1. A_RD_2 The ATF2 project @ KEK Final Focus prototype of the linear electron machine May 16 th 2008 Marc Verderi (LLR) for KEK, Saga Uni., Tohoku Univ., LAL, LAPP & LLR colleagues

2. ATF2 Goal Build and operate a scaled-down prototype of the linear electron machine final focus system. Target : –35 nm beam vertical size –2 nm beam control position, with intra-train feedback (like in ILC) –All in a reproducible and stable manner

3. extraction ATF2 (in construction) Temporary extraction line Final extraction line

4. ATF2 Schedule

5. A (very) few Highlights from KEK Tauchi Toshiaki (resp.), Urakawa Junji, Sugahara Ryuhei, Kuroda Shigeru, Okugi Toshiyuki, Tatsuya Kume, And Sugiyama Akira (Saga univ.), Sanuki Tomoyuki (Tohoku univ.).

6. Pictures of Quadrupole installation From R. Sugahara talk The last magnet is going to the destination Installation is finished 10 - 20 Dec. 2007 : 19 concrete base blocks were installed 7 - 9 Jan. 2008 : 22 movers and 19 quad-systems were installed

7. Shintake monitor Laser interferometer for beam size measurement From Masahiro Oroku talk Signal photons created by Compton effect on interference fringes –Energy peaks at 30 MeV They have to be disentangled from bgk brem. photons Both signal and bgk photons come as a burst Exploit shower profile to disentangle signal from bgk Signal Background

8. Observation of the Compton photon signal in Shintake  detector, using a “laser wire” Laser on Laser off Background subtracted Data Geant4 CsI(Tl) crystals (from Belle group) wrapped with teflon sheet and the Al foil 340mm(18.4 X 0 )

9. Shintake table in assembly hall (Mar. 12, 2008)

10. LAPP contribution Mechanical stabilization of Final Doublet A. Jeremie (resp.), N. Geffroy, B. Bolzon, G. Gaillard*, J.P. Baud * (*) No travel expenses expected

11. Final Doublet Elements to be supported & beam instrumentation devices SBPM QC3 SBPM FFTB 2.13 S3.00 SF1FF QF1FF 100 450.1 200 180 SBPM QC3 SBPM FFTB 2.13 S3.00 SD0FF QD0FF 100 76.2 450.1 200 18076.2 785380785380 2630 Sweeping Honda Shintake IP  400kg 30kg Cu:15kg FD layout: 2 quadrupoles 2 sextupoles 4 SBPMs Beam pipe New responsability

12. Relative stabilization ATF2 approach Final Doublet (FD) elements and beam instrumentation devices (e.g. Shintake) need to have “fixed” related positions –Tolerance in relative motions < 6 nm (in a first stage) –To meet the 35 nm vertical size requirement They are however too far apart, and too heavy together, to be put on a single stabilization device Strategy adopted is to have both “floating” coherently with / on top of floor vibrations –Coherence length of floor motions (4-5 meters) large enough to allow this

13. Reuse of CLIC table for FD support CLIC table at CERN reused: –But in passive mode –And adjusted at LAPP to beam line height Have to care that the table transmits “fully” all floor vibration frequencies –In the [0.1, 100] Hz range In particular, this means –No attenuation of some frequencies –No presence of eigenfrequencies of the {table+ FD elements} system in this range Basically equivalent to a large concrete block –But allows to stay flexible in support design –In particular, can be moved more easily

14. Adjust support to beam height New spool feet under magnet mover Relative motion between sextupole and table: 1.6nm only at 7Hz! Integrated RMS relative motion predicted at ATF2 between one sextuple and the honeycomb table Mover

15. Table to floor attachment study : four feet vs. entire side attachment No Mass 1400 kg Start with a simulation of a simple block with “4-feet” or “entire side” boundary conditions, with or without mass on table Attachment to floor = 4-feet Attachment to floor = entire side f eigen = 56.2 Hz  f eigen = 26.2 Hz   f eigen = 526.1 Hz f eigen = 135.2 Hz Lower eigenfrequency, but still suitable

16. 4 rigid feet attachement experimental setup Four adjustable rigid feet adjustable to avoid rocking of the table Beeswax for good vibration transmissions between floor and table Masses of 594kg Masses of 1188kg: weight of the magnets to put on the table

17. Magnitude of table transfer function First resonance of the table moving to lower frequencies with increasing weight on the table Table on 4 feet

18. Entire side attachment to floor experimental setup Masses of 1188kg (equivalent to magnets weight) Beeswax Good vibration transmissions between floor and table Bolt No beeswax No Mass table beeswax 3 plates sling Beeswax: Excellent vibration transmission. Easy to remove if needed.

19. Magnitude of table transfer function No masses: no resonances below 100Hz Masses of 1188kg: first resonance at 92Hz Table on entire side Note in addition this is about half of the “4-feet” case

20. LAPP schedule for 2008 April-May: new mover parts ready May: ATF2 magnets arrive at LAPP –Arrived on Tuesday, this week ! May-June: Vibration measurements with magnets, support and water flow July: vibration measurements with BPM support July: pack crates September-October: shipment and installation

21. LAL contribution Beam orbit control and correction algorithms Ph. Bambade (resp.), J. Brossard, C. Rimbault, M. Alabau Pons, Y. Rénier, Guy Le Meur*, Francois Touze* (*) No travel expenses expected

22. “Flight Simulator” Design and implement a simulation portable tool that provides a realistic emulation of the ATF2 machine hardware controls –Can be run both in simulation mode or in an actual machine control mode –Not limited to a unique “beam transport simulation engine” underneath Interfaces Lucretia, MAD, SAD & PLACET beam codes Common data structures in AML –Last but not least : provides safe, controlled access to ATF2 hardware controls Effort to make a collaborative development of the software –at present, ATF2 control software is the responsibility of a private company Workshop on AIL funding will take place at Orsay 18-20 th of June ! Operating currently the “flight simulator” in the actual control machine mode for the first time : –Read machine BPMs information –Compute feed-back corrections to be applied to the beam –And send correction to the beam line –Very first real results obtained !

