Radiation Patterns from Electron Beam Fusion Targets

Time-integrated x-ray pinhole photographs of gold spheres and hemispheres irradiated by focused intense relativistic electron beams have exhibited radiation patterns with a distinct, brightened edge or halo. This report describes Monte Carlo electron-photon transport calculations which were performed to analyze this halo effect. A locally 1-D model of the spherical targets is presented and is used to obtain information concerning the spectral variation of the radiation pattern. These results indicate that a complete model, including film response and effective pinhole size, is required for proper quantitative comparison.