High heat load fixed primary aperture for an undulator beamline with integral beam position monitors
- Structural Biology Center, Argonne National Laboratory, Advanced Photon Source, 9700 S. Cass Ave., Argonne, Illinois 60439 (United States)
A fixed primary aperture has been designed and built to limit the angular extent of radiation from an APS undulator onto a liquid nitrogen-cooled monochromator crystal. The design combines high heat load capability, simplicity and ease of manufacture, and integral thermal beam position monitors. The aperture is designed to absorb 9 kW, the amount produced by the APS undulator A at 300 mA beam current after passing through apertures in the front end. The device consists of a Cu-cylinder of 150 mm length and about 90 mm diameter with a tapered rectangular opening converging to 4 mmx2 mm (horizontalxvertical) at the narrowest point. Radial saw cuts along the cylinder axis from the outside in create fins which provide a large Cu-to-water interface. A cylindrical shell with water inlet and outlet manifolds is brazed to the outside of the cylinder. Conflat flanges are brazed to both ends for vacuum connection. Thermocouples inserted into holes drilled through the fins from top, bottom, left and right at the location of the narrowest opening provide differential temperature readings which are calibrated and translated into beam position. Sensitivity is heat load dependent and better than 0.1 mm at small and medium undulator gaps and better than 0.2 mm even at large gaps.
- OSTI ID:
- 21179511
- Journal Information:
- AIP Conference Proceedings, Vol. 417, Issue 1; Conference: 10. United States national conference on synchrotron radiation instrumentation, Ithaca, NY (United States), 17-20 Jun 1997; Other Information: DOI: 10.1063/1.54606; (c) 1997 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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