摘要
为研究辐射伏特效应氚核电池中氚钛源膜电子出射特性及其随时间的性能衰减,对源膜内氚衰变电子的输运与出射行为进行了深入研究。通过捕捉拟合及离散化处理获取离散型数字化氚衰变电子能谱,采用蒙特卡罗方法对源膜表面活度密度和电子出射功率的自吸收效应及衰减效应进行分析。同时,通过氚成像法的样品检测,验证模拟模型的可靠性。研究结果表明,随着源膜厚度增加,电子出射能谱峰值向高能区偏移直至8 keV附近;膜厚增加,导致自吸收效应增强、氚源能量浪费,源膜厚度不宜超过1000 nm;在特征参数(1000 nm厚、T/Ti比=1.9)下氚钛源膜具有519.5 mCi/cm^(2)的总活度密度,理论上可提供46.6 mCi/cm^(2)的表面活度密度以及2243.9 nW/cm^(2)的电子出射功率密度;考虑氚的衰减效应,特征参数源膜使用15 a后可提供约1000 nW/cm^(2)的电子出射功率密度。
In order to study the electron-emitting characteristics and decay effect of titanium tritide source films in betavoltaic batteries,the transport and emission behavior of electrons from tritium in the source films were studied.The apparent activity density,electron emission energy spectrum and apparent electron power of the source film were obtained,and the decay of the above performance indicators over time was evaluated.So as to provide a theoretical basis for the development ofβ-radiation volt effect isotope batteries with tritium as the radiation source.By capturing,fitting and discretization,the discrete energy spectrum of electrons from tritium decay was obtained for energy sampling of input electrons.On this basis,the Monte Carlo method was used to simulate the apparent activity density and electron emission energy spectrum of the source films,further calculated the apparent electron power,and analyzed the self-absorption effect and decay effect of the source films performance.At the same time,the high-purity titanium films were prepared by magnetron sputtering method.And after the tritium absorption of the diaphragm was completed,the apparent activity density of the titanium tritide source film samples was detected via tritium imaging method,which verified the reliability of the simulation model.The results show that the titanium tritide source films prepared by 500-2600nm have a tritium-to-titanium ratio of about 1.9,and the apparent activity density measured by tritium imaging is consistent with the simulation results.As the thickness of the source film increases,the peak of the electron emission energy spectrum on the surface shifts towards the high energy zone until close to 8keV.It exhibits the phenomenon of“hardening”,which may be due to the fact that high-energy particles are more likely to penetrate the material and lowenergy particles have a greater probability of being absorbed by the source film material.The increased thickness of the film leads to enhanced self-absorption effect,causing the waste of tritium source energy,and the apparent electron power tends to stabilize when the film thickness increases to about 1000nm.Therefore,the film thickness used should preferably not exceed 1000nm,aiming to avoid the waste of radioactive source.Titanium tritide source film with characteristic parameters(1000nm thick,T/Ti=1.9)has a total activity density of 519.5 mCi/cm^(2),which theoretically provides an apparent activity density of 46.6mCi/cm^(2)and an electron emission power density of 2243.9nW/cm^(2).Considering the decay effect of tritium,the source film with characteristic parameters can still provide an electron emission power density of about 1000nW/cm^(2)for 15years of using,which is about 44%of the initial power.
作者
郭忠晟
窦志昂
占勤
杨洪广
GUO Zhongsheng;DOU Zhiang;ZHAN Qin;YANG Hongguang(China Institute of Atomic Energy,Beijing 102413,China)
出处
《原子能科学技术》
EI
CAS
CSCD
北大核心
2023年第S01期297-304,共8页
Atomic Energy Science and Technology
基金
中核集团“青年英才”项目
关键词
辐射伏特效应氚核电池
氚钛源膜
蒙特卡罗模拟
氚成像法
自吸收效应
衰减效应
betavoltaic battery
titanium tritide source film
Monte Carlo simulation
tritium imaging method
self-absorption effect
decay effect
