Towards an NMC Ring: Dispersion suppressor

1
Towards an NMC RingDispersion suppressor long
straight section
PS2 meeting

• Y. Papaphilippou

October 24th, 2007
2
Outline

• The short NMC module
• Dispersion suppressor
• Arc
• Straight section
• Summary

3
The short NMC module

• 1 asymmetric FODO cell with 4 2 bends and a
  low-beta doublet
• Phase advances of 272o,260o per module
• ?t of 10i
• Five families of quads, with max. strength of
  0.1m-2
• Max. beta of around 60m in both planes
• Min. dispersion of -2.3m and maximum of 4.6m
• Chromaticities of -1.1,-1.7
• Total length of 71.72m
• Slightly shorter (1.1m) than last time to
  accommodate dispersion suppressor

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Dispersion suppressor cell

• Similar half module as for the NMC with 25
  dipoles (instead of 24)
• Using 4 families of quads to suppress
  dispersion, while keeping beta functions small
• Maximum beta of 70m
• Total length of 77.31m

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The NMC arc

• 5 NMC modules 2 dispersion suppressor cells
• Phase advances of (10.4p,10.2p) not matched
• ?t of 11.6i
• 9 families of quads, with max. strength of 0.1m-2
• Max. beta of around 73m in horizontal and 64m on
  the vertical plane
• Dispersion of -2.3m and maximum of 4.6m
• Chromaticities of -7.5, -11.9
• Total length of 513.22m
• Slightly longer than FODO arc (2.6m)

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Closing the ring

• Adding a straight section with 7 FODO cells,
  using 2 matching quadrupoles
• Straight drift of 9.5m
• Tunes of (12.1,11.4) not matched
• ?t of 12.1i
• 13 families of quads, with max. strength of
  0.1m-2
• Max. beta of around 71m in horizontal and 68m in
  the vertical plane
• Dispersion of -2.3m and maximum of 4.6m
• Chromaticities of -16.7, -25.8
• Total length of 1346m

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Summary

• Short NMC cell with dispersion suppressor and
  straight section with almost the same space
  characteristics as the FODO ring
• Low imaginary transition energy
• Reasonable optics functions
• In progress
• Dispersion suppressor refinement
• Matching to the straight section
• Module length optimisation
• Linear optics optimisation
• Beta function minimisation
• Working point matching and tunabilty
• Chromaticity correction
• Dynamic aperture evaluation

done
done
done