Investigation of background in large-area neutron detectors due to alpha emission from impurities in aluminium
2015 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 10, 1-14 p.Article in journal (Refereed) PublishedText
Thermal neutron detector based on films of (B4C)-B-10 have been developed as an alternative to He-3 detectors. In particular, The Multi-Grid detector concept is considered for future large area detectors for ESS and ILL instruments. An excellent signal-to-background ratio is essential to attain expected scientific results. Aluminium is the most natural material for the mechanical structure of of the Multi-Grid detector and other similar concepts due to its mechanical and neutronic properties. Due to natural concentration of alpha emitters, however, the background from alpha particles misidentified as neutrons can be unacceptably high. We present our experience operating a detector prototype affected by this issue. Monte Carlo simulations have been used to confirm the background as alpha particles. The issues have been addressed in the more recent implementations of the Multi-Grid detector by the use of purified aluminium as well as Ni-plating of standard aluminium. The result is the reduction in background by two orders of magnitude. A new large-area prototype has been built incorporating these modifications.
Place, publisher, year, edition, pages
IOP PUBLISHING LTD , 2015. Vol. 10, 1-14 p.
Instrumentation for neutron sources; Gaseous detectors; Materials for gaseous detectors; Neutron detectors (cold, thermal, fast neutrons)
Accelerator Physics and Instrumentation
IdentifiersURN: urn:nbn:se:liu:diva-124525DOI: 10.1088/1748-0221/10/10/P10019ISI: 000367674700021OAI: oai:DiVA.org:liu-124525DiVA: diva2:899507
Funding Agencies|CRISP project (European Commission 7th Framework Programme Grant) 2016-02-022016-02-012016-08-31