Minutes of the LIS Section meeting held on 1^st October 2007

Present: G. Arduini, S. Aumon, J. Barranco, E. Benedetto, C. Carli, M. Chanel, S. Gilardoni, M. Juchno, M. Martini, E. Métral, Y. Papaphilippou, G. Rumolo, B. Salvant.

General information (G. Arduini)

LHC RF fingers: tool to detect buckled RF fingers (ping-pong ball with 40 MHz receiver) has been successfully tested (see LTC presentation)

Stephan is presenting the results of the study on the resources required for the implementation of a fixed-target ion programme in the North Area to the ABMB (see ABMB presentation)

Requests for students and fellows for 2008 should be sent to Gianluigi as soon as possible.

Beam loss studies for the CT extraction (J. Barranco) - slides

The following points came out during the discussion (for follow-up by J. Barranco):

• The outputs of K2 and MARS programs should be compared to identify possible differences in the distributions of the products resulting from the interaction of the beam with the septum. In K2 only scattering processes are considered while MARS provides the distribution of all the particles resulting from the interaction of the beam with the septum. This could also explain why the losses in SS31 and immediately downstream monitors are underestimated for the simulations based on K2.

• The losses observed experimentally in SS57 and immediately downstream are not visible in the simulations. A magnetic septum is installed in that area. The aperture model should be verified in that area.

• The mean to track over a few turns the protons scattered by the electrostatic septum with large momentum offset should be carefully studied and discussed with F. Schmidt.

• A more realistic distribution should be considered for the beam.

Highlights for the COOL07 conference (C. Carli) - slides

Status of the machines

PS Booster (M. Chanel)

The problem of the tune measurement persists. Michel has not contacted M. Gasior, yet.

The intensity in the PS-Booster was limited by frequent trips of the cavity C04 at extraction on Ring 1. The cavity has been repaired now.

PS (S. Gilardoni, Y. Papaphilippou)

Follow-up of the tune measurement problem is ongoing. Not yet tried to see whether the observed problem in the tune measurement with large amplitudes occurs as a result of the large beam offset at the tune measurement pick-up.

2.2×10¹³ p/cycle have been extracted with a CT extraction for CNGS.

An iteration for the energy matching of PS - SPS has been completed and the radial position at extraction from PS has been increased from -10 to -6 mm. This is still 3 mm inward as compared to the orbit measured in 2006. The radial displacement of ~-3 mm is compatible with the increase of the circumference due to the extraction bump in SS16. The expected increase in circumference due to the bump is ~20 mm.

The radial position of the LHC beams at extraction should be measured to determine whether the same phenomenon is observed for these beams. Simone noted that the measurement of the orbit at extraction is not working for the LHC ion beams.

The camera in front of the AD target has been replaced and it was possible to measure the position of the beam. The beam profile could be determined only qualitatively but the antiproton yield remained unchanged after the change of the optics in the TT2-FTA line required for the suppression of the QKE58. The power converter has been removed by PO and it  is going to be re-used for the MTE.

SPS (E. Métral) - Week 39

Machine studies (E. Métral) - summary

Ions in the Injectors (C. Carli, M. Chanel, M. Martini)

Additional measurements of the mismatch at injection in the PS have been performed with the SEM wires in the ring. An empirical matching has been found. The origin of the mismatch observed this year is not understood fully. Christian has verified whether modifications have been performed in the last part of the injection line: nothing has been done according to C. Lacroix and R. Brown.

Measurements have been done of the initial conditions at the entry of the TT2 line. These are being analyzed by M. Martini taking into account also the effect of the multiple scattering in the stripper on the Twiss parameters.

Next meeting

Monday, 15^th October 2007 at 09:00 in room 354-1-001

Agenda

General information (G. Arduini)

Final report on the PS magnet model (M. Juchno)

TMCI studies in the SPS: results of the observations (B. Salvant)

Status of the machines (supervisors)

Status of Machine Studies (E. Métral)

A.O.B.

Back to Minutes