William Denis Markiewicz

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Development of high-field magnets using high temperature superconductors (HTS) is a core activity at the NHMFL. Magnet technology based on both YBCO-coated tape conductors and Bi-2212 round wires is being pursued. Two specific projects are underway. The first is a user magnet with a 17 T YBCO coil set which, inside an LTS outsert, will generate a combined(More)
Access to an ultra-wide bore (105 mm) 21.1 T magnet makes possible numerous advances in NMR spectroscopy and MR imaging, as well as novel applications. This magnet was developed, designed, manufactured and tested at the National High Magnetic Field Laboratory and on July 21, 2004 it was energized to 21.1 T. Commercial and unique homebuilt probes, along with(More)
The National High Magnetic Field Laboratory is constructing a 32 T all superconducting magnet. The high field insert coil, which produces about 17 T field, will be made of YBCO coated conductor. Due to the limited available coated conductor piece length, solder splice joints are necessary in the insert coil. In order for the magnet to achieve stable(More)
The design and fabrication of a 32 T, 32 mm cold bore superconducting magnet with high field REBCO inner coils is underway at the NHMFL. In support of the design, conductor characterization measurements have been made including critical current as a function of field, field orientation, temperature, and strain on conductors and joints. Various conductor and(More)
The present period is one of rapid development and major extension of the technology for high resolution and solid state NMR spectrometer magnets. Programs which have already been initiated have as their objective proton frequencies of 1 GHz and greater, eventually requiring HTS superconductors. These magnets will contain inner coils containing HTS(More)
The electromechanical performance of commercially available YBCO high-temperature superconductor (HTS) is characterized in support of the 32T all-superconducting magnet program at the National High Magnetic Field Laboratory. Accurate characterization of the HTS coated conductors mechanical properties are essential for the aggressive high-field magnet(More)
A 17 T high-temperature superconducting two-coil magnet (insert) to be operated in a 15 T low-temperature superconducting multisection magnet (outsert) is the most demanding part of the National High Magnetic Field Laboratory all-superconducting 32 T magnet system. The HTS coils are of the pancake type and to be wound with REBCO coated conductors/tapes(More)
Normal zone propagation rates are widely reported to be low in coils containing REBCO coated conductor, creating difficulties for quench protection of high field REBCO insert solenoids. A method of active quench protection using densely distributed heaters in high field REBCO coils has been proposed. When heaters are used to quench a sufficiently large(More)
A 32 Tesla, all-superconducting user magnet, which consists of two high temperature superconductor YBCO inner coils producing a field of 17 T in an low temperature superconductor Nb<sub>3</sub>Sn and NbTi outer magnet producing a background field of 15 T, is being developed at the National High Magnetic Field Laboratory. The YBCO inner coils are(More)
Insulation in a high field superconducting magnet plays a critical role. For high field magnets using coated conductor, insulation faces a few special challenges. In order to maximize the engineering current density, the conductor insulation has to be very thin (e.g. &lt;; 12.5 &#x03BC;m). In addition to required mechanical and dielectric integrity under(More)