Beam Dynamics Studies of the REX-ISOLDE Linac in Preparation for its Role as Injector for the HIE-ISOLDE SC Linac at CERN

TL;DR

This paper investigates the beam dynamics of the REX-ISOLDE linac's injector, focusing on matching beam parameters to the superconducting linac for CERN's HIE-ISOLDE upgrade, emphasizing the KONUS design challenges.

Contribution

It provides a detailed analysis and matching solution for the RFQ and IH cavity to optimize beam injection into the superconducting linac at CERN.

Findings

Successful reconstruction of RFQ beam parameters from measurements.

Design of a matching section for the SC linac.

Insights into KONUS beam dynamics challenges.

Abstract

The superconducting (SC) High Intensity and Energy (HIE) ISOLDE linac will replace most of the existing accelerating infrastructure of the Radioactive ion beam EXperiment (REX) at CERN, however, the 101.28 MHz RFQ and 5 MV IH cavity will remain in the role of injector for the upgrade, boosting the beam up to an energy of 1.2 MeV/u. We present the results of a beam dynamics investigation of the injector focused most critically on matching the longitudinal beam parameters from the RFQ to the SC machine, which is complicated largely by the IH cavity employing a Combined Zero Degree (KONUS) beam dynamics design. The longitudinal beam parameters at the RFQ are reconstructed from measurement using the three gradient method and combined with beam dynamics measurements and simulations of the IH structure to design the matching section for the SC linac.