Preparation And Properties Of Long Wavelength Plastic Scintillator

Although commonly used plastic scintillators have excellent comprehensive performance,they also have some shortcomings.The maximum emission wavelength is relatively short,and they are generally used in conjunction with photomultiplier tubes(PMTs).However,photomultiplier tubes can be affected by electromagnetic fields in strong electromagnetic fields,making them unusable and unable to achieve longdistance detection.As a substitute for PMT,silicon photomultiplier tubes(Si PM)can be used in strong electromagnetic fields,but the optimal detection wavelength is in the green light band.Therefore,in order to solve the radiation detection and long-distance radiation detection in strong electromagnetic field environments,it is necessary to use a long wavelength(>490 nm)plastic scintillator with its emission wavelength in conjunction with Si PM.In this paper,suitable secondary fluorescent dyes are selected,and long wavelength plastic scintillators are prepared by optimizing the process,so that their maximum emission wavelength can match the optimal detection wavelength of silicon photomultiplier tubes,thereby improving detection efficiency.A conventional plastic scintillator based on vinyl toluene was prepared by thermal polymerization,and the relationship between its performance and the ratio of primary and secondary fluorescent dyes was investigated.The results showed that the primary and secondary fluorescent dyes were 2,5-diphenyloxazole(PPO)and 1,4-bis(5-phenyl-2-oxazolyl)benzene(POPOP),respectively,and the fluorescence intensity was strongest when the concentration was 1.2 wt% and 0.05 wt%,respectively;The optimal concentration of plastic scintillator has a decay time of 2.07 ns,a quantum yield of92.70 %,a transmittance of up to 90 %,good thermal stability,and a glass transition temperature of 98 ℃.In order to improve radiation detection in strong electromagnetic field environments,a secondary fluorescent dye 7H benzimidazolo [2,1-A] benzo [DE]isoquinolin-7-one(BBI)was selected,and PPO was used as a primary fluorescent dye.A green plastic scintillator with a maximum emission wavelength of 500 nm was prepared.The relationship between its performance and the concentrations of PPO and BBI,as well as its impact on Decay time,was investigated.The results showed that when the concentrations of PPO and BBI were 1.2 wt% and 0.02 wt%,respectively,The fluorescence intensity is the strongest;The optimal concentration of plastic scintillator has a decay time of 3.53 ns that is 3.14 ns faster than commercial EJ-260(6.67 ns),a quantum yield of 75.44 %,accounting for 67.52 % of EJ-260(98.59 %),a transmittance of up to 85 %,good thermal stability,and a glass transition temperature of 95 ℃.It has a strong detection ability for low energy X-ray.In order to achieve long-distance radiation detection in strong electromagnetic fields,the secondary fluorescent dye N,N ’’-bis(2,6-diisopropylphenyl)-1,6,7,12-tetraphenoxy-3,4,9,10-perylene tetraimide(BIO)was selected,and the primary fluorescent dye was PPO.A red-light plastic scintillator was prepared,with a maximum emission wavelength of 610 nm.The relationship between its performance and the concentration of PPO and BIO was investigated.The results showed that when the concentration of PPO and BIO was 1.0 wt% and 0.06 wt%,respectively,the fluorescence intensity is the strongest,and the decay time of the optimal concentration plastic scintillator is 8.99 ns.The quantum yield is as high as 90.93 %,and the transmittance is as high as 88 %.It has good thermal stability and a glass transition temperature of 95 ℃.It can directly detect low energy X-ray.