Ion Path Length Compensation with Chicane V. Morozov, P. Nadel-Turonski, M. Sullivan MEIC R&D Meeting, JLab, May 29, 2014 F. Lin

Outline Naïve look Practical considerations Realistic estimate Conclusions 2

Naïve Look Triangular chicane with 20 m base and 1 m height  ~10 cm additional path length, solves some of the problem Chicane with double the height  ~40 cm additional path length, solves the whole problem, looks attractive 1 m 20 m 2 m 20 m 3

Some Practical Considerations Orbit curvature changes inside the dipoles  limit maximum sagitta R Using optimal curvature   4

Realistic Estimate Assume each dipole is 3 m long and bends by 50 mrad and require 40 cm path length increase 4 dipoles 8 dipoles 12 dipoles 16 dipoles 5

Realistic Estimate Consider solving half the problem, 20 cm path length increase 4 dipoles 8 dipoles 12 dipoles 6

Conclusions Naïve estimate looks attractive but, because of the finite dipole lengths, a realistic chicane comes out much longer. 12 dipole case seems best but the chicane length is still 66 m with the maximum orbit deviation of about 3.25 m. A chicane would solve a lot of problems though No orbit shifts in either collider ring No change of electron SRF frequency (ion SRF still has to accommodate harmonic jumps) No CEBAF synchronization problem Conceptually simple, almost no additional R&D needed  easier to convince reviewers that it will work? Easier to cost? Is such a chicane realistic? 7