Minutes of the LIS Section meeting held on 22^nd October 2012

Present: Fanouria Antoniou, Gianluigi Arduini, Hannes Bartosik, Michael Bodendorfer, Vincenzo Forte, Adriano Garonna, Cedric Hernalsteens, Antoine Lachaize, Meghan McAteer, Elias Métral, Bettina Mikulec, Tatiana Rijoff, Adrian Ulsroed, Raymond Wasef.

General Information (Gianluigi)

The yearly department meeting will take place on 3^rd December 2012.

Meeting rooms: 6-R-018: can be reserved by ABP members only from the indico interface. 6-R-012: can be reserved only by BE department members via the indico interface.

LHC:

Progressing well at ~1.1 fb^-1/week. The scrubbing run and the 25 ns MDs have been postponed to December given the risk of operating the injection kicker with higher background pressure. Frequent drifts in the trajectories of the beam in the injection line have been observed. Hannes has requested to monitor the orbit at extraction Need to monitor the orbit at SPS extraction to see whether this can explain the observed fluctuations and whether this is related to the Q20 optics.

IEFC

Matters concerning LS1:

• 27/6/2014 - 13/10/2014 SPS cold check-out + start-up with beam

• 13/10/2014 - 15/12/2014 Physics to NA

• 15/12/2014-15/04/2014 Replacement of irradiated cables in TDC2

• A possible run with ions in December 2014 is being considered for radiation cool-down purposes

Status of space charge studies and simulations in the PS Booster (Vincenzo) - slides

The simulations presented do not include the aperture of the machine yet although tests have been made to include at least the aperture limit in the PS-Booster, i.e. the beam scope.

Quadrupolar errors have been introduced as random errors with given r.m.s. distribution. No attempt has been done yet to introduce an effective error distribution corresponding to the opposite of the present resonance compensation multipole settings.

The analysis of the effect of the shorter dipoles in the injection region has been started. A working point of 4.1 (H)/4.21(V) has been considered. For this working point no significant deterioration has been observed (at least for the r.m.s. emittance). It was noted that the picture might change for working points closer to the half integer as we might be obliged to operate the PS Booster with high intensity beams.

Vincenzo presented a new technique to match the initial beam distribution to the machine parameters taking into account the effect of space charge. Gianluigi noted that it might be good to generate the initial beam distribution starting from injection and using the beam distribution of the beam delivered by the LINAC4. Vincenzo and Sasha are in contact with Alessandra Lombardi to get the relevant information.

MD studies have been performed to understand the effect of the present resonance compensation correctors. The correctors have been switched off at injection but no significant effect on losses has been observed. During the discussion it was noted that this could be the effect of the distance of the working point from the resonances which are normally compensated.

The tuning of the relative phase among the first and second RF harmonics give a different loss pattern at the end of the ramp from 50 to 160 MeV. This could be due either to capture losses or to space charge effects.

There are two options to introduce the aperture information in ORBIT-PTC: either in ORBIT or via the MADX description of the apertures. This is the preferred option but it needs to be tested.

Next meeting

Monday, 19^th November 2012 at 14:00 in room 6-R-012

Agenda:

General information (Gianluigi)

Presentation to be confirmed

Round table (all)

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