LiCAS

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LiCAS

• Linear Collider Alignement and Survey

Applied Geodesy Group
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Overview

• What is LiCAS
• The ILC survey problem
• The RTRS concept
• The LiCAS measurement principles
• Who works on LiCAS
• Where are we now
• Mechanics
• FSI
• LSM
• Where will we go next

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LC Survey Problem

• Survey is a multi step process with single
  tolerance budget driven by accelerator physics
• tunnel construction
• component fiducialisation
• component Survey ? LiCAS
• Components survey
• 200mm vertical our slice of tolerance budget
• over 600m betatron wavelenght
• Open air survey too slow and too inaccurate
• Need new instrument that matches requirements
• ATLAS ZEUS technologies (FSI straightness
  monitors) applicable to this problem

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LC Survey Problem
Fiducial marker
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RTRS concept
Tunnel Wall
LiCAS technology for automated stake-out process
Reconstructed tunnel shapes (relative
co-ordinates)
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LiCAS Measurement Principle
Internal FSI System Dz. Dx,Dy Da,Db between
cars
Extrenal FSI System measures Wall marker location
Straightness Monitor Dx,Dy Da,Db between cars
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Who works on LiCAS (Oxford team)
studentic
academic
Gregorz Grzelak
David Urner
DAQ-Eng. Ashley James started 21/06/04
Elec. Tech.
electronic
Mech. Tech. (Pool)
optic
mechanic
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Oxford Alumni
DESY Collaborators

• Johannes Prenting
• Markus Schloesser
• Ernst-Otto Saemann
• Daniel Kaempnter

Edward Botcherby
Robert Apsimon Peter Baker Ken Chuang
Thomas Zlosnik Simon Wilshin Chris Glassman
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Where are we now?
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RTRS global Mechanics

• Measurement car
• full 3D designs
• workshop drawings
• part production started
• Service car
• conceptual design
• commerical propulsion system ordered

measurement car

• Others
• vacuum system ready for production except for one
  seal test
• Tunnel see next slide

service car
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Tunnel preparation

• 60m long service tunnel at DESY
• fairly narrow ? difficult installation
• Tunnel walls all prepared (removed old cable
  trays)
• Air-conditioning installed
• Lighting installed
• Interlocked doors on both sides being installed
• power and network installed
• must perform some test on tunnel walls to check
  for stability
• tunnel completed in 2.5 month from now (beginning
  of June)

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LiCAS measurement units

• Design close to completion (1 month)
• waiting for choice of final LSM camera and FSI
  optics
• some changes in connectorisation, service routing
  and fibre feed-throughs
• Invar casts for bodies have been ordered
• design of components for internal FSI completed
• production mainly in-house

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FSI Status

• Two lasers operational, full DAQ chain working
  (custom photo detectors and amplifiers,
  commercial ADCs)
• Custom USB-2 based ADC board built, firmware
  under development now
• Expect to have complete custom detection and DAQ
  chain in two month from now
• basic measurement principle using EDFA proven,
  expected accuracy lt 1micron

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LiCAS FSI Implementation
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M-FSI extension for StaFF
AM Modulation _at_ f1
C-Band Amplifier (1520-1570)
FSI Laser 1
L-Band Amplifier (1572-1630)
FSI Laser 2
f2
AM Modulation _at_ f2
Splitter Tree
AM modulator
AM Modulation _at_ f3
AOM Dn
Michelson Laser
Adjust Dn
Cavity locked to reference laser or absorption
cell
Reference Laser
Quill
Retro Reflector
GLI
Readout Board
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New FSI Work
Splitter Tree

• Short 6-line FSI system for 3D wall marker
  reconstruction. Still using long line optics.

Amplifier
Laser
Retro Reflector
3D-Piezo Stage
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LSM status

• Geometry for LSM frozen (positions of cameras and
  beam splitters)
• One fully functional unit is operational with
• 1 low coherence length, near IR laser
  collimation optics
• 4 small, low cost analogue cameras 4-chan.
  grabber
• Choosing final cameras now (CMOS?)
• First versions of algorithm for calibration using
  differential motion of LSM unit
• Least squares fit
• Neural network
• Current resolutions O(1 micron)
• Studying view finding and accuracy of fitting as
  function of camera parameters and fitting
  algorithm
• Studying quality of beam (shape) through the hole
  system

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What do we do next

• Up to autumn 2005
• Completion of instrument choices
• cameras
• feed through
• external FSI optics
• Completion of FSI and LSM analysis codes
• FSI noise suppression
• camera calibration
• fitting algorithms
• Sub-system calibrations
• Construction of 3-car prototype
• Single car survey with CMM
• Installation in DESY test tunnel

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What do we 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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What do we do next

• Up to Spring 2008
• Operate improved first prototype at DESY
• Construct second prototype
• Operate second prototype in X-FEL
• Construct stake out instrument
• Operate stake out instrument in X-FEL

(needs additional funding)