Authentication and data quality monitoring with Safeguards HPGe detector systems

Authentication of the spectrum from a detector is important in remote monitoring applications, Safeguards monitoring and other critical measurement situations. Data quality is also important and the data quality monitoring here refers to the physical and electrical parameters of the detector, such as detector temperature, consistency of the high voltage, consistency of the low voltage preamplifier power, and preamplifier overload condition. All of these parameters can adversely affect the spectrum, both in peak areas and resolution. A detector system has been developed to provide both of these capabilities. The detector is controlled and monitored from the special features of the spectrometer. The authentication is accomplished with two codes. The first code is the serial number of the detector and the second code is a pseudo-random value stored in the detector at the beginning of data collection and verified at the end of data collection. The high voltage supply is integral to the detector. The value of the high voltage applied to the detector can be read by the spectrometer. The detector module also detects any change in the voltage and records an error if the change exceeds limits. The detector temperature is monitored and can be read by the spectrometer. If the temperature exceeds a set level, an error is recorded. The supply voltages are monitored at the detector. The detector module detects any change in the voltages and records an error if any change exceeds limits. By using the detector and spectrometer combination, the spectrum produced is known to have come from the specified detector and that all operating parameters were stable and valid during the data collection time.