Preparation And Characterization Of N/γ Discriminating Polysiloxane Scintillators

Polysiloxane materials have the advantages of strong radiation resistance(～10Mrad),high temperature resistance(>250 ℃),stable physical and chemical properties,and good mechanical properties,so they are very good in the field of radiation-resistant plastic scintillators.application prospects.Based on the hydrosilylation reaction,a series of polysiloxane scintillators were designed and prepared in this subject,and were tested by transparency observation,emission spectrum,transmission spectrum,neutron-gamma pulse shape discrimination ability,relative light yield,and energy scale.The effects of dye combination,dye concentration,and interaction between dyes on the performance of polysiloxane scintillators were studied by means of methods,and the theoretical analysis and discussion were carried out.The main research results are as follows:(1)Using vinyl-terminated poly-dimethyl-diphenyl-siloxane and hydrogen-ter-minated poly-methyl-phenyl-methyl-hydrogen-siloxane as matrix materials,poly-merized into a scintillator substrate under the action of Karstedt’s catalyst;A Series of polysiloxane scintillators were prepared by co-doping 3 dye systems of PPO-POPOP,PPO-DPA and PPO-TPB in the scintillator matrix.The results of characterization of the above scintillators shows that the scintillators using three dye systems show good optical transparency and neutron-γ discrimi-nation ability.Scintillator containing 4 wt%PPO-0.04 wt%POPOP performancesthe strongest neutron-γ discrimination ability and its pulse shape discrmination figure of merit reaches 0.91;the scintillator with 4 wt% PPO-0.04 wt%DPA has the highest light yield,which can reach 57 % of EJ-276 scintillator.Based on the scintillator matrix described in Polydimethyldiphenyl-polymethylphenylmethylhydrogensiloxane scintillator matrix,the dyes content in the scintillator was explored by doping the matrix with PPO and POPOP of different qualities.The results show that the scintillator with PPO content of 4 wt% and POPOP content of 0.04 wt% has better neutron-γ discrimi-nation ability(Fo M=0.91)and the highest light output ability(54.56% EJ-276).(2)Using vinyl-terminated polymethylphenylsiloxane and hydrogen-terminated poly-methylphenyl-methylhydrogen-siloxane as basic materials,polymerized into a scintillator matrix under the action of Karstedt’s catalyst;series of poly-siloxane scintillators were prepared by doping different concentrations of PPO and DPA.The results show that the scintillator with a PPO content of 6 wt% has the highest emission peak intensity、better optical stability and n-γ PSD ability.Based on the scintillator matrix described in Polymethylphenyl-polymethylphenylmethylhydrogensiloxane scintillator matrix,a large-size scintillatorwith a diameter of 50 mm was prepared with 6 wt% PPO and0.10 wt% DPA.The scintillator exhibited good transparency and excellent hardness,the performance characterization results of the scintillator show that: under the same type and concentration of dye doping,the neutron-γ discrimination ability of the large-sized scintillator is greatly improved compared with that of the scintill-ator with a diameter of 20 mm.Its n-γ PSD FOM reaches 1.0.(3)Add 4.0 wt% PPO,0.04 wt% POPOP and 1 wt% o-carborane to the scintillator matrix described in Polydimethyl diphenyl-polymethyl phenylmethyl hydrogensiloxane scintillator matrix;add 6.0 wt% PPO,0.10 wt% o-carborane to the scintillator matrix described in Polymethyl phenyl-polymethyl phenyl methylhydrogensiloxane scintillator matrix Polysiloxane scintillators containing thermal neutron capture element 10 B were prepared by DPA and 3 wt% o-carborane.The test results show that the scintillator containing o-carborane does not exhibit thermal neutron detection ability and also causes the scintillator light yield to decrease,which is mainly caused by the additive being a non-enriched element additive.