We have measured the K-shell and total internal conversion coefficients (ICCs), alpha_K and alpha_T, for the 109.3-keV M4 transition in 125Te to be 185.0(40) and 350.0(38), respectively. Previously this transition's ICCs were considered anomalous, with alpha values lying below calculated values. When compared with Dirac-Fock calculations, our new results show good agreement. The alpha_K result agrees well with the version of the theory that takes account of the K-shell atomic vacancy and disagrees with the one that does not. This is consistent with our conclusion drawn from a series of high multipolarity transitions.
Experimental evidence of (M1+E2) mixed character of the 9.2 keV transition in $^{227}$Th and its consequence for spin-interpretation of low-lying levels
Investigation of alpha-induced reactions on 127I for the astrophysical gamma process
为了给天体物理γ过程的模拟提供截面数据，用活化技术研究了α-诱发的~（127）I反应。精确测量了536.1keV γ跃迁的相对强度，其不确定度由13%降低到4%。通过测量特征X射线的产额，首次确定了127 I（α，γ）~（131）Cs反应的截面接近天体物理相关的能量区域，能量为9.50 <Ec. m。< 15.15由于反应模型的改进，$ MeV. The 127I(alpha,n)130Cs reaction was studied in the range 9.62 < Ec.m. < 15.15 MeV by measuring the yield of the 536.1 keV gamma-ray and at the lower part of this energy range by counting the characteristic X-rays. A comparison of the resulting cross sections to predictions of statistical model calculations confirmed the predictions of the astrophysically relevant averaged alpha width. Nevertheless, the newly derived stell…
Towards an energy measurement of the internal conversion electron in the de-excitation of the Th-229 isomer
Th-229的第一激发异构态具有非常低的能量，只有几个eV，可以形成高精度原子核激光光谱学的门户。同质异能态的激发能已经从精确的伽马光谱学中推断出来，但是它的不确定性仍然太大而不能开始激光光谱学。减少这种不确定性是该领域最紧迫的挑战之一。在这里，我们提出了一种方法来推断能量的异构体从光谱的电子发射时，异构体通过内部转换（IC）去激发。该实验建立在U-233的基础上，它衰变为Th-229，并以2%的分数填充同质异能态。U-233膜被几nm厚的停止层覆盖，并放置在α检测器和电子检测器之间，使得α粒子和IC电子可以被同时检测。减速场电极允许能量测量。在本设计中，Th-229 m IC电子的信号被从金属停止层的表面发射的低能电子掩蔽。我们用U-232和U-234进行参考测量，以研究系统效应，并研究各种方法来减少低能电子的背景。我们的研究提供了指导方针的实验设计，是能够检测IC电子和测量异构体的能量。
