Thermal stress analysis of a large aperture dipole magnet

Variable Energy Cyclotron Centre (VECC) is involved in the design of dipole and multipole magnets for a spectrometer having high acceptance for the Energy Buncher at the Low Energy Branch (LEB) of the Superconducting Fragment Separator (Super-FRS) to be built at Darmstadt, Germany under the umbrella of India and Facility for Antiproton and Ion Research (FAIR) collaboration. The cryostat of the dipole magnet, consisting of a bobbin structure and an epoxy impregnated superconducting coil, will be subjected to substantial amount of thermal stress when cooled to cryogenic temperature from room conditions. In this paper, a detailed thermal analysis of the coil and bobbin is carried out to have a clear idea about the displacements of the coil and the magnitude & direction of thermal stress developed. Finally structural integrity assessment of the structure is also done following ASME Pressure Vessel Code guidelines.