1 / 24

LHC Machine Status

LHC Machine Status. CERN-JINR Meeting, 11 October 2010 P. Collier (On behalf of the LHC team and international Collaborators). LHC Startup – Autumn 2009. November 20 th 2009 First beams injected and circulating November 29 th 2009 Both beams accelerated to 1.18 TeV simultaneously

charissa-boone
Télécharger la présentation

LHC Machine Status

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. LHC Machine Status CERN-JINR Meeting, 11 October 2010 P. Collier (On behalf of the LHC team and international Collaborators)

  2. LHC Startup – Autumn 2009 • November 20th 2009 • First beams injected and circulating • November 29th 2009 • Both beams accelerated to 1.18 TeV simultaneously • December 8th 2009 • 2x2 bunches accelerated to 1.18 TeV • First collisions at 2.36 TeV cm! • December 14th 2009 • Stable 2x2 at 1.18 TeV • Collisions in all four experiments LHC - highest energy collider Limited to 2 kA in main circuits (1.18 TeV) during deployment and testing of new Quench Protection System

  3. Commissioning and Running Scenario 2010/2011 • Following the technical discussions in the Chamonix workshop the CERN management and LHC experiments decided on the following Running scenario: • Run at 3.5TeV/beam with a goal of reaching and integrated luminosity of around 1fb-1 by the end of 2011. • This implies reaching a peak luminosity of 10+32 in 2010 • Then consolidate the whole machine for operation at 7TeV/beam during a long shutdown in 2012 • From 2013 onwards the LHC will be capable of the maximum Energy and Luminosity. The Primary goal for 2010

  4. Startup 2010 At this point there was a pause in operation of the machine for Physics in order to setup the machine for stable operation with nominal intensity per bunch (~1x10+11)

  5. Progress by the end of May 2010

  6. Operation May-August 2010 Essentially commissioning of injection, damper and RF, optics, setting up the collimation and machine protection systems and re-qualification for high bunch intensities

  7. Optics Beta-Beating Measurements through the year show an excellent reproducibility For the re-commissioning work in July, global corrections of the optics were done before starting the collimation set-up. Impressive results: Stable 10-20% beta beating around the machine

  8. Collimators Jaw Positions set using beam-based alignment at several points in the cycle and functions defined between them: Injection, High energy, squeezed optics (separated), squeezed optics (collisions) • At all times and conditions the hierarchy of the collimators and protection devices must be maintained. • Many dedicated qualification checks needed each time the operation cycle is significantly changed: • Betatron losses, • Off momentum losses, • Asynchronous dump tests

  9. Provoked vertical beam loss on beam 1 Momentum Cleaning Dump Protection Col. IR2 IR5 IR8 IR1 Collimation Team Cleaning Efficiency ~99.99%

  10. Crossing 2pb-1 Setup of high intensity bunches Peak Luminosity ~10+31

  11. 2 Weeks in August • Remarkable machine availability: impressive performance of cryogenics, QPS, converters, RF, instrumentation, collimators, injectors… • Very effective use of available time 25b 48b 50b

  12. Move to Bunch Trains • To make further progress it is necessary to pass to bunch trains • Decision made to pass to 150ns bunch trains from the injectors • Can potentially fill the LHC with 400+ bunches • But Increasing numbers of bunches to inject • Needed new optimization and checks of the injection process • Crossing angle needed throughout the operational cycle • Re-optimization and qualification of the collimation and machine protection systems • Especially the tertiary collimators around the experiments • Long-range beam-beam checks for the size of the crossing angle bumps needed • Smaller angles than nominal needed 170mR at injection, reduced crossing angle through the squeeze. • Opportunity taken to speed up the ramp 2A/s -> 10 A/s

  13. Ramping Faster • Ramp reduced from 46 to 16 minutes • Feedback on Tunes and orbit in the ramp and squeeze • Feed-forward of Q,Q’ |c| and orbit based on measurements • Ramp and squeeze is very reproducible …

  14. Crossing Angles

  15. Operation with Bunch Trains 22-Sep-2010: 24 bunches per beam13.5 h – ~170 nb-1 Peak Luminosity ~5x10+30 08-Oct-2010: 248 bunches per beam6.5 h – ~1700 nb-1 Peak Luminosity 8.8x10+31 • Progressively stepped up in number of bunches • Units of 48 bunches • 3 full cycles/dumps and around 20h of physics per step

  16. Performance to-date Presently Running with 248 bunches (1x10+11 ppb). Peak luminosity recorded = 8.8x10+31 cm-2s-1 Best Physics fill recorded 2.3pb-1 (200 bunches, in 13 hours)

  17. Next Steps • Increase to 344 bunches (2 more steps!) • Assuming we manage to follow this plan, by end of W41 we should collect another ~20-25 pb-1. • If the reserve is used for physics, with 6 fills per week it is possible to collect ~40 pb-1more since for 350 bunches fills deliver ~3-4 pb-1 per 12 hours. 104 200 296 Reserve! 248 344 152 3 ½ weeks of stable Ion operation Technical Stop

  18. Heavy Ion Run Parameters Initial interaction rate: 100 Hz (10 Hz central collisions b = 0 – 5 fm) ~108 interaction/106s (~1 month)

  19. Conclusions • All key systems performing remarkably well & there are some hugely complex systems out there. • Some commissioning still required, issues still to address • And NB there are still problems • Handling dangerous beams already - have to remain vigilant at all times (and not get carried away) • Performance with beam (losses, lifetimes, luminosity, emittance growth etc.) is very encouraging • Machine availability is excellent – the hard work of numerous teams • Almost reached 1032cm-2 s-1 our goal for the end of the year- just 10% to go!!!! • We are already looking ahead to the operating conditions next year – some studies to help decide this will take place this year.

  20. Additional Slides

  21. Stored Beam Energy

  22. Bunch Train Bumps ATLAS ALICE CMS LHCb B1 Hor 10 mm B1 Vert B2 Hor B2 Vert

  23. UFOs (Unidentified Falling Objects) • On 7th July we observed the first occurrence of fast beam loss events in the super-conducting regions of the ring: • Fast beam loss at a SC magnet over 0.5-2ms • Most events during stable beams: no lifetime issue before the event… • Loss at regions of very large aperture > 40 beam sigma (collimators between 6 and 15 sigma). • Hypothesis that it is probably ‘dust’ particles falling into the beam • Estimated size ~100 mm think Carbon-type object. • Two events in perfect coincidence (time & space) with TOTEM roman pot movements make this hypothesis rather convincing. LHCb IR7 IR1 Arc Arc Seem to be related to Intensity*Time s Time evolution of loss 1 bin = 40 ms 0.5 ms Dump trigger Excluded Totem UFOs

  24. High Backgrounds in recent fills • Vacuum activity in the common beam chamber of all experiments. • Local pressure bump around ± 60 m from the IP. • Uncoated segment of vacuum chamber at the warm-cold transition of inner triplets • Pressure rise driven by the presence of both beams • Higher backgrounds. • Driven by beam and bunch intensity • Possibly higher order mode heating from the beam. • Possibly due to synchrotron light heating desorption D1/D2 and Quads • Possibly Electron Cloud • NOT due to some beam losses as nothing on BLMs • Same order of magnitude everywhere (towards 10-7 mbar). • Gets worse when beam intensity goes up • Improves when running at same beam intensity • Cleaning effect • Valves will close if p > 4·10-7 mbar in 2 out of 3 gauges. Still ok. 1:30 – Ramp 2:00 – Squeeze 2:30 - Collide

More Related