Radon Flask Detector - Model 182
CE Seal

The Model 182 Radon Flask Counter is a light-tight sample box that uses scintillation techniques for the detection of radiation material. It consists of a light-tight cylindrical well, a two-inch photomultiplier tube (PMT) optically coupled to a light pipe, and an automatic high voltage On-Off switch.
During sample counting the radon flask is placed on the acrylic light pipe. The upper tube body assembly is held in place with two thumbscrews. A push-rod assembly will then automatically activate a microswitch allowing high voltage (HV) to be applied to the PMT. The HV is automatically disconnected upon removal of the tube. The cover may be removed without turning off the high voltage on the accompanying scaler/count-rate meter type instrument.
The Series "C" connector uses a one-wire system combining the HV and signal. A capacitor located in the tube socket blocks the signal part of the PMT. A terminal strip containing a filter circuit prevents unwanted noise from the microswitch's actuations.