Structural analysis of the 7.5 GeV superconducting dipole for the CEBAF High Momentum Spectrometer

CEBAF´s High Momentum Spectrometer, (HMS) dipole cryostat has been optimized in collaboration with the subcontracting manufacturer, ELIN-EA, to minimize the deformation of the cryostat and thus the stress on the coil under load conditions. The structural behavior of the cryostat was analyzed using the finite-element codes I-DEAS and ANSYS. The HMS dipole cryostat was designed to withstand the load conditions of cooldown, energization, and warm-up of the magnet. The cryostat is subject to the effects of thermal contraction during cooldown from ambient, 293 K, to 4.2 K. The energization of the magnet to the maximum current subjects the cryostat to the load of the Lorentz forces. The load conditions apply to the structural members of the cryostat, requiring modifications to the design to achieve minimum deformation and stress concentration in the cryostat. An extensive analysis of the dipole cryostat has been carried out to optimize the design. The finite-element analysis has been used throughout the design and fabrication process for quality control of the design.<>