New Beam Dynamics Simulations for the FAIR p-Linac RFQ

The construction of a 3.3m Ladder-RFQ at IAP*, Goethe University Frankfurt, has been finished successfully last summer. This RFQ is designed to accelerate protons from 95 keV to 3.0 MeV according to the design parameters of the p-Linac at FAIR**. Along the acceleration section the parameters modulation, aperture and synchronous phase are varied linearly with cell number, which differs from former designs from IAP Frankfurt. The ratio of transversal vane curvature radius to mid-cell radial aperture and the vane radius itself are constant. The development of an adequate beam dynamics design was done with the aid of the RFQGen-code and in close collaboration with the IAP resonator design team. The RFQ beam dynamics design could be successfully reproduced with the TOUTATIS-routine of CEAs*** TraceWin-code. Several new beam dynamics simulations were performed on the design. Among these were current and Twiss parameter studies as well as simulations concerned with the investigation of longitudinal entrance and exit gap field effects. Others were based on new measurements in the LEBT-line performed by the GSI**** Ion Source Group in April 2019. In the near future, further LEBT measurements and subsequent simulations (among other to design a well-fitting cone for the RFQ), as well as mechanical error studies in TOUTATIS, will follow.