P8 Shutter Review

July 26, 2005

P8 – Monochromatic Photon ShutterPresented by C. Chaffee and L. Gades

P8 Shutter

P8 shutter in 9-BM-A

P8 Shutter Locations

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

There are 18 P8 shutters at the APS.

P8 Shutter Features

Movable mono beam shutter

Beam collimator

Pumping Port

Tungsten collar at exit

Standard actuatorwith copper shaft

Redundant tungsten mono shutters work as a unit

P8 Shutter Features

Cooling “fins” increase SA:V ratioCooling not really necessaryTungsten melting point: 3422 oC

How is the P8 different?

No white beam stopNo bremsstrahlung collimatorP4, 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 coolingCooling fins

How is the P8 different?

Mono beam onlyEnergy comparison

White beam ~1000 keVPink beam ~30 keV or lessMono beam ~1 eV

How is the P8 different?

Mono beam onlyStopping power

White beam shutter ~6000 wattsMono beam shutter ~10 watts

Tungsten shieldingWhite shutter = 180mm Mono shutter = 60mm

Why use a P8 Shutter?

Cheap!SmallerLess complicated design

For beamlines that do not require a WBSFor beamlines that do not require a

bremsstrahlung collimatorStandard actuatorsEasy to reproduce

P8 Typical Failure Modes

Pneumatic actuators: designed to be exercised regularly, but are used only intermittently.

Cup sealsBecome setRight or wrong, past personnel put lubrication in

the cylinders

Bearings

P8 Typical Failure Modes

Inconvenient when it does failNo ports for access to the cylindersEntire 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 pathTungsten 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

Variations on the P8

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 P8-40Cylinder vertically oriented

Aperture = 0.75” x 3.25”

Stroke = 108mm

Aperture is turned 90o to allow for multiple offsets of the mono crystals

P8-60: Large Vertical Aperture

Contrast the stroke of the P8-60 with other P8 shutters

108mm

Standard P8 P8-60

31mm

P8-60: Large Vertical Aperture

Contrast the stroke of the P8-60 with other P8 shutters

31mm108mm

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 chamberPneumatic actuator designSide port for electromagmetic metal foil:

a diagnostic toolGot in the way and was blocking the beamRemoved

Acknowledgements

Thanks to the following people for contributing reference information

MU-CAT PersonnelDoug Robinson

BESSRC-CAT PersonnelMark Beno

APS PersonnelMohan Ramanathan