A method for measuring deviation from Lambert diffuse scattering law of ultracold neutrons on material walls

Fuente: arXiv
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Main Authors: Grigoriev, P. D., Kochev, V. D., Tsyplukhin, V. A., Dyugaev, A. M., Polishchuk, I. Ya.
Format: Preprint
Published: 2024
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author Grigoriev, P. D.
Kochev, V. D.
Tsyplukhin, V. A.
Dyugaev, A. M.
Polishchuk, I. Ya.
author_facet Grigoriev, P. D.
Kochev, V. D.
Tsyplukhin, V. A.
Dyugaev, A. M.
Polishchuk, I. Ya.
contents Modeling the motion of ultracold neutrons (UCNs) is crucial for assessing their losses, accurately measuring their lifetime, and describing other experiments. In material traps, it is necessary to account not only for specular but also for diffuse elastic reflection of UCNs from the trap walls. Typically, the Lambert cosine law is used to describe the angular distribution of diffusely scattered neutrons. However, this law lacks a rigorous theoretical derivation and is often violated. In our work, we propose an experiment to measure the deviation of the angular distribution of UCNs during diffuse scattering from the Lambert law. This deviation can be determined by the difference in the number of neutrons exiting through the central and end windows of a long narrow UCN trap. Monte Carlo simulations corresponding to a possible experiment have been performed, demonstrating a significant effect for different trap geometries.
format Preprint
id arxiv_https___arxiv_org_abs_2412_05106
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A method for measuring deviation from Lambert diffuse scattering law of ultracold neutrons on material walls
Grigoriev, P. D.
Kochev, V. D.
Tsyplukhin, V. A.
Dyugaev, A. M.
Polishchuk, I. Ya.
Instrumentation and Detectors
Atomic Physics
Modeling the motion of ultracold neutrons (UCNs) is crucial for assessing their losses, accurately measuring their lifetime, and describing other experiments. In material traps, it is necessary to account not only for specular but also for diffuse elastic reflection of UCNs from the trap walls. Typically, the Lambert cosine law is used to describe the angular distribution of diffusely scattered neutrons. However, this law lacks a rigorous theoretical derivation and is often violated. In our work, we propose an experiment to measure the deviation of the angular distribution of UCNs during diffuse scattering from the Lambert law. This deviation can be determined by the difference in the number of neutrons exiting through the central and end windows of a long narrow UCN trap. Monte Carlo simulations corresponding to a possible experiment have been performed, demonstrating a significant effect for different trap geometries.
title A method for measuring deviation from Lambert diffuse scattering law of ultracold neutrons on material walls
topic Instrumentation and Detectors
Atomic Physics
url https://arxiv.org/abs/2412.05106