Bochum 2018 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 52: Poster
HK 52.51: Poster
Thursday, March 1, 2018, 16:30–18:45, Audimax Foyer
Characterization of ultra-nanocrystalline diamond films as reflector for ultra-cold neutrons — Hadwig Sternschulte1,2, Stephan Wlokka2, •Andreas Frei2, Peter Geltenbort3, and Stefan Wenisch2 — 1Fakultät für Geistes- und Naturwissenschaften, Hochschule Augsburg, Germany — 2Heinz Maier-Leibnitz Zentrum, Technische Universität München, Germany — 3Institut Laue-Langevin, Grenoble, France
Diamond is an excellent reflector for ultra-cold neutrons (UCN) due to the high atom density in combination with a large bound coherent scattering length and low loss cross sections. As a material with high radiation hardness it is especially suitable for UCN reflectors close to a reactor core or a spallation target. Ultra-nanocrystalline diamond (UNCD) films have a very low surface roughness independent of the film thickness. They can be grown on various substrates with 3D geometries by chemical vapour deposition and are therefore promising candidates for UCN reflecting layers in superthermal sources for UCN, which are currently build up. UNCD films have so far not been used as UCN reflectors.
In this work we present the first measurements of the UCN storage properties of UNCD films. In a storage chamber made from stainless steel four side walls were covered with several µm thick UNCD films grown on 6” Si substrates. The experiments show a significant increase of the effective UCN storage time compared to the pure stainless steel chamber. The influence of the surface termination of the UNCD films on the effective UCN storage time will be discussed.