Minutes of the LIS Section meeting held on 14th January 2008

Present: G. Arduini, J. Barranco, O. Berrig; C. Carli, A. Franchi, S. Gilardoni; M. Giovannozzi, M. Martini, S. Maury, E. Métral, G. Rumolo, B. Salvant

General Information (G. Arduini)

Some changes have occurred in the AB structure. (AB Organigramme 2008) as well as in the AT structure (AT Organigramme 2008)

Lauriane Bueno has started to work as ABP secretary at 50% level every morning 8h30-12h00.

New SLS scheme has been communicated to staff.

No ion run of LEIR, PS, SPS in 2008. Only the Linac 3 is going to run with ions in 2008 with the new 18 GHz RF power.

Before the end of the year the LHC main bends in sector 4-5 achieved ~70 % of the nominal current.

Deadlines for EPAC08:

 

MTE Commissioning in 2008 (M. Giovannozzi) - slides

During the discussion it become evident that support will be required in the preparation of the beams required for the commissioning and operation of the MTE. In particular a flat beam will be required from the PS-Booster to equalize the population of the islands and of the core. Michel Chanel will follow-up the preparation of these beams in the PS-Booster.

We should make sure that a sufficient number of users is available in order to switch rapidly from one beam to another. The reliability of the archives should be assessed during the start-up.

Michel Chanel noted that blow-up in the PS-Booster might lead to losses in the transfer line from PSB to PS or at injection in the PS and added that the possibility to blow-up the beam in the PS should be kept open. Simone replied that losses at injection in the PS seem to be mainly related to the beam vertical size and he reminded that the attempts performed to blow-up the beams in the PS by means of the transverse feedback were not succesful.

Elias and Gianluigi noted that this might be due to the parameters used both for the excitation (duration, bandwidth, etc.). We should make sure that no action is taken preventing the use of the transverse feedback in the PS. In particular the planned use of the pick-up of the transverse feedback for the tune measurement should be conceived in such a way not to exclude the use of the feedback. Simone will follow that up.

 

Aperture issues in TT2 (QFO105) and SVD orbit correction for the PSBooster (O. Berrig) - slides

Olav presented the aperture calculations he did to verify the impact of an aperture reduction at the entry of QFO105 resulting from a modification of the vacuum chamber and in particular from a poor quality welding. From the discussion it become evident that not only the quality of the welding was very poor but the geometry of the vacuum chamber was also deformed and worries were expressed on the straightness of the flange (see photos taken by S. Mataguez received after the meeting - foto1 - foto2 - foto3) 

After the meeting Simone discussed with C. Lacroix. 2 new vacuum chamber (one for the spare QFO105) are going to be built aiming for installation before the start-up.

Olav gave a brief overview of SVD (singular value decomposition). This technique is used in MADX for orbit correction or for correction matrix conditioning. So far the number of eigenvalues that are retained in MADX is hard-coded. In the discussion it become evident that this should be a free parameter to be defined by the user. Olav will contact W. Herr to ask for this modification.

This feature of MADX was encountered when SVD was used in the analysis of the PSB orbit in view of the PSB beam based alignment.

Christian pointed out that it is preferable to use MICADO for beam-based alignment as this allows to identify the most effective correctors and to minimize the number of required movements.

Michel Chanel and Giovanni will discuss the issue with B. Mikulec and K. Hanke

 

Next meeting

Monday, 28th January 2008 at 09:00 in room 354-1-001

Agenda

General Information (Gianluigi)

Gamma jump in PS and PS2 (Elias)

Preliminary ideas for MD requirements in 2008

 

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