Saggu P, Mineeva T, Arif M, Cory D G, Haun R, Heacock B, Huber M G, Li K, Nsofini J, Sarenac D, Shahi C B, Skavysh V, Snow W M, Werner S A, Young A R, Pushin D A
Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L3G1, Canada.
Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L3G1, Canada.
Rev Sci Instrum. 2016 Dec;87(12):123507. doi: 10.1063/1.4971851.
Neutron interferometry enables precision measurements that are typically operated within elaborate, multi-layered facilities which provide substantial shielding from environmental noise. These facilities are necessary to maintain the coherence requirements in a perfect crystal neutron interferometer which is extremely sensitive to local environmental conditions such as temperature gradients across the interferometer, external vibrations, and acoustic waves. The ease of operation and breadth of applications of perfect crystal neutron interferometry would greatly benefit from a mode of operation which relaxes these stringent isolation requirements. Here, the INDEX Collaboration and National Institute of Standards and Technology demonstrates the functionality of a neutron interferometer in vacuum and characterize the use of a compact vacuum chamber enclosure as a means to isolate the interferometer from spatial temperature gradients and time-dependent temperature fluctuations. The vacuum chamber is found to have no depreciable effect on the performance of the interferometer (contrast) while improving system stability, thereby showing that it is feasible to replace large temperature isolation and control systems with a compact vacuum enclosure for perfect crystal neutron interferometry.
中子干涉测量法能够进行精确测量，通常在精心设计的多层设施内操作，这些设施可有效屏蔽环境噪声。在完美晶体中子干涉仪中，为维持相干性要求，这些设施必不可少，因为该干涉仪对局部环境条件极为敏感，比如干涉仪内的温度梯度、外部振动和声波。完美晶体中子干涉测量法操作简便且应用广泛，若能有一种操作模式放宽这些严格的隔离要求，将大有裨益。在此，INDEX合作团队和美国国家标准与技术研究院展示了真空环境下中子干涉仪的功能，并对使用紧凑型真空腔作为将干涉仪与空间温度梯度和随时间变化的温度波动隔离开的手段进行了特性描述。结果发现，真空腔对干涉仪的性能（对比度）没有可察觉的影响，同时提高了系统稳定性，从而表明用紧凑型真空腔取代用于完美晶体中子干涉测量法的大型温度隔离和控制系统是可行的。
