Warsop, C.M.

Paper	Title	Page
MOPCH114	Progress on Dual Harmonic Acceleration on the ISIS Synchrotron	309
	A. Seville, D.J. Adams, D. Bayley, N.E. Farthing, I.S.K. Gardner, M.G. Glover, A. Morris, B.G. Pine, J.W.G. Thomason, C.M. Warsop CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
	The ISIS facility at the Rutherford Appleton Laboratory in the UK is currently the most intense pulsed, spallation, neutron source. The accelerator consists of a 70 MeV H- Linac and an 800 MeV, 50 Hz, rapid cycling, proton Synchrotron. The synchrotron beam intensity is 2.5·1013 protons per pulse, corresponding to a mean current of 200 μA. The synchrotron beam is accelerated using six, ferrite loaded, RF cavities with harmonic number 2. Four additional, harmonic number 4, cavities have been installed to increase the beam bunching factor with the potential of raising the operating current to 300 μA. As ISIS has a busy user schedule the time available for dual harmonic work has been limited. However, much progress has been made in the last year and encouraging results have been obtained. This paper reports on the hardware commissioning and beam tests with dual harmonic acceleration.
MOPCH115	Transverse Space Charge Studies for the ISIS Synchrotron	312
	C.M. Warsop CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
	The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It is based on a 50 Hz proton synchrotron which, once the commissioning of a new dual harmonic RF system is complete, will accelerate about 3.5·1013 protons per pulse from 70 to 800 MeV, corresponding to mean beam powers of 0.2 MW. Following this upgrade, transverse space charge is expected to be one of the main intensity limitations, and is also a key factor for further machine upgrades. A programme of R&D on transverse space charge is now under way, aiming not only to improve the ISIS ring but also to exploit it as an experimental tool for testing theory and codes. This paper summarises work so far, outlining calculations for coherent envelope modes on ISIS, using numerical solutions of the envelope equation to show the expected behaviour near half integer resonance. Progress on work linking these predictions with more realistic beam models in space charge codes, and extending calculations to images, coupling and non linear resonances will be described. Plans and preparations for experiments, along with initial results, will also be presented.
TUPCH036	Modelling of Diagnostics for Space Charge Studies on the ISIS Synchrotron	1082
	B.G. Pine, S.J. Payne, C.M. Warsop CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
	The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It is based on a 50 Hz proton synchrotron which, once the commissioning of a new dual harmonic RF system is complete, will accelerate about 3.5·1013 protons per pulse from 70 to 800 MeV, corresponding to mean beam powers of 0.2 MW. Transverse space charge is a key issue for both present and proposed upgrades to the machine, and is the focus of current R&D studies. Experiments on the ISIS ring are central to this work, therefore understanding and quantifying limitations in present and proposed diagnostics is essential. This paper presents work studying and modelling the ISIS residual gas profile monitors, including the effects of non-uniformity in sweep fields, space charge and images. Progress on related work looking at other important diagnostics, e.g., position and envelope monitoring, will also be summarised.
TUZAPA02	ISIS Upgrades – A Status Report	935
	D.J.S. Findlay, D.J. Adams, T.A. Broome, M.A. Clarke-Gayther, P. Drumm, D.C. Faircloth, I.S.K. Gardner, P. Gear, M.G. Glover, S. Hughes, H.J. Jones, M. Krendler, A.P. Letchford, E.J. McCarron, S.J. Payne, C.R. Prior, A. Seville, C.M. Warsop CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
	Since 2002 several accelerator upgrades have been made to the ISIS spallation neutron source at the Rutherford Appleton Laboratory in the UK, and upgrades are currently continuing in the form of the Second Target Station Project. The paper reviews the upgrade programmes: a new extraction straight, replacement of the Cockcroft-Walton by an RFQ, installation of a second harmonic RF system, replacement and upgrading of installed equipment, design and installation of improved diagnostics in conjunction with beam dynamics simulations, the Second Target Station Project, design and construction of a front end test stand, and the MICE programme. The paper also looks forward to possible future schemes at ISIS beyond the Second Target Station Project.
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