Design study of a radio-frequency quadrupole for high-intensity beams

• 来源期刊: 中国物理C（英文版）
• 年，卷（期）: 2017,（7）
• 页码范围: 142-150
• 页数: 9页
• 语种: 英文
• DOI: 10.1088/1674-1137/41/7/077002

摘要

The Rare isotope Accelerator Of Newness (RAON) heavy-ion accelerator has been designed for the Rare Isotope Science Project (RISP) in Korea.The RAON will produce heavy-ion beams from 660-MeV-proton to 200-MeV/u-uranium with continuous wave (CW) power of 400 kW to support research in various scientific fields.Its system consists of an ECR ion source,LEBTs with 10 keV/u,CW RFQ accelerator with 81.25 MHz and 500 keV/u,a MEBT system,and a SC linac.In detail,the driver linac system consists of a Quarter Wave Resonator (QWR) section with 81.25 MHz and a Half Wave Resonator (HWR) section with 162.5 MHz,Linac-1,and a Spoke Cavity section with 325 MHz,Linac-2.These linacs have been designed to optimize the beam parameters to meet the required design goals.At the same time,a light-heavy ion accelerator with high-intensity beam,such as proton,deuteron,and helium beams,is required for experiments.In this paper,we present the design study of the high intensity RFQ for a deuteron beam with energies from 30 keV/u to 1.5 MeV/u and currents in the mA range.This system is composed of an Penning Ionization Gauge ion source,short LEBT with a RF deflector,and shared SC Linac.In order to increase acceleration efficiency in a short length with low cost,the 2nd harmonic of 162.5 MHz is applied as the operation frequency in the D+ RFQ design.The D+ RFQ is designed with 4.97 m,1.52 bravery factor.Since it operates with 2nd harmonic frequency,the beam should be 50％ of the duty factor while the cavity should be operated in CW mode,to protect the downstream linac system.We focus on avoiding emittance growth by the space-charge effect and optimizing the RFQ to achieve a high transmission and low emittance growth.Both the RFQ beam dynamics study and RFQ cavity design study for two and three dimensions will be discussed.