy amplifier model 672. The gain was set to x10 and the shaping time set to 2usec.

Run 6245 has a Cf-252 source place on a shelf approximately 80 cm below the He-3 tube that had been encased in 2" thick virgin poly.

Run 6246 recorded the background observed without the source over a 19 hour period.

The expectation from File:GE ReuterStokes.pdf is

Performed another measurement of the He-3 tube using the Cf-252 source. I used the bipolar output of the ORTEC spec AMP model 672. The He-3 tube is surrounded by a 2" thick layer of virgin poly. The virgin poly is then encased in a 2" layer of lead. The Cf-252 source was placed directly on top of the lead. Below is a measurement recorded in run #6295 taken over a 7 minute period Run #6596 was taken over a three day period.

If I normalize the rate per cm^2 of detector (project the cylinder to a 52 cm x 3 cm rectangle = 156 cm^2)

Cosmic rays produce 10^{3}/cm^2/sec

PAA->Draw("PADC785N[3]>>r6296N(500,0,1000)",".00000002473");

PAA->Draw("PADC785N[3]>>r6295N(500,0,1000)",".000015263");

Beam Tests

5/16/17: 44 MeV machine was being tuned at 2 MeV so I used the nCorHe3 configuration to look at the He-3 output when there shouldn't be neutrons in the Hall.

Run 6297: Timing AMp =2 Postamp to PADC set to gain of 10

Run 6298: Timing AMp=2 Postamp to PADC set to gain of 50

Run 6299: Timing AMp=adjusting during run Postamp to PADC set to gain of 50

Run 6300: Timing AMp=8 Postamp to PADC set to gain of 50

A CFD threshold of -181 mV will keep the He-3 tube timing amp from firing when the 44 MeV machine is running. The Cf-252 source rate was 200 +/- 40 Hz at this CFD setting.

For ADC do

FF->Draw("PADC.PADC785N[3]>>(500,0,1000)");

For TDC (Window is 1500 nsec wide)

FF->Draw("(TDC.TDC1190[1][28]-TDC.TDC1190[1][31])*0.1")

Check Timing with FF->Draw("(TDC.TDC1190[2][31]-TDC.TDC1190[1][31])*0.1")

The above should be about 200 ns

Run 6301, ran in PAA configuration with Cf 252 source on top of detector

PAA->Draw("PADC.PADC785N[3]>>r6301(2000,0,2000)")

5/23/17

32 MeV Beam 50 mA current

The He-3 tube is plugged into a scaler that counts all pulses (not just the ones during the beam gate).

Run#	Configuration
6310	710 +/- 20 Hz neutron rate during first 15 minutes, then 870 +/- 20 Hz neutron rate during second 15 minutes, UV broadband pass filter
6311	840 +/- 20 Hz neutron rate during first 15 minutes, then Hz neutron rate during second 15 minutes, 390 nm Filter
6313	390 nm Filter, HV = 1800 ( the HV has changed from run 6311)
6314	320 nm Filter
6315	320 + 330 nm Filter

the He-3 rate definitely increases during the irradiation (probably due to Hall Activity increasing)

5/24/17

32 MeV Beam 150 mA current 100 ns wide beam no beam stop, 4 mm thick (12 g) Yttrium in.

The He-3 tube is plugged into a scaler that counts all pulses (not just the ones during the beam gate).

2.54 mm Tungsten radiator

Run#	Configuration
6318	390 nm Pass filter, two peaks due to change in current, radiator in
6319	320 nm Pass filter, radiator in, ADC channel 500
6320	390 nm Pass filter, signal at ADC channel 500, radiator in
6321	390 nm Pass filter, signal at ADC channel 500, radiator OUT,
6322	320 nm Pass filter, signal at ADC channel 500, radiator OUT, peak at ADC chan 3200 like 390 nm filter
6323	"cold air humidifier ON', 320 nm Pass filter, signal at ADC channel 500, radiator OUT, peak at ADC chan 3200 like 390 nm filter,
6324	cold air humidifier OFF, 320 nm Pass filter, signal at ADC channel 500, radiator OUT,
6325	cold air humidifier ON, 320 nm Pass filter, signal at ADC channel 500, radiator OUT, beam current 150 mV in 1 Meg Ohm
6326	cold air humidifier OFF, 320 nm Pass filter, signal at ADC channel 500, radiator OUT, beam current 150 mV in 1 Meg Ohm,

the He-3 rate definitely increases during the irradiation (probably due to Hall Activity increasing)

5/25/17

32 MeV Beam 150 mA current 100 ns wide beam no beam stop

The He-3 tube is plugged into a scaler that counts all pulses (not just the ones during the beam gate).

