Time-resolved secondary triton burnup 14 MeV neutron measurement by a new scintillating fiber detector in middle total neutron emission ranges in deuterium large helical device plasma experiments

A middle-sensitivity scintillating fiber detector (hereafter middle Sci-Fi detector) that works at a deuterium-tritium neutron flux of ~105-107 cm−2s−1 was utilized to measure secondary deuterium-tritium neutron emission rates with high temporal resolution at a total neutron emission rate of 1013 to 1015 n/s, where strong magnetohydrodynamic (MHD) instabilities were observed in the large helical device deuterium plasma experiments. The gain and angular characteristics of the middle Sci-Fi detector were evaluated in an accelerator-based deuterium-tritium neutron source in the intense 14 MeV neutron source facility at Osaka University. Observation of 1 MeV triton transport due to MHD instability was performed by a middle Sci-Fi detector whose deuterium-tritium neutron counting rate was approximately 20 times higher than that of the conventional Sci-Fi detector. Fusion-born triton transport due to energetic-particle-driven MHD instability was observed using the middle Sci-Fi detector due to its high detection efficiency and high discrimination ability of deuterium-tritium neutrons from the sea of deuterium-deuterium neutrons.

Gamma—Ray Counters to Monitor Radioactive Waste Packages in the MICADO Project

One of the goals of the MICADO Euratom project is to monitor the gamma-rays emitted by radioactive waste drums in storage sites on a medium to long term basis. For this purpose, 36 low-cost gamma-ray counters were designed and built to act as a demonstrator. These counters, named SciFi, are based on a scintillating fiber readout at each end by a silicon photomultiplier, assembled in a robust arrangement in the form of 80 cm long pipes. Several counters will be placed around radwaste packages in order to monitor the gamma dose-rate by collecting a continuous data stream. The 36 sensors were thoroughly tested with a 22Na and a 137Cs gamma-ray sources, and with an AmBe neutron and gamma-ray source, the results are quite satisfactory, and the next step will be the test in a real environment.