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Emittance measurements setting-up and cross calibration

Emittance measurements setting-up and cross calibration. F.Roncarolo E.Bravin , S.Burger , B.Dehning , A.Goldblatt , A.Guerrero , V.Kein , M.Kuhn , S.Mazzoni , M.Sapinski , G.Trad LBOC 29 July 2014. Scope.

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Emittance measurements setting-up and cross calibration

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  1. Emittance measurements setting-up and cross calibration F.Roncarolo E.Bravin, S.Burger, B.Dehning, A.Goldblatt, A.Guerrero, V.Kein, M.Kuhn, S.Mazzoni, M.Sapinski, G.Trad LBOC 29 July 2014

  2. Scope 29 July 2014 • requirements for commissioning time with beam and for the ramp-up in intensity (including scrubbing) • assume the requirements for the preparation without beam will be dealt by the cold check-out team • a list of the modifications/improvements occurred during LS1 if not presented yet and a break-down of the activities and preparation required for: • operation with pilot bunches • operation with single nominal bunches • operation with trains (small number) • operation with trains (large number) • the goal of each step should be identified and the minimum beam characteristics and time requirements should be indicated

  3. Monitors 29 July 2014 Wire Scanners Synchrotron Light Monitors (BSRT) BGI Preliminary plans, to be discussed and revisited

  4. Beam Optics 29 July 2014 • Emittance via profile measurements means knowledge of the optics at monitors • Assumptions: • Betatron function measurements done in the early LHC re-commissioning • K-modulation in IR4 quads (at inj and flat top) • AC dipole (at inj, ramp and flat top) • Involvement of • BI + OP (Verena,Maria etc…) • ABP (Rogelio and team)

  5. Wire Scanners after LS1 29 July 2014 • HW: improved bellows • SW: Linux CPU not clear yet if HW will follow • To be tested this year • Transparent for OP • Maria/Verena writing new OP GUI • Automatic scans

  6. WS commissioning 29 July 2014 • Bumps (in || with BSRT) • Operational PM voltage + attenuation filter settings • As function of energy • Many scans @ injection + ramp + flat top before the intensity ramp up • Automatic scans (also during the ramp) to be validated during cold checkout • WS intensity limits vs energy

  7. WS intensity limits M.Sapinski • To allow the 7TeV intensities: • BLM thresholds must be adjusted since we will be close to quench level (but according to previous experience we should not quench). • Currently the thresholds are set following orbit bump scenario and would not allow these scans. 29 July 2014

  8. BSRT after LS1 29 July 2014 • B1 and B2 • New extraction mirror support (integrated into existing tank) • Interchangeable focusing optics to monitor near UV at high energy (reduce diffraction smearing during measurement of small beam sizes) • Minor changes on optical table equipment (e.g. pneumatic filter system instead of wheels) • Temperature monitoring in logging DB • Upgraded control SW

  9. BSRT after LS1 F.Roncarolo@ LMC#179 slides G.Trad @ Evian2014 slides G.Trad @ LS1 LBOC#17 slides 29 July 2014 • B1 Only • New (external) alignment and calibration line (BSRTR) • Shack-Hartmann mask to monitor extraction mirror deformation (light-destructive measurement) • Interferometry line

  10. BSRT B1 Layout after LS1 G.Trad 37 33 34 40 32 38 36 35 39 29 27 28 31 30 25 24 26 1 23 22 5 4 7 AGAP LDM 21 ShackHart. 2 3 sCMOS CCD 19 6 20 9 11 17 18 12 8 13 16 10 14 29 July 2014

  11. BSRT commissioning (imaging) 29 July 2014 • Reliability (alignment, HW, SW checks with beam) • Parasitic with any beam • CO bumps (inj and flat top) • As soon as nominal bunches available • Cross-calibration w.r.t WS (injand flat top) • As soon as nominal bunches (and ADT for blow-up) available • Heating / temperature monitoring • In 2012 evident effects for I>5e13p

  12. BSRT vs BTV calibration 29 July 2014 • We are investigating the opportunity and feasibility of calibrating WS and BSRT vs BTV systems in the dump line • Need to sort out • achievable resolution, sensitivity, required beam time • Present cameras are RAD-HARD, limited resolution and sensitivity, may change BTVSE and BTVD for standard CCD • nominal betatron and dispersion functions @ BTVs  expected beam size • Masking of BTV interlocks limited to safe beam? Can we extract and measure with BTV a nominal bunch at 6.5 TeV? • Commissioning time or MD ?

  13. Close Orbit Bumps • +-4mm @ WS and BSRT • Any new aperture and/or MPP constraint in 2015 to repeat bumps at injection and flat top? 29 July 2014

  14. WS-BSRT Commissioning Plan Overview N.B.: • BSRT Interferometry can be done in parallel to imaging • BSRT mirror deformation monitoring can NOT be done in parallel to imaging 29 July 2014

  15. … + Cross-calibration during VMS 29 July 2014 It is foreseen to perform a • WS • BSRT • Lumi+ Lumi region • SMOG cross-calibration campaign during VMS periods

  16. BGI 29 July 2014 • Changes during LS1: • New MCPs + new phosphor screens • Camera chip moved in a low radiation area • Temperature probes in vacuum (on 2 out of 4 BGIs) • Commissioning with protons: • Beam-based calibration and angular corrections • 1-2 hrs, at least 144 bunches, emittance <= 2um • Bumps (if allowed with 144 bunches) • Monitor sensitivity gain at flat top dominated by adiabatic damping  smaller beam sizes • Control feedbacks and new SW can be tested parasitically

  17. 29 July 2014 Thank you

  18. Interferometry commissioning 29 July 2014 • Slits out  test imaging • Setup polarizer • Find horizontal polarization only • Check imaging resolution dependence on rectangular iris aperture • Insert slit H • Setup operational vertical aperture of rectangular iris • Visibility vs slit separation • Determine operational slit separation • Repeat for V • Test H and V measurements

  19. 29 July 2014

  20. 29 July 2014

  21. BSRT – Interferometry (B1) • New project in collaboration with KEK (T.Mitshuashi), SLAC (A.Fisher), CELLS-ALBA (U.Iriso) • Interferometry: non-diffraction limited method widely used in electron machines to measure very small beam sizes Fringes ‘visibility’ contains information of proton beam size 29 July 2014

  22. Wire Scanners (WS) - Bellows R.Veness & WS team 29 July 2014 2012: (see LMC-148) LHC stopped 24 hours due to leak in wire scanner bellows. Fatigue failure suspected. 10’000 cycle bellows lifetime not consistent with current LHC usage. No bellows design data or spares available. 4 of the 8 units installed are close to the same number of cycles F.Roncarolo - LMC - 30-Apr-2014

  23. Wire Scanners (WS) - Bellows P.Magagnin/BI A.Gerardin/MME 29 July 2014 LS1 activities: • Scanner (LEP-design) ‘reverse engineered’ in existing space to allow integration of a bellows rated for 40’000 cycles • Complex drive mechanism is non-linear with friction – long analysis and experiment required to understand and simulate movement • Leaks created during final EB weld assembly at CERN in Feb ‘14 have been attributed to quality of materials in cable feedthroughs (MME) • Urgent re-manufacture of feedthroughs in progress (delivery June). Installation now not expected until end July. • Discussed with Julie & still seems to fit with current LSS4 planning (no margin)

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