HB2014 - List of Authors (Wilcox, C.C.)

Paper	Title	Page
MOPAB40	Studies of Loss Mechanisms Associated with the Half Integer Limit on the ISIS Ring	123
	C.M. Warsop, D.J. Adams, B. Jones, B.G. Pine, H. V. Smith, C.C. Wilcox, R.E. Williamson STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	ISIS is the spallation neutron source at the Rutherford Appleton Laboratory in the UK. The facility centres on an 800 MeV rapid cycling proton synchrotron, which provides 0.2 MW of beam power operating at high levels of transverse space charge (peak incoherent tune shift ~ 0.5), but with low loss. Half integer resonance is considered to be a main driver for loss that limits the intensity in high power, medium energy proton rings like ISIS. However, the detailed mechanisms causing loss as the half integer limit is approached are not well understood, particularly in the context of a real machine. In this paper we report progress on experiments on the ISIS synchrotron inducing half integer loss, comparing with detailed simulations and attempts to relate these to simplified theoretical and simulation models. Effects of longitudinal motion on growth mechanisms, e.g. in coasting, “frozen” bunched and rapid cycling bunched beams are discussed, as is how these losses might be minimised and thus the real space charge limit effectively increased.

Paper

Title

Page

Studies of Loss Mechanisms Associated with the Half Integer Limit on the ISIS Ring

123

C.M. Warsop, D.J. Adams, B. Jones, B.G. Pine, H. V. Smith, C.C. Wilcox, R.E. Williamson
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

ISIS is the spallation neutron source at the Rutherford Appleton Laboratory in the UK. The facility centres on an 800 MeV rapid cycling proton synchrotron, which provides 0.2 MW of beam power operating at high levels of transverse space charge (peak incoherent tune shift ~ 0.5), but with low loss. Half integer resonance is considered to be a main driver for loss that limits the intensity in high power, medium energy proton rings like ISIS. However, the detailed mechanisms causing loss as the half integer limit is approached are not well understood, particularly in the context of a real machine. In this paper we report progress on experiments on the ISIS synchrotron inducing half integer loss, comparing with detailed simulations and attempts to relate these to simplified theoretical and simulation models. Effects of longitudinal motion on growth mechanisms, e.g. in coasting, “frozen” bunched and rapid cycling bunched beams are discussed, as is how these losses might be minimised and thus the real space charge limit effectively increased.