Redesign of CERN LINAC3 RFQ for Lead 29+

Abstract

CERN Linac3 is at the heart of the CERN Heavy Ion Facility, providing 4.2 MeV/u ion beams to the Low Energy Ion Ring (LEIR). It mostly accelerates 208Pb29+, though in recent years runs were performed with 40Ar11+ and 129Xe22+, in view of the raising interest of the physics community towards lighter ions experiments. In the framework of the LHC Injectors Upgrade (LIU) project, measurements and beam dynamics simulations showed that a transmission bottleneck of Linac3 is represented by the RFQ. As this accelerator was originally designed for 208Pb25+, the lower beam rigidity of the heavy ions currently in used – and planned to be used – permits a redesign of the RFQ aimed at increasing its transverse acceptance, and thus the transmitted beam current. The methodology adopted and the results of this study are presented.CERN Linac3 is at the start of the CERN Heavy Ion Facility, providing 4.2 MeV/u ion beams to the Low Energy Ion Ring (LEIR). It mostly accelerates $^{208}$Pb$^{29+}$, though in recent years runs were performed with $^{40}$Ar$^{11+}$ and $^{129}$Xe$^{22+}$, in view of the raising interest of the physics community towards lighter ions experiments. In the framework of the LHC Injectors Upgrade (LIU) project, measurements and beam dynamics simulations showed that a transmission bottleneck of Linac3 is represented by the RFQ. As this accelerator was originally designed for $^{208}$Pb$^{25+}$, the lower beam rigidity of the heavy ions currently in use - and planned to be used - permits a redesign of the RFQ optics aimed at increasing its transverse acceptance, and thus the transmitted beam current. The methodology adopted and the results of this study are presented