23. Flight simulator used in machine control mode

24. First steering of extraction line -before correction-

25. First steering of extraction line -after correction-

26. Is 37 nm vertical size the limit at ATF2 ? Study explores in what extent can be varied the   * Originally motivated to start ATF2 with larger   * values –More comfortable situation, less sensitive to non-linearities Study shows that beam size down to ~17 nm might be achievable ! –Of large interest for CLIC machine, as demonstrating its chromaticity regime is feasible –Such low   * values are also of interest for ILC “pushed” machine

27. Extraction line commissioning Emittance in extraction line is known to be ~3 times worst than in damping ring –Need to be understood, as may involve part of the extraction line that will remain for ATF2 phase LAL people have been asked to investigate the problem and coordinate the effort –Together with extraction line instrumentation, activity promoted as an “R & D” task for ATF2

28. Investigations so far Could magnets shared with damping ring be the cause of the effect ? Explains only part of the problem…

29. LLR contribution Estimate of background from beam halo & beam dump with Geant4 Hayg Guler (post doc ANR) Marc Verderi (resp.)

30. Background estimation at ATF2 using Geant4 Activity started at LLR in April 2007 –Postdoc ANR Hayg Guler Use Geant4 to simulate the beam line + beam dump to estimate EM and neutron background levels –Neutron being mainly produced in the beam dump Need in addition to perform a set of dedicated measurements to cross-check the simulation estimates –Defining currently a set a “light” devices to measure EM and neutron backgrounds –Designing it so that it could be gradually put in place, and adapted according to what we will learn

31. Motivations for background measurements It is a “service task” to the ATF2 collaboration –Complementary to background measurements in beam monitors It can be a way to “prototype” bkgd estimation for ILC: –Use the same beam transport tool (BDSIM, Royal Holloway) than ILC Optic transport for beam central part, Geant4 for halo –Could we learn/invent a way to extrapolate from 10 5 electrons simulated in a beam to a typical 10 10 electrons in real life ? –Other sizable sources of EM bkgd than beam halo @ ATF2 ? Eg : beam gas ? –Is neutron production, in beam dump, well simulated in Geant4 ? As electro- photo-nuclear cross-sections large at low energy (< 100 MeV typically), ATF2 can provide a valuable answer to ILC –Is neutron transport well simulated also ? Eg does Geant4 simulate well neutron thermalization ? –…

32. Early measurements / observations made by Hayg in December 2007 Use single CsI (pure) crystal + PM, ~1 meter from dump (in temporary extraction line), reading signal at oscilloscope Observe a prompt peak (back-scattered photons) + delayed contribution due to neutrons thermalized in dump –Only “qualitative” agreement with (quick) simulation for now ! CsI + PM Dump (iron) Beam

33. ATF2 FJPPL Teams & budget

34. FJPPL ATF2 Teams French GroupJapanese Group NameTitleAffiliationNameTitleAffiliation Leader Bambade Philip DR2IN2P3/LALLeader Tauchi Toshiaki A. Prof.KEK Jérémie AndréaIR2IN2P3/LAPPUrakawa JunjiProf.KEK Verderi MarcCR1IN2P3/LLRSugahara RyuheiProf.KEK Brossard JulienIR2IN3P3/LALSugiyama AkiraA. Prof.Saga univ. Rimbault CécilePost-docIN2P3/LALSanuki TomoyukiA. Prof.Tohoku univ. Alabau Pons MariaPhDIN2P3/LALKuroda ShigeruR.A.KEK Rénier YvesPhDIN3P3/LALOkugi ToshiyukiR.A.KEK Geffroy NicolasPost-docIN2P3/LAPPTatsuya KumeR.A.KEK Bolzon BenoîtPhDIN2P3/LAPP Guler HaygPost-docIN2P3/LLR

35. Budget request for 2008-2009 Budget Request French TeamsJapanese Teams Item Euro Supported byItem k Yen Supported by Travel cost1200€Travel+per- diem 290K¥ Nb of travels 51450KEK  LAL 3CNRS  LAPP 3CNRS  LLR 2CNRS  Total 89600CNRS Per-diem cost 130 No of days11815400CNRS Total250001450

36. Conclusion KEK hospitality practice welcomes non-KEK people to bring “on the same foot” contributions to the ATF2 project –Making an accelerator based project driven as an HEP experiment ATF2 offers a wide range of opportunities to invent and deploy techniques in “real life” conditions –Stabilization, beam control, background simulation… –Shintake interferometer, laser wire, etc… –And it is a human size experiment AIL framework provides an actual help to better benefit of KEK hospitality –And helps in having exchanges and benefits between Japanese and French people This is particularly true and useful for young physicists –Certainly contributed to a favorable context for decision of next long term stays in KEK (Ph. Bambade, Y. Renier, F. Gournaris, B. Bolzon)

37. backup

38. New responsibility: BPM support SBPM QC3 SBPM FFTB 2.13 S3.00 SF1FF QF1FF 100 450.1 200 180 SBPM QC3 SBPM FFTB 2.13 S3.00 SD0FF QD0FF 100 76.2 450.1 200 18076.2 785380785380 2630 Sweeping Honda Shintake IP  S-band Cavity-BPM team: BPM design and fabrication: KNU BPM support design and fabrication : LAPP and SLAC BPM electronics: KEK and UK Cu:15kg

39. Need to fit with IP instrumentation FD support Up View Lateral View