Final Muon Ionization Cooling Channel using Quadrupole Doublets for Strong Focusing

Le résumé fourni par la source

Considerable progress has been made in the design of muon ionization cooling for a collider. A 6D normalized emittance of 0.123 cubic mm has been achieved in simulation, almost a factor of a million in cooling. However, the 6D emittance required by a high luminosity muon collider is 0.044 cubic mm. We explore a final cooling channel composed of quadrupole doublets limited to 14 Tesla. Flat beams formed by a skew quadrupole triplet are used. The low beta regions, as low as 5 mm, produced by the strong focusing quadrupoles are occupied by dense, low Z absorbers that cool the beam. Work is in progress to keep muons with different path lengths in phase with the RF located between cells and to modestly enlarge quadrupole admittance. Calculations and individual cell simulations indicate that the final cooling needed may be possible. Full simulations are in progress. After cooling, emittance exchange in vacuum reduces the transverse emittance to 25 microns and lets the longitudinal emittance grow to 70 mm as needed by a collider. Septa slices a bunch into 17 parts. RF deflector cavities, as used in CLIC tests, form a 3.7 meter long bunch train. Snap bunch coalescence combines the 17 bunches into one in a 21 GeV ring in 55 microseconds.

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