RESUMO
Deuterium-deuterium (D-D) neutron spectrum diagnostics in tokamaks are a challenging task with current technologies. To address this issue, we designed and tested a fast and compact helium-3 proportional counter with a diameter of 2.5 cm and an effective length of 15 cm and using Kr as a stopping gas. The detector achieved a resolution of 96 keV for 2.406 MeV neutrons with a pulse shaping of 2 µs. Test results indicate that this detector has the potential to form a D-D neutron spectrometer for tokamaks, composed of detector arrays.
RESUMO
A hard x-ray spectrometer based on a φ25 × 25 mm2 LaBr3 scintillator has been developed to measure the runaway electron bremsstrahlung. Simulation results by GEANT4 show that x rays with an energy of 15 MeV can be effectively detected. In order to tolerate a high count rate, a self-made fast shaping amplifier is used to process the detector output into a fast bipolar pulse. The tested energy resolution, which was 3.4% for Cs-137 662 keV gamma rays, shows that the shaping amplifier does not significantly degrade the energy resolution. The results of the HL-2A discharge show that the maximum count rate can reach 2 MHz, and the time resolution of the spectrometer can reach the millisecond level.