F. Antoniou, F. Asvesta, H. Bartosik, J.F. Comblin, G.P. Di Giovanni, M. Hostettler, A. Huschauer, B. Mikulec, J.-M. Nonglaton, T. Prebibaj
CERN, Meyrin, Switzerland
The CERN PS Booster (PSB) has gone through major upgrades during the Long Shutdown 2 (LS2) and the recommissioning with beam started in December 2020. Two of the aspects leading to improved operation will be described in this paper: a new tune control implementation; and a full re-alignment campaign. The operation of the PSB requires a large range of working points to be accessible along the acceleration cycle. As part of the LIU project, the PSB main power supply was upgraded to raise the extraction energy from 1.4 GeV to 2 GeV, in order to improve the brightness reach of the downstream machines. A new tune control implementation was necessary to take into account saturation effects of the bending magnets and the reconfiguration of the main circuits, as well as the additional complexity of the new H− charge exchange injection. The first part of the paper describes the implementation of the new tune control and its experimental verification and optimization. The second part describes the results of the PSB alignment campaign after LS2, giving emphasis to the method developed to perform a combined closed orbit correction through quadrupole alignments.
T. Prebibaj, S.C.P. Albright, F. Antoniou, F. Asvesta, H. Bartosik, C. Bracco, G.P. Di Giovanni, E.H. Maclean, B. Mikulec, E. Renner
CERN, Meyrin, Switzerland
IAP, Frankfurt am Main, Germany
In the context of the LHC Injectors Upgrade Project (LIU), the Proton Synchrotron Booster (PSB) developed an H− charge exchange injection system. The four short rectangular dipoles of the injection chicane induce focusing errors through edge focusing and Eddy currents. These errors excite the half-integer resonance 2Qy = 9 and cause a dynamically changing beta-beating in the first milliseconds after injection. Using the beta-beating at the positions of two individually powered quadrupoles, measured with k-modulation, correction functions based on a model response matrix have been calculated and applied. Minimizing the beta-beating at injection allows the machine to be operated with betatron tunes closer to the half-integer resonance and therefore with larger space charge tune spreads. In this contribution the results of the beta-beating compensation studies and the impact on the achievable beam brightness limit of the machine are presented.
Right click on video for Picture-in-Picture mode or Full screen display.