Ionization Cooling using Parametric Resonances

75496B Muon collider luminosity depends on the number of muons in the storage ring and on the transverse size of the beams in collision. As presently envisioned, large muon intensities will be required, due to limitations with ionization cooling, the intended method for cooling the beam. However, the proton accelerators needed to produce the required muon intensity are expensive, and the decay of the large number of muons in the storage ring create troublesome boundary radiation and make the physics experiments difficult. This project will combine ionization cooling with parametric resonances to produce beams with much smaller tranverse sizes, allowing high muon collider luminosity to be achieved with fewer muons. In Phase I, the theory of transverse beam cooling, using half-integer parametric resonances and ionization cooling, was extended to include methods to compensate for chromatic and angular aberrations. Computer programs were developed which were used to confirm the general analytical predictions and to compare the relative effectiveness of a quadrupole channel to one based on solenoids with alternating polarity. Phase II will further develop the theory and simulations in order to demonstrate that transverse cooling using parameteric resonances can relax the requirements on the proton driver, reduce the boundary radiation, and provide a better environment for experiments at muon colliders. Complete simulations using realistic models of all components of the parametric resonance cooling channel will be conducted. Commercial Applications and Other Benefits as described by the awardee: If the case for a muon collider as the next energy frontier machine can be made compelling, it becomes a candidate to be added to the other options for the High Energy Physics community. This technology should relax the requirements for muon production rates leading to a muon collider with reduced costs and accelerated schedules.