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DOI 10.5286/raltr.2017007
Persistent URL http://purl.org/net/epubs/work/34325959
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Record Id 34325959
Title The problem of lost neutron flux on the MAPS instrument, and how it was recovered
Abstract After a long ISIS shutdown on target station 1 during 2016, it was found that the neutron flux on the MAPS spectrometer was substantially compromised, with an energy-dependent reduction of between two and five measured. To determine and remedy the cause of this problem, extensive investigations were performed, both on the instrument and involving neutronic and ray-tracing simulations. The key measurement that provided the most insight into the nature of the problem was to use a pinhole camera setup to obtain a spatially-resolved image of the neutron source as viewed from the sample. This revealed a highly inhomogeneous distribution of flux from the source, in contrast to a similar measurement performed on the adjacent VESUVIO beamline which views the same moderator face but showed no such inhomogeneity. The problem was eventually solved by replacing the MAPS beamline shutter, an expensive and difficult task.
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Licence Information: Creative Commons Attribution 3.0 Unported (CC BY 3.0)
Language English (EN)
Type Details URI(s) Local file(s) Year
Report RAL Technical Reports RAL-TR-2017-007. STFC, 2017. RAL-TR-2017-007.pdf 2017