Chao Wang a b, Long Wei a b, Zhiming Zhang a b, Daowu Li a, Baotong Feng a, Yantao Liu a, Yu Xiang a b, Xin Li a b, Xiaopan Jiang a
a Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
b School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, China
## Abstract
The CdZnTe detector, a room-temperature semiconductor detector, has many applications for nuclear safety and nuclear medicine because of its high energy resolution and small size when compared with scintillator detector and high purity Germanium detector respectively. Radionuclide imaging is one of the most important applications that requires adequate three-dimensional position resolution. In this work, we used a CdZnTe crystal from eV Products with a pixelated anode to achieve approximately 1.0 mm position resolution on an electrode plane and 0.9 mm position resolution in depth when the CdZnTe detector’s pixel pitch is 2 mm and thickness is 5 mm. We also improved the energy resolution of a 662 keV full-energy peak in a 137Cs energy spectrum to 1.27% after running a selection of full-energy deposited events based on depth, compared with 4.06% without this operation.
## Introduction
Compared with other detectors, the CdZnTe detector, a room-temperature semiconductor detector, has many advantages, including good energy resolution, a lack of charge polarization in case of no ultra-high flux irradiation, and a size that makes it small enough to be used as a portable detector in gamma energy measurement [1], [2], [3], [4], [5]. In order to meet the needs of gamma-ray imaging in radiation safety monitoring, we recently decided to develop a Compton camera based on a pixelated CdZnTe detector. Many studies have confirmed that the performance of Compton cameras depends on the ability of the detector to accurately measure gamma-ray energy and locate the three-dimensional position of photons interacting with crystal [6], [7], [8]. In addition, this three-dimensional position information can also help the CdZnTe detector make more precise energy measurements of gamma-rays. Therefore, obtaining the three-dimensional position information of the interaction between photons and CdZnTe crystal is the first important work we need to complete.
In this article, we will provide a new method to obtain three-dimensional position information of interaction points and provide the corresponding position resolution based on our detector system. We first discuss the simulation of weighting potential distribution in our detector, which serves as the foundation of our research. We then introduce the method and detailed experimental design to obtain three-dimensional position information. After discussing and analyzing the results, we aim to improve the energy resolution of a 662 keV full-energy peak in a 137Cs energy spectrum based on events filtering. Finally, we conclude our work and describe future research plans.
CdZnTe Association (CdZnTe.com)
https://www.cdznte.com/thesis/achieving-sub-pixel-position-resolution-and-sub-millimeter-depth-resolution-using-a-pixelated-cdznte-detector.html