Solid state radiation measurement system for high flux applications

A solid state radiation measurement system was designed and developed to handle extremely high flux (approaching 0.9Mcps) and a large dynamic range. To achieve this the system utilizes a CdZnTe crystal that has undergone prior high flux testing with high bias to ensure it will not exhibit significant depolarization that will limit its ability to measure high flux. In addition, a preamplifier that produces a very narrow pulse (∼125ns FWHM), was designed and a high speed ADC was used to digitize the pulse. A Field Programmable Gate Array (FPGA) was implemented that allowed for scalable (2 or more channels counting asynchronously), high speed (130 MHz) pulse analysis in real time. The FPGA uses a pulse recognition algorithm to recognize pulses, even those beginning to pile up onto one another. This system was tested with a high energy (511keV) source that had an activity exceeding 10Ci.