RF, THERMAL, AND STRUCTURAL FINITE ELEMENT ANALYSIS OF FREQUENCY QUADRUPOLE (RFQ)

PXIE (Project X Injector Experiment) is a prototype front end system for the proposed Project X accelerator complex at Fermilab [1]. An integral component of the front end is a 162.5 MHz normal conducting CW (continuous wave) radio-frequency quadrupole (RFQ) accelerator that has been designed and is being fabricated by LBNL. The RFQ will accelerate H ions from 30 keV to 2.1 MeV [2]. The four-vane RFQ consists of four modules with a total length of 4.45 meters. Through application of finite element analysis (FEA), the electromagnetic fields and their resultant effect on the RFQ body temperature and the subsequent deformations due to thermal expansion have been simulated. The analysis methodology developed at LBNL allows for quick evaluation of RFQ temperature, stress, deformation and the resulting effect on frequency without requiring the construction of a prototype. The technique has been applied to the following: RFQ body, RFQ cutbacks, fixed slug tuners, and pi-mode rods. The analysis indicates that the total heat load on the RFQ will be approximately 80 kW, which is removed via water-cooled passages.