论文标题
$^{229} $ th异构体的核激发通过掺杂晶体中的缺陷状态
Nuclear excitation of the $^{229}$Th isomer via defect states in doped crystals
论文作者
论文摘要
当Th核在CAF $ _2 $晶体中掺杂时，一组电子缺陷态将出现在晶体带隙中，否则将为真空粉状辐射提供完整的透明度。理论上研究了这些缺陷状态与CAF $ _2 $ Crystal中8 eV $^{2.29m} $ th核异构体的耦合。我们表明，尽管以前被视为滋扰，但缺陷态通过使用光激光器涉及刺激发射或吸收的电子桥梁机制提供了核激发的起点。这些过程的速率至少是使用可用的光源比异构体状态的直接光激发的两个数量级。当反向机制触发时，核异构体种群也会发生淬火，从而导致通过电子壳快速而受控的衰变。这些发现与基于$^{2.29m} $ th异构过渡的可能的固态核时钟有关。
When Th nuclei are doped in CaF$_2$ crystals, a set of electronic defect states appears in the crystal bandgap which would otherwise provide complete transparency to vacuum-ultraviolet radiation. The coupling of these defect states to the 8 eV $^{229m}$Th nuclear isomer in the CaF$_2$ crystal is investigated theoretically. We show that although previously viewed as a nuisance, the defect states provide a starting point for nuclear excitation via electronic bridge mechanisms involving stimulated emission or absorption using an optical laser. The rates of these processes are at least two orders of magnitude larger than direct photoexcitation of the isomeric state using available light sources. The nuclear isomer population can also undergo quenching when triggered by the reverse mechanism, leading to a fast and controlled decay via the electronic shell. These findings are relevant for a possible solid-state nuclear clock based on the $^{229m}$Th isomeric transition.
