LCABD G' A' Blair, RHUL LCUK Meeting UCL 5th October 2005

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LC-ABDG. A. Blair, RHULLCUK MeetingUCL 5th
October 2005

• BDIR Meeting
• OSC
• Review meeting
• Future schedule
• Project Overview
• Beam Dump opportunity
• WP Brief summaries

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ILC-BDIR Workshop

• Royal Holloway, Univ of London
• 20-23 June 2005
• http//www.pp.rhul.ac.uk/workshop/

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135 Participants from all regions
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LC-ABD meeting at Cambridge

• 7th July 2005
• Despite lower attendance (London bombs), there
  were many good talks and lots of progress shown.
• The UK then made a strong presence at Snowmass
  with about 40 attendees.
• UK will host EGDE meeting on
• 25th Oct 2005

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OSC Membership

• Steve Myers, CERN, Chair
• Nick Walker, DESY
• Andrew Holland, Brunel
• Harry Smith, MRAO, Cambridge
• Howard Smith TMD
• Last meeting was in June 05, next is in
• February 06.
• Recommended a mid-term review (see below)
• All reports and talks can be found on LC-ABD
• Website.

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LC-ABD Review meeting
Will be held at Oxford on 24th October 2005

• Review Panel
• M. Tigner, Cornell, Chair
• Nick Walker, DESY (Rep. OSC)
• M. Ross, SLAC
• O. Napoly, Saclay
• D. Schulte, CERN
• J. Urakawa, KEK
• K. Yokoya, KEK

This is a technical review mainly for internal
LC-ABD use. However, we will need to provide a
report from this meeting for our OSC.
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LC-ABD Timeline
Programme finishes officially on 1st April 2007

• Schedule for next stage
• We need to provide an indication of strategy by
  the end of this year.
• This should provide
• Overview of the work-packages
• Estimate of the total cost
• Needs to be coordinated with group leaders for RG
  support for Oct 2006 to Sept 2011.
• Start of peer review of next LC-ABD phase by June
  2006 at the latest.
• The peer review will probably involve Gateway and
  so will be more (!) complex than the last round.
• We need to define the relevant grant break-points
  in the light of GDE schedule.

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LC-ABD Overview

• WP1 (D. Angal Kalinin)
• Lattice Design (D. Angal Kalinin)
• Simulations (J. Jones, G. White)
• WP2 Advanced Beam Diagnostics (G. Blair)
• Laser-wire (G. Blair)
• Bunch Longitudinal Profile (G. Doucas, A.
  Gillespie)
• Polarisation (I. Bailey)
• WP3 Alignment and Stabilisation (A. Reichold)
• LiCAS (A. Reichold)
• STAFF (D. Urner)
• WP4 Final Focus Luminosity Stabilisation (P.
  Burrows)
• Luminosity Stabilisation (P. Burrows)
• BPMs/Energy Spectrometry (D. Miller)
• WP5 Technology (M. Poole)
• Polarised Positron Undulater (J. Clarke)
• Crab Cavity System (A. Dexter)
• Collimation (N. Watson)

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Beam dump work in LC-ABD

• The ILC needs 6 high power (21MW) beam dumps
• The baseline design uses a water-based dump.
  This was studied for the TESLA and NLC projects
• The alternative design used a Noble gas dump,
  consisting of a column of Ar and a water cooled
  jacket.

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Initial work on gas dump issues

• Initially, a study will be made of gas/water
  dump hybrids
• This work will focus on energy densities along
  the absorbing column, for varying Noble gas
  pressure profiles

Pressure
I. Agapov
z
This is a prelude to a full work packages
beginning in 2006
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Beam Dumps
A possible extension of our programme First
meeting was at RAL on 14th September

• Workplan (depends on finding additional effort)
• Investigate gas-based beam dump
• Investigate gas/water based hybrid
• Identify synergy with wider UK programme
  (targets/dumps meeting Nov 30 2005? TBC)
• Draft memo will be submitted to LC-ABD PMC this
  week
• Identify future RD programme (May 2006)
• Produce full design for RDR (December 2006)

