Speaker
Description
The report is devoted to the development of gamma-ray spectrometry methods of energetic particle diagnostics, both in terms of hardware and analysis of experimental data. Measurements in the conditions of a thermonuclear experiment, i.e. in the presence of a stray magnetic field of the tokamak, high neutron and gamma background, hardly allow the use of serial laboratory equipment and require utilization of advanced methods of radiation registration, digital signal processing and algorithms for the analysis of experimental data [1]. The use of traditional scintillation spectrometers with PMTs is complicated by the presence of a variable magnetic field, a wide energy range of the measured radiation and a wide range of radiation fluxes entering the detector. All these factors affect the stability and linearity of the amplification tract of the spectrometer. A possible solution to this problem is the use of digital gain correction systems (LED illumination of the PMT) and advanced methods of digital signal processing. The development of semiconductor photodetectors (SiPM) offers the possibility of solving the problem of detector sensitivity to magnetic fields. However, the problems of gain linearity and radiation resistance of the devices remain. Detectors based on modern SiPMs demonstrate high count rates of up to 106 1/s while maintaining gain stability and energy resolution. The problem of radiation resistance of light detectors can be solved by modern methods of light transmission through liquid light guides over considerable distances with acceptable losses.
Semiconductor detectors such as HPGe have proven to be highly effective in providing information on the energy distribution of fast ions in JET experiments due to their high energy resolution. Using them in next-generation facilities like ITER and BEST requires solving the problem of correctly estimating measurement dead time using new digital signal processing methods. The most important requirement for the effective use of gamma-ray spectrometers in plasma measurements is the preliminary study of their characteristics at charged particle accelerators. The results of test measurements of detectors of different types, such as LaBr3 scintillation detectors with both conventional PMT and SiPM, as well as semiconductor HPGe spectrometers, on the cyclotron ion beam and in experiments on the Globus-M2 tokamak, are presented. New approaches to reconstructing energy ion, and electron distributions from measured photon emission are also discussed.
The study was supported by the RSF research project № 21-72-20007-P.
