Investigation of Nuclear Structure with Relative Self-Absorption Measurements
Investigation of Nuclear Structure with Relative Self-Absorption Measurements
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通过相对自吸收测量研究核结构
DOI：
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发表时间：
2015
期刊：
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通讯作者：
C. Romig
中科院分区：
文献类型：
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作者：
C. Romig
在这项工作中，一个特殊的应用核共振荧光技术已被使用，并进一步推进研究核结构的影响：所谓的相对自吸收实验。它们允许直接确定激发态的基态跃迁宽度，这是与模型计算进行比较的一个重要量，以及以独立于模型的方式确定各个状态的基态的能级宽度和分支比。进行了两次自吸收测量。一方面，我们研究了$^{140}$Ce原子核中低激发偶极态在俾格米偶极共振能区的绝对激发宽度和衰变模式。的核共振荧光测量，这是一个自吸收实验的一部分，以及实际的自吸收测量的结果分别为117和104激发态的$^{140}$Ce。将它们与之前的测量值进行比较，并结合统计模型进行讨论。另一方面，我们对Li ~（66）中激发能量为[3563] keV的T=1，J^{pi}=0^+1 $能级的自吸收进行了高精度测量。这种状态的精确测量的能级宽度可以作为现代ab-inito计算的基准。
In this work, a special application of the nuclear resonance fluorescence technique has been used and further advanced to study nuclear structure effects: so-called relative self-absorption experiments. They allow for the direct determination of ground-state transition widths of excited states, an important quantity for comparisons to model calculations, as well as the level width and the branching ratio to the ground state of individual states in a model-independent way. Two self-absorption measurements have been performed. On the one hand, the absolute excitation widths and the decay pattern of low-lying excited dipole states in the energy regime of the pygmy dipole resonance have been investigated in the nucleus $^{140}$Ce. The results of the nuclear resonance fluorescence measurement, which is part of a self-absorption experiment, as well as of the actual self-absorption measurement are presented for 117 and 104 excited states of $^{140}$Ce, respectively. They are compared to previous measurements and discussed with respect to the statistical model. On the other hand, a high-precision measurement of the self absorption of the $T=1$, $J^{pi}=0^+_1$ level at an excitation energy of unit[3563]{keV} in $^6$Li has been conducted. A precisely measured level width of this state can serve as a benchmark for modern ab-inito calculations.