论文标题
$^{229} $ th异构体能量的测量
Measurement of the $^{229}$Th isomer energy with a magnetic micro-calorimeter
论文作者
论文摘要
我们介绍了低能（0--60 $ \，$ keV）$γ$射线频谱的测量值（$^{233} $ u，使用专用的低温磁性微高致焦化。 $ \ sim $$ 10 \，$ eV的能量分辨率以及出色的增益线性，让我们使用四个补充评估方案在$^{229} $ th中测量低洼异构体状态的能量。最准确的方案确定$^{229} $ th Isomer Energy为$ 8.10（17）\，$ eV，对应于153.1（37）$ \，$ nm，基于$γ$ spectroscoppoy的精确值，并同意基于内部转换电子的最新测量值。我们还测量相关激发状态的分支比为$ b_ {29} = 9.3（6）\％$和$ b_ {42} = 0.3（3）\％$。
We present a measurement of the low-energy (0--60$\,$keV) $γ$ ray spectrum produced in the $α$-decay of $^{233}$U using a dedicated cryogenic magnetic micro-calorimeter. The energy resolution of $\sim$$10\,$eV, together with exceptional gain linearity, allow us to measure the energy of the low-lying isomeric state in $^{229}$Th using four complementary evaluation schemes. The most accurate scheme determines the $^{229}$Th isomer energy to be $8.10(17)\,$eV, corresponding to 153.1(37)$\,$nm, superseding in precision previous values based on $γ$ spectroscopy, and agreeing with a recent measurement based on internal conversion electrons. We also measure branching ratios of the relevant excited states to be $b_{29}=9.3(6)\%$ and $b_{42}=0.3(3)\%$.
