Characterization of diamond and organic scintillation detectors utilizing radiation sources for continuous plasma operation

Abstract

This paper provides a comprehensive study of neutron calibration methodologies, specifically highlighting the capabilities for n–γ discrimination in diamond and EJ-309, and stilbene scintillation detectors. The calibration process detailed in this study includes pulse height analysis and pulse shape discrimination, relying on the analysis of charge deposition resulting from both γ and neutron interactions. Utilizing 60Co and 252Cf radiation sources, the energy spectra of these sources are obtained. The characterized detectors were used in ST40 experiments and allowed acquiring neutron signal during a plasma shot with good agreement among diamond and scintillation detectors. Then, the diamond detector was cross-calibrated against indium activation foils placed at the same location in proximity to the ST40 during plasma shots: both detectors measured a neutron flux of ≈106 cm−2 s−1 at ≈1 m distance from the tokamak center, and the discrepancy between the diamond detector and the activation foils is ≈25%.