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.

2nCor_Equipment#PNNL_HpGe_X-cooler