Project Details
Projekt
Detector Development; Detectors tailored for different aspects of CRNS applications
Applicant
Professor Dr. Ulrich Schmidt
Subject Area
Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management
Term
since 2018
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 357874777
In the first phase of Cosmic Sense we successfully developed several detection systems based on boron-lined proportional counters. Our strategy focused on three different pillars: low background counting tubes, analogue front-end electronics with active background suppression and a data acquisition system (DAQ). After a proof-of-principle test with a prototype we developed two stationary detector types and a large scale system for roving. For the tubes we found the solution of sputter-deposited boron carbide coatings on high-purity copper substrates operated using a low-pressure argon-CO2 filling. Our two-path front-end electronics is able to determine pulse length and pulse height and suppresses background by filtering out any other event with different signal and drift characteristics than neutron conversions. The open-source open-hardware DAQ completes the system allowing independent operation in the field including telemetry. A specific functional problem became noticeable as a degradation of the pulse height spectra and consequently a loss of count rate could be observed. This was related to the formation of acid boric compounds inside the tube. Further investigations show an interrelation with the outgassing of rubber sealing. A replacement by metal sealings resolved this problem.Phase II will focus on the improvement of the current detector setup in order to improve the quality of the system. We envisage to increase the signal-to-noise ratio and the stability of the hardware and front-end electronics with respect to outdoor environmental challenges. The former is realised by adaptation of the detectors to the improvements from the RM Neutron Simulation, including the thermal neutron shields relevant for RM Vegetation. For the latter reducing noise and focusing on a precise signal topology identification also by means of neural networks yields a more efficient use of converter materials. Current CRN detectors cannot operate independently due to the incoming radiation correction obtained from remote data bases. We plan to investigate the potential use of integrating a muon detector as a monitor for incoming radiation which would allow a real-time adjustment. With further studies from RM Neutron Simulation we will develop in collaboration with RM Roving & Airborne and RM Smart Coverage detector modifications to shape the footprint and obtain spectral information, which can lead to a more precise measurement of the moisture distribution within the CRN footprint. Importantly, the strategy for this module is to develop working low-background concepts for tubes operated at atmospheric pressure. This will be mandatory for a lightweight CRN detector for airborne applications - using a low-power airship as a sensor platform in collaboration with RS Remote Sensing can improve CRNS by extending the measurement coverage to the kilometre scale and the increased field of view reduces the near-field sensitivity to local hydrogen pools.
DFG Programme
Research Units
