PNNL X-coolerII-GEM120P4
PNNL's HpGe X-cooler poptop detector
Model: GEM120P4
The above model number indicates that the detector has an relative efficiency of 120% with respect to a 3" x 3" NaI crystal, a resolution of 1.3 keV for 122 keV photons, resolution of 2.1 keV for 1.33 MeV photons, a peak to compton ratio of 86:1, and end cap diameter of 0.108 mm.
serial #: 44-TP41387A
GEM model => p-type => Usually a positive HV bias
GMX model => n-type => Usually a negative HV bias
HV shutdown signal
Condition 1: With the HV and HV Shutdown connected and the preamp disconnected the detector will be in shutdown mode as there will be no current signal from the preamplifier to the HV power supply.
Condition 2: With the HV , HV Shutdown and Preamp connected when the detector is warm, there will be a positive voltage signal to the HV power supply which will activate shutdown.
Condition 3: With the HV , HV Shutdown and Preamp connected when the detector is cold there will be a negative voltage signal from the preamp to the HV power supply which will allow the application of HV.
Condition 4: With the HV and Preamp connected and the HV Shutdown disconnected when the detector is cold the detector will be in shutdown mode.
Operations
Compressor
The compressor is a refrigeration unit that should remain horizontal. You have a time window from 5 minutes after the 120 Volts is interrupted until 10 min afterward to restore power. It is recommended that you allow it to settle for 6 hours if power is restored after 10 minutes. The compressor must not exceed an inclination angle of 10 degrees.
Detector
The detector may be positioned at any angle and height just do not exceed the bending limits of the cooling lines. (information confirmed by Vance Harmon at Ortec vance.harmon@ametek.com)