论文标题
低能电子的非弹性散射的$^{2.29m} $ th的激发
Excitation of $^{229m}$Th at Inelastic Scattering of Low Energy Electrons
论文作者
论文摘要
理论上在量子电动动力学的扰动理论的框架内研究了异常低的核异构体$^{229m} $ th $ th $（3/2^+，8.28 \ pm 0.17 $ eV）。 $^{2.29m} $ TH的计算出的交叉部分由极低的能量电子在范围9 ev-12 eV中的th Atom和th $^{1+，4+，4+} $ ions lie在$ 10^{ - 25} $ - $ 10^{ - $ 10^{-26} $ CM $ $^2 $中。横截面如此之大，在用电子束或电子（电气）电流进行实验中，为有效的$^{229m} $ Th有效的非共振激发打开了新的可能性。这可能是至关重要的，因为当前已知异构体状态的能量准确性不足以通过光子的谐振激发。此外，时间逆转过程的横截面也很大，因此，通过金属中的传导电子为$ \ oft11^{6} $ s $ s $^{ - 1} $的非辐射性$^{2.29m} $ th的可能性，即接近于内部的转换概率。
Excitation of the anomalously low lying nuclear isomer $^{229m}$Th$(3/2^+, 8.28 \pm 0.17$ eV) in the process of inelastic electron scattering is studied theoretically in the framework of the perturbation theory for the quantum electrodynamics. The calculated cross sections of $^{229m}$Th by the extremely low energy electrons in the range 9 eV--12 eV for the Th atom and Th$^{1+,4+}$ ions lie in the range $10^{-25}$--$10^{-26}$ cm$^2$. Being so large, the cross section opens up new possibilities for the effective non-resonant excitation of $^{229m}$Th in experiments with an electron beam or electron (electric) current. This can be crucial, since the energy of the isomeric state is currently known with an accuracy insufficient for the resonant excitation by photons. In addition, the cross section of the time reversed process is also large, and as a consequence, the probability of the non-radiative $^{229m}$Th decay via the conduction electrons in metal is $\approx10^{6}$ s$^{-1}$, that is, close to the internal conversion probability in the Th atom.