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• Work Package 1

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• Lattice Design Team
• Daresbury
  Laboratory
• R. Appleby
• F. Jackson
• J. Jones
• D. Angal-Kalinin
• Cockcroft Institute
• L. Jenner

Slides from D Angal-Kalinin (LC-ABD _at_ Cambridge
meeting)
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Optics codes

• Extraction line design
• Guinea_PIG, MAD, DIMAD
• MATLAB ? MAD, TRANSPORT, TURTLE
• DIMAD comparison with BDSIM (Orsay, RHUL)
• Collimation Studies
• MERLIN, STRUCT,
  DBLT
• (Manchester, RHUL, COLSIM task in
  EuroTeV)
• Final Focus Studies
• MAD, BETA, DIMAD, TRANSPORT, TURTLE
• ATF2 optics and tuning studies
• MAD, TRACY, BETA
• Will start using SAD soon for
  ATF/ATF2 work.

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2 mrad Crossing angle Extraction line design
SLAC-BNL-UK-France task force Several design
iterations since Nov04

• Shared magnets for incoming and outgoing
• Need large magnet apertures to accept both
  electron beams and photons.
• Final doublet optimised for incoming and outgoing
  beam.

SF1
SD0
QF1
QD0
T. Maruyama
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Interaction Region in BDSIM

• Full IR Geometry modelled in BDSIM
• Using MySQL geometry database
• Currently using the Stahl design for L 4.1m
• Includes a full Solenoid Field Map
• Choose from TESLA, GLD, or SiD fields

J. Carter (RHUL)
Z Component
Radial Component at 1m from beamline
Screenshot of an IR Design in BDSIM
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BDSIM
We have constructed it applied it to CLIC
BDS ILC BDS PETRA Laser-wire (benchmark SR) 1st
public release under CVS. (I. Agapov, RHUL) Jan
05. Developing GRID implementation
Beamlines are built of modular accelerator
components
Full simulation of em showers

• Others are now applying it to
• CLIC IR (Uppsala)
• ILC 20 mrad extraction line (Oregon)
• ILC 2 mrad IR (CCLRC, Orsay, RHUL)
• ILC Energy spectrometer (Oregon RHUL)
• ILC neutrons, beam dumps, (RHUL,
  DESY, collab. With FNAL/SLAC)
• Energy Recovery linac (Daresbury)

All secondaries tracked
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Halo Studies in the Interaction Region

• Track Halo electrons from the Final Doublet and
  Interaction Region
• Also track associated Synchrotron Radiation
• Check Halo material passes all apertures

Area of Halo SR distribution hitting QF1 for Nx
Vs Ny
Halo Synchrotron distributions at QF1
Nx 9.0, Ny 45
Nx 9.0, Ny 68
Pocket
Units are numbers of sigma for collimation depth

• Next step is to track this material along the
  extraction line. Check for low energy particles
  backscattering back

J. Carter
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Collimation depths
20 mrad
2 mrad
Long doublet
http//www.slac.stanford.edu/xorg/lcd/ipbi/lcws05/
maruyama_backgrounds.ppt
Short doublet
F. Jacksons talk BDIR workshop
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BeamStrahlung
Glen White, SLAC/QMUL Snowmass 2005
200m
ILC IR

• Diagnostics of bunches at IP.
• 3 potential sources of information
• Energy-distribution of Pairs.
• Number-distribution of Pairs.
• Energy-distribution of Photons.

BeamCal
Photon Detector
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G. White, Snowmass 2005
MULTI-BUNCH INTEGRATED ILC SIMULATIONS
Luminosity through example seed bunch train
showing effects of position/angle scans.
All beam data from simulation runs are stored
online at http//hepwww.ph.qmul.ac.uk/lcdata
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Feedback BPM background environment and BDS
designTony Hartin QMUL - Snowmass 2005
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Jim Jones

• Finally have a generalised method of analysing
  the tolerances on the ATF magnets in terms of
  field or position errors
• Can be used with real errors to analyse effects
  on beam very simply
• Have produced a set of specifications for the
  multipole components and for the position
  tolerances for all of the final focus line
  quadrupoles and sextupoles
• Data is not specific to a given tolerance
  specification (i.e. 2 or 10 beam size increase)
• Analysis using tuning knobs is ongoing, and
  correction works well
• Analysis of other tuning scenarios, as well as
  model of BBA may also be useful

