Gamma-Probe for Locating the Source of Ionizing Radiation

摘要

The radionuclide diagnostics unit, described in the article, detects pathological changes of organs and systems of a person. The device is a portable detector of gamma rays that allows to diagnose superficial malignancies using radiopharmaceuticals injected into the body. The gamma probe uses crystal LaBr3:Ce as a scintillator and silicon photomultiplier SiPM as a photodetector. The focus of this paper is the improvement of the amplifier, which originally produced misshapen pulses unsuitable for energy discrimination. Using LTSP-ICE, a free circuit-modelling program, we performed extensive simulation of both the SiPM and the amplifier. From this work, we determined that high input impedance and unnecessarily high gain were the source of the distortion. Another amplifier better suited to the SiPM parameters was simulated and then prototyped.