Testing a novel sensor design to jointly measure cosmic-ray neutrons, muons and gamma rays for non-invasive soil moisture estimation

Abstract

Abstract. Cosmic-ray neutron sensing (CRNS) has emerged as a reliable method for soil moisture and snow estimation. However, the applicability of this method beyond research has been limited due to, among others, the use of relatively large and expensive sensors. This paper presents the tests conducted to a new scintillator-based sensor especially designed to jointly measure neutron counts, total gamma-rays, and muons. The neutron signal is firstly compared against two conventional gas-tube-based CRNS sensors at two locations (Austria and Germany). The estimated soil moisture is further assessed at four agricultural sites in Italy based on gravimetric soil moisture collected within the sensor footprint. The results show that the signal detected by the new scintillator-based CRNS sensor is well in agreement with the conventional CRNS sensors and with the gravimetric soil moisture measurements. In addition, the muons and the total gamma-rays simultaneously detected by the sensor show promising features for a better correction of the incoming variability and for discriminating irrigation and precipitation events, respectively. Further experiments and analyses should be conducted, however, to better understand the added value of these additional data for soil moisture estimation. Overall, the new scintillator design shows to be a valid and compact alternative to conventional CRNS sensors for non-invasive soil moisture monitoring that can open the path to a wide range of applications.

Toward Large‐Scale Soil Moisture Monitoring Using Rail‐Based Cosmic Ray Neutron Sensing

“…For example, the local natural background of incoming cosmic ray neutrons might have temporarily deviated from the data used as recorded at Jungfraujoch at > 600 km distance. Local incoming correction strategies with muon detectors have been recently suggested by Stevanato et al (2022) and Gianessi et al (2022), and might have the potential to correct existing deviations such as the unrealistic fluctuations observed during a day without precipitation) or shielded topographic terrain (e.g., F1). The prospects of higher sensor performance (i.e., increased counting rates), incorporation of additional land cover data (e.g., biomass), and more frequent calibration campaigns may increase the quality of the provided SWC product.…”

“…We also employed a commercially available stationary CRNS sensor from May 2022 onwards to compare these results with the SWC from the Rail-CRNS system. The stationary CRNS sensor was a Finapp-5 neutron, muon and gamma-ray detector based on 6 Li and scintillator technology (Finapp s.r.l., Italy; see also Stevanato et al, 2019;Gianessi et al, 2022). The sensor was installed at the meadow site M, close to one of the WSN nodes (cf.…”

Incoming Neutron Flux Corrections for Cosmic‐Ray Soil and Snow Sensors Using the Global Neutron Monitor Network

“…The correction itself is of a linear form. We also note that there have been attempts to create local corrections for intensity by adding muon sensors to CRNS stations (see Gianessi et al, 2022), however, this approach is in its infancy and widespread application requires further research and testing.…”

Three years of soil moisture observations by a dense cosmic-ray neutron sensing cluster at an agricultural research site in north-east Germany

“…Details are contained in the data repository. uses a multiwire proportional chamber with solid 6 Li (Fersch et al, 2020;Patrignani et al, 2021); StX-140-5-15 apply 10 Blined converters; the FINAPP3 probe relies on a multi-layer zinc sulfide and Ag-100 doped scintillator mixed with 6 Li fluoride powder (Gianessi et al, 2022). In addition to epithermal neutrons, two devices also recorded thermal neutron count rates which might have the potential to support the separation of signals from soil moisture, vegetation, or snow (Tian et al, 2016;Jakobi et al, 2018).…”

“…2) was operated from May 2021 until May 2022. For detector-related technical details, we refer to Gianessi et al (2022).…”