Summary notes of the LCU meeting on 22/04/2008

Present: IA, MA, HB, MG, WH, JJ, PL, MM, AM, TP, TR, FS, SW, FZ

Report from meetings

• ICC -> MG
  A topic discussed was the potential issue with radiation on electronics in the LHC tunnel following the CNGS experience. This is in particular a worry for electronics close to the betatron collimation in IR7. On the longer term, it is planned to move electronics further away or improve the shielding for electronics. On the shorter term, it was asked to see if the betatron cleaning in the early operation could partially be done in IR3 which has less electronics close to the beam, rather than in IR7. A presentation on the performance of this mixed configuration (betatronic and momentum cleaning in IR3) will be given at the next LTC.
• SLM -> MG
  Job descriptions have been prepared for the White Paper activities like LHC IR upgrade, Linac4,  PS2, and Phase II collimation system. This should soon allow to open up a number of jobs for recruitment.

5 TeV parameter list ->  MG (pdf)

MG showed slides he prepared (based on the work of W. Herr, J. Jowett, E. Métral, T. Pieloni, E. Shaposhnikova) for the LHCCWG this afternoon and asked for feedback. The transverse parameters for 5 TeV have largely been checked already. Here he concentrated mainly on the longitudinal parameters and in particular the dependence on the longitudinal emittance. To get to the nominal 2.5 eV s requires blow up in the LHC, which might not be available initially.

Using emittance blow up in the SPS, it is possible to make sure that the longitudinal emittance at injection into the LHC is at least 1 eV s. This is already expected to give sufficient Landau damping to avoid single bunch instabilities for the intensities considered in early operation, that is of up to 9.e10 protons/bunch. He also discussed the intra beam scattering and the reduced damping from synchrotron radiation. Overall parameter lists have been prepared. Different bunch schemes were considered in will be described in a forthcoming note by WH et al. HB asked about longitudinal halo produced by Touschek scattering, which is probably increased at lower emittance and may stay longer in the machine before it is lost by synchrotron radiation. Smaller longitudinal emittance also implies shorter beam spots for the experiments.

Release of the MAD-X on-line monitor and demo -> IA (pdf)

IA reported about the MAD-X on-line model and demonstrated running the online manager on a PC running linux.

A user guide can be found here. He showed that this allows to run MAD-X and python scripts and to display results, as well as use and creation of knobs. A milestone for the on-line model is its application in the SPS start-up this year and the transfer line re-commissioning. The model uses an afs repository and it was stressed that this should be directly connected to the afs files maintained by TR. The on-line monitor appears to run currently only on PCs with a particular linux installation and it was asked to make the program more system independent and in particular allow it to run from lxplus.

What was shown is the so-called expert mode, where the user can import MAD-X scripts written with a special syntax. A more user-friendly interface is provided through LSA.

It is planned to organise a meeting next week with interested people in ABP to discuss the list of applications already available and to get feedback on additional items.

AOB
None.

Last update:22-April-08

MG & HB

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