Oct. 6, ILC Positron Source Group Meeting Short report by S. Riemann September 2006, RAL

Oct Goal of the Workshop facilitate the development of the collaboration to design and carry out R&D for the ILC Positron System organize the international activities  essential work for the TDR accomplished on a priority basis  reduce unnecessary duplication and activities not relevant to the ILC e+ system requirements Regular meetings to discuss status, progress, and plans for the various positron system design and R&D

Oct Why? How? At the moment the positron source groups are a loose confederation of interested participants Need a collaboration that takes responsibilities for our activities Categorize activities in topics  discuss its contribution to e+ production; technical feasibility; need for design, simulation, R&D, and prototyping status of each activity should be discussed including the availability of resources (people and funding), milestones, schedules, and impediments

Oct Topics Target Systems Ian Bailay/Tom Piggot OMD Jeff Gronberg Capture RF Juwen Wang Target Hall Vinod Bharadwaj Undulator Scheme Jim Clarke Laser Compton Scheme Masao Kuriki Conventional Scheme Bharadwaj/Sheppard Accelerator Physics Gudi Moortgat-Pick Polarisation Sabine Riemann Spokesman of the collaboration: J. Sheppard

Oct This Workshop Undulator Scheme Laser Compton Scheme Target Station/Target Damage OMD/AMD Accelerator Physics target hall design, activation & remote handling

Oct UK Undulator Prototyping R&D Goal Develop reliable magnetic modelling technique Develop undulator manufacturing technique Manufacture and test first full scale undulator module (4m) by end of July 2007 Beam test of 4-m undulator module at Daresbury Lab – fall Pre-production prototype – Y. Ivanyushenko

Oct Prototypes family Y. Ivanushenko

Undulator 4m module Two sections of the undulator magnet He bath vesselThermal shield Cold Mass

Oct LAL Activities (A. Variola) R&D on a high finesse optical cavity: Goals: 1) operate a very high finesse Fabry-Perot cavity in pulsed regime - 2 mirrors cavities Gain: Started in Sept ) reduction of the laser beam size (waist) - 4 mirrors non-planar cavity - Setup started in Sept starting to evaluate a new scheme for the Compton source, (ERL based), the new idea seems promising Studies on channeling for the conventional solution

Oct Optical Setup at Orsay

Oct Experiment setup. Laser & Cavity installed Present status

Oct Target Systems  U Liverpool (EUROTeV) working in collaboration with SLAC and LLNL  Developing water-cooled rotating wheel design.  0.4 radiation length titanium alloy rim.  Radius approximately 1 m.  Rotates at approximately 1000 rpm. Constraints: Wheel rim speed determined by thermal load and cooling rate Wheel diameter determined by radiation damage and Materials fixed by thermal and mechanical properties and pair- production cross-section I. Bailey

Oct Radiation Aspects (Target) Material Damage Material Activation  remote handling - see also talk of T. Broome Studies done by A. Ushakov: - activation and target damage - activity and dose rates for different source types (see also EPAC paper)

Oct Target Damage A. Ushakov

Oct Target and capture section AMD Design Further evaluation of pulsed/continuous design. Look in more detail at cooling and stress issues. Magnet Loading on Wheel Try to bring simulations and experimental data closer. Look at required motor power, additional heat input. Overall design (undulator, collimator, target,AMD/OMD, …)

Oct J. Gronberg

Oct J. Gronberg

Oct. 6, Eddy Current Simulations LLNL - preliminary Initial “Maxwell 3D” simulations by W. Stein and D. Mayhall at LLNL indicate: ~2MW eddy current power loss for 1m radius solid Ti disc in 6T field of AMD. <20kW power loss for current 1m radius Ti rim design. However - Simulations do not yet agree with SLAC rotating disc experiment. 8” diameter Cu disc rotating in field of permanent magnet. Possibility of OPERA-3D simulations at RAL. See AMD Session

Oct Issues for the rotating target A. Mikhailichenko Model erected (using FlexPDE Solutions)  field calculations performed  consequences for shower loss and transverse deflection fields and pulsed torques in pulsed solenoid case

Oct A. Mikhailichenko

Oct A. Mikhailichenko

Oct Start-to-end Model of the Positron Source e- Undulator Electron Gamma Shower code: EGSnrc Particle dynamic code: PARMELA Analytical + Monte carlo Wai Gai et al. studied the e+ yield in the immersed target case. Including both polarized (60%) and unoplarized cases. Many undulator and drive beam parameters investigated. Also studied the drive beam jitter and found it is not a severe problem. A lot more cases to be done.

Oct Topic leaders are working on summaries and to-do lists Next meeting in ~4 months (February) Main work: parameter lists, target studies, …, reliable working scheme (Compton)  redo simulations - for an overall design of the source