Minutes of the LIS Section meeting held on 28th March 2011

Present: G. Arduini, S. Aumon, H. Bartosik, C. Carli, S. Gilardoni, A. Lachaize, M. Martini, Y. Papaphilippou, G. Prior,  M. Newman

General Information (Gianluigi)

IPAC11: the deadline for the submission of the abstracts to Oliver is the end of this week. LIS participants to the confernce: Gianluigi, Simone, Stephan. Hannes will apply for a student grant.

Soon the preparations for the next Fellow Committee will start: Simone is going to submit a request for a fellow for the PS Upgrade Studies.

The deadline for the submission of requests for technical or doctoral students is 4/4/2011. Requests should be sent to Oliver and Delphine with copy to me.

LHC:

The machine has been operated successfully with 75 ns beam with up to 200 bunches. The record luminosity achieved last year has been exceeded and a new record value of 2.5x1032 cm-2s-1 has been achieved.

During the second part of last week the machine has been operated t 1.38 TeV (energy corresponding to the energy per nucleon during the ion run) as requested by ALICE.

The first technical stop has started this morning. Operation will resume at the end of the week and after recovery scrubbing with 50 ns beam will start.

 

Gianluigi asked Sandra whether the model of the PSB to PS transfer line is available in the optics repository. She replied in the affirmative.

 

Beam Stability - Impedance in the PS - (Sandra) - slides

Microwave instability is observed at injection on the AD beam with standard settings. This instability is observed over ~1 ms. With 2 GeV injection the slip factor will decrease and the threshold for this instability might decrease.

The measurements of the detuning with intensity performed in the transverse plane do not show and significant tune shift with intensity in the horizontal plane at flat-top (26 GeV/c). A tune shift is observed in the vertical plane only. The tune shift measured in the vertical plane is by almost a factor 2 larger as compared to previous measurements.

Consistency between tune shift and rise time needs to be understood.

 

Round table (all)

Simone:

Capacitors of the POPS active filter have been damaged. The specifications for these capacitor must be reviewed. The PS magnets have been reconnected to the old Main Power Supply and to the rotating machine. The noise on the Bdot signal has disappeared and the audible noise coming from the magnets has disappeared. It is not clear yet whether the beam is oscillating at this frequency or not.

There are still problems with the 5 turns correction for the CT. It stops converging after a couple of iterations. Investigations continue.

The data of the extraction bump need to be checked to see whether the bump has large non closure and whether this could be responsible for the pulse-to-pulse variation in the beam trajectory

Energy variations have been observed in the injected beam.

Myriam:

The analysis (FFT) of the data on trapping efficiency and on the spill are being analyzed.

Gersende:

MARS simulation data still being investigated. A summer student has been assigned to participate to the Neutrino Factory studies.

Hannes:

Simulations of the space charge effects in the SPS have started. The Laslett tune shift due to indirect space charge estimated by ORBIT-PTC is much smaller than that estimated with Laslett formula. Gianluigi commented that he would expect a small tune shift due to indirect space charge.

Next meeting

Monday, 11th April 2011 at 14:00 in room 354-1-001

Agenda

 

 

Back to Minutes