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Discusses the use of pressurized bladders for stress control of superconducting magnets. Placement of the bladder between the coil pack and the iron yoke; Increase in stress in the shell during cooling; Achievement of final and maximum stress in the shell before the magnet is energized; Difference in thermal expansion between the aluminum shell and the inner iron yoke.

A high field Nb3Al common coil magnet is under development as an R&D of "Advanced Superconducting Magnets for the LHC Luminosity Upgrade", in the framework of the CERN-KEK cooperation program. The goal of this research is to demonstrate the feasibility of high field magnet wound with Nb3Al cable. The common coil approach and the shell-based structure were adopted in the design of this magnet. Besides three Nb3Al coils, two Nb3Sn coils were included to increase the peak field of the whole magnet. The two types of coils were designed with different straight lengths to reduce the peak field of the Nb3Sn coils. The peak fields of the Nb3Al and Nb3Sn coils are 13.1 T and 11.8 T respectively. An aluminum shell together with four aluminum rods applies stress to the coils to overcome the Lorenz force during excitation. Two different support structures for the superconducting coils were introduced in this paper. The development status is also presented. [ABSTRACT FROM AUTHOR]

The Heavy Ion Fusion (HIF) program is progressing through a series of physics and technology demonstrations leading to an inertial fusion power plant. The High Current Experiment (HCX) at Lawrence Berkeley National Laboratory is exploring the physics of intense beams with high line-charge density. Superconducting focusing quadrupoles were developed for magnetic transport studies at the HCX. A baseline design was selected following several pre-series models. Optimization of the baseline design led to the development of a first prototype that achieved a conductor-limited gradient of 132 T/m in a 70 mm bore, without training, with measured field errors at the 0.1% level. Based on these results, the magnet geometry and fabrication procedures were adjusted to improve the field quality. These modifications were implemented in a second prototype. In this paper, the optimized design is presented and comparisons between the design harmonics and magnetic measurements performed on the new prototype are discussed. [ABSTRACT FROM AUTHOR]