A Virtual Frisch-Grid Geometry-Based CZT Gamma Detector for In-Field Radioisotope Identification

TL;DR

This paper introduces a portable, wireless CZT gamma detector with a virtual Frisch-Grid geometry, capable of identifying radioisotopes across a broad energy range for in-field applications.

Contribution

The development of a compact, battery-powered CZT detector with integrated digital processing and wireless streaming for efficient radioisotope identification in the field.

Findings

Effective energy range from keV to 2 MeV demonstrated

3D interaction position reconstruction achieved

Compact and wireless design suitable for field use

Abstract

We present a Virtual Frisch-Grid geometry-based CZT gamma detector developed for identifying different radioisotopes over an energy range from single keV up to 2 MeV, and useful for efficient characterization of CZT crystals. The detector is built with a 3 x 3 matrix of CZT crystals, each measuring approximately 6 mm x 6 mm x 15 mm. The charge generated within the sensor's active volume is read out via an anode connected directly to the AVG3_Dev integrated circuit. A current signal induced by charge drift is collected on side pads of the crystals, enabling reconstruction of a 3D interaction position. This paper discusses the design, development, and performance of the standalone, mobile detector system, which integrates the AVG3_Dev readout IC developed at Brookhaven National Laboratory, high-speed FPGA-based with per-channel digital signal processing, and embedded system capabilities. The device is compact, battery-powered, and supports wireless data streaming, making it suitable for field operations towards radioisotope identification.