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Future MD Ideas

Run 3 MDs Ideas

  • 3 New ballistic optics flavors:
    • Ballistic with beta* de-squeeze at top energy to reach above 1Km beta in dipoles, to study quadrupolar errors in dipoles. This is specially important in view of HL-LHC D2 b2 errors.
    • Telescopic for tune jitter measurements with enhanced arcs.
    • Ballistic with large vertical dispersion.
  • Half integer tune.
  • 60 degrees arc cell phase advance for HE-LHC (or ⅓ HE-LHC), and for improving knowledge on LHC itself as phase advance samples errors differently and arc sextupoles are factor ~2 weaker (more linear machine): arc errors, MCS shifts + coupling, BPM aberrations (beam signal closer to pure sin).
  • Experience HL-LHC-like injection optics with beta*=6m (pilots only).
  • Look at 11 T flux jumps with TbT data, possibly using a new optics with enhanced beta functions.
  • 2 possible experiments with TOTEM to understand the assymetry of the local dispersion in IR5:
    • Measurements with flat orbit, >60 bunches.
    • Measurements with ballistic optics.
  • Non-90 degrees arc cell phase advance to ease correction of errors in the arcs (reduce the knob degeneracy of orbit bumps at sextupoles).
  • Measure optics at smallest beta* for a long time, looking for an effect as in SKEKB where Final Focus quadrupole strength drifted by 0.01%. https://kds.kek.jp/event/39396/
  • Try Closed Orbit Distortion optics measurement as in SuperKEKB with 3-6 orbit correctors per plane and orbit fitting.
  • Tilting triplets to correct local coupling to operate without MQSX.
  • Switching off MCS and main sextupoles in one arc to evaluate possible (systematic) vertical or horizontal misalignment of dipoles by measuring coupling and beta-beating during the b3 decay. In a previous MD there was a quadratic coupling increase due to the orbit bump in the arc (maybe the one without MS, tbc).
  • Crazy MD for this, could be shifting the edge of some dipoles up to see change in coupling.
  • Tilting a triplet quadrupole to check validity of the tilt measurement (with and/or without beam).
  • Measure bad BPMs with low and high intensities to detect possible issues with the comparator (transistor).
    Also swap connections between good and bad BPM to identified.
  • Have one BPM unplugged to detect its noise until next technical stop.
  • Momentum compaction factor from Qs versus Voltage.
  • Snap-back with forced 3D oscillations (optics, chroma,...).
  • Maybe not OMC: 24h pilot at top energy to use damped beam for BSRT resolution measurement.
  • 0.5 um bunch from new injector chain?? Good for optics measurements, BSRT calibration etc.
  • K-Modulation with Xing angle and OFB off for Leon's Xing angle reconstruction.
  • Arc K-modulation.
  • K-modulation in IR4 during the energy ramp.
  • Reduce to one the DCCTs per circuit with pilot in the machine and ATS optics to see the impact of 2 DCCTs. Michele Martino also proposes increasing in 1ppm the noise of the DCCTs in one or all dipole PCs to see impact on tune jitter.
  • Commissioning?: Measure amplitude detuning coming from CMS solenoid by having the on and off measurements.
  • IR non-linear corrector offsets measurement.
  • Emittance growth from octupoles and chroma.
  • Amplitude detuning measurement versus crossing angle with b6 corrector on, for 5 crossing angles to evaluate performance of the technique for b6 correction.
  • Amplitude dependent optics: Dedicated settings at injection as PoP (Thomas & Barbara), alternative techniques in parallel (K-modulation with decohered beams and amplitude dependent segment-by-segment).
  • IR2 non-linear correction -> Dedicated squeeze for IR2 to allow for good triplet characterization to shed light on b4.
  • Amplitude detuning in ballistic optics.
  • ADT for single kicks.
  • b5 RDTs.
  • Measurement and correction of a3 RDTs at injection for lifetime optimization (correcting with MSSX and MSS).
  • Reduce RF voltage to decrease synchrotron tune to limit the emittance blow-up during excitation with driven and natural tunes close to each other.