Photon Shutters. Figure 1. Assembled and exploded view of the photon shutter assembly with main components highlighted.

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Sheryl Neal
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Photon Shutters This document presents a detailed overview of ADC s beam stop and safety shutter design. Beam stops are designed as high heat load absorpers to provide equipment protection.

1 Photon Shutters This document presents a detailed overview of ADC s beam stop and safety shutter design. Beam stops are designed as high heat load absorpers to provide equipment protection. For applications requiring personnel protection, safety shutters are designed to provide high heat load and radiation absorption. ADC has designed these components to be easily removed from the beamline. This reduces the downtime required for the beamline while these critical front-end components are replaced or repaired. The following paragraphs, figures, and attached drawings will present the detailed design of ADC s beam stop and safety shutter offerings. ADC s stops and shutters consist of three major components a linear pneumatic actuator, water cooled absorber, and a vacuum chamber. These shutters are designed for ease of assembly and servicing. Figure 1 below shows the complete assembly of a photon shutter along with an exploded view highlighting the major components. By using a 4-way cross, the beam stop assembly and actuator assembly can be removed without disconnecting components directly fromt the beamline. A similar pneumatic actuator is used for ADC s safety shutter design, shown in Figure 2. The longer length absorber is attached to the actuator at two points. A rectangular UHV chamber houses the absorber allowing the actuator and absorber to be removed as a single unit. Figure 1. Assembled and exploded view of the photon shutter assembly with main components highlighted.

Beamstop Assembly Water-cooled absorbers can be provided in a range of shapes and sizes to meet individual user needs. Typically absorbers are made of OFHC copper or Glidcop.

2 Figure 2. Assembled and Exploded View of a safety shutter assembly with main components highlighted. Using a rectangular UHV chamber allows for the absorber and linear actuator to be lifted directly out of the beam line. Beamstop Assembly Water-cooled absorbers can be provided in a range of shapes and sizes to meet individual user needs. Typically absorbers are made of OFHC copper or Glidcop. OFHC copper absorbers are brazed to OFHC cooling tubes eliminating the need for direct water to vacuum joints. A water-cooled OFHC copper block absorbs radiation from the incoming beam. For high heat load applitcations, the incidence surface of the absorber is angled to spread out the beam foot print. Detailed finite element analysis (FEA) is performed on all absorber designs to verify that cooling is sufficient to avoid thermal fatigue failure. A typical beam stop assembly is shown in Figure 3 below. An example FEA report for a beam stop is presented in the Appendix. Figure 3. View of a typical beam stop assembly. Copper cooling tubes brazed into the beam stop block are ran through a modified CF flange and vacuum brazed. Ends of the copper tubes are fitted with Swagelok connections. Weight of the copper block is supported by a stainless steel shaft and bracket.

Linear Pneumatic Acuator ADC has designed a pneumatically actuated linear drive was designed to manipulate beam stop and safety shutter absorbers.

3 Linear Pneumatic Acuator ADC has designed a pneumatically actuated linear drive was designed to manipulate beam stop and safety shutter absorbers. The simple actuator design allows for quick installation onto the beamline. Different strokes and bellows sizes are easily configured with this design. To simplify the task of replacing the bellows in the case of failure, the actuator was designed with an off-center pneumatic cylinder. Figure 4 shows the actuator assembly. A large guide shaft is placed between the bellows and the actuator. This shaft supports the moment load that results from the force of atmosphere on the bellows and the actuating force of the pneumatic cylinder. Figure 4. Multiple view of the linear pneumatic actuator assembly with key components identified. To ensure smooth motion, a large diameter shaft is used. A self-lubricating bearing guides the shaft. This bearing has good impact performance and is self-lubricating. To minimize edge loads on the sleeve bearings, a generous spacing is used. To prevent the actuator from rotating, a smaller diameter stabilizing shaft is used. This shaft prevents rotation without overconstraining the actuator. Both the guide shaft and stabilizing shaft are attached to an upper and lower fixed plate. A sliding plate connects to the pneumatic cylinder and upper flange of the bellows. Total stroke of the actuator is easily adjusted in the design and can be tailored to fit individual needs. Position indicators located at the upper end of travel and lower end of travel are used. Two pairs of limit switches are used to provide redundant indication of beamstop position. Air flow to the pneumatic cylinder is controlled by a solenoid valve and flow control valves on the cylinder. UHV Chamber Various types and sizes of chambers can be provided for beam stop and safety shutter assemblies. Figure 5 shows a modified 4-way cross that is used for mounting a beam stop. The upstream side of the cross is a 4 ½ CF, non-rotatable with clearance holes. A 4 ½ CF, rotatable

with clearance holes is located on the downstream side of the beamstop. The downstream flange has a machined flat and reamed hole for placing a fiducial marker.

4 with clearance holes is located on the downstream side of the beamstop. The downstream flange has a machined flat and reamed hole for placing a fiducial marker. Steel plates, ¾ thick, are welded onto either side of the cross. Three holes in each plate provide clearance for either M6 or 1/4 mounting bolts. Figure 5. Isometric and top view of the custom 4-way cross that interfaces the photon shutter assembly with the beamline. For applications that require a larger absorber, UHV box chambers can be used to mount the actuator. By using a box chamber with a vacuum sealed lid, the lid with attached actuator can be removed together. An example of this type of setup is shown in Figure 2. A wide range of flange sizes and additional ports can be provided with the box chambers. Appendix The sections that follow provide additional views of ADC s beam stop and safety shutter designs. An example FEA is provided that shows ADC s process for verifying the design of cooling systems for OFHC copper and glidcop absorbers.

5 Beam Stop Assembly 126 Ridge Rd., PO Box 187, Lansing, NY 14882

6 Safety Shutter Assembly 126 Ridge Rd., PO Box 187, Lansing, NY 14882

PUSH PULL DEVICES. Section 03. Introduction to Push Pull Devices 044. Magnetically-coupled devices. MPPRL - Rotary and Linear Motion 046

PUSH PULL DEVICES. Section 03. Introduction to Push Pull Devices 044. Magnetically-coupled devices. MPPRL - Rotary and Linear Motion 046 Section PUSH PULL DEVICES Introduction to Push Pull Devices 044 Magnetically-coupled devices MPPRL - Rotary and Linear Motion 046 MPPL - Linear Guided Motion 048 MPP - Linear Unguided Motion 050 Edge-welded