## Run 3 MDs Ideas ### Linear Optics Related * 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 1/3 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. ### Coupling Related * 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). ### BPM related * 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-mod related * 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. ### Non-Linear Optics Related * 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.