Design of the brazing cycle for the IFMIF/EVEDA-RFQ (Radio Frequency Quadrupole) modules using coupled thermal-structural finite element analyses

Luigi Ferrari, Adriano Pepato

Istituto Nazionale di Fisica Nucleare

Giovanni Meneghetti
University of Padova

The Radio-Frequency Quadrupole of the linear accelerator prototype consists of 18 modules for a total length of 9.8 m long. The components dimensions and materials adopted require the couplings of part by means of vacuum brazing. The differential behavior of CuC2 and AISI316LN and the need to limit the overall deformations after the soldering process, induced to adopt a single step brazing. The brazing studied with a finite element thermal cycle considering the modules and the oven.

The characterization of the components’ and oven’s geometry and materials as and their thermal contacts will be described. Simplified thermal models are used for data determination, by adjusting the emissivity surface conditions and the reduction of surface area exposed.

Validation is obtained by the comparison of the temperatures measured by the thermocouples on components, with the corresponding simulated ones. Thanks to a coupled thermal-structural model, which accounts for the thermal expansion curves of the adopted materials, a tailored brazing cycle could be designed. It made possible to reduce the geometric distortion of modules components having greater mass.