Brief Summary of LPA MD on 19 June 2012 Jose Abelleira, Xavier Buffat, Chandra Bhat, Karel Cornelis, Riccardo De Maria, Stephane Fartoukh, Rossano Giachino, Eva Barbara Holzer, Mike Lamont, Themis Mastoridis, Alick Mcpherson, Kazuhito Ohmi, Giulia Papotti, Tatiana Pieloni, Ferdico Roncarolo, Ghislain Roy, Belen Salvachua, Daniel Valuch, Frank Zimmermann, …

started 3.5 hours late (LHC RF crowbar repair, PS 10–MHz cavity), then 1 h machine set up; first MD beam injected ~13:45 Special hypercycle for Piwinski MD 2 bunches of 1.5 e11 per bunch (+pilot), go to collision tunes, & collapsed crossing angles at IP1 and 5, and separation at IP 1,5, and 8; then looked for collisions. Filling scheme with one bunch colliding in IP1,5,and 8, and other bunch colliding in IP 8 only. Impossible to find collisions at ATLAS and CMS, but LHCb could be optimized... decision to dump & re-inject with higher intensity 2 bunches of ~2.4e11 injected without separation bump, IP1/IP5 crossing angle at zero, and collision tunes – Clear luminosity signals in ATLAS and LHCb – No clear Luminosity readings from CMS (some signal towards the end of the MD) ; problem with BSRT data acquisition  LHCb spectrometer ramped down in steps to zero. LHCb spectrometer was left at 0 strength after the MD MD history

LPA MD conditions 2.4e11 / bunch; 2 bunches per beam 1st bunch collides in IP 8 only 2 nd bunch collides in IPs 1, 5 and 8 injection energy, 1.5 ns bunch length,  ~2  m ADT off, orbit feedback off, TCTs at coarse settings, IR angle bumps zeroed in IPs 1 and 5 IP8 crossing angle 4 mrad, 2 mrad, 0 (varied with spectrometer strength) collision tunes estimated Piwinski angles ~ 1.1, 0.6, 0 largest Piwinski angle ever!

LPA MD overview CMS lumi signal appears at last ATLAS lumi signal reduced (steering effect) LHCb luminosity signal zero in the database

only short quiet period (30 s?) at 50% spectrometer strength LPA MD overview with IP correctors X. Buffat, T. Pieloni

LPA MD bunch intensities X. Buffat, T. Pieloni

LPA MD bunch intensities X. Buffat 100% 50% ~15% 100% 50% ~15% bunch with 3 collisions loses much more intensity; steepest loss at 50% of LHCb spectrometer strength; best lifetime at 0 strength Jose Abelleira, Chandra Bhat, Xavier Buffat, Karel Cornelis, Riccardo De Maria, Rossano Giachino, Mike Lamont, Themis Mastoridis, Alick Mcpherson, Giulia Papotti, Tatiana Pieloni, Ghislain Roy, Belen Salvachua, Daniel Valuch, Frank Zimmermann, + … qualitatively consistent with expectation

MD simulation by K. Ohmi 1 day 2 h

EmitX beam 1EmitX beam 2EmitY beam 1EmitY beam 2 17: /-0.01  m (1 collision) 2.07+/-0.01  m (3 collisions) 2.17+/-0.00  m (1 collision) 2.56+/-0.02  m (3 collisions) 17: /-0.1  m (1 collision) 2.10+/-0.03  m (3 collisions) 2.0+/-0.1  m (1 collision) 1.6+/-0.1  m (3 collisions) 2.17+/-0.01  m (1 collision) 1.72+/-0.03  m (3 collisions) 2.11+/-0.01  m (1 collision) 1.64+/-0.01  m (3 collisions) 17: /-0.01  m (1 collision) 2.0+/-0.1  m (3 collisions) 2.01+/-0.01  m (1 collision) 1.56+/-0.02  m (3 collisions) 2.11+/-0.04  m (1 collision) 1.67+/-0.02  m (3 collisions) 2.07+/-0.05  m (1 collision) 1.53+/-0.08  m (3 collisions) LPA MD bunch emittance bunch with 3 collisions shrinks

BBQ X. Buffat, T. Pieloni

BBQ Almost fully saturated X. Buffat, T. Pieloni

BSRTs Got stuck on single bunch the one colliding in IP1-5-8… No apparent reasons for this… X. Buffat, T. Pieloni BSRT software had got stuck!?

R. De Maria bunch length

Profile Measurements Approximate locations C. Bhat

Bunch 1 Traces:Bunch Intensity= 2.4E11ppb (2 nd Injection)  = 0.43 nsec (Gaussian) FWHM=1.00 nsec Relative Area=0.32  = 0.45 nsec (Gaussian) FWHM=1.07 nsec Relative Area=0.28 Start of the MDEnd of the MD C. Bhat

Bunch 2 Traces:Bunch Intensity= 2.4E11ppb (2 nd Injection)  = 0.42 nsec (Gaussian) FWHM=0.98 nsec Relative Area=0.22  = 0.44 nsec (Gaussian) FWHM=1.05 nsec Relative Area=0.14 Start of the MDEnd of the MD C. Bhat

plan review luminosity data from LHCb and CMS (not in logging database) further analysis intensity and luminosity lifetime for different spectrometer strengths MD note soon – editor Jose Abelleira