# Presentation: 188825

## 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 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 actuator
- with copper shaft

- Redundant
- tungsten
- mono shutters work as a unit

**Notes:**
Note:  copper was used for the shaft to dissipate heat.  Because this cooling has not been needed, some of the P8’s are now being built with stainless instead of copper.

## P8 Shutter Features

- Cooling “fins” increase SA:V ratio
- Cooling not really necessary
- Tungsten melting point:  3422 oC

**Notes:**
Cooling not really necessary:  power on the order of milliwatts

## 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

**Notes:**
Shutters that we have seen so far have either been mode shutters, or have been able to stop white beam and pass mono beam downstream.

## 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

**Notes:**
3-ID-C P8-20

## 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

## 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

**Notes:**
Special safety concern:  with the shutter on its side, gravity cannot cause it to “fail safe.”  An extension spring was installed so that the shutter would be pushed closed, should the pneumatics fail
Still issues of strain on some of the parts.  Thus, this design was used only temporarily at 3-ID until the P8-60 was complete.

## P8-60:  Large Vertical Aperture

- Re-designed P8-40
- Cylinder 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

- 31mm

- 108mm

- Standard P8 (3-ID-C)

- P8-60 (3-ID-B)

**Notes:**
The P8-60 design has been successful.  Sector 3 plans to replace the standard P8 in 3-ID-C with a P8-60.  

## P8-50:  Compact Design

- P8 designed for the NID-X backscattering beamline

- Stroke = 31mm

- Aperture = 2.00” x 1.00”

**Notes:**
Note:  Some beamlines like this compact design.  24-BM and 24-ID each ordered a P8-50.
Note:  No pumping port

## 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