Application of Nuclear Physics Methods for Plasma Diagnostics on a Gas-Dynamic Trap

A diagnostic system has been developed on the gas dynamic trap (GDT) for detecting deuterium fusion products as well as X rays and γ rays produced by interactions of superheated electrons with structural elements of GDT and by capture of neutrons by nuclei of surrounding materials. The diagnostic system consists of the following three subsystems. The first subsystem is used to measure the longitudinal intensity profile of the dd-fusion reaction. It is based on diode detectors of 3.02-MeV protons and preamplifiers capable of operating with large-area diodes mounted in specially developed detector modules. The detectors are located inside the vacuum chamber of the GDT; they operate in the counting mode, which allows absolute measurements of the reaction-product flux with a time resolution of ~100 μs. Such detectors were created taking into account the operating experience of a proton detector based on an experimental diode in the GDT experiment. The second subsystem is composed of detectors developed earlier on the basis of SPM-5 plastic scintillator and a photomultiplier tube (PMT). These detectors are operated in the current mode and are intended to measure the neutron-generation intensity with a time resolution as high as 25 μs. These detectors are used jointly with the proton detectors in experiments with the additional heating to determine the contribution of γ rays and hard X rays. The third subsystem is a new neutron and γ-ray spectrometer based on a stilbene scintillator and a PMT, which was used for the first time in the experiment with deuterium plasma at the GDT facility. The detector is capable of separating particles of different types, in particular, under the operating conditions of the facility when superheated electrons are generated.