A5018512856- Physics of Superconductivity and Magnetism
- Superconducting Materials and Applications
- Advanced Fiber Optic Sensors
- Superconductivity in MgB2 and Alloys
- Iron-based superconductors research
- Advanced Fiber Laser Technologies
- Magnetic and transport properties of perovskites and related materials
- Magneto-Optical Properties and Applications
- Advanced Condensed Matter Physics
- Magnetic confinement fusion research
- Photonic Crystal and Fiber Optics
- Photonic and Optical Devices
- Particle accelerators and beam dynamics
- Advanced Optical Sensing Technologies
- Rare-earth and actinide compounds
- Graphene research and applications
- Particle Accelerators and Free-Electron Lasers
- Semiconductor Lasers and Optical Devices
- Frequency Control in Power Systems
- Machine Learning in Materials Science
- Advanced DC-DC Converters
- Geophysics and Sensor Technology
- Magnetic Properties of Alloys
- Intellectual Capital and Performance Analysis
- Advanced Sensor and Energy Harvesting Materials
Victoria University of Wellington
2021-2024
University of Cambridge
2019-2022
Imperial College London
2013-2016
Moseley Hall Hospital
1996
Abstract This paper presents a roadmap to the application of AI techniques and big data (BD) for different modelling, design, monitoring, manufacturing operation purposes superconducting applications. To help superconductivity researchers, engineers, manufacturers understand viability using BD as future solutions challenges in superconductivity, series short articles are presented outline some potential applications solutions. These futuristic routes their materials/technologies considered...
Abstract High temperature superconducting (HTS) flux pumps can generate ultra-high currents (>1 kA) without the requirement for thermally inefficient room current leads. Ultra-high enable physically smaller magnets with significantly less inductance unlocking new design opportunities. However, limited by intrinsically low electrical power efficiencies, existing HTS cannot output high voltage or power. In this work, we design, devise, and experimentally verify a transformer–rectifier type...
This paper presents experimental and modelling results of an ultra-compact self-rectifier flux pump energizing a superconducting coil. The device fits inside volume 65x65x50~mm generates up to 320~A dc through the coil peak output voltage 60~mV. We also develop present full electromagnetic effective circuit model compare its predictions results. show that our can reproduce accurately charging load it reproduces systematic dependence maximum current on input waveform. experiments together...
Abstract The Insertion Device group of the Paul Scherrer Institute has started an R&D program on a high temperature superconducting undulator to reduce period length and increase undulator's magnetic field well beyond present capability. Simulation results for 10 mm 4 gap staggered array GdBCO bulks predict peak above 2 T. Building existing working principle design simulated performance, first experimental 5 6.0 short measured in new test facility available at University Cambridge will...
Superconducting flux pumps (FP) are capable of supplying superconducting circuits with high currents by additively current over a number cycles without introducing large amounts heat into the cryogenic environment. FPs can be broadly classified two types: dynamo and transformer rectifier. Modelling behaviour these systems is an emerging field. In this work model half wave magnetically switched rectifier FP created in MATLAB/Simulink/Simscape presented. Unlike existing models, characteristics...
The performance of HTS transformers is integral to predictability outputs in transformer-rectifier flux pumps. To date, little attention has been given compact using stacked-tape cables. Current sharing behaviour with cable secondary windings studied here experimentally. Secondaries 1-4 tapes are tested a 500:1 transformer. Two modes coupling identified. Firstly, primary inductive determines current during changes current. Secondly, shared between loops when held constant. This caused by...
The incredible current density and high magnetic field generation possible with high-temperature superconductors (HTS) have the potential to revolutionize energy generation, e.g. high-power generators, compact fusion devices. However, an open issue that limits applications of this class is challenge rapidly detecting a hot spot which can lead quench. Owing inherent advantages fibre optic sensors, they are promising candidates be integrated in HTS magnets for hot-spot detection. In paper,...
Transformer-rectifier flux pumps provide an elegant solution for high current generation ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$>$</tex-math></inline-formula> 1 kA) in superconducting magnets. By using step-down transformers and switches they can charge magnets with minimal heat-load between the external cryogenic components. High temperature superconductors' type-II superconductivity enables...
Quasi-continuous arrays of fiber Bragg gratings (FBGs) show great promise for quench protection in superconductors. The number identical and the reflectivity individual are important parameters determining sensitivity system to a local temperature or strain perturbation. We apply shift wavelength single FBG through spectrum an array up 1000 gratings, map out detection given <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math...
Transformer-rectifier flux pumps are DC superconducting power supplies capable of charging magnets to high currents and stored magnetic energies. Here, we demonstrate a full-wave pump assembled from high-temperature (HTS) wire that utilizes switches controlled by applied field. A negative offset occurs in the secondary circuit during operation which is related output load current. feedback control system proposed demonstrated account for offset. Increasing primary current proportional...
