1 / 14

Luminosity Production and Beam Management at LHC: July 18, 2011

On July 18, 2011, multiple fills were conducted at the LHC, including Fill #1955 with 1092 bunches and Fill #1956 with 1380 bunches. High temperatures and interlocks were managed during beam operation, with various adjustments made to BPM phasing, tunes, and chromaticity. Challenges included high loss rates and vacuum spikes, affecting luminosity targets, particularly for ALICE and LHCb. Despite interruptions, new record luminosities were achieved briefly before encountering beam dumps due to cryogenic issues and interlocks.

stuart-carver
Télécharger la présentation

Luminosity Production and Beam Management at LHC: July 18, 2011

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. Monday 18.7.2011 1 fill with 1092 bunches (6 h stable beams) 3 fills with 1380 bunches (20 minutes in stable beams)

  2. Fill # 1955 • 9:49 Dump: RQTL7.L7B1tripped fill #1955 • Integrated luminosity [pb-1]: Atlas: 18.8 CMS: 18.7 LHCb: 6.1 • Remote reset of the QPS crate on RB.A81 • Unusually high temperature on collimator TCSG.D4L7.B1 (position “right up”) without beam: 55 deg  interlock masked

  3. Fill # 1955

  4. Fill # 1956 • 11:55 beam injected: • Re-adjusting BPM phasing (E. Calvo) • Tune, chromaticity • MKI kicker length checked by M. Barnes • Emittance(inj): ~ 2.5 μm rad bunch intensity: ~ 1.2E11 • Beam Intensity: 1.66E14 • Injection • Beam 1 MSIB: 54% of BLM threshold • Transfer line: BPM partly missing – partly high oscillations

  5. Fill # 1956 • Waited 1 hour after injection for UFO’s to calm down • trip of RCD.A56B1 and RCO.A56B1 during the ramp, beam survived  reset and reloaded at flat top • Not obvious to find target luminosity Alice • 15:40 DUMP: Cryo lost probably due to SEU on a thermometer at a current lead (beam2 IP5).

  6. Fill # 1956

  7. Fill # 1957 • Injection: • MKI vacuum B2: spike of 1.5E-8 bar • Injection losses B1 up to 70% of BLM threshold (MSIB) • Wait ½ hour for UFO’s to calm down • Emittance(inj): ~ 2.2 μm rad bunch intensity: ~ 1.3E11 • Beam Intensity: 1.77E14 Energy/Beam: 100 MJ • 35% of BLM threshold on TCTVB.4L2 83s integration time  consider adapting 83s thresholds

  8. Vacuum up to ~2E-7 mbar in IP3 and IP7

  9. Fill # 1957 • BRAN Luminosity 1.4 – 1.5 • But only for a couple of seconds

  10. Fill # 1957 • DUMP: BLM voltage status interlock in IP7 caused by high losses when going in collision

  11. Fill # 1958 • Wait ½ hour after injection for UFO’s to calm down • Emittance(inj): ~ 2.0 μm rad bunch intensity: ~ 1.2E11 • Beam Intensity: 1.66E14 • mask the BLM HV status interlock in IP7 in the SIS for the first minutes of the collisions • BLM_SR7_C_HV_STATUS would have given an interlock when adjusting LHCb luminosity • Atlas and CMS adjustment before went without large losses • Alice adjustment afterwards without big losses • Alice optimized: factor 10 below target luminosity

  12. IP7: Vacuum spike and BLMs in warning when adjusting LHCb

  13. New record luminosity … but not for long 22:39 beam dump: cryo lost in sector 3-4

  14. PLAN • Beam back: this afternoon • Alice collision scheme? • Luminosity production with 1380 bunches • Adiabatically decrease emittance and increase bunch intensity • BLMs: • adapt 83s collimator thresholds • SIS HV interlock?

More Related