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Wake fields Collimation studies
R. Barlow, G. Kourevlev, A. Mercer, A.
Bungau Manchester

• Have implemented Wake Functions into Merlin
  higher order modes
• 5 terms give a good description
• Will include resistive wakefields
• Tidy up code and put into Merlin library
• Will use ANSYS to study material shocks, thermal
  expansion etc.
• Compare with experimental data
• Simulate Halo in Merlin

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Optics for beam diagnostics

• Collaboration with Laser wire team for ATF/ATF2 ?
  1 mm sy

L.Jenner ATF, May 2005

• Study proposed tuning and emittance section for
  the ILC
• Beam sizes for laser wire estimate increase in
  length of the section
• Requirements of generic beam diagnostics for ILC
  BDS
• Accuracies and resolutions for these devices
• Optimise the BDS lattice including beam
  diagnostics

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• Work Package 2

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Laserwire - PETRA
UCL
Progressing really well
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PETRA laser-wire 2d system

• 2-d scanning system
• Mechanics designed built at Oxford
• Optics electronics on order
• Final construction at RHUL with UCL Oxford
• Will be shipped to DESY in November 2005

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ATF Extraction line laser-wire
Vacuum vessel lens Designed and built at Oxford
Vacuum vessel installed in ATF Oct 05 Data taking
planned for Dec 05
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Bunch profile diagnostics with coherent
Smith-Purcell radiation
Wade Allison , Victoria Blackmore, George Doucas,
Colin Perry and M.F. Kimmitt (Dept. of
Physics, Univ. of Essex)

• Detector electronics work well
• Screening from X-rays successful
• But.
• Strong background level
• The current filtering system is not optimal.
• Light-collection system not very efficient
• Hence, Smith-Purcell signal is adequate at
• 1GHz but rather weak at 25MHz.

• Next
• Measure the background accurately
• and subtract from SP signal.
• Carousel with 3 gratings blank

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Electro-optic characterisation of ultra-short
relativistic electron bunches

• Allan Gillespie, Jonathan Phillips - University
  of Dundee
• Allan MacLeod - University of Abertay Dundee
• Steve Jamison - University of Strathclyde (Dundee
  Group)
• Collaborators at FELIX Rijnhuizen
• Lex van der Meer, Giel Berden, Britta Redlich

New Temporal Decoding method proves superior
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Currently (Sep 2005) installing
temporal-decoding experiment at DESY

• First tests on sub-500fs bunch
• Calibration experiments with transverse
  deflecting cavity

Assembly in place in TTF tunnel

• situated at 140m point on TTF, at EOS station
• beam energy 450 MeV
• adjacent to LOLA cavity (transverse RF
  deflector)

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Q300pC, E50MeV
Berden, Jamison, et al., Phys. Rev. Lett. 93
114802 (2004)
Measurements have been made with 150pC lt Q lt
300pC

• Demonstrated profile measurement of
  650fs FWHM bunches, 300pC
• Current time resolution is 300fs
• Challenges remain in getting sub-200fs
  resolution - materials, EO response,
  deconvolution, ...
• Techniques are applicable to CSR measurements
  - non-invasive nature may be very useful
  (e.g. beam halo)
• Many variations of EO detection possible
  scope for addressing specific diagnostic
  requirements

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Robust Spin Polarisation LC-ABD WP2.3

• I.R. Bailey, J.B. Dainton, P. Cooke, T.
  Greenshaw, L.I. Malysheva (University of
  Liverpool )
• D.P. Barber (DESY/Hamburg)
• G.A. Moortgat-Pick (University of Durham/CERN)
• J.A. Clarke, O.B. Malyshev, R.J. Reid, D.J.
  Scott, B. Todd (CCLRC ASTeC Daresbury Laboratory)
• Y. Ivanyushenkov, E. Baynham, T. Bradshaw, S.
  Carr, J. Rochford (CCLRC Rutherford Appleton
  Laboratory)

• Simulate transport of spin polarisation from e- /
  e sources to interaction region.
• Current activity.
• Simulate bunch-bunch depolarisation effects at
  interaction point.
• Current activity.
• Full cradle-to-grave LC spin polarisation
  simulations.
• Assess degree and robustness.
• Initial simulation results expected March 2006.
• Validate tools against experimental data.
• Assess LC polarimetry designs.

