The Role of the Spatial and Temporal Radiation Deposition in Inertial Fusion Chambers

Full text: The future reactor chamber wall of HiPER will have to withstand short energy pulses (some μs long) of 5 to 20 MJ mostly in form of X-rays and charged particles every 100 to 200 ms (i.e. around 25% of the produced 20 - 100 MJ inertial fusion energy (IFE)). This energy, if not avoided, will heat, stress, erode and damage the chamber wall and final optics. A wise selection of wall material and chamber dimensions has to be taken in order to minimize the damage so that the facility can be fully functional during its planned lifetime. The figure of merit for both, x-ray and charged particle threats, is the maximum fluence (J/cm2) which the chamber components can resist without risk of failure. However, it is of paramount importance to understand that this upper limit comes determined by how these particles deposit their energy spatially and temporally on the materials. Roughly speaking, these two characteristics of the particle-matter interaction depend on the energy and temporal spectra of the incident particles and the absorption and energy transport properties of the material. Calculations using different approaches for energy deposition on tungsten will be presented, showing the importance of the spatial and temporal deposited energy profile in Inertial Fusion Tungsten armor material. (author)