Author Description

This dissertation, "Study of Bi-2223 High Temperature Superconducting Tapes for RF and Gradient Coils in Magnetic Resonance Imaging" by Jing, Yuan,, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled Study of Bi-2223 High Temperature Superconducting Tapes for RF and Gradient Coils in Magnetic Resonance Imaging submitted by Yuan Jing for the degree of Doctor of Philosophy at The University of Hong Kong in April 2006 Since the discovery of high temperature superconductor (HTS) by Bednorz and Muller in 1986, there has been a fast development in research and industry. In the domain of MRI, HTS materials are firstly used in RF receive coil to greatly reduce the coil noise and hence improve the signal-to-noise ratio (SNR). Epitaxial thin films such as YBCO are excellent for their good alignment of grains and extremely low surface resistance, so they are well-suited for RF receive coils to significantly increase the image SNR or shorten the scan time. SNR improvements of up to tens of times have been successfully demonstrated for high field micro-imaging or low field imaging, where the sample loss dominates the total loss. However, many intrinsic restrictions and engineering issues associated with HTS thin films limit their large-scale applications and commercialization. Bi-2223 tape is such a flexible and low-cost commercial HTS material that shows promise for use in both passive low-power electronic applications to increase SNR and active high-power electrical applications to reduce power loss. In this thesis, the use of Bi-2223 HTS tapes for RF and gradient coils for MRI is consid