12. July 2002Visit of Jonathan Dorfan to RAL1 Linear Collider Alignment and Survey LiCAS

12. July 2002 Visit of Jonathan Dorfan to RAL 2 Overview Why and how Oxford wants contribute to a linear collider LiCAS Phase I (build survey) The survey problem Our solution Our Experience (ATLAS & ZEUS) Our Resources LiCAS Phase II (online alignment) The alignment problem Steps towards a solution

12. July 2002 Visit of Jonathan Dorfan to RAL 3 Why and how Oxford wants to contribute to a LC ? Why: Physics ! Our technologies and expertise are applicable to collider survey and alignment Beam instrumentation work already exists in UK How: Will be releasing large technological capabilities from ATLAS construction phase (next two years) This gives ability to take up similar sized project Open mind about other tasks

12. July 2002 Visit of Jonathan Dorfan to RAL 4 LiCAS Phase I (TESLA survey, build and repair) Collider Survey Collider alignment at build time 200 m (vertical) over 600m Todays open air survey technology fails both in speed and accuracy We want to build survey instrument that matches requirement Apply our technologies (FSI, straightness monitors) to new problem

12. July 2002 Visit of Jonathan Dorfan to RAL 5 Survey & Alignment are difficult This is the main beam line

12. July 2002 Visit of Jonathan Dorfan to RAL 6 Special boundary conditions in TESLA Many beam lines Very tight space (1m wide) Space also serves as emergency escape route Automated process (induced radiation environment, re-align without re-opening collider) Horizontally and vertically curved sections, (R min >500m) Some sections geometrically straight, others following geoid Some sections with significant slopes Electronically noisy environment No long-term stable reference monuments

12. July 2002 Visit of Jonathan Dorfan to RAL 7 LiCAS Phase I Automatic survey train measures reference markers in tunnel wall Later (not too late!!) measure collider against reference markers Instrument internal lines in vacuum Use scalable laser technology (EDFA & telecom style lasers) DESY during FEL installation Want same scheme for TESLA & NLC FSI-distance measurements straightness monitors straightness monitor beam reference markers tunnel wall single car with sensors

12. July 2002 Visit of Jonathan Dorfan to RAL 8 LiCAS Phase I (Our experience with alignment so far) FSI for ATLAS Large scale O(800 lines) on-line survey system for the ATLAS inner detector. Optimised for minimum mass Self-calibration to silicon detectors co-ordinate system using X-Ray scanning system In large scale production now Straightness monitors Transparent silicon detector system for ZEUS vertex detector Similar transparent Si from ATLAS muon system tested on TESLA undulators for FEL test beam line CCD based system for ATLAS x-ray scanner

12. July 2002 Visit of Jonathan Dorfan to RAL 9 LiCAS Phase I & II (FSI extrapolation) Today: = 117 L=0.4m L/L = 0.29 ppm Phase I: =1 L=5m L/L = 0.5 ppm Phase II: =1 L=10m L/L = 0.1 ppm 7 th digit changes L =4*10 8 nm =117nm

12. July 2002 Visit of Jonathan Dorfan to RAL 10 ATLAS FSI components Retro Reflectors Quills

12. July 2002 Visit of Jonathan Dorfan to RAL 11 Alternative Solutions Alternative scheme: stretched wire over 25m for vertical position hydrostatic levelling system for horizontal position same train layout but different measurement modules Drawbacks not suitable for geometric straight or sloping sections (very important for NLC style collider !) not suitable for strongly curved sections many measurement steps to get to a single position slow (many mechanical moves and measurements) lower resolution (limits use as diagnostic tool after initial survey)

LiCAS Cast Nikhil Kundu Grzegorz Grzelak academic electronic mechanic +1 student

Name 01/0202/0303/0404/0505/06 Faculty: Armin Reichold Roman Walcak RA: Ankush Mitra 100 Paul Coe Grzegorz Grzelak Electronics: David Howell Mark Jones 1050 Nikhil Kundu 2050 Colin Perry Pete Shield 1040 Roy Wastie 3050 Mike Dawson Richard Makin 1040 Mechanics: Wing Lau Brian Ottewell Students: John Green 50 (>Oct.) next100 next John Nixon 100 (>Sept.) 100 (<March) Edward Botcherby 100 (Aug.&Sept.) Total: ~260~

12. July 2002 Visit of Jonathan Dorfan to RAL 14 Project Constraints Timescales: short term: 1st year, compatible with DESY installation of TTF3 medium term: 2 nd -3 rd year, compatible with DESY operation of FEL in TTF3 and similar test-beams else where. long term: 4 th - infinity, general development of LC alignment scheme for both TESLA and NLC Funding: short term: Oxford PP internal, guaranteed 15K£ Paul Instrument fund, possibly O(60K£), medium term: PPAP project, Basic Technology fund long term: funding together with LC project on UK scale Lots of good people Many good ideas Small capital funds

12. July 2002 Visit of Jonathan Dorfan to RAL 15 LiCAS Phase II (online alignment)

12. July 2002 Visit of Jonathan Dorfan to RAL 16 LCs move… (time scales of ground motion) 70nm Powerspektrum of ground motion in various HEP tunnels LEP: 60 to 180 m/Jahr

12. July 2002 Visit of Jonathan Dorfan to RAL 17 …the beam moves even more (length scales of ground motion) wavenumber : 1/ [m -1 ] 1/25m relative beam motion Relative beam motion vs. wavenumber of ground motion But wavelength > 25m do not matter all that much

12. July 2002 Visit of Jonathan Dorfan to RAL 18 Magnet Sensitivities (position dependence) Sensitivity S of magnets in FF of NLC Drift < 5Hz < Jitter Drift assumed to be corrected for by beam S(Drift): 25nm - 8 m S(Jitter): 0.5nm m <1nm 25nm <8 m 8 m closer to interaction point

12. July 2002 Visit of Jonathan Dorfan to RAL 19 Effect on Luminosity (time scale) TESLA Luminosity versus log(time/sec) assume: ideal beam corrections, ATL groundmotion (HERA) 2s20s 1week must move magnets now

12. July 2002 Visit of Jonathan Dorfan to RAL 20 LiCAS Phase II (online alignment) Address slow alignment with f<O(Hz) Fixed alignment Grid on most sensitive components (BDS, final focus) Total length O(1km) Total number of SM stations O(500) develop cheap camera and readout system Total number of FSI lines O(5000) Profit from scalability and cheap telecom fibres/amplifiers Add fixed frequency laser to FSI system and use as Michelson interferometer: FSI gives O( m) absolute alignment Michelson Mode gives O(nm) stabilisation (optical anchor) DESY in FEL operation ESPI afterburner for straightness monitors ??