UK ILC-Related R&D

1. UK ILC-Related R&D G. A. Blair Royal Holloway Univ. London EGDE Meeting, Oxford 25th October 2005 • LC-ABD Programme • Overview of the projects • Future prospects

2. UK funding for accelerator science for particle physics 2004 - 2007 UK funding agency, PPARC, secured from Govt. £11M for ‘accelerator science’ for particle physics, spend period April 04 – March 07 Bids peer-reviewed and preliminary new allocations made Oct 21 2003: ILC-Beam Delivery £7.2M from PPARC + £1.5M from CCLRC 2 university-based accelerator institutes G. Blair, RHUL

3. Accelerator Institutes 2 New institutes for Accelerator science: Cockcroft: Lancaster, Liverpool, Manchester - based at DL campus. 12 New academic positions. John Adams Institute: Oxford, RHUL: - based at both institutes 6 new academic positions. G. Blair, RHUL

4. Financial Summary UK LC-ABD G. Blair, RHUL

5. ILC: LC-ABD Collaboration • Bristol • Birmingham • Cambridge • Dundee • Durham • Lancaster • Liverpool • Manchester • Oxford • Queen Mary, Univ. London • Royal Holloway, Univ. Of London • University College, London • Daresbury and Rutherford-Appleton Labs; 41 post-doctoral physicists (faculty, staff, research associates) + technical staff + graduate students G. Blair, RHUL

6. Overview of Projects G. Blair, RHUL

7. UK LC-ABD Work Packages • Lattice design and beam simulations (D. Angal-Kalinin) • Advanced beam diagnostics (G. Blair) • Alignment and survey (A. Reichold) • Final focus luminosity stabilisation and spectrometry (P. Burrows) • e+ undulator, crab cavity system, wakefields/collimators (M. Poole) G. Blair, RHUL

8. LC-ABD Review Panel • O. Napoly (Saclay) • M. Ross (SLAC) • D. Schulte (CERN) • M. Tigner ( Cornell; Chair) • J. Urakawa (KEK) • N. Walker (DESY; representative of PPARC OSC) • K. Yokoya (KEK) The Panel met for the first time yesterday (24th October 2005) and have provided feedback on our current programme and will provide input to our future plans.

9. WP1.1 Machine Optics (D. Angal-Kalinin) • Form a strong optics team within the UK to be able to provide the necessary input to other LC-ABD work packages • Understand the ILC BDS designs • Set up all the necessary optics and tracking codes for the optics design. • Contribute to the ILC lattice design and layout with international collaborators • Provide the input decks of the evolving lattices to other work packages • Contribute to the optics design for the test facilities for the ILC and participate in the beam tests

10. 2 mrad Optics Design • Final Focus and extraction line optimized simultaneously • Quadrupoles and sextupoles in the FD optimized to • cancel FF chromaticity • focus the extracted beam SLAC-BNL-UK-France Task Group O.Napoly, 1997 QF1 pocket coil quad : C. Spencer G. Blair, RHUL

11. Optics for beam diagnostics • Study proposed coupling correction and emittance diagnostics section for the ILC • Beam sizes for laser wire  increase in length of section? • Requirements of generic beam diagnostics for ILC BDS • Accuracies and resolutions for these devices • Optimise the BDS lattice including beam diagnostics • Optics design to achieve 1mm sy in ATF extraction line • Participate in LW runs with WP2.1 to verify the optics LW G. Blair, RHUL

12. WP1.2 Simulations (J. Jones, G. White) • Design www-accessible code management/archive facility. • Improve ground-motion models and develop models of facilities noise. • Generate benchmark beam-beam interaction results for different ground-motion models, parameter sets, and machine designs; store results in database. • Develop BDSIM into a user-friendly package with improved documentation and code-management that is used widely in UK BDS studies. • Develop simulation of beam halo, and its production. • Develop expertise in the design of the beam diagnostics section (modeling realistic backgrounds to find optimal placement of laser-wire system). • Study backgrounds generated in the ILC IR and the effect on the performance of the IP fast-feedback system. • Study alignment and tuning strategies for the ATF2 extraction line and for the ILC BDS. • Numerical wakefield and collimation studies. • Background tracking simulations for ESA FONT BPM tests. • Simulations of ILC IP beam parameter reconstruction using event shape analysis from beamstrahlung hitting forward calorimeters.

13. Multi-Seed Luminosity Studies with the ILC Simulation Model LUMI Feedback Optimisation (Position + Angle) 350 GeV CME ANG + IP Fast Feedback 500 GeV CME G. Blair, RHUL

14. BDSIM Beamlines are built of modular accelerator components Full simulation of em showers All secondaries tracked Screenshot of an IR Design in BDSIM G. Blair, RHUL

15. WP2.1 – Laser-wire (G. Blair) • Extract full returns from the investment made in the PETRA + ATF laser-wires, develop new hardware and techniques there and gain experience with a fast-scanning system. • RAs and students to work with the ATF and PETRA accelerator physicists in machine studies and in devising new optics schemes to minimise the beam spot-size at the laser-wire position. • Develop a strong UK laser facility from which to develop a mode-locked laser system for the laser-wire and use it to expand into a wider range of laser-based beam diagnostics. • Produce a performance study of the operation of laser-wires and other laser-based beam diagnostics in a realistic BDS, using full simulations and realistic background levels.

