High-speed gas neutron detector for thermometry of thermonuclear plasma

Abstract The article deals with the problem of measuring the temperature T i of ions in D–T plasma. To measure T i , it is proposed to use a gaseous proportional counter operating in the current mode. For the selection of current pulses it is proposed to use the property of products of nuclear reactions which are the alpha-particle and the residual nucleus to form the braking peak of ionization when stopped (so called Bragg’s effect). Neutron energy distribution consists of events characterized by current pulses with two peaks — due to the alpha particle and the residual nucleus. This selection method allows excluding the so-called “wall effect”, i.e. events that do not fully fit into the volume of the counter. As has been shown such kind of neutron detector can achieve an energy resolution of about 10 − 3 .