Few open points for follow-up:
Priority 1
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Optimize losses in RCS chain for best overall performance, allowing different transmission in the two or three machines
- Difficult with lots of degrees of freedom: straight-forward only for constant acceleration
- Difficulty of different magnets (ramp rate)
- How to distribute total RF length over different machines? Minimization of overall total voltage?
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Acceptable longitudinal emittance growth in the RCS chain and how to quantify it exactly?
- Needs figure from low-energy acceleration (low energy), longitudinal emittance for colliders as a starting point. Criteria also on how much bunch is distorted. What is acceptable bunch shape deviation in the collider?
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How do define a reasonable synchronous phase?
- First start for constant acceleration, then real ramps
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Average gradient of RF sections
- 1.3 GHz: agreed 30 MV/m (conservative) and 45 MV/m (aggressive)
- 800 MHz?
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Transient beam loading and counter-rotating bunches and multi-turn effects?
- Avoid that counter-rotating bunches meet in RF section
- Impact on placement of RF around the circumference?
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Longitudinal matching
- How to generate the short bunch length required for the transfer into the collider ring?
- Longitudinal matching of RCS with pre-acceleration stages (injection) and collider (ejection)
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Can the ILC cavity (possibly in a modified form) be used for the muon RCS?
- Power in higher-order modes (HOMs) is potential show-stopper
- Need refined paek and average power calculations for HOM couplers
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Resistive wall impedance?
- David following chamber materials
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More detailed lattice model, beyond smooth approximation.
- David developed a MAD-X lattice generator (from high-level machine parameters for muon RCS)
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Introduce chromaticity in transverse studies, do we need sextupoles?
Priority 2
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Cost functions per machine part: could one make an assumption for a cost per unit length of RF (plus some infrastructure cost offset per RF section), idem for unit length of magnets?
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Would two RCS be sufficient to accelerate from 60 GeV to 1.5 TeV?
- Does not look very attractive
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Is transition gamma of ~20 a good number for the first RCS stage?
- Check various transition gammas and their impact -> David to present
Further options
Treated, at least in some detail
