Minutes of the LIS Section meeting held on 6^th October 2008

Present: M. Aiba, G. Arduini, S. Aumon, J. Barranco, E. Benedetto, O. Berrig, C. Carli, M. Chanel, A. Franchi, S. Gilardoni, M. Martini, S. Maury, B. Salvant

General Information (Gianluigi)

Students in accelerator physics from EPFL are supposed to have some practical training (one day per week). P:ossible subjects for a small project should be sent to Tatiana Pieloni and Gianluigi.

Germany is favouring collaborations between CERN and german universities. Possible collaboration subjects should be sent to Gianluigi.

Computing resources for impedance and space charge simulation will be centralized for the department and financement will come from a central budget. IT infrastructure and support will be used.

The fixed target north area programme will be stopped today for 2008. CNGS will continue until 3/11/2008 (note the change communicated after the meeting). This should be taken into account for the prioritization and planning of the machine studies in the injectors.

Round Table (all)

PS (Simone, Sandra)

The PS to SPS synchronization at 14 GeV/c requires more tie than initially expected. The amount of time available on the flat-top for the adiabatic capture is not sufficient. For that reason the cycle has to be modified to gain some time at flat-top. It is expected to gain 20 ms at injection and 30 ms at the 3.5 GeV plateau.

Measurements of the initial conditions in TT2 have been taken by Elena. Results are being analyzed both for the islands and the core.

Tests for comparing different longitudinal structures for the fixed target beam should be done in parallel for the fixed target beam.

The instrumentation seems to work now. The new wire scanner electronics is being tested and an application (still expert) is available since a few days.

Preliminary tests of the new orbit system have been conducted and the outcome is positive.

Studies for the instability at transition have started but most of the time has been spent in debugging the instrumentation. The wall current monitor is not working (it seems that a cable is broken) and the transverse wide and pick-up is not working as well. Some measurements with the wall current monitor could be taken only in the central building.

LINAC4 (Christian, Masamitsu, Michel Chanel, Stephan)

Studies are ongoing on the effect of the injection chicane on the optics. Large beta beating is observed mainly in the V-plane when the bump is on due to the edge focussing of the injection bumpers and the working point which is very close to the half integer.

Possible solutions being investigated:

• Sector magnet

• Longer bumpers

• Possibility to compensate with individually powered quadrupoles or better with Q-strips (first tests in the PSBooster indicate that these elements are fast enough for that application) if individually powered.

Civil engineering for LINAC4 will start after the LHC Inauguration fest on 21/10. The buildings should be ready by end of 2010. There might be some impact on the traffic because of the trucks transporting earth to the dump (the final location of the dump is being discussed).

SPS (Benoit)

Preliminary measurements have been conducted with long bunches with RF OFF to identify the frequency spectrum of the transverse instabilities developing in the SPS. A maximum bunch length of 12 ns could be delivered by the PS. Investigations will continue in order to produce longer bunches that would provide a better resolution. This could help in identifying the sources of impedance in the SPS.

Optics models (Olav)

The MADX optics model for FT61 is available. The position of the elements has been determined from layout drawings. Some discrepancies have been found with respect to the survey data and TS/SU will verify the position of all the elements during the next SD. Gianluigi suggested to Olav to inform Ray Brown so to make sure that this TS/SU activity is included in the shut-down planning.

Simone asked whether the model for the FTN line is available. Olav replied in the affirmative.

Discussions are ongoing with F. Schmidt in order to understand some discrepancies observed between MADX and PTC.

 Neutrino factory and CLIC (Michel Martini)

A. Vivoli (fellow) has arrived at CERN and Michel is working with him on the IBS issues for the CLIC damping rings. These studies could be of interest also for the ion beam in the SPS at injection.

 Next meeting

Monday, 20^th October 2008 at 10:00 in room 354-1-001

Agenda

General Information (Gianluigi)

Electron cloud simulations for the beam dump kickers in the SPS (Giovanni)

Instability and impedance measurements in the PS Booster (Diego)

Round Table (all)

A.O.B.

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