Superconductivity is the technology that enabled the construction of the most recent generation of high-energy particle accelerators, the largest scientific instruments ever built. In this review we trace the evolution of superconducting materials for particle accelerator magnets, from the first steps in the late 1960s, through the rise and glory of Nb–Ti in the 1970s, till the 2010s, and the promises of Nb3Sn for the 2020s. We conclude with a perspective on the opportunities for high-temperature superconductors (HTSs). Many such reviews have been written in the past, as witnessed by the long list of references provided. In this review we put particular emphasis on the practical aspects of wire and tape manufacturing, cabling, engineering performance, and potential for use in accelerator magnets, while leaving in the background matters such as the physics of superconductivity and fundamental material issues.

/pdf/superconducting-materials-and-conductors-fabrication-and-539ox8ddpx.pdf

Superconducting Materials and Conductors:. Fabrication and Limiting Parameters

Enhancement of magnetoresistance due to hall current in aluminium-copper composite

Since the discovery of superconductivity almost a century ago, there has been a steady increase in the variety of superconducting magnet applications. Progress in superconducting magnet technology has resulted in applications in areas of basic science, medicine, separation, and levitation. Performance improvements in a variety of materials, from low-temperature to high-temperature superconductors, are the foundation of recent rapid development. In addition, large increases in affordable computing power, along with steady refinement of three-dimensional analytical tools and improved materials characterization, have allowed many more advanced magnet concepts to be realized directly in hardware without scale prototype testing than was previously possible. This in turn has broadened opportunities for new science and technology results in many fields including the basic sciences, medical imaging, fusion, environmental remediation, and transportation. In this paper, a few examples of these applications will be discussed, representing a range in magnetic field, current density, and overall size, from the practical to the developmental.

Superconducting magnets and their applications

An aluminium stabilized, thin superconducting solenoid is required for the central field of 1.5 T for the BABAR detector. The winding is supported by an aluminium alloy outer cylinder, which provides hoop strength to the coil. The coil has dimensions of 3 m in diameter and 3.7 m in length. The current density is graded to meet the field uniformity requirements of /spl plusmn/2%. A hexagonal flux return, comprised of a barrel and two end doors provides the external flux path for the field. Additional material is required in the end caps to shield the flux from the beam line magnets. To accommodate the muon detectors, the barrel and end caps are segmented into 20 plates of different thickness. Special attention is given to the support of the coil and cryostat to account for seismic loading. The coil is indirectly cooled to 4.5 K using the liquid helium thermo-siphon technique and cooling channels welded to the support cylinder. Automatic cooldown and cryogen supply to the coil and its 40 K radiation shield is done by a helium liquefier/refrigerator via coaxial, return gas screened, flexible transfer lines.

The superconducting magnet for the BABAR detector of the PEP-II B Factory at SLAC

Specifications and performance experience of pool boiling cooled magnets

A large thin-wall superconducting solenoid has been constructed at Saclay and mounted on a large detector CELLO. This is one of the experiments installed on the e+e- colliding beam facility PETRA at DESY (Hamburg).

Construction and Test of the Cello Thin-Wall Solenoid

A large superconducting magnet system has been installed and is currently operated at the PETRA storage ring (Desy/Hamburg) for the CELLO detector. This system has been carried out as a joint collaboration of CEN/, Saclay and ITP/Karlsruhe and includes as main components a large "thin wall" solenoid cooled by force flow in a pipe bonded to the winding, two bath-cooled compensating solenoids, a 450 W liquifier-refrigerator unit and all connecting lines and appropriate control equipment designed for long-term automatic operation. The system has been in operation for nearly two years with continuous runs exceeding three months and has provided considerable technical experience.

G. Mayaux

Papers

Construction and Test of the Cello Thin-Wall Solenoid

Long term experience on the superconducting magnet system for the CELLO detector