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Spin Transport at the ILC
Beam Delivery System
Linac
Damping Ring
Positron Source
Linac
Undulator
150GeV e-
Intense polarised e beam
5GeV e
250GeV e
Interaction Point
Depolarisation Misalignments, EM fields,
Synchrotron radiation, resonance, bunch-bunch
250GeV e-
Beam Delivery System
Linac
Damping Ring
Electron Source
Linac
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WP 2.3 Activity for next 6 months

• Continue RA PhD student SLICKTRACK training
• Nov 05
• Complete ILC SLICKTRACK code development
• Dec 05
• Complete first assessment of damping ring
  depolarisation
• In collaboration with EUROTeV WP3
• Compare with previous Wolski and Bate paper
  (MERLIN)
• Dec 05
• Finish commissioning CAIN
• Aug 05
• Complete first assesment of CAIN ILC bunch-bunch
  simulations
• Dec 05

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• Work Package 3

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FSI News
Splitter Tree

• Short 6-line FSI system for 3D wall marker
  measurement works without collimation optics

Amplifier
Laser
Retro Reflector
3D-Piezo Stage
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What to do next

• Up to Spring 2006
• Operate prototype at DESY
• commissioning
• many calibration programs on full train
• multiple test surveys of tunnel
• tuning of operation and analysis algorithms
• study of systematic errors
• Up to Spring 2007
• In Oxford
• Improvements of component calibration programs
  hardware
• Design of second generation instrument for X-FEL
• much smaller ? fits into X-FEL tunnel and maybe
  ATF-2
• much simpler ? reduce from RD to production
  functionality
• 6 cars
• Design stake out instrument

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StaFF at ATF

• Target Accuracy
• O(10 nm) vertical displacement between KEK and
  SLAC BPMs.
• Refer 6-D coordinate changes of KEK BPMs via
  middle triangle to the SLAC BPMs.

SLAC BPM
Floor node
KEK BPM
RD at KEK Run single arm prototype in
accelerator environment. Measure angular
deflection of I beam. Mount floor and BPM
nodes. Survey mounted nodes. Jan 06 Mount
vacuum tubes. Install interferometer. Setup and
first test of system Apr 06

• Red lines Michelson interferometer displacement
  meters O(1nm) resolution
• Multilateration requires absolute distance meter
  with mm resolution FSI
• FSI and Michelson (M-FSI) in the same
  interferometers !

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• Work Package 4

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WP4.1 Beam-based Feedback Systems Status
Plans for Snowmass

• FONT
• Queen Mary Philip Burrows, Glen White, Glenn
  Christian,
• Hamid Dabiri Khah, Tony Hartin, Stephen
  Molloy,
• Christine Clarke, Christina Swinson
• Daresbury Lab Alexander Kalinin, Roy Barlow,
  Mike Dufau
• Oxford Colin Perry, Gerald Myatt

FONT3 PCB amplifier FB
Same drive power as needed for ILC
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FONT3 Installation in ATF extraction line
Adjustable-gap kicker
BPM ML11X
BPM ML12X
BPM ML13X
Superfast amplifier
Superfast BPM processor
Feedback
Aim TOTAL latency lt 20 ns

• Demonstrated feedback with delay loop
• Ultra-fast system total latency 23 ns
• Varied main gain, delay loop length, delay loop
  gain
• system behaves as expected
• Beam quality limited time (6 shifts) did not
  allow detailed optimisation of system parameters

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FONT4 Prototype Digital Feedback System

• ATF/(ATF2) 1.3 GeV beam, 3 bunches with spacing
  c. 150ns
• FONT4 (2005-6)
• modified FONT3 BPM front-end signal processor
• digital FB system
• modified FONT2 solid-state amplifier 300ns long
  o/p pulse
• FEATHER adjustable-gap kicker
• Aiming for first demonstration of FB w. ILC-like
  bunches
• latency 100ns (electronics)
• stabilisation of 3rd bunch at um level
• Possible first component tests at ATF December
  2005/March 2006

