Diffraction of slow neutrons by holographic SiO_2 nanoparticle-polymer composite gratings

TL;DR

This study investigates how holographic SiO2 nanoparticle-polymer gratings affect slow neutron diffraction, revealing how parameters influence efficiency and demonstrating a high diffraction efficiency using Pendellösung interference.

Contribution

It presents the first application of holographic gratings in SiO2 nanoparticle-polymer composites for slow neutron diffraction, achieving high efficiency through Pendellösung effects.

Findings

Diffraction efficiency up to 83% for very cold neutrons.

Grating thickness impacts neutron diffraction performance.

Decay of the grating structure limits efficiency at larger thicknesses.

Abstract

Diffraction experiments with holographic gratings recorded in SiO$_2$ nanoparticle-polymer composites have been carried out with slow neutrons. The influence of parameters such as nanoparticle concentration, grating thickness and grating spacing on the neutron-optical properties of such materials has been tested. Decay of the grating structure along the sample depth due to disturbance of the recording process becomes an issue at grating thicknesses of about 100 microns and larger. This limits the achievable diffraction efficiency for neutrons. As a solution to this problem, the Pendell\"{o}sung interference effect in holographic gratings has been exploited to reach a diffraction efficiency of 83% for very cold neutrons.