Summary notes of the LCU meeting on 28/10/2013

Present: HB, RdM, MHF, MF, GG, PH, JJ, ALan, LL, GR, AS, MS, RT, AV, RV

Report from meetings

• SLM and general information -> MG
  Planning for IPAC'14 has started with a first discussion of abstract proposals and requests for attendance. ABP typically submits many papers. We should make an effort to minimise overlap and aim for fewer, high quality contributions. Massimo reminds that at least one of the authors must attend the conference.
  Massimo said that the beam instrumentation group works on the design of a new VELO-like detector with tracking and precise timing, to be installed in IP4. This is done in collaboration with other groups including us for optics and aperture.
  Massimo said he continues to follow up on aperture in general for the current and future LHC. The region between D1 and D2 has the transition from a single combined beam pipe to the two beam apertures which requires special attention.
  Massimo reported that he received an email from TOTEM reporting unusual discrepancies observed in the special low energy 1.38 TeV run. This may point to an energy offset, to be clarified with Jörg Wenninger. Maybe settings were scaled without proper hysteresis correction, to be checked with magnet experts like Ezio et al. Rogelio said he will check if we have optics measurements at this energy.
  Massimo reminded us about the upcoming RLIUP workshop which starts tomorrow and the annual HL-LHC - LARP workshop scheduled for the week of 11 November in Daresbury.
• LBS -> HB
  Helmut said that the LHC background study group meeting last week had several contributions on simulations and their extensions towards the HL-LHC. Slides and minutes are on indico.
• MAD-X status -> LD, GR
  Ghislain said that differences in results observed using different compilers were identified and resolved. Laurent and Yngve completed automatic builds and tests which run every day on the MAC-Mini server. A new MAD-X production release is planned for next week. Two to three weeks later, it is planned to make the transition to using new updated natural constants, to be followed after further testing and a short transition period by a new MAD-X pro release.
  Ghislain follows up on the MAD-X online model. One aim is to revive and improve the online aperture meter and another to have a working model with the essential components ready working when the LHC restarts with beam in early 2015. Another aim is to provide a "save machine button". The idea is to provide easy access to the machine settings in machine studies. In addition to a snapshot of actual settings, this should also provide access to the time history from the beginning of the fill.
• SixTrack status -> RdM
  Eric identified a potential problem related to crab cavities on BOINC. This is currently under investigation and should not keep us from continuing the work which does not rely on crab cavities.
  Matthias and Pascal work on exact drifts. This is in particular of interest for collimation. Testing has started, using a modified local branch. The modifications will be included in the main software after successful testing.

Impact of 7 TeV magnetic errors on optics -> ASL (slides)

Andy Langner reported about recent work by him done with input from Rogelio and Massimo. The magnetic model for 7 TeV based on FIDEL was presented by Nicholas Aquilina in LBOC#4. Andy used a statistical model to simulate the expected spread and calculated how much beta-beat this would induce before and after the squeeze. He finds that the errors are small (see the slides for details).

Optimization of the filling scheme for ions in the LHC -> MS (slides)

Michaela studied the optimization of filling schemes for lead ion operation in the LHC. She developed an empirical model which predicts the evolution of key parameters including intensity, emittance and luminosity. Bunch by bunch variations are taken into account. 

With a small number of tunable parameters, the model can well reproduce the evolution of beam parameters observed in the Pb-Pb operation in 2011. She used this model to compare the expected luminosities for different injection schemes including slip stacking and evaluate the possible gain from a kicker upgrade in the SPS.
Details are given in the slides and will be presented in the upcoming RLIUP workshop.

Massimo suggested to also look into a possible injection upgrade using a rf-deflector similar to what is used for CTF3.

AOB 

None

Last update: 13-November-2013

MG & HB

Back to LCU Minutes