16. Laserwire - PETRA + UCL 11.2.05 New EUROTeV Laser arrived at DESY in October 2005 G. Blair, RHUL

17. ATF-LW Vacuum Chamber Built at Oxford DO + Workshop Vacuum Tested At DL G. Blair, RHUL

18. WP2.2 – Longitudinal profile (A. Gillespie, G. Doucas) • Develop non-destructive sub-picosecond longitudinal bunch profile diagnostics. • Investigate two complementary techniques: Electro-optic and Smith-Purcell radiation. • EO: Optimise technique for ultra-short bunches • EO: Work towards simplifying laser requirements • EO:Investigate integration with laser timing distribution systems • SP: Two more runs at FELIX, mid-November and Jan.-Feb. 2006 • SP: Planning for SLAC, 28GeV but different bunch structure. • SP: Continuing theoretical work: rapid re-construction of bunch shape, other radiative processes. • SP: Close contact & comparison with EO technique.

19. Electro-optic Signal vs Coulomb Field “crossed-polariser” configuration  EO signal  [Coulomb Field]2 Q=300pC, E=50MeV Berden, Jamison, et al., Phys. Rev. Lett. 93 114802 (2004) measurements have been made with 150pC < Q < 300 pC LC-ABD review meeting, 24th Oct. 2005 19

20. Detector array LC-ABD review meeting, 24th Oct. 2005

21. WP2.3 – Polarisation (I. Bailey) • Develop specialised tools to simulate e- / e+ spin transport through each region of the ILC. • Simulate bunch-bunch depolarisation effects at interaction point. • Full cradle-to-grave ILC spin polarisation simulations. • Assess degree and robustness. • Validate simulations against experimental data. • Assess ILC polarimetry designs. • Determine any additional experimental measurements required to validate software. • Investigate polarimetry layout. • Produce the associated simulation package.

22. G. Blair, RHUL

23. Bunch-Bunch Interaction Simulations TESLA parameters PINIT=1.0 low Q parameters PINIT=1.0 G. Blair, RHUL Before interaction During interaction After interaction

24. WP3 – LiCAS/STAFF (A. Reichold) • Evaluate impact of survey & alignment process on performance & operation of ILC • Demonstrate principle feasibility of survey & alignment process based on LiCAS-Rapid Tunnel Reference Surveyor. • Develop technological and scientific expertise necessary to provide survey & alignment system for ILC • Evaluate case for stabilisation / monitoring system for ILC final focus for critical BDS magnets • Demonstrate feasibility of M-FSI sensor • displacement @ nm resolution • absolute position @ mm resolution • usable for above cases • Demonstrate relative position measurement of accelerator components in realistic accelerator environment using network of M-FSI sensors

25. 2.5m measurement car service car Mechanics Status • Service cars for RTRS • Measurement unit design 80% • Compensated vacuum FSI reference interferometers G. Blair, RHUL

26. Optics Status Splitter Tree Amplifier • pW level uncollimated short line FSI • collimated long line FSI • Optimised LSM camera choice Laser Retro Reflector 3D-Piezo Stage LiCAS update

27. WP4.1 – Final Focus Luminosity Stabilisation (P. Burrows) • Simulate (also within WP1.2): • beam transport damping ring -> IP • including ground motion, real hardware response, noise… • performance of intra-train, pulse-pulse, upstream orbit FBs • integrated FB performance + lumi stabilisation strategy • Prototype components required for ILC intra-train + pulse-pulse beam feedback system(s): BPMs, signal processor, feedback circuit, amplifier, kicker • Demonstrate system performance with real beam • Collaborate with international GDE partners • FONT4 digital FB system: prototyping and testing at ATF • Investigation of ring -> extraction-line feed-forward system at ATF • FONT@ESA

28. FONT3 installation on ATF beamline BPM processor board FEATHER kicker Amplifier/FB board ATF beamline installation June 05

29. FONT1,2,3: Summary 67 ns 2002 2004 54 ns 23 ns Even fast enough for CLIC intra-train FB! 2005

30. WP4.2 – BPM Spectrometry (D. Miller, D, Ward) • Development of BPM magnetic spectrometer for beam energy measurement: Resolution of 1 part in 104 • Comparable stability over many hours or days • ATF NanoBPM collaboration • Basic study of cavity BPMs • Ultimate BPM limit (resolution and stability) • 2 triplets of cavities in ATF extraction line • Long term stability tests (~8 hours) • SLAC End station A • Tests of the design of a magnetic chicane • Operation mode of spectrometer • BPM only run in Feb/Mar 2006 • Full chicane tests in Autumn 2006 • Spectrometer specific BPM designs • Cavity design • Electronics • Testing and validation • Electromagnetic cavity design started • Electrical prototypes to be tested at UCL early summer 2006

