A boron-coated GEM detector for thermal neutron transmission: Design and first results.

Cancelli S., Muraro A., Perelli Cippo E., Murtas F., Croci G.
  Giovedì 15/09   15:00 - 18:30   Aula L - Christa Mc Auliffe   VI - Fisica applicata, acceleratori e beni culturali   Presentazione
Experiments at modern neutron spallation sources require an ever increasing number of detectors with advanced features such as high spatial resolution and high detection efficiency. The most common neutron detector is based on $^{3}He$, but the well-known $^{3}He$ shortage makes this kind of detectors not a valuable option. A suitable alternative are gas-based detectors like GEM-based ones. The detector presented in this contribution is characterised with the presence of the innovative boron-coated GEM foils (BGEM), a standard GEM foil coated on both sides with a boron layer. The presence of many BGEM foils, at least 6 or more, will allow to reach an expected detection efficiency in the order of $20%$. This contribution presents the design of the detector, the numerical simulation of a multi-layer boron-coated GEM (MBGEM) detector and the preliminary tests of a prototype at L.E.N.A reactor. The MBGEM detector prototype has been built up in two configurations, with either 3 (3MBGEM) or 6 (6MBGEM) foils in order to study the rise of the detection efficiency with the number of layers. Data analysis shows that the detection efficiency rises from $7%$ for the 3MBGEM detector to $11%$ for the 6MBGEM.