Simulations of the head-tail instability on the ISIS synchrotron
Williamson RE., Adams DJ., Jones B., Warsop CM., Kornilov V.
Copyright © 2014 CC-BY-3.0 and by the respective authors. ISIS is the pulsed spallation neutron and muon source at the Rutherford Appleton Laboratory in the UK. Operation is centred on a loss limited 50 Hz proton synchrotron which accelerates 3×1013 protons per pulse (ppp) from 70 MeV to 800 MeV, delivering a mean beam power of 0.2 MW. Present studies are focussed on key aspects of high intensity beam dynamics with a view to increasing operational intensity, understanding loss mechanisms and identifying possible upgrade routes. Of particular interest is the head-tail instability observed on ISIS, which is currently a main limitation on beam intensity. This paper presents initial simulations using HEADTAIL to compare with experimental data taken on the ISIS synchrotron. The details and assumptions of the impedance model and simulations are discussed. Plans for future head-tail measurements, simulations and analysis are outlined.