1. MCS meeting 20/11/2015 S. Guiducci

2. Introduction Yesterday meeting has shown an interest in a large physics community to incremental development of muon accelerators capability At present we do not have the resources available for a muon collider design study How to proceed? Start from the results of the US Muon Accelerator Program conceptual design (see M. Palmer’s slides at https://indico.cern.ch/event/450863/timetable/#20151118.detailed ) Make a list of the resources needed to assess the feasibility of a muon 6D cooling demonstrator based on the MAP concept

3. 6D cooling demonstrator MAP concept The MAP concept of a cooling system capable of a 6D emittance reduction by a factor 10 5 (MAP Higgs factory requirement L=, DE/E=) is linear The advantage of linear with respect to ring is the possibility to tune the cell parameters as far as the emittances are reduced: large apertures and relatively low magnetic fields are required at the beginning, while very high fields and smaller apertures are needed for the final cells. The technical systems require detailed engineering but are considered feasible A start to end simulation done with specialized codes gives the 10 5 emittance reduction factor

4. Preliminary questions To get the Higgs Factory muon bunches at the entrance of the cooling channel a high power proton driver and target system and a challenging front end are required: is it possible to have a significative cooling demonstration using muon bunches with reduced specifications? Is there an EU lab which can provide (with a reasonable investment) muon bunches with specifications (energy, time structure, intensity, emittances) suitable for a cooling demonstrator? Is it possible to implement the cooling demonstrator in steps? Is it needed/useful a technical demonstration of a final cell of the cooling channel before having a proper muon beam to demonstrate the cooling? Is there a possible utilization of the cooled beam for physics?

5. Initial resources Minimal resources needed to give an answer to these questions: – people to perform start-to-end simulations to evaluate the possible configurations (specialized codes have been developed by MAP, a collaboration to get these codes could be initiated) – experts in targets and muon sources to provide a preliminary study of the type of muon bunches (fitting a 325 MHz bucket) which could be achieved in the EU labs without major investments In a preliminary stage experts of the more challenging technical systems should give an advice in order to use systems and parameters that are considered feasible(or suggest topics requiring R&D) for: – high field magnets – RF in magnetic fields

6. An example of the linear cooling channel requirements stageB(T)Aperture (cm)type A12.450SC solenoid A46.025SC solenoid B8154.5Nb 3 Sn stageRF frequency (MHz)RF gradient (MV/m) A132522 A465028 B865028 RF requirements Required solenoidal fields in the linear cooling channel Stages A1-A4 before, B1-B8 after bunch recombination 6D emittance reduction 10 5 total length 0.96km, net transmission ~21%

7. Summary Expertise needed Start to end simulations Target and muon capture High field magnets High gradient RF in magnetic fields