Positron Update ILC R&D Meeting/ March 12, 07 VB & JCS Positron Source Meetings RDR Beijing Positron Meeting Target & Remote Handling OMD Optics FLUKA validation experiment

Positron Source Layout

Meetings Regular meetings 10.30AM (PST) Wednesdays - positrons ANL, LLNL, SLAC,Cornell Alternate between hardware issues and optics Maybe expand the invitation list 08.00 AM (PST) Thursdays - target SLAC, Daresbury, RAL, DESY-Z, ANL, LLNL Alternate between target design & hall activation 08.00 AM (PST) Wednesdays – E166

Positron RDR Update Positron RDR , in good shape Numbers need to be checked and finalized Figures are fine, one or two could be even better April 1 deadline for complete RDR draft June or so for non-draft RDR & paper version EDR plans being hatched.. E166 getting closer to publishing!!!

Positron Collaboration Meeting ILC Positron Source Collaboration Meeting Collaboration to meet three times a year 1st meeting at RAL last November 2nd meeting in Beijing before GDE meeting Main web page : http://hirune.kek.jp/mk/ilc/positron/IHEP/ Summaries: http://hirune.kek.jp/mk/ilc/positron/IHEP/summary.html 19 attendees , 6-9-4 USA-Europe-Asia , 2 from SLAC : John & Feng)

Target Summary Topic Action Items: A. Target Systems (I. Bailey/ T. Piggott) Source alternative magnet solutions for first proposed UK target prototype - Ian B to coordinate. LLNL to evaluate DL target prototype design for vibrational modes and compatibility with water-cooling design (flow rates, etc) - Tom P to coordinate. Rationalise proposed UK prototyping wrt available funding - Ian B to coordinate. Continue evaluation of alternative target materials - Chris D to coordinate. Seek further clarification from BINP on their 1ms OMD work - Vinod B to coordinate. Adopt common geometry for eddy current simulations (based on UK prototype?) - Jeff G to coordinate. Beam window issue remains unresolved? Wei + Alexander to discuss.

Target Wheel

Target Hall Summary Topic Action Items: D. Target Hall (I. Bailey on behalf of V.B.) Evaluate dose rates for short times after shutdown (1 hour, 1 day) - Andriy (DESY) Complete detailed target station geometry for FLUKA - Luis (DL) Include material absorption effects in FLUKA simulations - Andriy (DESY) Carry out benchmarking of FLUKA using Ti alloy at SLAC - John (SLAC) Get feedback on impact of 53 hour changeover on availability - Vinod (SLAC) Evaluate need to include photon collimator in remote-handling module - Lei (Liverpool) Evaluate activation of water in water-cooled systems - Andriy (DESY) Evaluate shielding requirements compatible with 53 hour remote-handling schedule - Andriy (DESY) Evaluate achievable vacuum. Assess need to evolve pillow seal design. - Ian (Liverpool) Does ILC plan to have a central hot cell facility? - Vinod (SLAC) Develop detailed remote-handling scenarios - Mike W (RAL) Assess need for remote-handling for KAS - Vinod (SLAC)

Target Remote Handling Estimated 53 hour replacement time

Optical Matching Device (OMD) factor of 2 in positron yield (3 if immersed target) DC solenoid before target or pulsed flux concentrator after target Pulsed device is the baseline design Target spins in the magnetic field of the OMD Eddy currents in the target – need to calculate power Magnetic field is modified by the eddy currents – effect on yield?? Eddy current mitigation Reduce amount of spinning metal Do experiment to validate eddy current calculations Look for low electrical / high thermal conductivity Ti-alloys Other materials such as ceramics No OMD Use focusing solenoidal lens (1/4 wave) – lower fields OMD is upgrade to polarization!!!!!

Eddy Current Experiment Proposed experiment Layout at Cockcroft Institute/Daresbury (this summer) Eddy current calculation mesh - S. Antipov, W. Liu, W. Gai - ANL

Calculated Eddy Current Power Nominal RPMs

OMD Progress Baseline target Alternative target RAL, ANL and Cornell have done Eddy current simulation which produce consistent results with multiple codes. Estimates for power dissipation in the target are >100kW for a constant field and are considered excessive. Evaluation of ceramic target material is on-going. No conclusions. Radiation damage of the superconducting coil is still TBD but may not be worthwhile unless a solution can be found for the eddy currents. ANL simulation of beam heating in windows shows that an upstream window is feasible but a downstream window is not. Alternative target Capture efficiency for the lithium lens target and ¼ wave solenoid is still TBD Thermal heating and stress for the lithium lens is still on-going. Thermal stress calculation for the liquid metal target is still on-going

OMD Plans and Actions (baseline target): ANL will simulate eddy currents in the pulsed magnet configuration. UK will evaluate suitability of non-conducting materials for the target Daresbury/Cockroft/RAL will spin a one meter target wheel in a constant magnetic field and will measure the forces. Eddy simulations will be calculated and benchmarked against this configuration Plans and Actions (alternative targets): ANL will determine the capture efficiency for ¼ wave focusing optics and lithium lens. LLNL will evaluate the survivability of lithium lens to beam stress Cornell will specify an initial design of a liquid metal target. LLNL will calculate the Stress-strain behavior of the outgoing beam window.

Candidate Ceramics Titanium Alloy Ti-6Al-4V Grade 5 Annealed Isotropic Graphite IG-43 “Macor” Machinable Glass-ceramic “Shapal-M” Machinable Aluminium Nitride AlN Aluminium Nitride Si3N4 Silicon Nitride (Hot Pressed) “Sialon”Solid Solution BN Boron Nitride B4C Boron Carbide (Hot Pressed) SiC Silicon Carbide (Reaction Bonded) SiC Silicon Carbide (Hot Pressed) WC 94 / Co 6 Tungsten Carbide / Cobalt BeO 99.5% Beryllia Al2O3 99.9% Alumina ZrO2 / MgO Zirconia(Magnesia stabilised) YO99.9% Yttrium Oxide Carbon-Carbon

Optics Source optics laid out. Need to look at details Beam loss and collimation Component interferences (target halls, DR injection) Refine and document optics and beam physics

FLUKA Validation Experiment

FLUKA Validation Experiment SLAC/CERN Collaboration (RP groups) Validation of FLUKA activation calculations 100 W 30 GeV electron beam in ESA at SLAC Cylindrical copper dump Samples around the dump (including a Ti-4V-6Al) Look mr/hour and gamma spectrum from irradiated samples Run at the beginning of April …

Experiment Setup