• G.A. Mulhollan, J.C.B. Bierman
  Saxet, Austin, Texas
• A. Brachmann, J.E. Clendenin, E.G. Garwin, R.E. Kirby, D.-A.L. Luh, T.V.M. Maruyama
  SLAC, Menlo Park, California
• R.X.P. Prepost
  UW-Madison/PD, Madison, Wisconsin

Spin-polarized electrons are commonly used in high energy physics. Future work will benefit from greater polarization. Polarizations approaching 90% have been achieved at the expense of yield. The primary paths to higher polarization are material design and electron transport. Our work addresses the latter. Photoexcited electrons may be preferentially emitted or suppressed by an electric field applied across the active region. We are tuning this forward bias for maximum polarization and yield, together with other parameters, e.g., doping profile Preliminary measurements have been carried out on bulk GaAs. As expected, the yield change far from the bandgap is quite large. The bias is applied to the bottom (non-activated) side of the cathode so that the accelerating potential as measured with respect to the ground potential chamber walls is unchanged for different front-to-back cathode bias values. For a bias which enhances emission, the yield nearly doubles. For a bias which diminishes emission, the yield is approximately one half of the zero bias case. The size of the bias to cause an appreciable effect is rather small reflecting the low drift kinetic energy in the zero bias case.

• A. Brachmann, J.E. Clendenin, E.G. Garwin, R.E. Kirby, D.-A.L. Luh, T.V.M. Maruyama, D.C. Schultz, J. Sheppard
  SLAC, Menlo Park, California
• R.X.P. Prepost
  UW-Madison/PD, Madison, Wisconsin

The SLC polarized electron source (PES) can meet the expected requirements of the International Linear Collider (ILC) for polarization, charge and lifetime. However, experience with newer and successful PES designs at JLAB, Mainz and elsewhere can be incorporated into a first-generation ILC source that will emphasize reliability and stability without compromising the photocathode performance. The long pulse train for the ILC may introduce new challenges for the PES, and in addition more reliable and stable operation of the PES may be achievable if appropriate R&D is carried out for higher voltage operation and for a simpler load-lock system. The outline of the R&D program currently taking shape at SLAC and elsewhere is discussed. The principal components of the proposed ILC PES, including the laser system necessary for operational tests, are described.

• B. Parker, M. Anerella, J. Escallier, M. Harrison, P. He, A.K. Jain, A. Marone, K.-C. Wu
  BNL, Upton, Long Island, New York
• T.W. Markiewicz, T.V.M. Maruyama, Y. Nosochkov, A. Seryi
  SLAC, Menlo Park, California

We present a compact superconducting final focus (FF) magnet system for the ILC based on recent BNL direct wind technology developments. Direct wind gives an integrated coil prestress solution for small transverse size coils. With beam crossing angles more than 15 mr, disrupted beam from the IP passes outside the coil while incoming beam is strongly focused. A superconducting FF magnet is adjustable to accommodate collision energy changes, i.e. energy scans and low energy calibration runs. A separate extraction line permits optimization of post IP beam diagnostics. Direct wind construction allows adding separate coils of arbitrary multipolarity (such as sextupole coils for local chromaticity correction). In our simplest coil geometry extracted beam sees significant fringe field. Since the fringe field affects the extracted beam, we also study advanced configurations that give either dramatic fringe field reduction (especially critical for gamma-gamma colliders) or useful quadrupole focusing on the outgoing beam channel. We present prototype coil winding test results and discuss our progress toward an integrated FF solution that addresses important machine detector interface issues.

• M. Woods, R.A. Erickson, J.C. Frisch, C. Hast, R.K. Jobe, L. Keller, T.W. Markiewicz, T.V.M. Maruyama, D.J. McCormick, J. Nelson, N. Phinney, T.O. Raubenheimer, M.C. Ross, A. Seryi, S. Smith, Z. Szalata, P. Tenenbaum, M. Woodley
  SLAC, Menlo Park, California
• D.A.-K. Angal-Kalinin, C.D. Beard, F.J. Jackson, A. Kalinin
  CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
• R. Arnold
  University of Massachusetts, Amherst
• D. Bailey
  ,
• R.J. Barlow, G.Yu. Kourevlev, A. Mercer
  UMAN, Manchester
• S.T. Boogert, A. Liapine, S. Malton, D.J. Miller, M.W. Wing
  UCL, London
• P. Burrows, G.B. Christian, C.C. Clarke, A.F. Hartin, S. Molloy, G.R. White
  Queen Mary University of London, London
• D. Burton, N. Shales, J. Smith, A. Sopczak, R. Tucker
  Microwave Research Group, Lancaster University, Lancaster
• D. Cussans
  University of Bristol, Bristol
• C. Densham, J. Greenhalgh
  CCLRC/DL, Daresbury, Warrington, Cheshire
• M.H. Hildreth
  Notre Dame University, Notre Dame, Iowa
• Y.K. Kolomensky
  UCB, Berkeley, California
• W.F.O. Müller, T. Weiland
  TEMF, Darmstadt
• N. Sinev, E.T. Torrence
  University of Oregon, Eugene, Oregon
• M.S. Slater, M.T. Thomson, D.R. Ward
  University of Cambridge, Cambridge
• Y. Sugimoto
  KEK, Ibaraki
• S.W. Walston
  LLNL, Livermore, California
• N.K. Watson
  Birmingham University, Birmingham
• I. Zagorodnov
  DESY, Hamburg
• F. Zimmermann
  CERN, Geneva

The SLAC Linac can deliver damped bunches with ILC parameters for bunch charge and bunch length to End Station A (ESA). A 10Hz beam at 28.5 GeV energy can be delivered to ESA, parasitic with PEP-II operation. During the engineering design phase for the ILC over the next 5 years, we plan to use this facility to prototype and test key components of the Beam Delivery System (BDS) and Interaction Region (IR). We discuss our plans for this ILC Test Facility and preparations for carrying out experiments related to Collimator Wakefields, Materials Damage Tests and Energy Spectrometers. We also plan an IR Mockup of the region within 5 meters of the ILC Interaction Point to investigate effects from backgrounds and beam rf higher-order modes (HOMs).