Environmental Stabilization of Perfect-Crystal Neutron Interferometry Using a Large Vacuum Chamber with Cryogenic Sample Access

TL;DR

This paper presents a large vacuum chamber with cryogenic sample access for perfect-crystal neutron interferometry, enabling environmental stabilization and new investigations like superconductivity.

Contribution

Introduction of a versatile vacuum chamber with cryogenic capabilities for neutron interferometry, reducing environmental noise and allowing cryogenic sample measurements.

Findings

First cryogenic-cooled sample measurement by neutron interferometry

Contrast measured with Ni60Cu40 sample from 4 K to 300 K

Vacuum chamber effectively isolates interferometer from environmental fluctuations

Abstract

Perfect-crystal neutron interferometry has been a useful tool in measuring nuclear-interactions, probing fundamental physics, and exploring quantum phenomenon. Historically, neutron interferometry experiments have been carried out at room temperature and standard atmospheric pressure. However, neutron interferometry is sensitive to changes in the local environment, especially thermal gradients across the crystal, resulting in phase drifts and systematic uncertainty. A need for measurements performed in different sample environments compound these issues. Fortunately, the use of a vacuum chamber has been shown to be an effective method of environmental isolation for perfect-crystal neutron interferometers. A large volume, highly versatile vacuum chamber has been installed at the Neutron Interferometry and Optics Facility at the NIST Center for Neutron Research to isolate interferometry from local temperature and pressure deviations as well as allowing for the introduction of cryogenically cooled samples. The prospect of incorporating a cryostat within a neutron interferometer opens up new areas of investigation, such as superconductivity. In addition to describing the vacuum chamber, we report on the first measurement of a cryogenic-cooled sample by a neutron interferometer. For this demonstration contrast was measured with a Ni60Cu40 sample between 4 K to 300 K.