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4.2 Energy Spectrometry
M. Slater, M. Thomson, D. Ward (Cambridge) S.
Boogert, F. Gournaris, A. Lyapin, S. Malton, D.
Miller, M. Wing (UCL)
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ESA
47

• Work Package 5

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WP5.1 Helical Undulator for a Polarised
Positron Source

• Agreed at the Workshop on Positron Sources for
  the ILC
• at Daresbury Lab
• April 11th 13th 2005

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Permanent magnet design
final assembly carried out by Liverpool
University and delivered to DL - June 05
E166 Initial results An asymmetry in the photon
detectors 0.85 A clear positron signal in the
CsI 426 MeV CsI asymmetry? Probably not Most
promising runs gave an asymmetry of 0.9 but we
cant show this was definitely due to
polarisation
See Gudis talk For latest status
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5.2 Crab Cavity
Philippe Goudket ASTeC Graeme Burt Lancaster
University Carl Beard ASTeC Alexander
Kalinin ASTeC Amos Dexter Lancaster University
Magnetic field distribution of a TM110 mode
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ERLP Phase Experiments

• Tolerance for a 20mrad crossing angle with 1.3GHz
  cavities
• 3 voltage stability ?
• 2 degrees absolute phase error ?
• 0.022 degrees phase jitter !
• Possible solution
• A fast phase control method recently developed
  by M. Liepe (Cornell) demonstrated phase
  stability in the order of at least 0.02 degrees
  rms .

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5.3 Collimation
Project web http//hepunx.rl.ac.uk/swmd/
Programme

• RF impedance bench tests within CI (calibration,
  etc.) Beard, Sopczak, J. Smith, R.Carter
• Benchmark against known spoiler profile, large
  taper angle, MAFIA etc. simulation
• Carl Beard started to set up MAFIA simulations,
  survey h/w
• Use cold test results to
• Provide data to assist development of improved
  e.m. modelling in problematic regimes
• Also within UK, build up expertise (non-LC
  applications)
• (Within EUROTeV) collaborate with TU Darmstadt
• Alternative spoiler profiles, (at least) relative
  performance
• Theoretical studies Tucker, Burton, Shales
  (Lanc.)
• Direct beam measurement at SLAC CCLRC, Lanc.,
  Birmingham
• With FP6 funding, extend into material damage
  studies
• CCLRC Engineering Department, Manchester,
  Birmingham

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Collimator Wakefields

• Wakefield beam tests at ESA
• SLAC Proposal T-480 (Tenenbaum, Watson et al),
  4/2005
• Many people involved directly, see proposal
• Part of evolving programme of ILC tests at ESA
• Purpose
• Commision/validate CollWake Expt. at ESA
• Additional study of resistive wakes in Cu
• First study of 2-step tapers
• Development of ECHO-3D code (TEMF) for shallow
  tapers/short bunches
• Schedule
• Short run, 4-8 Jan. 2006, 4 collimators
• Longer run, 20 Feb. 1 Mar. 2006, 8 collimators
• Status
• Beamline prep., DAQ, BPM set up ongoing
• First 4 sets of collimators designed and
  fabricated in house at RAL (ODell, Greenhalgh),
  ready to ship
• Related activity
• Implementation of validated/realistic 3D
  wakefunctions in Merlin
• Collimator damage studies also envisaged at ESA

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Wakefield Modelling

• Programme of
• RF bench tests (ASTeC, Lanc.), less directly
  applicable
• More emphasis on E.M. modelling
• Extending WF simulations to GDFIDL (J.Smith),
  comparisons with MAFIA (Beard)
• New RA (EUROTeV) at ASTeC to start late Oct.,
  effort on data analysis, ESA tests, collimator
  damage
• More ideas!

MAFIA GdfidL
Transverse wake (V/C)
S (cm)
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a
r1/2 gap
As per last set in Sector 2, commissioning
Extend last set, smaller r, resistive WF in Cu
7mm
cf. same r, tapered
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Wakefield box
ESA sz 300mm ILC nominal sy 100mm
(Frank/Deepa design)
Magnet mover, y range ?1.4mm, precision 1mm