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Beamline around IP8

Short summary of last weekend’s LHC and LHCb results, using slides of Richard Jacobbson and Olaf Behrendt from the Tuesday meeting of Aug 26. Beamline around IP8. TED. TDI. IP8. TED: 28 tonne beam stopper ~ 200 meter from LHCb TDI: Collimator with 5 meter long jaws

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Beamline around IP8

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  1. Short summary of last weekend’s LHC and LHCb results, using slides of Richard Jacobbson and Olaf Behrendt from the Tuesday meeting of Aug 26

  2. Beamline around IP8 TED TDI IP8

  3. TED: • 28 tonne beam stopper • ~ 200 meter from LHCb TDI: • Collimator with 5 meter long jaws • About 50 meters from LHCb • Cannot be fully closed!

  4. What happened Friday • 14.00: Machine closed-up • 16.00: Access to TI8 to unblock the dump at the end of TI8 + access to solve cryogenics problems at point 2 • 16.50 : CMS opens a ‘green door… • 17.50: Beam down to dump (TED) at the end of TID • VELO Tracks !!! • 19.00: TED taken out • Problem with LHC timing • 20.00 – 20.30: Beam down to TDI after some struggle • 20.38: First shot on TDI • 20.53: TDI open and first shot straight to point 7 (3km)!

  5. <- Beam monitor near TDI Beam screen near point 7 (after LHCb!)

  6. Saturday • Aperture measurements between point 7 and 8 • LCHb was off (apart from beam conditions monitor) Sunday • Beam on TED from ~10:30 to 12:30 • Whole VELO on

  7. Beam incidents on Saturday • LHCb BCM pulled beam dump at three dumps on TDI • 11:22, 12:10, 12:47 • BLMs on triplets and around TDI did not show ‘much’ higher losses • Loss appeared as a concentrated shower at ~9 o’clock in BCM as seen along Beam 2 • Hypothesis: Compatible with little or no kick and TDI open at top • 7400 nA max (!)seen in sensor 2 as compared to <200 nA during TDI dumps on Friday night • 36 pA/mips  >105 particles per sensor  >107 particles assuming an area of 10x10cm2 BCM Downstream station 0 7 1 8x8mm2 ? Beam 2 2 6 5 3 4

  8. VELO results

  9. TED Run 1 (22.08.08) • 5 modules on each side switched on • timing adjusted to expected SPD trigger signal[from SPD and VELO signal propagation times] • data taking with 15 consecutive triggers[window of 350 ns around the expected signal] • compensation for not optimal timing by • lowering the cluster thresholds • enhancing the signal amplification

  10. A First Glimpse of Beam

  11. First reconstructed tracks in VELO run: 30764 event: 156 time: 17:56?

  12. linked hits • not not linked hits

  13. Timing central trigger

  14. TED Run 2 (24.08.08) • all Si modules switched on • all but 10 sensors read out [TELL1 problems] • timing window reduced to 5 consecutive triggers

  15. run: 30933 event: 1

  16. run: 30933 event: 12

  17. Sunday’s run Also other subdetector were on IT, PRS, SPD, Muon and PileUp

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