Research On Ionizing Radiation Dose Sensing Based On Silica Cladding Crystal Scintillation Fiber

As an improved scintillation detector,the scintillation fiber radiation detector has a good application prospect in ionizing radiation detection because of the advantages of high radiation detection efficiency and high radiation hardness of scintillation detector,as well as the advantages of optical fiber sensor,such as anti-electromagnetic interference,long-distance transmission,sensor integration,and so on.In order to further improve the ionizing radiation sensing capability of scintillation fibers,realize the miniaturization of the sensing system and the remote online measurement of ionizing radiation,a comprehensive study has been carried out on the silica cladding LYSO:Ce crystal scintillation fiber?SLCF?,and the electron radiation is taken as the measurement object.The main research work is as follows.Firstly,the radiation detection principle of scintillation fiber is analyzed,including the interaction between electron radiation and matter,the radiation luminescence mechanism of inorganic scintillator and the working principle of photomultiplier tube,which provides the basis for the selection and design of scintillation fiber and the construction of radiation sensing system.Secondly,based on the basic requirements of the scintillator for the detection of ionizing radiation,according to the performance parameters of rare earth scintillator doped with cerium,the high performance scintillator,yttrium lutetium silicate doped with cerium,LYSO:Ce is selected as the core material to improve the scintillation performance of silica cladding crystal scintillation fiber.In the aspect of preparation technology,aiming at the problem that the process defects of the traditional rod-in-tube method cause the scintillation performance decrease of the scintillation fiber,the inert gas is used as the protection atmosphere to fabricate SLCF on the basis of rod-in-tube method to avoid the radiation response weakness of scintillation fiber due to the oxidation of Ce³⁺.At the same time,the silica cladding YAG:Ce crystal scintillation fibe?SYCF?is fabricated as the contrast object.Then,in order to verify the feasibility of SLCF in electron radiation sensing,the electron radiation responses of SLCF,SYCF and plastic scintillation fiber?PSF?are studied by the simulation electron irradiation experiment based on Geant4,the high energy particle transportation software.At the same time,the influence of the length of SLCF on its radiation response is studied by simulation experiments,and the length of SLCF under laboratory irradiation condition is optimized,which provides reference for the preparation of fiber samples in irradiation experiment.Finally,a preliminary radiation sensing system based on scintillation fiber is set up,and the electron radiation responses of SLCF,SYCF and PSF are studied by electron irradiation experiments.The results show that SLCF has a high radiation response than others,which is helpful to improve the radiation sensing ability of scintillation fiber.Meanwhile,to improve the practicability of the sensing system,the improved radiation sensing system is built.The transmission optical fiber and coupling structures are introduced to simplify the structure of the hardware system and realize the miniaturization of the sensing part of the system,and the function of the control software is optimized.The results of the electron irradiation experiment show that the response output of the system is greatly improved,and the radiation response of SLCF is still at a high level.In order to further study the radiation sensing characteristics of SLCF,based on the improved radiation sensing system,the effects of the irradiated length of SLCF,the distance between SLCF and radiation source,and the angle between SLCF and electron beam on the radiation response of SLCF are studied.It is found that the radiation response of SLCF is positively correlated with the above three factors,which provides guidance for the optimization of the detection parameters of the radiation sensing system.