Ponente
Descripción
Neutrons, as highly penetrating radiation, engage in complex interactions with matter
depending on their energy and nuclear structure. In underground facilities, fast neutrons
originate from nuclear reactions induced by the intrinsic radioactivity of rock and cavity
walls, as well as from the constituent materials of detectors, shieldings, and supporting
structures. Consequently, radiogenic neutrons constitute an important background that
limits low counting rate experiments in dark matter and neutrino searches, as well as in
experimental nuclear astrophysics. Understanding and quantifying the production of these
radiogenic neutrons is essential for assessing or mitigating the neutron background
affecting experiments in underground physics. On the other hand, secondary neutrons,
spanning a wide energy range from hundreds of keV to hundreds of MeV, are continuously
produced from cosmic-ray interactions in the upper atmosphere. This component
dominates the ambient neutron flux observed at ground level or higher altitudes. The
measurement of cosmic-ray neutrons is thus connected with various fields such as
cosmic-ray physics, space weather monitoring, the study of single event upsets (SEUs) in
microelectronics, and environmental dosimetry.
In this contribution, the HENSA project (www.hensaproject.org) is introduced. The High
Efficiency Neutron Spectrometry Array (HENSA) is a state-of-the-art spectrometer based
on gaseous proportional neutron counters. An overview of the research with HENSA in
underground facilities is presented, focusing on the latest results from experiments at the
Canfranc Underground Laboratory (LSC, Spain) and the INFN Gran Sasso National
Laboratory (LNGS, Italy). Furthermore, the study of cosmic-ray neutrons with HENSA is
discussed, including the mapping of cosmic-ray neutrons across Spain (vertical cutoff
rigidities 5-9 GV) during quiet solar conditions at the beginning of solar cycle #25, and the
development of a new HENSA version, called HENSA++, optimized for space weather and
environmental dosimetry applications. Finally, the future needs on R&D for neutron
detectors based on gaseous proportional counters, as well as the perspectives of the
HENSA project are outlined in this talk.
