Thermal fatigue tests on CuCrZr photon shutters

The CuCrZr alloy has emerged as a preferred material for thermal absorbers in synchrotron light sources, bal-ancing mechanical strength, thermal conductivity, and cost-effectiveness. However, thermal fatigue design criteria for CuCrZr components under high-intensity X-ray beam exposure are not well established. This gap exists due to a lack of experimental data from test specimens subjected to several thousand cycles of localized high temperatures exceeding 300 °C. To address this gap, thermal fatigue tests were conducted on three CuCrZr photon shutters at the NSLS-II instrumentation front end. The experimental setup, receiving an X-ray beam from an undulator, provided a peak power density ranging from 19.95 W/mm² to 38.80 W/mm² on the photon shutters’ surfaces. Within the beam footprints, calculated peak temperatures ranged from 326.8 °C to 416.5 °C. This paper presents the experimental setup, the test results, and finite element analyses of the thermomechanical response of the photon shutters. Based on both experimental and analytical findings, thermal design guidelines are proposed for CuCrZr absorbers, masks, and photon shutters.