Development and performance calibration of position sensitive detector based on LaBr3(Ce) crystal coupled with SiPM

Abstract

BackgroundThe detectors of traditional gamma-ray imaging systems cannot meet the radiation detection requirements of positioning for the nuclear industry application. LaBr3(Ce) crystal is a crystal with high light output, very short decay time of luminescence and large density. As a new type of photoelectric conversion device, SiPM has the advantages of small size, anti-magnetic field interference, low power supply voltage, and good time resolution compared with position sensitive photomultiplier tube (PSPMT).PurposeThis study aims to develop a position sensitive detector based on the LaBr3(Ce) crystal coupled with SiPM to achieve high energy resolution, high count rate and miniaturization.MethodsAn 8×8 LaBr3(Ce) crystal array with pixel size 6.4 mm×6.4 mm×20 mm per crystal bar was employed to couple 8×8 SiPM array with silicone grease to form the position sensitive. Then the corresponding readout circuit was designed according to the characteristics of the pulse signal. Finally, 137Cs point sources with different activities were used to test the performance of this detector system and conduct calibration.ResultsTest results show that the average energy resolution of the 64 crystal strips of the detector module is 4.96%, of which the best energy resolution is 3.92% and the worst is 5.91%. Subsequent testing and calibration of the peak position uniformity and sensitivity uniformity of each crystal strip pixel achieve good results.ConclusionsThe position sensitive detector based on the LaBr3(Ce) crystal coupled with SiPM can meet the design requirements of gamma camera imaging in the nuclear industry in terms of energy resolution, peak position uniformity and sensitivity uniformity.

Keywords

• labr3(ce) crystal
• position sensitive detector
• γ camera
• correction of sensitivity uniformity
• correction of peak position uniformity