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32. G. Blair, RHUL

33. WP5.1 – Helical Undulator (J. Clarke) • Optimise undulator design solution. • Technology decision underpinned by prototyping. • NEG pumping validation. • Measured + validate prototype PM / SC module performance. • Select preferred magnet technology type. • NEG pumping trials. • Value engineered magnet solution. • Electron beam transmission tests. • Recommendations to ILC GDE. • Simulations: • Magnetic field distributions from magnets / current elements. • e- beam trajectory through undulator including effect of undulator imperfections. • Synchrotron radiation production. • Spatial, energy and spin distributions. • SR induced desorption of gases. • Multipacting (SLAC).

34. Superconducting Helical Undulator Parameters Superconducting bifilar helix First (20 period) prototype constructed (RAL) Cut-away showing winding geometry G. Blair, RHUL

35. } Optimised to minimise forces between halves of undulator Permanent Magnet Undulator Prototype • Halbach magnets (NdFeB) • 20 × 14mm periods • 4mm inner diameter • 8 blocks per ring • 8 rings per period Field measurements ongoing at Daresbury Laboratory G. Blair, RHUL

36. WP5.2 – Crab System (A. Dexter) • Study quadrupole effects on crab rotation. • Study cavity to cavity phase tolerance and cavity to beam phase tolerance. • Study of frequency for crab cavity system. • Electromagnetic design studies. • Alternative cavity designs. • Evaluation of Fermilab 3.9GHz CKM cavity. • Planning of phase control experiments, measuring cavity to cavity jitter on existing • s.c. cavities and the performance of phase control systems. • Study of higher order modes. • Numerical multipacting study for dipole cavities. • Develop models of phase control systems. • Develop a phase control system suitable for the crabbing system. • Warm models of the Fermilab cavity to investigate trapped modes. • Evaluate minimal cavity beam clearance • Development of couplers and LOM/HOM damping systems. • Study cryostat requirements. • Undertake Daresbury ERL Prototype phase control experiment.

37. WP5.3 – Collimation (N. Watson) • Development improved EM modelling methods • Benchmarking wakefield calculations against experiments • SLAC ESA beam test / data analysis • RF bench tests (training/code comparisons) • Tracking simulations with best models of wakefields • Simulations of beam damage to spoilers • Material studies using beam test • New spacetime covariant field-theoretic description of electron beam dynamics is • under development • - Includes a covariant perturbation expansion of the electric current about • the forward light cone • - Exact solutions and their relation to solutions obtained using the • perturbation scheme are under scrutiny • - Will be used to analyse dynamics of an electron beam in collimator geometries, predications to be compared with results from conventional EM modelling packages

38. Wakefield box 1500mm ESA sz ~ 300mm – ILC nominal sy ~ 100mm (Frank/Deepa design) Magnet mover, y range = 1.4mm, precision = 1mm G. Blair, RHUL

39. 38 mm h=38 mm L=1000 mm a r=1/2 gap As per last set in Sector 2, commissioning Extend last set, smaller r, resistive WF in Cu 7mm G. Blair, RHUL cf. same r, tapered

40. WP? – Beam Dumps (R. Appleby) • Test the feasibility of the gas/water dump hybrid idea, through simulation • The gas energy density along the column • Gas dump pressure issues • Activation studies with CINDER90 • Carried out by university staff, with support from experts and engineers • Deliver a report on gas dump feasibility • The hybrid uses a shorter gas dump as a passive beam expander, in front of a water-based dump • The idea, which arose out of discussion with target people, is very attractive • Water dump window problems eased • Beam expander failure unlikely • Other benefits e.g. reduced neutron flux coming back from the water dump

41. FUTURE FUNDING OF LC-ABD Current PPARC support ends in March 2007 Future proposed programme will need to be peer reviewed by the end of 2006 to ensure continuity. The proposal for the next phase will need to take into account overall international status, UK role/responsibilities and timescales for TDR etc. Funding for accelerator R&D awarded in SR2002 has been built into the PPARC baseline. Linear collider R&D is given high priority by PPARC. There are long term commitments to the two accelerator R&D centres.

42. LARGE CAPITAL FACILITIES FUND Linear collider is a bid from PPARC to the OST Large Capital Facilities Fund – separate funding line retained by OST for capital construction projects. Prioritisation exercise currently underway of bids from all Research Councils – outcome not yet known but if given high priority, any funding could be for the construction phase only. Discussions with OST continue. PPARC will have to balance the need to maintain momentum, with the funds available and other calls on the PPARC budget.