1. MEIC Shifting Magnet
Tim Michalski
August 6, 2015

2. Maximum change in magnet spacing
Arc Chicane
Using current 22.8 m FODO cell design (8 m 3 T dipoles with 3.4 m separation)
One chicane per arc (also helps with synchronization of the 2nd IP), one extra FODO cell per arc
Takes up cells, which could otherwise be used for chromaticity compensation
x = 52 cm
x = -69 cm
Total bending angle and z length are fixed
# of FODO cells
# of magnet moved
Path length change
Radial movement range
Maximum change in magnet spacing 3
4 dipoles, 5 quads
10 cm
+52 / -69 cm
20 mm 4
6 dipoles, 7 quads
+36 / -39 cm
14 mm 5
8 dipoles, 9 quads
+28 / -29 cm
11 mm 2

3. Concept Layout of Superferric Arc Half Cell Magnets

4. Magnet Interconnect From LHC (Superferric Magnets Will Be Similar)

5. Considerations for Repositioning Superferric Magnets
Moving radially inward and outward is feasible
Use slides and measurement scheme to make repeatable
Rotation of magnets will be required as well
Considerations for interfaces between magnets and to outside world
Beamline Vacuum – bellows between adjacent beam pipe vacuum chambers
Insulating Vacuum – bellows between adjacent Arc Half-Cells (?)
Power – “service loop” for conductors
Cryogens – may require flex hoses between adjacent Arc Half-Cells and assessment of U-Tubes

7. Considerations for Repositioning PEP-II Magnets
Moving radially inward and outward is feasible
Use slides and measurement scheme to make repeatable
Rotation of magnets will be required as well – if doing a short string
Considerations for interfaces between magnets and to outside world – no major issues
Vacuum – assess capacity to expand/contract RF shielded bellows between rafts
Potential to use different bellows for different energies
Current design architecture has the Electron Collider Ring suspended above the Ion Collider Ring

8. Considerations for Repositioning PEP-II Magnets
Length of Bellows is .125m or 4.92”
Location of Bellows
With a single bellows in a Arc Half-Cell, Raft and Dipole must be moved as a pair.
Without Corrector
With Corrector

9. SuperKEK B and PEP-II HER Shielded Bellows
PEP-II HER Bellows

10. Potential Positioning Systems