Overlapping. beta. decay and resonance neutron spectroscopy of levels in /sup 87/Kr
Overlapping. beta. decay and resonance neutron spectroscopy of levels in /sup 87/Kr
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重叠。
DOI：
10.1103/physrevc.28.602
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发表时间：
1983
影响因子：
3.1
通讯作者：
K. Kratz
中科院分区：
文献类型：
--
作者：
S. Raman;B. Fogelberg;J. Harvey;R. Macklin;P. Stelson;A. Schroeder;K. Kratz
使用两种不同的方法研究了/sup 87/Kr的能级，特别强调了非结合区。第一种方法包括使用中子飞行时间技术对/sup 86/Kr的富集气体靶进行中子捕获和透射测量。以这种方式，中子宽度被确定为低于400 keV的39个共振和捕获面积低于90 keV的14个共振。第二种方法是56-s /sup 87/Br的衰变研究，其中已建立了/sup 87/Kr的能级方案，显示在结合区有126个能级，在未结合区有12个能级。详细比较了中子共振，...伽马.. -射线衰变和可用的缓发中子结果。几乎一对一的对应关系存在于目前观察到的p波共振低于250千电子伏和水平/sup 87/Kr通过缓发中子发射研究。整体…贝塔.. -从本数据导出的强度分布示出了宽的共振状结构。然而，没有观察到明显的选择性。beta..在/sup 87/Kr的未结合区域中衰减到单个水平。发现/sup 86/Kr的中子俘获截面约为5 mb，30 keV中子的麦克斯韦能量分布。讨论了延迟中子能谱作为获得能级密度信息的新工具的未来。«少
Energy levels in /sup 87/Kr have been studied, with special emphasis on the unbound region, using two different methods. The first method comprises neutron capture and transmission measurements on an enriched gas target of /sup 86/Kr using neutron time-of-flight techniques. In this way, neutron widths were determined for 39 resonances below 400 keV and capture areas for 14 resonances below 90 keV. The second method is a decay study of 56-s /sup 87/Br in which a level scheme for /sup 87/Kr has been established that shows 126 levels in the bound and 12 levels in the unbound region. A detailed comparison amongst the neutron resonance, the ..gamma..-ray decay, and available delayed neutron results has been made. Almost a one-to-one correspondence exists between the currently observed p-wave resonances below 250 keV and levels in /sup 87/Kr studied through delayed neutron emission. The overall ..beta..-strength distribution derived from the present data shows broad resonancelike structures. However, no marked selectivity is observed in the ..beta.. decay to individual levels in the unbound region of /sup 87/Kr. The neutron capture cross section of /sup 86/Kr is found to be about 5 mb for 30-keV neutrons with a Maxwellian energy distribution. The future of delayedmore » neutron spectroscopy as a new tool for obtaining level-density information is discussed.« less