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ABT/BTP studies

ABT/BTP studies. ABT/BTP, OP, Collimation, BLM, QPS teams. Tests To be Performed. Injection Studies: LHC 25 ns injection Nominal emittance and injection quality (IQ): TI2 Investigation on MKI UFOs at injection Quench margin at injection Finish TCDQ angular scan. Injection Studies.

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ABT/BTP studies

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  1. ABT/BTP studies ABT/BTP, OP, Collimation, BLM, QPS teams

  2. Tests To be Performed • Injection Studies: • LHC 25 ns injection • Nominal emittance and injection quality (IQ): TI2 • Investigation on MKI UFOs at injection • Quench margin at injection • Finish TCDQ angular scan

  3. Injection Studies • Injection of beams with different parameters from the SPS has to be studied with a view to exploring the parameters likely to be needed for future LHC operation. • Injections have to be attempted with large transverse emittances, longer bunch length and different bunch spacing, including 25 ns batches. • Limits have to be investigated in terms of beam losses, protection device settings, injection/abort gap cleaning, emittance preservation, intensity transmission etc. • An attempt has to be made to calibrate the scrapers in the SPS, address reproducibility and check the response on the TCDIs. • The effect of transverse blow-up and longitudinal blow-up has to be studied.

  4. Outline Plan: LHC 25 ns Injection Wednesday 29/06 10:00 -16:00 • Can be done before MD (GR/VK/JW/KC) • establish 24 bunches 25 ns 1.1e11 p+/b, ~3 mm emittanceon cycle in SPS. • extract onto upstream TEDs (based on 50 ns settings) and first steering if needed • extract onto downstream TEDs and detailed TL steering. • establish trajectory references and BLM levels at collimators. • Requirements: • Both beams, 450 GeV, Injection Optics, No orbit/optics change • During MD proper • inject with 12 bunches at 50 ns and check steering. • copy steering settings 50 ns -> 25 ns • change SPS cycle to 25 ns and test beam injection into LHC. • correction of injection oscillations and steering for beam loss at TCDIs. • if required opening to +/-5 s of most critical TCDI collimators. • if required basic re-setup of most critical TCDI collimators, plus change of interlocks • When injection ~OK: Capture setup (RF adjustment) – max 1 hour • When capture ~OK, Setup damper with single bunch/25 ns – at least 1 hour • If time available: accumulation of some 24b batches in each beam (as many as feasible - injection scheme VK), surveying vacuum, losses, cryoheatload, ... • Recovery • revert all settings to 50 ns ones • revert all interlock thresholds to 50 ns ones, and separate cross-check • test injection of 12b at 50 ns still OK.

  5. Outline Plan: Nominal Emittance + IQ TI2 Thursday 30/06 16:00 – Friday 01/07 01:00 • Requirements: • Both beams (but mainly B1), 450 GeV, Injection Optics, No orbit/optics change, possible changes of RF and Feedback settings in the SPS. • Scan different emittances (up to nominal and/or bigger) • Pilot bunch in inject and dump mode, INDIV, mainly12 nominal bunches • Scan longitudinal parameters: • Injection with 12 nominal bunches • 800 MHz, measure emittance, measure satellites, check BQM response, check diamond response, check losses on TDI and TCDI, LDM…. • Radial steering (follow with tune), check losses, emittances • Other longitudinal parameters to be defined (T. Bohl) • Scraping : • Injection with 12 nominal bunches • Note down settings of scraper • Open scraper in V in steps and check losses and emittances • Restore nominal scraper settings and check if it comes back to original losses and emittance • Repeat in H plane (nominal settings for V scraper) • Put H scraper settings to nominal • Put in screens in TT10 to blow up the beam • Check losses at point 1 (scraper in LSS1) and, if needed, adjust scraping (should only scrape tails) . • Measure emittance • Extract and check losses on TCDIs through IQC

  6. Outline Plan: Nominal Emittance + IQ TI2 Thursday 30/06 16:00 – Friday 01/07 01:00 • Effect of momentum collimator in TI 2 (TCDIV.20607): • 12 bunches • 800 MHz to produce longitudinal tails • Check losses on TCDIs • Move further in the momentum collimator • Check losses on the TCDIs • Sensitivity of losses on trajectory steering TI 2: • 12 nominal bunches • Trajectory steering: single kicks (few mm) with different correctors (e.g. MCIAH.20804, ~90deg. phase advance downstream) • Check losses as a function of trajectory steering • Parallel studies: MKI UFOs investigation for B2 while performing IQ check studies with B1 • Recovery • Trim back all settings (emittance, scraper, BTV, collimators….) to nominal operation • Test injection of 12b at 50 ns with nominal settings still OK.

