LIQUID-NITROGEN COOLING OF MONOCHROMATOR CRYSTALS EXPOSED TO INTENSE SYNCHROTRON RADIATION

Using insertion devices as intense light sources in the new, third generation storage rings leads to considerable heat load at the first optical element in the beamline. To minimize the thermal slope of these elements it is proposed to cool them cryogenically. In this article we present first tests of liquid nitrogen cooling of silicon and germanium crystals exposed to high intensity synchrotron radiation. The test were performed with white radiation from the HARWI wiggler at the Hamburger Synchrotronstrahlungslabor (HASYLAB). During the experiment the DORIS ring was running at 3.7 GeV electron energy and up to approximately 100 mA current. The maximum power at the sample surface was approximately 100 W with power densities of up to 0.4 W/mm2. The minimization of thermal deteriorations by cryogenic cooling is demonstrated unambiguously by optical interferometry.