Liu, W.

Paper	Title	Page
MOPP046	Collimation Optimizations, Capture Efficiency, and Primary-Beam Power Loss in the ILC Positron Source	649
	F. Zhou, Y. Nosochkov, J. Sheppard SLAC, Menlo Park, California W. Liu ANL, Argonne, Illinois
	The ILC positron beam generated from a thin Ti target has a wide energy spread and large transverse divergence. With the collection optics immediately downstream of the target and pre-acceleration to 125 MeV, the collected positron beam still has a long tail of positrons with low energies and large transverse divergence, which will be lost in the rest of the ILC positron source beamline. A collimation system is proposed and optimized for the case of a shielded target with quarter-wave transformation collection optics so that the power loss in the magnets and RF structures is effectively controlled within the acceptable level and in the damping ring (DR) within 640 W, assuming 3× 1010 of the captured positrons per bunch in the DR. In this case, the capture efficiency and DR injection efficiency are 13% and 99.8%, respectively. The lower capture efficiency is expected to result in higher injection efficiency and therefore, a lower power loss in the DR. The capture efficiency for the cases of a shielded target with flux concentrator and 5-T immersed target with flux concentrator is 20% and 30%, respectively, with the collimation system.
WEPP148	Generation of High Gradient Wakefields in Dielectric Loaded Structures	2835
	M. E. Conde, S. P. Antipov, F. J. Franchini, W. Gai, F. Gao, R. Konecny, W. Liu, J. G. Power, Z. M. Yusof ANL, Argonne, Illinois C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio
	Dielectric loaded wakefield structures have potential to be used as high gradient accelerator components. Using the high current drive beam at the Argonne Wakefield Accelerator Facility, we employed cylindrical dielectric loaded wakefield structures to generate accelerating fields of up to 100 MV/m. Short electron bunches (13 ps FWHM) of up to 86 nC are used to drive these fields, either as single bunches or as bunch trains. These recently tested standing-wave structures have a field probe near the outer edge of the dielectric to sample the RF fields generated by the electron bunches. Monitoring of these high intensity RF fields serves to verify the absence of electric breakdown.
WEOBG03	The Design of the Positron Source for the International Linear Collider	1915
	J. A. Clarke, O. B. Malyshev, D. J. Scott STFC/DL/ASTeC, Daresbury, Warrington, Cheshire I. R. Bailey, J. B. Dainton, K. M. Hock, L. J. Jenner, L. I. Malysheva, L. Zang Liverpool University, Science Faculty, Liverpool E. Baynham, T. W. Bradshaw, A. J. Brummitt, F. S. Carr, A. J. Lintern, J. Rochford STFC/RAL, Chilton, Didcot, Oxon V. Bharadwaj, J. Sheppard SLAC, Menlo Park, California A. Bungau UMAN, Manchester N. A. Collomb STFC/DL, Daresbury, Warrington, Cheshire R. Dollan Humboldt Universität zu Berlin, Berlin W. Gai, Y. Ivanyushenkov, W. Liu ANL, Argonne, Illinois J. Gronberg, W. T. Piggott LLNL, Livermore, California A. F. Hartin OXFORDphysics, Oxford, Oxon S. Hesselbach, G. A. Moortgat-Pick Durham University, Durham K. Laihem, S. Riemann, A. Schaelicke, A. Ushakov DESY Zeuthen, Zeuthen T. Lohse Humboldt University Berlin, Institut für Physik, Berlin A. A. Mikhailichenko Cornell University, Department of Physics, Ithaca, New York N. C. Ryder University of Bristol, Bristol
	The high luminosity requirements and the option of a polarized positron beam present a great challenge for the positron source of a future linear collider. This paper provides a comprehensive overview of the latest proposed design for the baseline positron source of the International Linear Collider. We report on recent progress and results concerning the main components of the source: including the undulator, collimators, capture optics, and target.
	Slides