Diagnostics Summary G. Blair RHUL 23rd June 2005 Laser Wire Mini Workshop Chair: J. Urakawa, J. Frisch EUROTeV Chair: G. Blair

Diagnostics I Laser Wire Mini Workshop Chair: J. Urakawa, J. Frisch (08:30->12:00) (Location: Arts) (Room: G3A--) Micron electron beam optics at ATF extraction line for laser wire experiment P. Karataev / KEK ATF Laser-wire Optics N. Delerue / Oxford ATF infrastructure plans + discussion D. Howell / Oxford PETRA laser-wire analysis S. Malton / UCL PETRAIII Laser-wire T. Kamps / BESSY EO Scanning possibilities A. Bosco / RHUL UK Laser-wire project: plans G. Blair / RHUL Aims: Define+ decide key parameters for ATF extraction line LW Discuss recent scans + analysis from PETRA LW Aim towards ATF2 LW project and ILC LW needs

University College London (UL) Laser-wire People BESSY T. Kamps DESY H. C. Lewin, S. Schreiber, K. Wittenburg, K. Balewski Oxford R. Bingham, S. Dixit, B. Foster, N. Delerue, D. Howell, A. Reichold Royal Holloway (UL) Agapov, G. Blair, G. Boorman, A. Bosco, J. Carter, L. Deacon, F. Poirier, M. Price, C. Driouichi University College London (UL) S. Boogert, S. Malton CCLRC Daresbury L. Jenner KEK Aryshev, H. Hayano, P. Karataev, K. Kubo, N. Terunuma, J. Urakawa Kyoto N. Sasao SLAC A. Brachmann, J. Frisch, M. Ross Project web page: http://www.hep.ph.rhul.ac.uk/~lbbd/

Laserwire - PETRA See talk by S. Malton, this workshop + UCL RHUL UCL 11.2.05 + Oxford RHUL UCL DESY CERN See talk by S. Malton, this workshop

Practical Considerations I f1 geometry is challenging Limitations from power Limitations from angle Surface optical quality Alignment tolerance See talks by N. Delerue + D Howell in this workshop.

Practical Considerations II See talks by N. Delerue in this workshop. f1 Lens design is challenging Limitations from power Limitations from ghost images Alignment tolerance

Diagnostics II EUROTeV Chair: G. Blair (08:30->12:00) (Room: G3A--) Confocal Resonator Beam Position Monitor Ferrari, A / Uppsala Uni. Precision Cavity BPM + WBCM: Wide-Band Current Monitor L.Soby / CERN The Cold Re-entrant Q-BPM design C. Simon /CEA/Saclay Development of non-invasive micron beam size diagnostics using optical diffraction radiation P. Karataev / KEK High Energy Polarimetry F. Zomer / LAL, Orsay Timing and Phase Monitoring J. Sladen / CERN Fast Lumi Monitoring C. Grah / DESY-Zeuthen Fast Lumi Spectrum Measurement F. Poirier / RHUL Precision Energy Spectrometry D. Miller / UCL Aims Discuss and define the EUROTeV tasks Explore synergies and potentials for lumi-spectrum

Confocal Resonator Pickup A. Ferrari (Uppsala)

PBPM- L. Soby (CERN) Requirements Aperture: 4mm Resolution: 100nm Absolute precision: 10μm Rise time: <15ns Dynamic range: ±1.5mm (15 bits) Linearity error: < 1% 24H stability: 1μm Vibrations <100nm Low frequency cutoff: 100kHz High frequency cutoff: 30MHz Bake out temperature: 150C Operating temperature: ~20C Vacuum: 10-9 Torr

WBCM-Requirements L. Soby (CERN) Beam current monitor with > 20GHz band width for measurement of intensity and bunch to bunch longitudinal position. Main beams, drive beams and damping rings. Impedance 4 W Lf cut-off, direct output 250 kHz Lf cut-off, integrator output 10 kHz Hf cut-off 7 GHz Number of feed thru 8 Gap length 2 mm Beam aperture diameter 40 mm Length 256 mm Flange type DN63CF Max temp. bake-out 150 ºC Low frequency cutoff: 100kHz Bake out temperature: 150C Operating temperature: 20C Vacuum: 10-9 Torr 100kHz-20GHz WB signal transmission over 10-20m.

