Perry, C.

Paper	Title	Page
TUOCM01	First Measurements of the Longitudinal Bunch Profile at SLAC Using Coherent Smith-Purcell Radiation at 28GeV	1026
	V. Blackmore, G. Doucas, B. Ottewell, C. Perry OXFORDphysics, Oxford, Oxon R. Arnold, S. Molloy, M. Woods SLAC, Menlo Park, California M. F. Kimmitt University of Essex, Physics Centre, Colchester
	Coherent Smith-Purcell radiation has been demonstrated as a technique for measuring the longitudinal profile of charged particles bunches in the low to intermediate energy range. However, with the advent of the International Linear Collider, the need has arisen for a non-invasive method of measuring the bunch profile at extremely high energies. Smith-Purcell radiation has been used for the first time in the multi-GeV regime to measure the longitudinal profile of the 28GeV SLAC beam. The experiment has both successfully determined the bunch length, and has also demonstrated its sensitivity to bunch profile changes. The challenges associated with this technique, and its prospects as a diagnostic tool are reported here.
	Slides
TUPC033	IP BPM Position Error at CLIC due to Secondary Emission from Beam-beam Backgrounds	1122
	A. F. Hartin, R. Apsimon, P. Burrows, C. I. Clarke, C. Perry, C. Swinson OXFORDphysics, Oxford, Oxon G. B. Christian ATOMKI, Debrecen B. Constance, H. Dabiri Khah JAI, Oxford A. Kalinin STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	Beam-beam background impacts on the IP BPM are studied for the CLIC machine. The large number of coherent pairs ( 1.8×108 charges per BPM strip per bunch crossing) for the CLIC-G default parameter set, potentially leads to a large secondary emission in the BPM strips. Detailed GuineaPig++ and Geant studies reveal, however, that the coherent pairs travel down the extraction line without significant secondary showering. Geant studies of the CLIC incoherent pairs show a flux of secondary emission two orders of magnitude less than that expected for the ILC 1 TeV high luminosity scheme. Since previous studies showed that FONT IP BPM signal distortion for the ILC was of no concern, then it can also be neglected at CLIC.
THPC114	Design and Performance of a Prototype Digital Feedback System for the International Linear Collider Interaction Point	3245
	P. Burrows, B. Constance, H. Dabiri Khah, J. Resta-López JAI, Oxford R. Apsimon, P. Burrows, C. I. Clarke, A. F. Hartin, C. Perry, C. Swinson OXFORDphysics, Oxford, Oxon G. B. Christian ATOMKI, Debrecen A. Kalinin STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	We present the design and preliminary results of a prototype beam-based digital feedback system for the Interaction Point of the International Linear Collider. A custom analogue front-end processor, FPGA-based digital signal processing board, and kicker drive amplifier have been designed, built, and tested on the extraction line of the KEK Accelerator Test Facility (ATF). The system was measured to have a base latency of approximately 140 ns, increasing to approximately 148 ns with the inclusion of real-time charge normalisation.