  7. Investigation on MKI UFOs at injection • Investigation on the sources of the UFOs seen at the injection kickers MKI. The ‘background’ rates will be measured for specified beam condition, by pulsing the MKI on a gap in the partly filled machine. • These rates should be compared with those obtained after movement of the vacuum valves – this should be programmed during physics some days before the MD period begins, and can be repeated after the movement of the injection BTVs at a later date. • The dependence of the UFO rate, on pulsing the MKI kickers individually, will be tested by a special configuration (ABT equipment experts + special procedure, EDMS doc). • In case the kickers are pulsed on the circulating beam, or a batch is injected by accident, the TDI positioning will ensure protection of the LHC aperture. Injection of any beam while pulsing only a single kicker should be prevented by putting a transfer line TED in the “in” position • If time permits tests could be made with the MKQA kickers to see if the UFO effects are reproduced there.

  8. Installed Additional Equipments • Four additional mobile BLM monitors have been installed along the MKIs in point 8 (See Fig. 1, red squares)

  9. Outline Plan MP Class C Thursday 30/06 16:00 – Friday 01/07 01:00 • Requirements: • Beam 2, 450 GeV, Injection Optics, No orbit/optics/RF/Feedback change • 1236 nominal bunches • Measurements will be performed in parallel with B1 injection studies. • Benchmark UFO rate under controlled conditions during injection; • sequence stop for ~1 hour at around ~1000 bunches • check rate for MKI pulsing each 5 minutes, on gap in circulating beam. • Need to obtain enough UFO counts to be able to see changes. • Repeat for different configurations (depending on time available and efficiency): • With only one magnet pulsing (D) (E. Carlier) • With only one magnet pulsing (A) (E. Carlier) • With all MKI pulsing but 1 us pulse length. • After many pulses, or extended SoftStart • Rate with same total intensity but different train length ( e.g. 2 x 144 or 8 x 36) • Recovery • After the MD, nominal fine MKI delays will have to be re-loaded and re-validated via the IQC MP EDMS doc!

  10. Quench Margin at Injection • Motivation: 18/04/2011 MKI D flashover • 36bunches hitting the TDI with 75-90% of the nominal MKI deflection • Nearly all p+ of these 36 bunches impacted TDI/TCLIB  12 magnets quenched • Check loss rate at Q6 in IR8 downstream the TCLIB  scale for 288 bunches • The MD will address the quench margin at injection with the help of special QPS monitoring on selected magnets, such as Q6.L8 downstream of the TCLIB in IR8 and Q4.L6 downstream of TCSG.4L6 in IR6. • The MD will require controlled beam losses on the magnets and monitoring of the QPS signals. This will require installing QPS monitoring also at this location.

  11. Installed Additional Equipments • 1 permanent BLM has been installed on the TCLIB monitor in 6L8, with an additional filter in order to overcome the electronics saturation on the already existing TCLIB BLM during the test. This monitor is not connected to the BIS. • The systems to observe “quenchinos” have been installed for RQ4.L6 and RQ8.L8 New filtered BLM

  12. Outline Plan MP Class C Sunday 03/07 14:00 – 22:00 • Requirements: • Beam 2, 450 GeV, Injection Optics, No optics/RF/Feedback change, possible beam bumps to create losses at Q6.L8 • TCLIB and TCSG.4L6 need to be closed to create losses • Pilot, 1 bunch < 2 ×1010 p+ (3 ×1010 p+ ?) • Measurements: • Inject 1 pilot bunch (for B2) with TCLIB collimator at different settings (from nominal aperture ~ 6.8 s to ~-3 s) • Check losses at TCLIB (filtered monitor) and downstream magnets, specifically Q6.L8 • Check voltage drop at Q6.L8 (special QPS equipment) to detect quenches/quenchinos • Repeat with higher intensity bunch if pilot intensity too low to observe anything • If time left, inject 1 pilot bunch onto the TCSG.4L6 (set at ~-3 s ) and check voltage drop at downstream Q4.L6. • If no quench achieved by steering beam onto collimators, try steering low intensity bunch (2 ×109p+) directly into the magnets using local orbit correctors and inject and dump mode. This experiment has been done indirectly several times at injection due to configuration faults. • Masked elements • TCLIB and TCSG.4L6 position interlocks need masking to move across interlock limits • BLMs injection region and IP6 masked • BPM interlocks in IP6 masked • Recovery • TCLIB and TCSG.4L6 have to be set back to their nominal settings. • All masked interlocks unmasked • All bumps removed MP EDMS doc!

  13. TCDQ angular scan During/after quench margin at injection studies: • Finish B1 TCDQ angular scan(-250 urad) (during) • Do complete B2 TCDQ angular scan (after) • Requirements: • Pilot beam circulating, 450 GeV, injection optics • Move TCP and TCDQ • Mask BLM and BPM in Point 6 • Use MKQ to blow up the beam

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