Closed-orbit prognosis, correction and manipulation for the PIMMS synchrotron

Closed-orbit control is a basic ingredient for the efficient performance of any circular accelerator. The paper summarises the results of the simulations of the expected orbit distortions before and after correction for the PIMMS (Proton Ion Medical Machine Study) synchrotron. Different situations that lead to a deterioration of the orbit, such as broken position monitors and correctors, misalignment of the magnetic and diagnostic elements with time, have been examined. In particular, the consequences of lowering the injection energy of the space-charge-dominated proton beam have been investigated. The possibility of local orbit correction during extraction by applying closed bumps has been analysed. Finally, on the basis of the demands of both the global orbit correction and the local corrections at top energy, the corrector dipoles specifications have been evaluated.