Several Common Scintillator ¦Ã-irradiation Characteristics Of Resistance

The scintillation detector combined by scintillator and photoelectric multiple tube(PMT) or photoelectric duct(PD) is the mostely chosen in netron pulse andγpulse radiation detecting.In some qualifications for measuring pulse radiation field we have no chose to place the photoelectric scintilation detectors under the irradiating of the intense pulse radiation source,thus the ridiation hardness of photoelectric scintilation detectors must be calculated when the nutron orγpulse radiontion field is too indense.When detecting the dense radiation field the density of neutron pulse orγcan amount 10²⁵/S～10³¹/S,the fluorescence transmissivity and the light yield of scintillator may be reduced because of dense ionizing radiation.The reduction of scintilation efficiency and the accretion of nonlinear effects between light output and the density of pulse irradiation source finally result in the detected pulse waveform being aberration from the true pulse,the measuring data being distortion and even the measuring losing meaning.The research of neutron andγirradiation resistibility of some commonly used scintillator is the focused problem in the study of dense pulse radiation field.This disquisition integrates the research theγirradiation resistibility of some frequently used scintilators into the practice of dense pulse radiation field parameters measuring.In the experimental study the chosen scintillator contains inorganic crystal CeF₃,NaI(T1),BaF₂ and plastic scintillator ST-401,ST-1422,NE111 etc.We measure and compare the sensitivity of scintillation detector before and after the scintillator is irradiated by 1×10¹³Î³/cm²,2×10¹³Î³/cm²,5×10¹³Î³/cm²,1×10¹⁴γ/cm², 3×10¹⁴γ/cm²,thus a consult can be given when we chose scintillator in pulse radiation field measuring.In the irradiation risistibility characteristic study of scintillator,the sensitivity calibration of the scintillation probe made up of scintillator and PMT or PD is a necessary process.We have measured the relative sensitivity of scintillation probe under the pulseγ-ray(maximumγ-ray energy is 800keV and average energy is about 200keV) and DPF pulse neutron source.The scintillator is irradiated by irradiation center's strong ⁶⁰Co source which the radiation doserate is so dense to 11.35Gy/min,so the vested dose can be obtained in a short time.The result shows that the sensitivity of all researched scintilltor is visibly reduced when the irradiation dose is up to 1×10¹⁴γ/cm².In this paper we also have researched the relation of sensitivity reduction and the irradiation cumulative dose using ST-401 and CeF₃ crystal.When the irradiation dose is under 5×10¹³Î³/cm² the sensitivity of the two kinds of scintillator has no obvious reduction and the radiation dose achieve or exceed 1×10¹⁴γ/cm² the sensitivity reduce obviously.