A prototype of SiPM-based scintillator Compton camera with capacitive multiplexing readout

Abstract

Compton camera is capable of visualizing the distribution of radioactivity based on the Compton scattering kinematics, and can be applied in nuclear accident emergency response, radioactivity decontamination, homeland security and etc. A prototype of Compton camera has been constructed consisting of two 4×4 SiPM-Ce: GAGG scintillator arrays. The signals of a SiPM array were converted into 4 position-weighted outputs with capacitive network circuit and collected by a CAEN digitizer. Two-dimensional flood images and energy responses of two detector modules were obtained. The average energy resolution of single elements of the two detector modules was 6.6% FWHM at 662 keV. Imaging performance of the prototype camera was evaluated with a 137 Cs point source and a 22 Na point source. Efficiency of the prototype for the 137 Cs point source located right in front was measured to be 0.09%. The angular resolution of a 137 Cs point source placed right in front of the camera was 7.2 • FWHM. Isotopic images of the two gamma-ray sources were obtained with spatial resolutions of 8.2 • FWHM for 137 Cs and 8.8 • FWHM for 22 Na.

Performance evaluation of MACACO II Compton camera

“…Simulations have been carried out with the aim of reproducing the performance of the Compton telescope prototype. The detectors have been modeled as LaBr 3 scintillator crystals with a density 5.08 g/cm 3 . Other elements that are part of the detector (black holders, SiPMs, aluminum housing and PCBs) were also simulated, whereas the acquisition boards (DAQs), the structure supporting the detector and the climatic chamber were not considered in the simulation.…”

“…In recent years Compton cameras have been developed using different types of detectors, e.g. scintillator crystals coupled to SiPMs [3], solid state [4] or gaseous detectors [5]. In particular, SiPMs are being used increasingly on CCs due to their easy handling [6].…”

Enhancing large-area Geiger-mode avalanche photodiode performance through dynamic memristor quenching: a study on improving count rate, reducing jitter and mitigating afterpulsing

“…millimeter scale) are mostly realized on the basis of detector array which usually face fill factor difficulties. [22][23][24] If the performance of discrete GmAPDs of the millimeter scale could be enhanced, they would be ideal for bio-imaging. 11) However, when the GmAPD is too large, a serious RC delay phenomenon will deteriorate the counting rate and timing jitter, affecting the counting speed, and the charge accumulation caused by discharge will cause the afterpulsing phenomenon, 25,26) affecting the dark count.…”