| The photomultiplier tube is used to photoelectric conversion and electronic multiplication in the composition of scintillator detector, and PMT technology has become more mature through decades of development. With the development of nuclear power and the increasing request for better living environments, the portable instruments have been favored more and more by people in industrial production, laboratory construction, environmental monitoring,etc. Silicon photomultiplier tubes are semiconductor devices, with the working mechanism of avalanche multiplication, used in many fields widely.The signals readout circuits and preamplifier circuits are designed based on the information of fluorescence photons and the parameters of silicon photomultiplier tubes. The performance of SiPM is studies from several experiments. The results show that when SiPM work in -30? to 20?, the fluctuation pulse amplitude is withiną2.5%; When working in 20? to 40?,the pulse changed roughly linearly with the rising of temperature, the average rate is about 5%. The magnetic field has no effect on SiPM when working on the purpose of photoelectric conversion. SiPM are putted in standard irradiation field (10Gy/h) for 20 hours continuously, more than 200Gy in total, the signal pulse amplitude changes slightly. The internal gain of SiPM is linear with the reverse bias within a certain range of the voltage changes.The design scheme of surface contamination instrument is presented through the detailed analysis about the properties of the SiPM anda-ray, ?-ray, respectively. The material of the Probe adopts plating zinc sulfide plastic flash sheet; The optical cavity is designed by the calculation of one professional software; At the same time, preamplifier circuit, signal discriminator circuit, power supply circuit are designed and debugged. The results show that the working performance of circuit is stable; The detection efficiency of surface contamination instrument is: ??30%(241Am), ??30%. |
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