Abstract The recent adoption of high- T c superconductor (HTS) wires for ultra-high field magnet windings provide great promise future applications, such as high-power generators and Tokamak fusion reactors. However, an open issue with the use HTS is challenge rapidly detecting a hot spot which could lead to quench. Optical fiber sensors have been shown be promising alternatives voltage-based quench detection method. In this paper, we report on ultra-long Bragg gratings (ULFBG) hotspot at...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation S. Venuturumilli, A. C. Francis, E. Pantoja, R. W. Taylor, J. M. Brooks, D. Moseley, Badcock, Bumby; Temperature dependent behavior of a kA-class superconducting flux pump with continuous cylindrical stator. Appl. Phys. Lett. 13 November 2023; 123 (20): 202601. https://doi.org/10.1063/5.0169553 Download...
Abstract Bulk superconductors can act as trapped-field magnets with the potential to be used for many applications such portable medical magnet systems and rotating machines. Maximising trapped field, particularly practical magnetisation techniques pulsed field (PFM), still remains a challenge. PFM is dynamic process in which magnetic driven into superconducting bulk over milliseconds. This flux motion causes heating complex interplay between thermal properties. In this work, local density...
One of the potential applications ring-shaped, single grain RE-Ba-Cu-O bulk superconductors is in desktop magnetic resonance imaging (MRI) and nuclear (NMR) systems as an alternative to conventional permanent magnets. The higher field available from magnetized could significantly improve performance such systems, well reduce their size increase portability. pulsed magnetization (PFM) method provides a fast, compact cost-effective for magnetizing these materials trapped However,...
Optical fibre Bragg grating (FBG) sensors have been used for cryogenic temperature and strain measurements in a variety of applications, e.g., hotspot detection high-temperature superconductor magnets. In such application, the sensitivity FBG its reflection spectrum strongly depend on methods chiefly adhesion elasticity bond, birefringence effect. To investigate those features, Draw Tower Gratings (DTG®) with Ormocer coating FemtoSecond (FSG) polyimide are mounted V-shaped grooves surface...
Abstract Iron-core electromagnets are widely used as applied-field switches in high-temperature superconducting (HTS) flux pumps. It was recently reported that the critical current ( <?CDATA $I_{\mathrm{c}}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>I</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">c</mml:mi> </mml:mrow> </mml:msub> </mml:math> ) of HTS wire is suppressed by up to 45% air gap iron core. Here, it self-field a single tape...
Abstract We report a new methodology in bulk MgB 2 ring production for use small-scale magnetic shielding or bench-top nuclear resonance systems. This process is modified field-assisted sintering technique (mFAST) which enables direct formation of the rings without need machining additives into precursor powder. The and trapped field capabilities three mFAST were determined using zero-field- field-cooled experiments. Individual bulks trap fields up to 1.24 T at 20 K comparable highest...
We investigated the effects of gamma irradiation on radiation-induced attenuation (RIA) in photosensitive (Ge-doped) and radiation-hard (F-doped) fibers at cryogenic temperatures (77 K) under different photobleaching conditions. show that increasing probe power (1550 nm) injecting lower wavelength light (970 both resulted a significant reduction RIA fiber types, where were intrinsically more resistant to RIA. Deconvolution growth curves revealed was composed transient long-term components...
Here we study the magnetotransport properties of ferropnictide crystals ${\text{BaFe}}_{2}{\text{As}}_{2}$ and ${\text{BaFe}}_{1.985}{\text{Co}}_{0.015}{\text{As}}_{2}$. These materials exhibit a high field linear magnetoresistance that has been attributed to quantum model. In this model, is dependent on concentration scattering centers in material. By using proton-beam irradiation change defect density, find dependence magnitude quite clearly contravenes prediction. A number other scaling...
One potential application of magnetized RE-Ba-Cu-O (where RE = rare earth or Y) bulk superconductors is as a high-field alternative to conventional permanent magnets in desktop NMR and MRI systems. Pulsed field magnetization (PFM) one the most promising practical methods magnetizing such bulks. However, trapped fields obtained by PFM are much lower than those using quasi-static like field-cooling (FCM) due heating during PFM. Furthermore, superconducting rings have proved more difficult...
Optical fiber Bragg gratings (FBGs) are well suited for applications as temperature or/and strain sensors in harsh environments, e.g., detecting thermal hot spots high-temperature superconductor (HTS) fusion energy magnets at cryogenic temperatures and high radiation environments. To maximize the signal-to-noise ratio (SNR) of FBGs to a spot, we propose have them mounted V-shaped grooves HTS' copper former. investigate differences between different adhesives on transferring heat this...
High-temperature superconductors (HTS) can carry and withstand enormously high current densities magnetic field respectively, which provide great promise for future energy generation, e.g., high-power generators compact fusion systems. However, an open issue with the use of HTS is challenge rapidly detecting a potentially catastrophic quench, tends to be localized. To overcome challenge, we propose proactively monitor event hot spot (temperature rise) using fiber Bragg grating (FBG) sensors....