Input from LMC & Chamonix Frank Zimmermann LSWG, 21 March 2011
LMC 23 February & 16 March: • LHC machine studies should be handled lightly • do not spend more time talking about the studies than doing them • MDs should be based on an analysis of list coming out of Chamonix • clear need to prioritize – and introduce categories, e.g. short term and long term • develop a proposal for an MD schedule, e.g. which MDs should be done when and in which order • for the sake of MD efficiency, operations people should be strongly involved; they are familiar with procedure and software • MD reports within a week of experiment being done • after filtering of the MD requests an MD schedule proposal should be presented to LMC by Ralph Assmann and Frank Zimmermann • early on experiments to quantify parameter limits from beam-beam point of view, especially long-range beam-beam and a few other MDs related to machine protection • tracking of changes and recovery procedures for transitions back to physics after MDs
LMC 23 February & 16 March cont’d: • define what can be the EOF studies • 1) what will be allowed as EOF study? • 2) what will be the envelope? • 3) what can/should (not) be done in stable beams?
MD Studies relevant for 2011/12(S. Myers, G. Papotti): • abort gap cleaning at 3.5 TeV • injection slot cleaning • beam-beam studies • tune diagram exploration • optimization of ramp (DONE) • optimization of turnaround time (DONE) • no pre-cycle after short access (DONE) • test the continuous functions for ramp, squeeze, collide • test combined ramp and squeeze • end-of-fill luminosity scans for emittance measurement • hands-off squeezed (but not colliding) single bunches for single beam parameter evolution measurement • beam tests (quench test location + injection region) to improve radiation field calibration • test for p-Pb operation J. Jowett • 90-m optics H. Burkhardt
MD Studies relevant for HL-LHC(L. Rossi, O. Brüning): • beam-beam limit as a function of long range collisions, separation and crossing angle. W. Herr. Detailed MD proposal in preparation. • luminosity leveling using angle, separation and beta*. R. De Maria. Team and proposal in preparation. • test ATS optics in the present LHC to understand feasibility, limitations and merits; test as well collision with bx≠by. S. Fartoukh. • intensity limits from impedance by measuring coupled-bunch instability rise time and coupled-bunch tune shifts w..r.t. transverse damper, collimators, chromaticity, bunch spacing and intensities. E. Metral. Some results may be produced parasitically • intensity limits from e-cloud, in particular during scrubbing run (but also at 25 ns). G. Arduini, G. Rumolo, F. Zimmermann, E. Metral. Some results may be produced parasitically • effect of a large Piwinski angle, in practice with longer than nominal bunch length, nominal or close to nominal synchrotron tunes and beam parameters corresponding to a total head-on beam-beam tune shift of ~0.02 at zero crossing angle. S. Fartoukh, F. Zimmermann • compare crossing schemes: H-V, V-V, H-H planes, F. Zimmermann • LHC beam qualification for injector MDs ?, e.g. double batch injection