Temperature-dependent topography of novel cryocooled shrink-fit cylindrical crystal

Abstract As the Diamond Light Source progresses towards becoming a fourth-generation synchrotron with the Diamond-II upgrade, there is a requirement for the development of novel approaches to the cooling of optics to enable them to cope with the associated higher heat loads. In this paper, we present a novel, indirectly cryogenically cooled monochromator assembly comprising a cylindrical silicon crystal and utilising an interference fit with an additively manufactured copper heat exchanger. Its performance is evaluated through use of experimentally validated numerical simulations. The novel monochromator was placed on the B16 test beamline at Diamond Light Source, where the strain distribution over its active surface was imaged using X-ray topography over a temperature range of 83 K to 150 K, revealing progressive relaxation of strain from 83 K to 120 K. The experimentally validated numerical model was used to predict the performance of the novel monochromator under a projected thermal load for the I19 beamline for Diamond-II, with a predicted thermal contact conductance in the order of 10000 W/m2K and RMS tangential slope errors of less than 1 µrad.