A. Chance – Dispersion Matching and spurious dispersion correction

Insertion are matched via dispersion suppressor and 2 additional quadrupoles per side if needed.

Tune is matched via the FODO cells in the long arcs only, short arcs stay at 90 degree phase advance.

No specific phase advance between IP and first sextupole yet.

Spurious dispersion peak of up to 5m in the triplet without correction. Non-negligible dispersion beating in the arcs.

Correction scheme: orbit bump in short arcs.

Rogelio agrees to only use short arc for orbit bump

Problems: orbit offset of ca. 9 mm, x/y beta beating of 5/2 %

Rogelio comments that fixed phase advance can reduce orbit and beta beating by ~50%.

A. Chance, B. Dalena and J. Payet should make proposal for IR phase advance and first strong sextupole.

A. Chance - Symmetric vs asymmetric IRs/arcs

Current design: anti-symmetric insertions, symmetric arcs. Number of FODO cells to be discussed. Large number of possibilities. What is the best?

Options:

1. All arcs and insertions anti-symmetric

2. short arcs and insertions anti-symmetric, long arcs symmetric

Tracking studies and higher order optics will help decide on symmetry vs. anti-symmetry.

Implementation of alternatives is not much work.

Antoine ask whether there are preferences for symmetry or anti-symmetry.

Rogelio replies that there are no preferences yet, to be determined as shown in R. Martin's presentation.

Barbara asks if symmetric IRs will be studied. Rogelio replies that IRs will stay anti-symmetric, only (anti)-symmetry of arcs should be studied.

Rogelio comments that 2. of shown options would be best.