ANL, Argonne, Illinois, USA
Designing photon absorbers for next generation multibend achromat storage rings can be challenging considering the high power densities and limited space that will typically be present. The potential for problematically high material temperatures and thermal gradients can be expected to be greater than that for previous generation machines on account of the shorter source-to-receiving surface distances. Conventionally, photon absorbers are made from copper which is highly opaque to x-rays. A consequence of this is that the majority of the heat is absorbed within a very short distance of the surface. Utilizing materials that allow a more volumetric absorption of the radiation can improve the efficiency of heat removal as it can keep surface temperatures and thermal gradients lower than would otherwise be possible. This paper discusses multiphysics analysis of a crotch absorber for the APS Upgrade project (APS-U) via full-coupling of heat-transfer and structural mechanics. The simulation results are discussed in detail.
ANL, Argonne, Illinois, USA
The basic problem for photon absorbers in a particle accelerator is to remove a large quantity of heat from a small space. Heat pipes and vapor chambers excel at precisely this so it is natural to consider them for the application. However, even though this technology has been proven to be an excellent thermal management solution for cooling everything from laptops to satellite shields in space, they have yet to be adopted for use in particle accelerators. The use of heat pipes and vapor chambers are thermal transport devices which work on the principle of capillary-force-driven two-phase flow. These devices are highly customizable and offer very high effective thermal conductivities (5,000-200, 000 W/m/K) depending on many factors including size, shape, and orientation. This paper discusses feasibility of the use of heat pipes and vapor chambers as the primary heat transport devices in particle accelerator photon absorbers. We discuss their limitations and advantages via careful consideration of analysis and simulation results assuming properties described in the literature and manufacturer specifications.
