Commercial developments in synchrotron optical components: a novel coolant for high-heat-load optics

摘要

Abstract: We describe a novel coolant suitable for high heat load optics called Binary-Ice$+R$/. This coolant exploits the latent heat of microscopic ice particles in a water/antifreeze mixture, which confer an effective specific heat capacity up to eight times that of water. Binary-Ice$+R$/ has a film heat transfer coefficient several times that of water or brine which reduces the thermally induced strain in optical components compared to identical water-cooled configurations. Furthermore, the coolant temperature only increases by a few degrees under normal operating conditions, yielding uniform cooling. Finite element analysis has been used to model a thin silicon $LB@111$RB crystal that is back-cooled by brine or Binary- Ice$+R$/ with an incident power density of 4 Wmm$+$MIN@2$/ commensurate with a modern bending magnet monochromator. Water cooling was found to be impracticable due to the thermal bump inducing a spread in the selected bandwidth which was greater than 50% worse than the intrinsic resolution of Si$LB@111$RB@, and a downward shift in the energy by more than the intrinsic bandwidth. By comparison Binary-Ice$+R$/ yielded the intrinsic resolution at low energies and a shift in the energy by only 10% of the bandwidth. The application of Binary-Ice$+R$/ for cooling of diamonds in undulator monochromators, and for the cooling of x-ray mirrors and multilayers is also discussed. !33