Demonstration of a Single-Crystal Reflector-Filter for Enhancing Slow Neutron Beams

Journal Article · Tue Jun 14 00:00:00 EDT 2016 · Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment

DOI:https://doi.org/10.1016/j.nima.2016.06.047· OSTI ID:1295104

Muhrer, Guenter ^[1]; Schönfeldt, Troels ^[2]; Iverson, Erik B. ^[3]; Mocko, Michal ^[4]; Baxter, David V. ^[5]; Hügle, Thomas ^[3]; Gallmeier, Franz X. ^[3]; Klinkby, Esben ^[2]

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1. European Spallation Source (ESS), Lund (Sweden); Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Los Alamos Neutron Science Center (LANSCE)
2. Technical Univ. of Denmark, Roskilde (Denmark); European Spallation Source (ESS), Lund (Sweden)
3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Los Alamos Neutron Science Center (LANSCE)
5. Indiana Univ., Bloomington, IN (United States). Center for Exploration of Energy and Matter

The cold polycrystalline beryllium reflector-filter concept has been used to enhance the cold neutron emission of cryogenic hydrogen moderators, while suppressing the intermediate wavelength and fast neutron emission at the same time. While suppressing the fast neutron emission is often desired, the suppression of intermediate wavelength neutrons is often unwelcome. It has been hypothesized that replacing the polycrystalline reflector-filter concept with a single-crystal reflector-filter concept would overcome the suppression of intermediate wavelength neutrons and thereby extend the usability of the reflector-filter concept to shorter but still important wavelengths. In this paper we present the first experimental data on a single-crystal reflector-filter and compare experimental results with hypothesized performance. We find that a single-crystal reflector-filter retains the long-wavelength benefit of the polycrystalline reflector-filter, without suffering the same loss of important intermediate wavelength neutrons. Ultimately, this finding extends the applicability of the reflector-filter concept to intermediate wavelengths, and furthermore indicates that the reflector-filter benefits arise from its interaction with fast (background) neutrons, not with intermediate wavelength neutrons of potential interest in many types of neutron scattering.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC05-00OR22725; DMR-0220560; DMR-0320627; AC52-06NA25396; AC05–00OR22725; AC52–06NA25396
• OSTI ID: 1295104
• Alternate ID(s): OSTI ID: 1425705
• Journal Information: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 830; ISSN 0168-9002
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
Moderator
Neutron
Beam
Reflector-filter