Measurements of ultracold neutron upscattering and absorption in polyethylene and vanadium
Measurements of ultracold neutron upscattering and absorption in polyethylene and vanadium
复制标题
DOI：
10.1103/physrevc.88.037601
复制
发表时间：
2013-09-03
影响因子：
3.1
通讯作者：
Zeck, B. A.
中科院分区：
文献类型：
--
作者：
Sharapov, E. I.;Morris, C. L.;Zeck, B. A.
作为超冷中子的有效“吸收剂”的元素的中子截面研究对于核物理、粒子物理、宇宙学和引力等领域的许多精密实验都是至关重要的。在这种情况下，“吸收”包括中子的捕获和上散射到UCN能量区域以上的能量。现有的数据，特别是关于氢的数据，两者之间或与理论都不一致。在本报告中，我们描述了在洛斯阿拉莫斯国家实验室UCN设施中进行的UCN上散射截面对钒和氢在CH2中的测量，同时测量了这些元素的辐射捕获截面。我们测量了CH2中氢的sigma(up) = 1972 +/- 130 b，低于理论预期，而钒的sigma(up) = 25 +/- 9 b，与固体中热激发中子加热的预期一致。
The study of neutron cross sections for elements used as efficient "absorbers" of ultracold neutrons (UCN) is crucial for many precision experiments in nuclear and particle physics, cosmology and gravity. In this context, "absorption" includes both the capture and upscattering of neutrons to the energies above the UCN energy region. The available data, especially for hydrogen, do not agree between themselves or with the theory. In this report we describe measurements performed at the Los Alamos National Laboratory UCN facility of the UCN upscattering cross sections for vanadium and for hydrogen in CH2 using simultaneous measurements of the radiative capture cross sections for these elements. We measured sigma(up) = 1972 +/- 130 b for hydrogen in CH2, which is below theoretical expectations, and sigma(up) = 25 +/- 9 b for vanadium, in agreement with the expectation for the neutron heating by thermal excitations in solids.