Title: HENSA at Laboratori Nazionali del Gran Sasso (LNGS): characterization of the neutron flux
Speaker: Nil Mont-Geli on behalf of the HENSA collaboration1
Neutrons are one of the main sources of experimental background affecting rare event searches carried out in underground laboratories. A good knowledge on the underground neutron flux, including potential temporal fluctuations, and their spectral distribution is, therefore, required. To that end the High Efficiency Neutron-Spectrometry Array (HENSA) was designed.
HENSA is a neutron detection system based on the Bonner Spheres principle. It is composed by several independent long 3He-filled proportional counters embedded in moderating material blocks with variable sizes in order to provide sensitivity in a wide range of neutron energies, from thermal ones up to tens of MeV.
Early versions of HENSA have already been used for the characterization of the neutron background in the Canfranc Underground Laboratory (LSC) and in the shallow underground facility Felsenkeller in Dresden. In April 2024 a version of the HENSA spectrometer was installed in hall A of the LNGS.
An overview of the HENSA project will be presented. In particular, the talk will be focused on the current experimental campaign in hall A of the LNGS, the first results and the near and mid-term future plans.
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Nil Mont Geli
PhD student
Institut de Tècniques Energètiques - Universitat Politècnica de Catalunya
Institute of Energy Technologies - Technical University of Catalonia
Avinguda Diagonal 647
08028 Barcelona
