Cosmic rays detector for the measurement of snowpack by both neutrons and muons absorption

The amount of water stored in mountain snowpack as Snow Water Equivalent (SWE) is notably difficult to measure due to the complexity of the snowpack and the remoteness of the areas of interest. Well-established methods include in-situ coring campaigns performed by specialized personnel, estimations by computational models usually relying on meteorological observations, and remote sensing by satellites. Each method has its own limitations, leaving a gap in temporal and spatial resolution that highlights the importance of deploying proximal sensors providing continuous SWE measurements in remote areas.

Recently, probes based on the detection of cosmic rays have emerged as a suitable candidate, with the development of devices based on either the absorption of neutrons or muons by the snowpack. The detector manufactured by Finapp is characterized by the patented feature of being able to contextually detect and discriminate both neutrons and muons with the same device.

The setup for SWE measurements is composed by a Finapp probe on the ground and a reference detector on a mast, out of the snowpack, to monitor the incoming cosmic rays flux. A network of 25 such systems has been deployed on the Italian mountains of the Veneto region, spanning elevations between 1400 and 2600 m asl, integrating them to pre-existent meteo-nivological stations managed by the Regional Environmental Protection Agency of Veneto (ARPAV).

SWE can be calculated basing on the drop of either neutron counts or muons counts by the ground detector. In this presentation we will compare the two methods, with a special attention to their notably different footprint, and the advantages of their simultaneous availability will be highlighted. The SWE trends will be also compared to field campaigns, historical trends and computational models.