Design of 57.5 MHz CW RFQ structure for the Rare Isotope Accelarator Facility

• Published in: Pramāṇa Vol. 59; no. 6; pp. 977 - 988
• Main Authors: Ostroumov, P N, Kolomiets, A A, Kashinsky, D A, Minaev, S A, Pershin, V I, Tretyakova, T E, Yaramishev, S G
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Nature B.V 01.12.2002
• Subjects: Electrodynamics; Emittance; Heavy ions; Ion beams; Ion sources; Ions; Linear accelerators; Liquid cooling; Resonant frequencies; Uranium
• ISSN: 0304-4289; 0973-7111
• DOI: 10.1007/s12043-002-0147-8

The Rare Isotope Accelerator (RIA) facility includes a driver LINAC for production of 400 kW CW heavy-ion beams. The initial acceleration of heavy ions delivered from an ECR ion source can be effectively performed by a 57.5 MHz 4 m long RFQ. The principal specifications of the RFQ are: (1) formation of extremely low longitudinal emittance: (2) stable operation over a wide range of voltage for acceleration of various ion species needed for RIA operation; (3) simultaneous acceleration of two-charge states of uranium ions.CW operation of an accelerating structure leads to a number of requirements for the resonators such as high shunt impedance, efficient water cooling of all parts of the resonant cavity, mechanical stability together with precise alignment, reliable rf contacts, a stable operating mode and fine tuning of the resonant frequency during operation. To satisfy these requirements a new resonant structure has been developed.This paper discusses beam dynamics and electrodynamics design of the RFQ cavity, as well as, some aspects of the mechanical design of this low-frequency CW RFQ.