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UP: Fachverband Umweltphysik
UP 15: Methods - Measurement Techniques
UP 15.1: Talk
Thursday, March 10, 2016, 15:15–15:30, H41
The method of soil moisture sensing by cosmic ray neutrons — •Markus Köhli1, Martin Schrön2, and Ulrich Schmidt1 — 1Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Germany — 2Helmholtz-Zentrum für Umweltforschung - UFZ, Leipzig
Probing soil moisture at intermediate scales in between those of satellite based systems and local measurements has turned out to be feasible by detecting environmental neutrons. The technique of passively sensing neutrons originating from cosmic particle air showers offers the possibility of detecting water by averaging over hectares. The key characteristic of the method is the exceptionally high moderation performance of hydrogen. It slows down fast neutrons whereas other heavier elements independent of the chemical composition rather reflect them. The environmental neutron density therefore strongly depends on the water content present around the sensor. We present Monte Carlo based simulations and measurements to study the footprint of this method for various conditions. Intensity and range dependencies can now be described by analytical functions. Especially the altitude of the sensor is the target of interest.