Filter method and silicon detectors to measure the temperature of a hot dense thermal deuterium plasma from its quantum bremsstrahlung

Abstract

The filter method, used to measure the temperature of a hot (T> 1 keV) deuterium plasma through its bremsstrahlung emission, is studied taking into account two new features: (i) the bremsstrahlung emission (accounted for, up until now, by its classical approximation) is described by its quantum expression, (ii) real solid-state silicon detectors are considered, instead of ideal ones. Deductions are made concerning the best choice of the detector and the corresponding adequate filter for different temperature ranges; the limits of the temperature ranges are established considering the minimum number of points necessary to identify the shape of the spectrum curve, as well as the loss of efficiency of the detectors at high energies. An upper bound is set to the measurable temperature. Neutron radiation damages to the Si detectors, at current and foreseen levels, are considered and shown to impose no serious limitation to the practical applicability of the method.