Minutes of the LIS Section meeting held on 4th October 2010

Present: G. Arduini, H. Bartosik, C, Carli, P. Jackson, M. Newman, A. Lachaize, G. Prior

General Information (Gianluigi) 

5 IC slots are been opened for ABP (4 Accelerator physicists and 1 for Electromechanics engineer)

Gianluigi informed the members of the team about that JY Hemery, a former ABP staff recently died.

Status of LHC: Up to 152 bunches have been injected in the LHC and luminosities in excess of 5x1031 cm-2 s-1 have been produced.

Vacuum activity has been observed in the experimental straight sections. It is not yet clear whet is the origin (electron cloud, HOM, desorption induced by synchrotron light).

Round Table (all)

Hannes

Hannes has attended the HB2010 workshop. He was impressed by a talk by Nagaitsev http://hb2010.web.psi.ch/proceedings/papers/tho1d01.pdf on non-linear optics for high intensity machines.

Hannes discussed with Molodozhentsev (KEK) about the magnetic error table for the J-PARC ring. Only sextupolar errors have been used for the modelization. The requirements on the maximum allowed magnetic errors has been based on the expected losses at the collimators.  The magnetic errors measured on the magnets of the J-PARC ring are worse than assumed for the PS2 but only the sextupolar component has been taken into account for the simulation of the expected losses at the collimators.

Antoine

Antoine has continued to work on the MTE for PS2. 20 % capture efficiency per island obtained on paper. Effect of the momentum spread and the effect of the chirp has been considered. Aperture issues need to be studied. Gianluigi proposed to have a summary of the PS2 study (optics, dynamic aperture, MTE) at one of the forthcoming Section Meetings.

Christian

The EPC experts have confirmed that the power converters for the active compensation of the tune shift introduced by the tune shift induced by the injection chicane in the PS-Booster with LINAC4 are feasible. LINAC4 simulations: the parallel computation cluster from IT should become available. It is important to restart the activity for the simulation of the injection process and of the expected performance with LINAC 4 for the fixed target and LHC beams. Christian is going to discuss with Molodozhentsev for the PTC version with space charge and interface to ORBIT in order to understand the advantages of such a version. Christian has verified that the existing kickers could be used for the LHC beam extraction even for a high energy (2 GeV) extraction from PSB.

Gersende

Discrepancies between MARS and FLUKA were observed. A factor 2 less muon production was estimated from MARS as compared to FLUKA. This discrepancy is now understood (bug found in MARS) and it has been fixed and the two simulation programs now provide results agreeing within 20%. Energy deposition in the superconducting solenoids calculated from both simulation programmes are still too high to be compatible with the operation of the superconducting solenoids of the muon production front-end. For the moment there is no clear technical solution.  Different configurations for the shielding are being considered. Gianluigi suggested to contact somebody in the magnet team in order to get some guidance on the value of acceptable energy deposition limits.

Myriam

Myriam is analyzing the pole face windings data to find correlations with the fluctuations observed in the MTE. She is also reviving the PS aperture model based on Mathematica to study aperture issues in case of an MTE extraction scheme with an electrostatic septum.

Next meeting

Monday, 18th October 2010 at 14:00 in room 354-1-001

Tentative agenda

 

 

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