Run#	Configuration
6346	320 nm Pass filter
6347	320 nm Pass filter, changed pulse width between 100 and 800 ns
6348	320 nm Pass filter, change amplitude
6353	320 nm Pass filter plus UV filter PMT small aperture in the hole, change beam current from 100 to 200 to check normalization
6354	320 nm Pass filter, plus UV filter PMT small aperture in the hole
6355	320 & 330 nm Pass filter, plus UV filter PMT small aperature in the hole
6356	390 nm Pass filter, plus UV filter PMT small aperture in the hole,
6357	390 nm Pass filter, plus UV filter PMT small aperture in the hole, No change
6358	390+320 nm Pass filter, plus UV filter PMT small aperture in the hole,
6359	390 nm Pass filter, plus UV filter PMT small aperture in the hole, Reproducibility check
6360	390 nm Pass filter, plus UV filter PMT small aperture in the hole, increase current from 150 to 200 mA
6361	390 nm Pass filter, plus UV filter PMT small aperture in the hole, current 150 mA, mister ON
6362	390 nm Pass filter, plus UV filter PMT small aperture in the hole, current 150 mA, mister OFF

PMT linearity test

PMT[5] = PMT in the cell looking at the mirror

Suspect PMT was linearly responding to beam current at 50 ns widths and 75 mA peak, 32 MeV

Run#	Current (nV*sec)	PMT[5](PADC chann #)	PMT[5] Fstop
6377	3.8
6378	8.5	1600	Cut wide pulse current in half and shortened pulse to 50 ns, pulse very hard to measure at 50 ns
6379	2.2	837	current changed during run
6380	3.5	1200
6381	4.3	704	Position 1=open, at position 3, diameter = 26 mm
6382	4.5	190	Position 1=open, at position 6 diameter=3.5 mm
6383	4.7	1214	Position 1=open, at position 1 diameter = 31 mm
6384		1237	Position 1=open, at position 1, double width to 100 ns
6385		1237	Position 1=open, at position 1, double width to 200 ns (ADC overflow!)

Current calibration

Changed beam current using width of the beam

Run#	Charge	PADC Chann#	Configuration
6337	[math]10 \times \frac{1.47 \times 10^{-6}}{50} = 0.294[/math] uC	3625 [math]\pm[/math] 26	current calibration, 1.47 uV*sec in 50 Ohms, 2.2 usec, x10 attenuator
6338	0.1588	2098 [math]\pm[/math] 6	current calibration, 794 nV*sec in 50 Ohms, 1.1 usec, x10 attenuator
6339	0.058	1093 [math]\pm[/math] 4.7	current calibration, 429 nV*sec in 50 Ohms, 550 nsec, x10 attenuator
6340	0.0378	504[math]\pm[/math] 4	current calibration, 189 nV*sec in 50 Ohms, 225 nsec, x10 attenuator
6341	0.0208	342 [math]\pm[/math] 3	current calibration, 104 nV*sec in 50 Ohms, 125 nsec, x10 attenuator

slope=8.53252e-05 +/- 6.47968e-06 y-intercept=-0.0189951 +/- 0.0141188

Micro-Coulombs (uC)

FF->Draw("PADC.PADC785N[1]*8.53252e-05>>r6338(5000,0,1)");

Run#	Charge	PADC Chann#	Configuration
6366	[math] \times \frac{330 \times 10^{-9}}{10^6} = 0.294[/math] uC	1351 [math]\pm[/math] 14	current calibration, 330 \pm 5 uV*sec in 1 Meg Ohms, 2.2 usec,
6367		792 [math]\pm[/math] 9	current calibration, 190 \pm 5 nV*sec in 1 M Ohms, 2.2usec
6368		496 [math]\pm[/math] 5	current calibration, 106 \pm 3 nV*sec in 1 M Ohms, 2.2usec
6371		1066 [math]\pm[/math] 10	current calibration, 265 \pm 4 nV*sec in 1 M Ohms, 2.2usec

5/26/17

32 MeV Beam 150 mA current

UV wide band filter on cell PMT, Aperature wide open

Run#	Cell PMT [5]	FC [7]
6389	3142	1509
6390	2231	908
6391	1191	447
6392	708	287 (have full current near end)
6393	2642	1147
6394	1605	580
6395	1889	696 (changed current near end of run)
6396	698	279
6397	390	183 (changed current near end of run)

filters on cell PMT, NO Aperature, Mixed field (taken during irradiation)

Run#	Cell PMT [5]	FC [7]	[5]/[7]	comment
6401	3503	1743	2.0	320 nm filer
6402	110	1614	0.07	330 + 320 nm filters
6403	2972	1519	1.956	390 nm Filter

data below shows two regions of linearity root [6] FF->Draw("PADC.PADC785N[5]/PADC.PADC785N[7]"); root [7] FF->Draw("PADC.PADC785N[7]","PADC.PADC785N[5]/PADC.PADC785N[7]<2"); root [8] FF->Draw("PADC.PADC785N[7]","PADC.PADC785N[5]/PADC.PADC785N[7]>2");

Run#	Cell PMT [5]	FC [7]
6403	2972	1519
6404	2017	894
6405	1259	526
6406	758	332
6407	422	209
6408	2620	1312
6409	1657	702
6410	934	398
6411	549	254

Run#	Cell PMT [5] / FC [7]	Mist
6411	2.15	Off
6413	1.951	ON
6414	1.944	Off
6415		On

go_back

2nCor_44#Equipment