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Title: Boron carbide coatings for neutron detection probed by x-rays, ions, and neutrons to determine thin film quality

Due to the present shortage of {sup 3}He and the associated tremendous increase of its price, the supply of large neutron detection systems with {sup 3}He becomes unaffordable. Alternative neutron detection concepts, therefore, have been invented based on solid {sup 10}B converters. These concepts require development in thin film deposition technique regarding high adhesion, thickness uniformity and chemical purity of the converter coating on large area substrates. We report on the sputter deposition of highly uniform large-area {sup 10}B{sub 4}C coatings of up to 2 μm thickness with a thickness deviation below 4% using the Helmholtz-Zentrum Geesthacht large area sputtering system. The {sup 10}B{sub 4}C coatings are x-ray amorphous and highly adhesive to the substrate. Material analysis by means of X-ray-Photoelectron Spectroscopy, Secondary-Ion-Mass-Spectrometry, and Rutherford-Back-Scattering (RBS) revealed low impurities concentration in the coatings. The isotope composition determined by Secondary-Ion-Mass-Spectrometry, RBS, and inelastic nuclear reaction analysis of the converter coatings evidences almost identical {sup 10}B isotope contents in the sputter target and in the deposited coating. Neutron conversion and detection test measurements with variable irradiation geometry of the converter coating demonstrate an average relative quantum efficiency ranging from 65% to 90% for cold neutrons as compared to a black {sup 3}He-monitor. Thus,more » these converter coatings contribute to the development of {sup 3}He-free prototype detectors based on neutron grazing incidence. Transferring the developed coating process to an industrial scale sputtering system can make alternative {sup 3}He-free converter elements available for large area neutron detection systems.« less
Authors:
; ; ; ; ; ; ;  [1] ;  [2] ; ; ;  [3] ;  [4] ;  [5]
  1. Helmholtz-Zentrum Geesthacht, Max-Planck-Straße 1, 21502 Geesthacht (Germany)
  2. RUBION-Zentrale Einrichtung für Ionenstrahlen und Radionuklide, Ruhr-Universität Bochum, 44780 Bochum (Germany)
  3. Helmholtz-Zentrum Geesthacht, Außenstelle an der Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universität München, 85747 Garching (Germany)
  4. Georg-August Universität Göttingen, Geowissenschaftliches Zentrum, 37077 Göttingen, Germany and Außenstelle an der Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universität München, 85747 Garching (Germany)
  5. European Spallation Source ESS AB, P.O. Box 176, 221 00 Lund (Sweden)
Publication Date:
OSTI Identifier:
22412968
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; BACKSCATTERING; BORON 10; BORON CARBIDES; COATINGS; COLD NEUTRONS; COMPARATIVE EVALUATIONS; CONCENTRATION RATIO; HELIUM 3; IRRADIATION; MASS SPECTROSCOPY; NEUTRON DETECTION; NUCLEAR REACTION ANALYSIS; QUANTUM EFFICIENCY; RUTHERFORD BACKSCATTERING SPECTROSCOPY; SPUTTERING; SUBSTRATES; SURFACE COATING; THIN FILMS; X RADIATION; X-RAY PHOTOELECTRON SPECTROSCOPY