Analysis of Thermal Characteristics of Locally Inclined Targets under Irradiation by Proton Beams with a Gaussian Current Distribution

Abstract

The applicability of the stepwise approximation of the Gaussian current density distribution is justified for calculating the thermal properties of flat and locally inclined targets (LIT) in the ANSYS program. Within the framework of a six-zone model, numerical simulation of the temperature of flat and axially symmetric LIT was carried out for uniform and several variations of Gaussian distributions of the irradiating current density. The analysis of the obtained temperature dependencies for the flat target variant reveals that they represent the sum of two contributions: a constant one, independent of the coordinate, and a variable, Gaussian one. It has been shown that transitioning from a uniform current density distribution to a Gaussian one results in similar changes in the temperature regimes of both targets. This prevents additional risks of LIT overheating due to the combined influence of the target’s corrugated surface and the inhomogeneity of the irradiating current in its Gaussian distribution. A comparative analysis of heat fluxes from the target holder into the water was carried out for various Gaussian distributions of the irradiating current density. It has been demonstrated that the maximum gain in critical heat flux values into the water is achieved when choosing LIT, provided that a uniform current density distribution is maintained through the target. In this case, the efficiency coefficient, i.e., the ratio of the maximum allowed currents, is 1.45. For Gaussian current density distributions, the gain monotonically decreases when the standard deviation parameter Sigma decreases but remains practically acceptable, with an efficiency coefficient of 1.29, down to the minimum considered value of Sigma = 3.14 mm.