Numerical Analysis of Electron-Beam Induced Heating within High Z Solid Targets

Abstract

Electron-beam induced heating within solid targets of high atomic number Z such as Ta and W in x-ray sources is investigated with a method of numerical analysis. The depth-dose curve for pulsed electron beams of energy ranging from 5 to 50 keV is calculated by using the Monte Carlo method. From the depth-dose curves, the projected range as a function of beam energy is determined by means of analytical expressions in the limited range of 73_??_Z_??_74. A volume heat source in the heat diffusion equation can be written in terms of the projected range and a normalized Grun function. The normalized Grun function is expressed by a polynomial which can be calcuated by a balanced reationship of the incident beam energy density. The heat diffusion equation has been appield to numerically calculate temperature profiles within the targets as a function of time. The results can be used to determine the maximum surface temperture and the thickness of melted targats for different incident energy densities. Usefulness of these results in manufacturing processes using electron-beam heating such as hardening, cutting and welding has been pointed out.