He3Tube Equipment

Analog Signals

He3 Tube neutron detectors, 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 1" thick virgin Poly and set to 1250 Volts. Using Ortec pre-amp 142PC serial # 787.