1. 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

2. Positron Source Layout

3. 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

4. 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!!!

5. 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 :
Summaries:
19 attendees , USA-Europe-Asia , 2 from SLAC : John & Feng)

6. 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.

7. Target Wheel

8. 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)

9. Target Remote Handling
Estimated 53 hour replacement time

10. 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!!!!!

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

12. Calculated Eddy Current Power
Nominal RPMs

13. 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

14. 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.

15. 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
Al2O % Alumina
ZrO2 / MgO Zirconia(Magnesia stabilised)
YO99.9% Yttrium Oxide
Carbon-Carbon

16. 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

17. FLUKA Validation Experiment

18. 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 …

19. Experiment Setup