CHRPR Operations Manual
The TSA Systems VM-250AGN portal monitor is a set of two pillars made to detect nuclear material in a vehicle. Each pillar contains two polyvinyl toluene (PVT) plastic gamma ray detectors and four 3 He neutron detectors, as well as a power supply and electronics to process the output from these detectors. Pacific Northwest National Laboratory (PNNL) has designed and built a continuous high-resolution PVT readout (CHRPR) for the TSA portal to allow spectral readout from the gamma and neutron detectors. The CHRPR helps differentiate between different types of radioactive material through increased spectroscopic capability and associated developments. The TSA VM-250AGN continually monitors the levels of gamma ray and neutron radiation that occur around the pillars. A presence sensor records the passage of vehicles between the two pillars. An alarm is generated when radiation levels exceed a preset alarm threshold. The outputs of the radiation detectors inside each pillar are amplified and shaped by the SCA-775 single channel analyzer unit. Information from both SCA-775 units is passed to the SC-770 detector interface module and processor in the master pillar. This module analyzers count readings, triggers any appropriate alarms, and can output timestamped measurements to a serial connection.