Diffraction of slow neutrons by holographic SiO2nanoparticle-polymer composite gratings

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 Pendellösung interference effect in holographic gratings has been exploited to reach a diffraction efficiency of 83% for very cold neutrons.

Holographic Gratings for Slow-Neutron Optics

“…The latter can be increased by tilting crystals [58] or holographic gratings of limited thickness [46] around an axis parallel to the grating vector. Therefore, this so-called Pendellösung interference effect allows to control the diffraction efficiency to a certain extent.…”

Effects of chain-transferring thiol functionalities on the performance of nanoparticle-polymer composite volume gratings

“…We attribute this improvement to the premature termination because of doping with thiols in free radical-mediated chain-growth polymerizations since the average polymer chain length shortens and the nonlocal photopolymer response can be reduced [19]. This result is particularly advantageous for efficient Bragg diffraction of a slow-neutron beam by an NPC volume grating, where its high spatial frequency response is required since the grating spacing enters the inverse of the KleinCook parameter quadratically [12,20,21].…”

Современное Состояние Разработки Светочувствительных Сред Для Голографии (Обзор)

“…Голографические решетки, изготовленные в фотопо-лимеризующейся регистрирующей среде, содержащей наночастицы SiO 2 , успешно использовались для исследо-вания дифракции медленных нейтронов [80]. Акриловые среды этого типа, содержащие наночастицы SiO 2 , а так-же Au, оказались пригодными для изготовления двумер-ных фотонных кристаллов [81].…”