Minutes of the LIS Section meeting held on 26th November 2007.

Present: M. Aiba, G. Arduini, S. Aumon, J. Barranco, E. Benedetto, O. Berrig, M. Chanel, C. Carli, A. Franchi, S. Gilardoni, E. Métral, Y. Papaphilippou, D. Quatraro, G. Rumolo, B. Salvant.

 

General information (G. Arduini)

Approved list of LIS participants to EPAC08:

S. Gilardoni, Y. Papaphilippou, G. Rumolo, E. Benedetto, B. Salvant (if paid by EPFL), J. Barranco (if paid by CIEMAT).

The people who are not in the list can submit abstracts provided that among the authors there is someone (not necessarily in ABP or ABP/LIS) whose participation is approved.

The deadline for the submission of the abstracts to Oliver is: 13/12/2007 morning (with copy to Gianluigi). Please do not wait the last minute.

The deadline for the submission of the papers to BEAM07 (for those who were speakers) is 12/12/2007. Please send Gianluigi a copy before submitting it.

On the 5th April there will be an Open Day for CERN staff, followed by Public Open Day on the 6th April. There will be an LHC press/media day some time in the period May to July, and an Official LHC inauguration on 21st October. For more info (http://ab-div.web.cern.ch/ab-div/Meetings/ABMB/2007/20071119.html). Volunteers are extremely welcome!!!!

Collection of subjects for the annual report is ongoing: present ideas for the injectors (Progress of the ion commissioning, Reduction of the radiological impact of losses in the for the operation of the high intensity beams, Progress of the MTE). Any suggestion is welcome (ASAP). R. Bailey is collecting the list of possible arguments and later he will come back with requests for short contributions.

Status of the optics repository (O. Berrig) - slides

A few items need to be addressed:

  1. The aperture model needs to be checked in LSS5 against the layout drawings ==> Olav
  2. The strengths of the extraction sextupoles for the extraction without Q-split (Q-split=integer horizontal phase advance between West and North extraction) need to be inserted. Gianluigi will send the strength to Olav (done)
  3. T. Kramer has not provided yet the information concerning the improvements he has done to the aperture model. Gianluigi will contact him.
  4. The transition optics for the PS should be added ==> Olav
  5. Discussion are ongoing for a possible modification of the definition of the correctors in MADX. Olav should contact F. Schmidt to learn more about that.
  6. Some of the aperture types in MADX will be discontinued. Olav to discuss with F. Schmidt and B. Jeanneret.
  7. It was pointed out that the optics for the CT transfer has not been modified (the QKE58 is not used for this type of extraction). On the other hand the optics for the AD transfer has been rematched to take into account the suppression of the QKE58 in the PS ring ==> Olav.
  8. The definition of the orbit correctors in the PS ring should be verified ==> Olav.
  9. The LEIR injection line optics and aperture model is still missing ==> Olav.
  10. Gianluigi will pass to Olav the latest TT20 optics files.

Gianluigi encouraged the members of the section to use the optics files in the CVS optics repository and to provide feedback to Olav. Whenever new optics or aperture information is available this should be passed to Olav.

PS bellows (B. Salvant) - slides

B. Salvant presented the results of the simulations and of the experimental studies conducted for the PS bellows in order to determine the maximum tolerance of the transverse displacement that can be applied to PS bellows. Simulations and experimental data indicate that the maximum displacement that can be applied is of the order of 1 mm.

Elias asked whether there are alternatives to applying transverse displacements to the bellows. A possible alternative consists in misaligning the upstream and downstream straight sections provided these do not contain quadrupoles or higher order multipoles and provided that sufficient aperture is available.

Elias asked whether a similar problem exist for the SPS. Gianluigi replied that most of the bellows in the SPS have circular cross section and for that reason they are more "tolerant" to displacements.

Michel C. noted that welded bellows can accept larger displacements as compared to hydroformed ones.

Machines

PSB

Finally no vacuum leak was detected. A bad reading of a vacuum gauge and an ion pump is suspected (probably due to grounding problems).

Gianluigi asked whether it has been decided if the PSBooster will be realigned during the shut-down. Michel replied that he is going to collect more information. Elias pointed out that from the PS experience it is very important to verify the alignment of the BPMs. The BPMs in the PSB have their own alignment targets. We should make sure that the BPMs in the PSB are surveyed too. ==> M. Chanel 

Next meeting

Monday, 10th December 2007 at 09:00 in room 354-1-001

Preliminary Agenda

General information (G. Arduini)

Head-tail instability in the PS on the long injection flat-bottom (E. Métral)

Nominal ion beam in LEIR: observations and what needs to be done (M. Chanel, t.b.c.)

A.O.B.

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