Double-undulator tests of a diamond monochromator at the Advanced Photon Source

We have tested the thermal performance of a water-cooled diamond double-crystal monochromator under twice the typical undulator thermal load at the Advanced Photon Source (APS). With two 3.3-cm-period undulators installed in series in the APS sector 1 straight section, the maximum power and normal power density incident on the first crystal were 705 W and 312 W/mm2, respectively. The maximum power and surface power density absorbed by the cooled diamond were 140 W and 16.7 W/mm2, respectively. The monochromator performed well under this large power load, demonstrating the viability of using water-cooled diamonds for high-intensity synchrotron radiation beamlines.