Transverse emittance blow-up in compact proton synchrotrons caused by the space-charge effects

Space charge effects play significant role in low-injection-energy synchrotrons with the repetition frequency less than 1 Hz. Accurate consideration of these phenomena is required in the case of ´medical´ proton machines to avoid limitation of the beam intensity. Common features of these accelerators are small ring circumference (~20+25 m), small injection energy (<10 MeV) and the ´flat´ beam cross-section, produced by the multi-turn injection to accumulate the required beam intensity (~10¹¹ particles per pulse). In the compact proton synchrotron the high-order resonances can be excited by the beam itself without any magnetic field imperfection. To minimise the transverse emittance blow-up during the capture process that leads to particle losses, the parameters of the machine should be optimised. We studied the influence of space charge effects on the beam parameters during the ´quasi-adiabatic´ capture process. The report presents results of simulations of these effects for the ´medical´ machines, based on the multi-particle tracking in the 6 dimensional phase space including the transverse and longitudinal motion