Undulator Orientation & Electron Beam Spacing Should the undulator frames be toward the central aisle or the tunnel walls? What is the optimum spacing.

Undulator Orientation & Electron Beam Spacing

• Should the undulator frames be toward the central aisle or the tunnel walls?

• What is the optimum spacing between the electron beams in the two undulators?

Slide 1Orientation & Spacing Undulators, M. Rowen, 6-15-11

Orientation & Spacing Undulators, M. Rowen, 6-15-11

Orientation of Undulators

• The issue is whether to face the undulators frame side to the wall, initial plan, or frame to the center aisle, alternate plan.

Slide 2

Frame towards aisleElectron beam at 3.0m separation

Frame towards wallsElectron beam at 2.5m separation

Pros for Frames Toward Aisle:

• Undulator vacuum chamber can be installed and aligned before the undulator is installed.

• Undulator can be removed independently; no other components need to be removed. Undulator can be removed without breaking vacuum.

• Easy access to the undulator mechanical parts for maintenance.

• Reduces the need to access the wall aisle.• Greater beam separation at the electron dump and FEE

areas. Can also increase separation of electron beam with frames toward

the aisle.


Cons for Frames to Aisle - Alignment

• Alignment is a major problem with the frames toward the aisle. Would require twice as many setups, i.e. twice the labor and result in slightly reduced vertical positioning accuracy. Initial alignment will take two crews instead of one. Doubling the cost of the

initial alignment. The crossbar will limit the geometry of the fiducials on the undulator jaw. The accuracy of the roll measurement of the roll will the decreased.

Mapping the position of undulators will require three times more setups due to the limited field of view.

Taking measurements of the vacuum chamber once the undulator is installed might be impossible. This depends on the final position of the crossbar of the undulator support and the spacing of the two undulators.

If the vacuum chamber is aligned beforehand we will have an additional leveling step.


Cons for Frames to Aisle – Beam Separation

• Requires wider x-ray beam spacing (3.0m – 3.1m) With the present (5-24-11) undulator frame layout the

beams need to be 3.06m apart to maintain a 1.5m aisle. Requires larger angle at switching magnet to switch

between hard and soft x-ray undulators. Paul Emma says he could do 3.1m if that is required. May have some negative effect on the beam.


Cons for Frames to Aisle – Magnetic Measurement

• The large variable gap undulators will be much more labor intensive to remove to the MMF.

• in situ magnetic measurements to determine if there is degradation of the magnets is a possible approach. No defined procedures for in situ measurements. Need to set up a group to look at what can be done in

this area.

• Will likely to require removal of undulator vacuum chamber. This would be more straight forward if frames are toward

the wall.Slide 6Orientation & Spacing Undulators, M. Rowen, 6-15-11

Vacuum Chamber Orientation

• Orientation of the vacuum chamber strong back effects alignment.

• Strong back to the frame would be better for alignment, but the chamber strong back would have to fit through the open undulator jaws. It is not clear this can be done.

• Placing the strong back toward aisle will reduce area expose on lower jaw for roll alignment and access to only one surface of vacuum chamber for vertical position.

• Vacuum chamber orientation needs to be assessed.


Undulator Hall – 2.5M Spacing




Access Through Undulator Line

Rack behind Undulators

Racks required only every 2nd or 3rd undulator depending on rack height.

Undulator Hall with Racks Under Quad stands


Electronics Racks

Pass Through

Racks required only every 2nd or 3rd undulator.

Conclusion Undulator Orientation

• The undulators should be oriented with their frames toward the tunnel walls.

• This is driven by: Improved configuration of alignment. Better access for in situ magnetic measurements. Does not require a change in electron beam separation.


Electron Beam Separation

• Is 2.5m the optimum electron beam separation? Need to move undulators and other large items down

central aisle way. Need access to back side of undulators for access to

electronics and maintenance. Need to be able to search the undulator hall. Need egress and access for emergencies.

• Clear space through electron beam dump.• Space at down stream end front end.• Space between hard and soft x-ray stations.


Effect on Electron Optics

• Should be able to increase separation between hard and soft x-ray lines to 2.75m without major changes to electron optics.

• Just move bend to bring beam back to parallel down stream a bit.

• By 3.0m need to increase angle of switching magnet, as there is not enough free z space.

• Need to confirm this with Paul Emma.


Dump Area

• Access between components in dump area is limited. Stands need to be redesigned Greater separation between electron beams would be

beneficial.


Experimental Stations

• Assuming 2.75m electron beam separation can increase spacing between nearer soft x-ray station and hard x-ray lines from 2.64 to 2.89m.


Front End

• Spacing with 2.75m separation at down stream front end is still reasonable. Possibly move south shielding wall out some.


ShieldingFront EndEH2



Conclusions

• Increasing beam separation to 2.75m: Improves access through dump area Space at between hard and soft x-ray lines. There a small benefit for alignment. Need to confirm:

• No significant effect on electron beam.• There are significant additional issues on fire safety and egress.• No major changes with searches.

May need to keep tunnel side walls free of utilities.


Cables & Utilities

• Keep cable and conduits off the floor. Eliminate this trip hazard. Cables and conduits should drop from over head.

• For alignment clear lines of site must be maintained (see presentation C. LeCocq). Cables and conduits drops must be limited to specific

areas. 70cm below each wall monument must be kept clear for

leveling fixtures (see presentation C. LeCocq).

• Possible run local cables to components along back of undulators.


Local Cable Runs Along Back of Undulators


Cable Trays supported from floor for local cables from equipment to electronics racks

Electronics Rack

Undulator Orientation & Electron Beam Spacing Should the undulator frames be toward the central aisle or the tunnel walls? What is the optimum spacing.

Documents

undulator frames

orientation spacing

undulators frame

aisle beam separation

position of undulators

wall aisle

undulator support

undulator jaw