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P8 Shutter Review July 26, 2005. P8 – Monochromatic Photon Shutter Presented by C. Chaffee and L. Gades. P8 Shutter. P8 shutter in 9-BM-A. P8-20 3-ID-C 11-ID-A (3) 18-ID-C 19-ID-C 22-ID-C P8-30 1-BM-B 9-BM-A 11-BM-A 19-BM-C 22-BM-C. P8-50 NID-X 24-ID (ordered 2) P8-60 3-ID-B
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P8 Shutter ReviewJuly 26, 2005 P8 – Monochromatic Photon Shutter Presented by C. Chaffee and L. Gades
P8 Shutter P8 shutter in 9-BM-A
P8-20 3-ID-C 11-ID-A (3) 18-ID-C 19-ID-C 22-ID-C P8-30 1-BM-B 9-BM-A 11-BM-A 19-BM-C 22-BM-C P8-50 NID-X 24-ID (ordered 2) P8-60 3-ID-B 16-ID-A 30-ID P8 modified 6-ID-A P8-81 5-BM-A P8 Shutter Locations There are 18 P8 shutters at the APS.
P8 Shutter Features • Movable mono beam shutter • Beam collimator Redundant tungsten mono shutters work as a unit Standard actuator with copper shaft Tungsten collar at exit Pumping Port
P8 Shutter Features • Cooling “fins” increase SA:V ratio • Cooling not really necessary • Tungsten melting point: 3422 oC
How is the P8 different? • No white beam stop • No bremsstrahlung collimator • P4, P5, P6, P7 are generally used in conjunction with a double crystal monochromator, which shifts the mono beam 35mm above the white beam path. • No water cooling • Cooling fins
How is the P8 different? Mono beam only • Energy comparison • White beam ~1000 keV • Pink beam ~30 keV or less • Mono beam ~1 eV
How is the P8 different? Mono beam only • Stopping power • White beam shutter ~6000 watts • Mono beam shutter ~10 watts • Tungsten shielding • White shutter = 180mm • Mono shutter = 60mm
Why use a P8 Shutter? • Cheap! • Smaller • Less complicated design • For beamlines that do not require a WBS • For beamlines that do not require a bremsstrahlung collimator • Standard actuators • Easy to reproduce
P8 Typical Failure Modes • Pneumatic actuators: designed to be exercised regularly, but are used only intermittently. Cup seals • Become set • Right or wrong, past personnel put lubrication in the cylinders • Bearings
P8 Typical Failure Modes • Inconvenient when it does fail • No ports for access to the cylinders • Entire actuator must be removed
P8 Typical Failure Modes • Shutter is designed to “fail safe.” • If the pneumatics were to fail, the tungsten block would fall into the beam path • Tungsten falls farther than it needs to • Even if shutter stroke is slightly off, the tungsten still falls far enough to stop the beam • Hard stop below the tungsten • It cannot fall through, beyond the beam path
P8-20: ID Mono Shutter • Standard P8 design for ID beamlines Stroke = 31mm Aperture = 3.25” x 0.75”
P8-30: BM Mono Shutter • Standard P8 design for BM beamlines Stroke = 31mm Aperture = 4.825” x 0.75”
P8-20 vs. P8-30 ID vs. BM: It’s all in the collimator aperture BM Aperture = 4.825” x 0.75” ID Aperture = 3.25” x 0.75” P8-20 P8-30
P8-40: Temporary Design • Entire P8 is turned 90o to provide a vertically tall aperture: 0.75” wide x 3.25” tall Extension Spring
P8-60: Large Vertical Aperture • Re-designed P8-40 • Cylinder vertically oriented Stroke = 108mm Aperture is turned 90o to allow for multiple offsets of the mono crystals Aperture = 0.75” x 3.25”
P8-60: Large Vertical Aperture • Contrast the stroke of the P8-60 with other P8 shutters 108mm 31mm P8-60 Standard P8
P8-60: Large Vertical Aperture • Contrast the stroke of the P8-60 with other P8 shutters 108mm 31mm Standard P8 (3-ID-C) P8-60 (3-ID-B)
P8-50: Compact Design • P8 designed for the NID-X backscattering beamline Stroke = 31mm Aperture = 2.00” x 1.00”
6-ID-A Modified P8: What’s different? • Geometry of the vacuum chamber • Pneumatic actuator design • Side port for electromagmetic metal foil: a diagnostic tool • Got in the way and was blocking the beam • Removed
Acknowledgements • Thanks to the following people for contributing reference information • MU-CAT Personnel • Doug Robinson • BESSRC-CAT Personnel • Mark Beno • APS Personnel • Mohan Ramanathan