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Thursday 24.6

Thursday 24.6. 08:30 Loaded by mistake squeeze function to 2 m  Dumped beams 10:30-13:00 Test of new algorithm for long. Emittance blow-up to minimize oscillations in bunch length observed in the past

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Thursday 24.6

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  1. Thursday 24.6 • 08:30 Loaded by mistake squeeze function to 2 m  Dumped beams • 10:30-13:00 Test of new algorithm for long. Emittance blow-up to minimize oscillations in bunch length observed in the past • Could only be tested with bunch population of 2 x 1010 p and no ramp was possible due to lack of time and no beam from SPS • For the time being reverted to previous algorithm for the night • 13:00-13:30 Rotated Ring2 by 200 psw.r.t. Ring 1 based on the observations done by the experiments (displacement of the interaction point by ~3 cm) . 8:30 meeting

  2. Thursday 24.6 • 13:30 Started LBDS verifications at 450 GeV slowed-down by problems with SPS (frequent compensator trips) & TI8 problems (Beam2 not available from 6pm to 8pm): • TCSG/TCDQ settings cross-checked with TCP sigma scan. • Measured gap at TCSG in P6 for different TCP settings. • Check of TCDQoffset. • Moved TCDQ to different positions and cross-checked with an orbit bump the polarity and setting. --> OK. • Check of P6 orbit interlock BPMresponse. • Moved parallel vertical bump in P6 until BIS state toggles. • Dump with maximum energy offset AND max orbit excursion. 8:30 meeting

  3. Thursday 24.6 • Still outstandingLBDS tests at 450 GeV: - dump with max energy offset and max orbit excursion with 2e10, taking into account all permutations of energy off-sets and bumps: 8 dumps to be performed. - asynch dumps from extreme orbit positions have to be checked with 1e11: 4 dumps to be performed.But OK to declare stable physics over the night - missing dumps tomorrow! • 20:30 Problems rearming the LBDSdump both beams BLM crate is not sending data. • Trying to reboot the crate cfv-sr5-bpmb1la which was unreachable • The optical link in SR5.L card 5 shows errors with a result of beam dump requests. The redundancy was not able to provide valid data. • The card in question has been exchanged. 8:30 meeting

  4. Thursday 24.6 • In light of the SPS compensator and TI8 problems we decided at 7pm to change the initial schedule for the day: • Continue with LBDS studies until team has to take off. • Start preparation of physics fill as soon as the SPS is ready again • Postpone the TOTEM setup until Friday when the SPS is again running reliably. • 22:30: Both beams are again available for the LHC • Start preparations of the the physics fill with 3 bunches a 1011 per beam • Inject high intensity beams with: • B1 H = 2.3 V= 2.35; B2 H = 3.8 V = 3.8 at 450 GeV • B1 H= 4.6V= 5.6; B2 H= 7.4 V = 7.5 at 3.50 TeV • 00:30: Preparing for squeeze after flat top adjustments • 00:50: Starting to squeeze. • 01:30: Collapsing the separation bumps  no apparent losses but Beam 2 lifetime worse than Beam 1 (t > 100 hours t ≈ 50 hours) 8:30 meeting

  5. Thursday 24.6 • LHCf can not display the ARM 2 status (undefined on their page1) but is OK in reality • Lumi scans: • 02:00: LHCb requests a lumi scan Sudden beam loss and lifetime degradation observed during scan. • 02:40: Scan for ATLAS. • 03:30: Scan for CMS  adjustments in vertical plane result in 30% increase. • 04:00: Both beams dumped (2.5 hours of physics): • Fast horizontal drift seen at the BPMin 4L6. Nothing seen in the adjacent monitors. • 05:20: Lost RB.A78 after ramp down at 450 GeV: • need access. 8:30 meeting

  6. Thursday 24.6 • Bunch length during ramp: 8:30 meeting

  7. Friday 24.6 • Feedback trims during the squeeze: 8:30 meeting

  8. Friday 24.6 • Separation bumps before collisions: 8:30 meeting

  9. Friday 24.6 • Orbit @ IPs after collapsing the separation bumps: 8:30 meeting

  10. Friday 24.6 • Stable Beams @ 3.5 TeV with 2.5 1011 per beam in 3 bunches: 8:30 meeting

  11. Friday 24.6 • Intensity and lifetimes during LHCbLumi scan: 8:30 meeting

  12. Friday 24.6 • Plan for the day: • Finish off outstanding LBDS validations. • Test sequence for squeeze and collapsing separation bumps via sequencer with low intensity beams. • TOTEM setup @ 450 GeV in the after noon. • Hump measurements at 450 GeV (if time premits). • Physics fill. 8:30 meeting

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