Elements Of X Ray Diffraction

Superconducting magnets are one of the most important and expensive part of reactor-scale tokamaks. Severe operating conditions such as a strong magnetic field, operational current and mechanical load, significant rate of field and current variation, nuclear heating and thermal load, impose specific requirements on the superconducting coil design. This chapter presents the theoretical basis and technical solutions for the different stages of the ITER coil production: the design and manufacturing of composite NbTi and Nb3Sn strands; multistage twisted cable fabrication and jacketing; and the coil winding, insulation and heat treatment. The major technical solutions and manufacturing processes were verified in the course of the ITER model coil test program. Original computation techniques and an integrated set of models for predictive and parametric thermal–hydraulic simulations of the superconducting magnets of magnetic fusion reactor were developed and implemented in computer codes Vincenta/Venecia. The codes and numerical models have been adopted as numerical tools for the complex analysis of the ITER magnets and the cryogenic system.

Superconducting Magnet Systems

We introduce carbon onto boron sites in ${\mathrm{MgB}}_{2}.$ The resulting changes in crystal lattice constants and superconducting transition temperature ${T}_{c}$ are characterized by x-ray-diffraction, magnetic susceptibility, and electrical resistance measurements. The consequence of approximately 10% carbon doping of boron sites is a 1% contraction of the intraplane lattice dimension (with no appreciable change in the interplane dimension) and a lowering of ${T}_{c}$ by approximately 7 K. The relative contributions to the shift in ${T}_{c}$ from lattice contraction and charge transfer are evaluated.

Effects of Carbon-Doping on Superconductivity in Magnesium Diboride

Comparative study of electronic structure of alkaline-earth = borides

Abstract Clinical magnetic resonance imaging (MRI) is characterised by the use of large, expensive whole-body magnets. In recent years the need for these large magnets has been challenged by the evolution of compact and targetted magnet systems. The compact whole-body magnet is epitomised by the Phillips T5 system. This system is easy to site, magnetically shielded and short enough to minimise claustrophobic effects. The targetted approach has been pursued by Otsuka with a 1.5 Tesla small bore clinical system. This system has been designed to image heads, spines and knees: about 90% of the work load of a conventional whole-body system. To maintain good patient access in this small magnet system, Otsuka have developed a range of local magnetic field gradients and radiofrequency (rf) coils. The ultimate compact imaging system is a 0.5T research magnet sited at Exeter University. This magnet is about 1 6 the size of a typical whole-body magnet and was originally intended for imaging the knee but has also produced some high-quality images of the head. It is also possible to use even smaller magnets for niche role applications. Several research groups have used 30cm in-vivo magnet systems (usually used for small animals) to image wrists,hands and fingers. These machines have generated excellent images of peripheral joints that would have been difficult to obtain in whole body machines.

Superconducting Magnets for Magnetic Resonance Imaging

····································································································· 1 Acknowledgments ···································································································· 3 Certification ································································································· 4 Table of

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Hyunseock Jie

Papers

Isotope Based Superconductors for Fusion Application