Particle-In-Cell Simulation of RFQ in SSC - Linac

TL;DR

This paper presents a 3D particle-in-cell simulation of a 52MHz RFQ linac designed for the SSC, demonstrating high beam transmission efficiency and good beam quality, with analysis of error effects for engineering tolerances.

Contribution

It introduces a detailed simulation of the RFQ linac using BEAMPATH, highlighting stable operation, beam quality, and error tolerance analysis, which are novel for this specific design.

Findings

Beam transmission efficiency is at least 95%.

Accelerated beam has good transverse and longitudinal quality.

Vane errors and space charge effects influence beam parameters.

Abstract

A 52MHz Radio Frequency Quadrupole (RFQ) linear accelerator (linac) is designed to serve as an initial structure for the SSC-linac system (injector into Separated Sector Cyclotron). The designed injection and output energy are 3.5 keV/u and 143 keV/u, respectively. Beam dynamics study in RFQ was done using 3-dimensional particle-in-cell code BEAMPATH [1]. Simulation results show that this RFQ structure is characterized by stable value of beam transmission efficiency (at least 95%) for both zero-current mode and for space charge dominated regime. The beam accelerated in RFQ has good quality in both transversal and longitudinal directions, and could be easily accepted by Drift Tube Linac (DTL). Effects of vane errors and of the space charge on beam parameters are studied as well to define the engineering tolerance for RFQ vane machining and alignment.