Intense synchrotron radiation from high power wiggler sources has long been a difficult high-heat-load problem to the design of properly cooled x-ray optics. Large, high power and very intense beams thermally distort crystal optics, reducing throughput and broadening rocking curves. An internally cooled silicon monochromator has been fabricated which demonstrated the capability of diffracting wiggler radiation of unprecedented power without significant degradation of the beam. Cooling water flows through rectangular cooling channels 1 mm wide, 1 mm below the diffracting surface, fed by a manifold bonded to the underside of the diffracting crystal. In an attempt to improve high power performance, a second monochromator was fabricated with a pin-fin cooling structure instead of channels. Both used a novel silver diffusion bond to ensure leak-tight UHV performance. Recent test results at wiggler station F2 show a linear behavior of the x-ray flux with increasing storage ring current up to a total power of 3 kW and a peak surface power density of 5 W/mm2. The improved monochromators have led to an increase of x-ray flux by a factor of six over previous contact-cooled designs and show that internal water-cooling can be an effective solution to high-heat-load problems at high power wiggler stations.
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