Decoupling of a neutron interferometer from temperature gradients

Abstract

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.

Next-generation high transmission neutron optical devices utilizing micro-machined structures

“…With this device a path separation of only 60 µm was obtained, which was later improved to a few centimeters with a perfect crystal Mach-Zehnder interferometer relying on Bragg diffraction 29 . The perfect crystal interferometer allowed for a number of investigations on neutron properties and interactions with unprecedented precision [30][31][32][33][34] but suffered some important drawbacks including a narrow wavelength acceptance and difficulty of fabrication [35][36][37][38] .…”

Generalizing the Quantum Information Model for Dynamic Diffraction

“…The theory of dynamical diffraction, which was originally developed by Cowley and Moodie for electron propagation through lattices [13], describes the behavior of neutrons inside perfect crystals and must be used over the kinematic theory when the crystal thickness or mosaic block size is larger than the extinction length [14][15][16][17]. However, use of the standard theory can only reasonably accommodate relatively-simple crystal geometries [18], strain fields [19,20], and incoming beam phase spaces [21,22], factors which impact device design and can bias experimental results [7,9,11,23,24].…”

Angular alignment and fidelity of neutron phase-gratings for improved interferometer fringe visibility

“…[3][4][5][6][7][8] Nonetheless, the wide spread adoption of this technique was hindered by its narrow wavelength acceptance and the stringent requirements for environmental isolation, beam collimation, and setup alignment. [9][10][11][12] A less demanding setup is a grating-based, Mach-Zehnder interferometer which relies on the coherent control and mixing of the various grating diffraction orders. [13][14][15][16][17] However, these interferometers require using cold (λ ∼ 5 Å) or very cold neutrons (λ ∼ 100 Å) with a high degree of collimation; greatly limiting their wide spread use.…”