C. Simon CEA/Saclay Cold Re-entrant Q-BPM design The reentrant BPM is a resonant cavity with 4 feedthroughs and analog and digital electronics Good resolution ~1µm and good “centering accuracy” <1µm Now, the cleaning of the cavity, with the holes, is ok. Tests in DESY were made Good resolution time. The damping time for the re-entrant cavity is 9.5ns. Robust in the cold Tests on the new system at the beginning of 2006 Plot of the output voltage (behind electronics) vs position of the beam Voltage Δ/Σ [a.u] Position of the beam (mm) ILC meeting

Liapine UCL Spectrometer design BPM triplet Dipole magnet Possible 3/4 magnet spectrometer designs 3 Magnets Deflection angle measured from offset and distance Beam incline influence on BPM measurements 4 Magnets Translation of beam Extra precision dipole required Simple translation of BPMs for maximum sensitivity Dipole magnet

Results from ATF - resolution May 2005 data Fitting algorithm Calibration using hexapod movers Resolution ~ 35 nm Stable: 20 nm drift over 2 hours, around 80 nm of jittering over few minutes

Summary of EUROTeV TPMON Phase Detection Requirements Single-shot ± 50MHz bandwidth 0.1 degree resolution Limited linear range OK Amplitude range? Alexandra Andersonn and Jonathan Sladen Develop, build and test 30GHz beam phase measurement system aiming for 0.1 degree (9fs) resolution Precision synchronization is a feasibility issue for CLIC Phase detection will be at a lower, intermediate frequency, developments may be of interest to other machines Things to do next More work on summed analogue multipliers Review other phase detection methods Choose IF

Fabry-Perot cavity & pulsed laser R. Bernier, J. Bonis, V. Brisson, R. Chiche, R. Cizeron, G. Guilhem, M. Jacquet-Lemire, D. Jehanno, R. Marie, K. Moenig, V. Soskov, A. Variola, Z. Zhang, F. Zomer Outline Introduction : 2 laser needs for ILC Fabry-Perot cavity, in pulsed regime R&D at LAL : description & status

Fabry-Perot cavity filled with a pulsed laser Electron beam 1ps Pulsed laser Fabry-Perot cavity with Super mirrors A priori impossible because of the laser frequency width: Dn ≈1/(1ps)=1THz for picosecond laser (c.f. 3kHz cavity banwidth for a gain of 104) In fact possible with mode-locked lasers

A wedge is used to act on the gimbal mount in vacuum R. Cizeron, R. Marie, J. Bonis

Summary R&D EUROTEV at LAL/Orsay : 2005-2007 Fabry-Perot cavity for a polarimeter 1ps/100fs pulses of energy 100 mJ/pulse@76MHz Moderate input Ti:sa laser beam power but very high cavity finesse 30000-300000 Feedback on frep & f0 [need for a high quality mode-locked laser beam] Concentric OR ring cavity to reduce the laser beam size mechanics & feedback conception started If this R&D gives satisfaction Study of the implementation for a polarimeter A new laser source should be considered to match the laser power required for an e+ polarised source study (100mJ/pulse@~300MHz)

D. Miller UCL Physics needs the Luminosity weighted spectrum at collision. Three components: 1. Precision measurement of absolute incoming energy. Main goal of ESPEC project. Rest of talk. BPM spectrometer in upstream chicane. 2. Measurement of shape of incoming spectrum. Long term concern. Maybe Laserwire upstream? (Downstream: Eric Torrence, earlier this morn.) 3. Correction for beamstrahlung and beam fluctuations. Event-based: Bhabha acollinearity, e+e- Z, +- etc. (Active study at UCL {+ new collaborators} see Stewart Boogert’s report to top/QCD at LCWS)

BeamCal: Beam Diagnostics and Fast Luminosity Monitoring e+e- pairs from beamstrahlung are deflected into the BeamCal 15000 e+e- per BX => 10 – 20 TeV ~ 10 MGy per year “fast” => O(μs) Direct photons for q < 400 mrad (PhotoCal) Deposited energy from pairs at z = +365 (no B-field, TESLA parameters) C. Grah DESY

Results of Analysis C. Grah DESY Parameter nom. in phot. pairs σx 553 nm 4.2 1.5 σy 5.0 nm 0.1 0.2 σz 300 μm 7.5 4.3 beam offset x 0 nm 4.0 6.0 beam offset y 0 nm 0.16 0.4 vertical waist shift 360 μm 14 24 C. Grah DESY

Fast Luminosity Spectrum Measurement Aim Bhabha & Beamstrahlung generator  Interface Luminosity Calorimeter Response matrix Parameters estimation technique Estimation result Unfolding Choice of regularisation parameter Summary Outlook Freddy Poirier - RHUL/JAI f.poirier@rhul.ac.uk Freddy Poirier – ILC-European workshop 2005

Summary Unfolding helps drastically to gain in accuracy for the beam energy spread measurement. Larger mean errors in the estimated parameters for the unfolded results. Lumi. spectrum reconstructed correctly (not minimum χ2). Relative errors Tau=6*107 Freddy Poirier – ILC-European workshop 2005

the speakers and particpants Diagnostics Summary A big thankyou to all the speakers and particpants