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Researchers at the NIST Center for Neutron Research have developed and installed a large vacuum chamber at the Neutron Interferometry and Optics Facility to improve the stability of perfect-crystal neutron interferometers by isolating them from thermal gradients and atmospheric pressure fluctuations. The chamber also enables the use of cryogenically cooled samples, which has historically been unavailable in neutron interferometry experiments. As a demonstration, the team performed the first interferometric contrast measurement of a Ni60Cu40 alloy sample across a temperature range of 4 K to 300 K, validating the system's capability.
Why it matters
This advancement expands the range of physical phenomena accessible to neutron interferometry, including the study of superconductivity and other low-temperature quantum effects, which could yield new insights into fundamental physics and material properties. Improved environmental control also reduces systematic uncertainties, enhancing the reliability of precision measurements in nuclear and quantum physics research.
arXiv:2605.18874v1 Announce Type: new
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.