Speaker
Description
The Linear IFMIF Prototype Accelerator (LIPAc) is designed to accelerate 125 mA of D+ to 9 MeV in CW. The very high power stored in the beam (~1.1 MW) and the use of superconductive RF cavities requires precise control of beam losses (target <1e-6). On the other hand the intense beam is affected by strong space charge forces that easily results in significant halo formation. This contribute is difficult to simulate because requires large number of particle tracking and precise knowledge of input phase space. In this work we present the use of Bayesian optimization of transport optic (4 quadrupoles + 4 steerers) to minimize the halo losses by observing vacuum response in the sector. As a single beam pulse with inappropriate optics could lead to permanent damage of the machine, we include constraint of negligible losses from beam core in simulations. The algorithm successfully and safely reduced vacuum in sector by a factor of ~3 within two hours of operation. After analysis of newly set-point we find that the proposed optics results both in a compromise matching of core and halo distribution and a reduction of particles ejection from the former to the latter.
