White, G.R.

Paper	Title	Page
MOZCH02	Start to End Simulations of Low Emittance Tuning and Stabilization	31
	P. Tenenbaum, A. Seryi, M. Woodley SLAC, Menlo Park, California D. Schulte CERN, Geneva N.J. Walker DESY, Hamburg G.R. White Queen Mary University of London, London
	The principal beam dynamics challenge to the subsystems between the damping ring and the collision point of future linear colliders is expected to be the tuning and stabilization required to preserve the transverse emittance and to collide nanometer-scale beams. Recent efforts have focused on realistically modelling the operation and tuning of this region, dubbed the Low Emittance Transport (LET). We report on the development of simulation codes which permit integrated simulation of this complex region, and on early results of these simulations. Future directions of LET simulation are also revealed.
	Video of talk
	Transparencies
MOPLT108	TESLA Linac-IP Simulations	788
	G.R. White Queen Mary University of London, London D. Schulte CERN, Geneva N.J. Walker DESY, Hamburg
	We have formulated integrated simulations of the transport of the electron and positron bunches in the Linear Collider from the linac entrance through the beam delivery system and the interaction region, taking wakefield effects into account. We have set up the simulations to run on the 64-cpu prototpye Grid cluster at QMUL and generated results for various sets of input parameters for the TESLA and NLC machines. For TESLA we have evaluated the distortion of the phase-space of the bunches at the interaction point due to wakefields. We have calculated the luminosity degradation and the production of photons and e+e- pairs. We have simulated the performance of the intra-train beam feedback systems based on bunch position, angle and luminosity measures, and have evauated the luminosity recovery potential of these systems for TESLA and NLC.
THPLT156	Simulations of IP Feedback and Stabilization in the NLC	2822
	L. Hendrickson, J.C. Frisch, T.M. Himel, T.O. Raubenheimer, A. Seryi, M. Woodley SLAC, Menlo Park, California G.R. White Queen Mary University of London, London
	Keeping nanometer-sized beams in collision is an essential component in achieving design luminosity in a linear collider. The NLC stabilization strategy is conservative by including enough redundancy so that if some piece doesn't work to specification or the incoming beam motion is worse than expected, the beams will still be kept in collision. We show simulation results with both realistic and pessimistic assumptions about the response of the ground motion, inertial stabilization, interbunch and intertrain feedback systems. By providing backup systems, and by assuming that some systems may perform more poorly than expected, we can achieve a high level of confidence in our ability to successfully stabilize the beams.
MOPLT107	Nanosecond-timescale Intra-bunch-train Feedback for the Linear Collider: Results of the FONT2 Run	785
	P. Burrows, T. Hartin, S.M. Hussain, S. Molloy, G.R. White Queen Mary University of London, London C. Adolphsen, J.C. Frisch, L. Hendrickson, R.K. Jobe, T. Markiewicz, D.J. McCormick, J. Nelson, M.C. Ross, S. Smith, T.J. Smith SLAC, Menlo Park, California R. Barlow, M. Dufau, A. Kalinin CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire G. Myatt, C. Perry OXFORDphysics, Oxford, Oxon
	We report on experimental results from the December 2003/January 2004 data run of the Feedback On Nanosecond Timescales (FONT) experiment at the Next Linear Collider Test Accelerator at SLAC. We built a second-generation prototype intra-train beam-based feedback system incorporating beam position monitors, fast analogue signal processors, a feedback circuit, fast-risetime amplifiers and stripline kickers. We applied a novel real-time charge-normalisation scheme to account for beam current variations along the train. We used the system to correct the position of the 170 nanosecond-long bunchtrain at NLCTA, in both 'feed forward' and 'feedback' modes. We achieved a latency of 53 nanoseconds, representing a significant improvement on FONT1 (2002), and providing a demonstration of intra-train feedback for the Linear Collider.