| With the development of the research and application of nuclear detection technology, it has demanded nuclear detectors with good applicability to the environment. In some cases, the temperature always changes, and also with the presence of electric and magnetic fields, but the optical-electrical transducer is vulnerable to the temperature, electric field, magnetic field. Therefore it is necessary to develop optical-electrical transducer away from harsh environment, so that the detector can work stably. The traditional scintillation detectors usually combine the scintillation and optical-electrical transducer together; this type of detector has some limit in some cases. So that this is very important to do some research of the optical fiberγ-ray radiation detector.This paper designs a type of optical fiber y-ray radiation detector, this detector uses the optical fiber as transmission medium, which separates the probe from the photomultiplier tube, and it can be used under harsh environment for the real-time online monitoring of nuclear radiation. This detector can apply to the low energy and low dose rate of theγ-ray measurement; and can be able to meet the radiation environment testing of nuclear facilities in some cases.With the help of simulation and calculation, this paper has designed a type of detector with the high efficiency and sensitivity, including detector structure and the great match between the various components. Using the MNCP procedures, we have simulated the interaction between theγ-ray and the crystal, and designed the probe's structure reasonable, including the choice of the crystal material, the size of the crystal, and the requirement of the structural packaging. We also develop construct for the coupling between the scintillator and the optical fiber. By the way of calculation, we select the lowest attenuation optical fiber as the transmission medium. After the parameters analysis and comparison, we choose the suitable PMT and APD which is the best match with the crystal luminescence spectra as the photoelectric transducer.Based on the NaI (T1) and CsI(T1), this paper designs two sets of detector systems. The first set is that using NaI(T1) scintillation crystal for the sensitive material, PMMA plastic optical fiber as transmission fiber, PMT for the electron converter; the second is that using CsI(T1) scintillation crystal for the sensitive material, PMMA plastic optical fiber as transmission fiber, APD to electron converter. Both systems perform very well, they can be used for some ranges y-ray detecting,... |
