46 / 2015-10-24 17:29:57

A Low-power Portable Digital Spectroscopy for CZT Gamma-ray Detector

Spectroscopy, CdZnTe (CZT), Universal Serial Bus (USB), Portable, Low-power, Field Programmable Gate Array (FPGA).

A portable, low power, digital spectroscopy for CdZnTe (CZT) detector is designed and described in this paper. Its readout electronics is implemented with waveform sampling, Flash-based FPGA (Field Programmable Gate Array) and USB (universal serial bus) technique. The CZT detector, with an effective thickness of 3mm and a diameter of 5mm, is mounted on the same PCB board with high voltage supply module and low noise preamplifier. Current signal from CZT detector is integrated by a charge sensitive amplifier and then shaped by a CR-RC3 shaper. The shaped signal is sampled by a 12-bit ADC and then processed by an IGLOO Flash-based low power FPGA in a digital module. A USB interface is adopted both for low voltage and high voltage power supply, and communicating with a host computer, which results in a portable solution with maximum power consumption of about 450mW. In the host computer, a graphic user interface (GUI) software is developed based on Labwindows/CVI, for real-timely displaying the energy spectrum or waveform of shaping signal. Test results showed that the dynamic range of the spectroscopy can reach 240fC (equivalent to about 7 MeV energy deposition in CZT detector) and the intrinsic noise (in RMS) for the electronics is less than 0.3fC (equivalent to about 8.7 keV).