Minutes of the LIS Section meeting held on 9^th March 2009

Present: M. Aiba, G. Arduini, S. Aumon, E. Benedetto, O. Berrig, C. Carli, M. Chanel, S. Gilardoni, C. Hansen, M. Martini, E. Métral, N. Mounet, Y. Papaphilippou, D. Quatraro, G. Riumolo, B. Salvant, E. Wildner.

General Information (Gianluigi)

Gianluigi introduced a new member of the Section: C. Hansen. He is a fellow who is going to work with E. Wildner on the beta beam study. He will initially work on the RF gymnastics required for ion accumulation. He is going to work in collaboration with S. Hancock who has studied a scheme to inject new beam in the core of the longitudinal distribution to maximize the brightness of the accumulated beam.

The OP days and the ATOP days have taken place. The following issues should be studied in order to help the team responsible for the magnets of the PS-SPS complex to take a decision on the spare policy:

• Can we run without a quadrupole in LEIR ==> C. Carli and M. Chanel
• Can we re-use a multiple in the PS-Booster recuperating it from another position in the machine? ==> M. Chanel
• Can we run without one or more Pole Face Windings in the PS? ==> S. Gilardoni 

Summary and Conclusions of the CERN-GSI Workshop (18-19/2/2009) (Elias)

Elias presented a summary of the presentations given at the workshop and the possible subjects of study of interest for CERN and GSI. Possible studies include:

• Simulations with MICROMAP (space charge simulation code written by G. Franchetti) to study the effects of parameters like coupling, chromaticity for the PSB with LINAC4 and PS2. This could help in the definition of the working point and machine settings and reduce the number of simulations with ORBIT limiting them to a few detailed cases.
• Study of the effect of chromaticity on blow-up and losses with the LHC nominal beam. Experiments can be performed now thanks to the availability of the transverse feedback and to the possibility of correcting tune and chromaticity thanks to the operation of the Pole Face Windings in 5 current mode. Presently the PS is operated at injection with natural chromaticity. Furthermore coupling is used to stabilize the LHC beam at injection. 
•  Study of flat bunches for the LHC and to improve the reproducibility of the longitudinal splitting process in the PS.
• Effect of space charge on TMCI threshold could be studied in the PS at transition by varying the transverse emittance of the beam delivered by the PS Booster.
•  Benchmarking of the CST Particle Studio simulation programme with theoretical expressions for non relativistic beams and understanding of present issues (instability of the result for cylindrical shapes and factor 4.4 for the transverse wake when comparing simulations with theory for rectangular vacuum chambers.

Elias will contact O. Boine-Frankenheim to propose some of the studies and to see how to proceed. ==> Elias

Next meeting

Monday, 23^rd March 2009 at 14:00 in room 354-1-001

Agenda:

• General Information (Gianluigi)
• Beta Beam Study (Elena Wildner)
• Round Table (all)

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