• S. Hancock, C. Carli, J.F. Comblin, A. Findlay, K. Hanke, B. Mikulec
  CERN, Geneva

Since the CERN PS Booster cannot simultaneously provide the beam brightness and intensity required, the nominal (25ns bunch spacing) proton beam for the LHC involves double-batch filling of the PS machine. Linac 4, which is under construction, will eventually remove this restriction. In the meantime, the request for 50 and 75ns bunch spacings to mitigate electron cloud effects has lowered the intensity demand such that the Booster can meet this in a single batch without compromising beam brightness. Single-batch transfer means providing two bunches from each of three Booster rings and, in turn, that the bunch spacing is modified by the addition of an h=1 rf component to the h=2 in the Booster in order to fit the h=7 rf buckets waiting in the PS (whilst leaving one bucket empty for kicker purposes). Following the first experiments performed in 2008, the rf manipulations in the Booster have been refined and those in the PS have been modified to cope with single-batch beams. This latest work is presented for both the 50 and 75ns variants.

• H. Damerau, S. Hancock, M. Schokker
  CERN, Geneva

To cope with the large variety of different beams for the LHC, the RF beam control in the CERN PS has evolved continuously to improve its flexibility and reliability. Single-bunch beams, several different multi-bunch beams with 25, 50 or 75 ns bunch spacing at ejection for LHC filling, as well as two lead-ion beam variants are now regularly produced in pulse-to-pulse operation. The multi-bunch beam control for protons can be easily re-adjusted from 0.25·10¹¹ to 1.3·10¹¹ particles per ejected bunch. Depending on the number of bunches injected from the PS Booster, the length of the ejected bunch train may vary from 8 to 72 bunches. This paper summarizes recent improvements in the low-level RF systems and gives an outlook on the future consolidation.

• M. Giovannozzi, E. Benedetto, A. Blas, T. Bohl, S. Cettour Cave, K. Cornelis, D.G. Cotte, H. Damerau, M. Delrieux, J. Fleuret, F. Follin, T. Fowler, P. Freyermuth, H. Genoud, S.S. Gilardoni, S. Hancock, O. Hans, Y. Le Borgne, D. Manglunki, E. Matli, G. Metral, E. Métral, M. Newman, L. Pereira, F.C. Peters, Y. Riva, F. Roncarolo, L. Sermeus, R.R. Steerenberg, B. Vandorpe, J. Wenninger
  CERN, Geneva
• F. Franchi
  ESRF, Grenoble

Following the analysis of the results obtained during the first year of beam commissioning of the CERN multi-turn extraction, a number of changes have been introduced in the beam manipulations performed in the CERN Proton Synchrotron. This includes a different control of the linear chromaticity, the setting of the non-linear magnets used to split the beam, and the longitudinal structure in the PS. The results obtained during the 2009 run are presented and discussed in detail, including the beam performance in both the PS and the SPS, as well as the optics measurements in the transfer line between the two circular machines.

Slides