Preparation And Properties Of Organometallic Compounds Doped Plastic Scintillators

With the rapid development of nuclear technology research and application,the demand and types of nuclear radiation detectors are also increasing.Plastic scintillators,due to their advantages of low-cost,high environmental stability,and ease of preparation in large size,have attracted growing attention.Traditional plastic scintillators are mainly composed of light elements such as carbon,hydrogen and oxygen,resulting in the low density and low effective atomic number(₀0))),thereby rendering them incapable of achieving gamma-spectroscopy detection.The loading of organic heavy metal compounds provides an effective avenue for gamma-spectroscopy detection for plastic scintillators.In this paper,the preparation and properties of plastic scintillators loaded with organic copper compound and organotin compounds were studied on the premise of determining the best formula and preparation technology.PVT-based plastic scintillators samples with different concentrations of Cu I（PPh₃）₂（t-Bu Py）ranging from 0 to 3 wt%were synthesized via bulk polymerization method,with high optical transmittance of over 80%.The loading of Cu I（PPh₃）₂（t-Bu Py）has little effect on the position of fluorescence emission peak and X-ray induced radioluminescence emission peak of plastic scintillator.However,radioluminescence intensity gradually decreases with the increase of doping concentration.In addition,under the irradiation of ¹³⁷Cs and ²³⁹Pu sources,the light yield also decreases with the increase of loading concentration.Through the further study on the properties of PVT/2 wt%Cu I（PPh₃）₂（t-Bu Py）sample and PVT/2 wt%Cu I（PPh₃）₂（t-Bu Py）/2 wt%PPO sample,the physical mechanism of Cu I（PPh₃）₂（t-Bu Py）on the reduction of the light yield of plastic scintillators were proposed.After the high-throughput screening and the improvement of the preparation technology,six organotin compounds loaded PVT plastic scintillators with different loading concentrations were successfully prepared by free polymerization.All organotin compound loaded samples demonstrate the capability of gamma spectroscopy detection with fast decay characteristics.Among them,plastic scintillators loaded with tributyl（1-ethoxyvinyl）tin,tributylphenyltin and 2-（ributylstannyl）thiophene have better comprehensive performance.20 wt%tributyl（1-ethoxyvinyl）tin-loaded plastic scintillator has the best scintillation performance with a light yield of 7,100 ph./Me V and an energy resolution of11.7%@662 ke V.However,for the plastic scintillator loaded with 2-（ributylstannyl）thiophene,they have higher transmittance than that loaded with tributyl（1-ethoxyvinyl）tin,and thus demonstrate better scintillation performance with a larger size.The light yield of 1-inch and 2-inch diameter with 30 wt%2-（ributylstannyl）thiophene loaded plastic scintillators are 5,400 ph./Me V and 5,100 ph./Me V,with an energy resolution of 14.4%and 17.8%,respectively.