# IEEE Transactions on Applied Superconductivity

### Early Access Articles

Early Access articles are made available in advance of the final electronic or print versions. Early Access articles are peer reviewed but may not be fully edited. They are fully citable from the moment they appear in IEEE Xplore.

## Filter Results

Displaying Results 1 - 25 of 216
• ### Planarized process for single-flux-quantum circuits with self-shunted ${\rm Nb/Nb}_x{\rm Si}_{1-x}/{\rm Nb}$ Josephson junctions

Publication Year: 2019, Page(s): 1
| | PDF (1204 KB)

We describe our process for fabricating single-fluxquantum circuits for applications in communications metrology, advanced computing, and quantum information. The process flow includes four superconducting metal layers, one junction layer, one palladium-gold bias resistor layer, and a contact pad layer. Planarization using chemical-mechanical polishing is performed on the two lower insulating laye... View full abstract»

• ### A Numerical Study of Quench in the NHMFL 32 T Magnet

Publication Year: 2019, Page(s): 1
| | PDF (2386 KB)

The National High Magnetic Field Laboratory (NHMFL), Tallahassee, FL, USA, has developed, built, tested and commissioned a 32T all-superconducting user magnet system combining two series-connected high-field high-temperature superconductor (HTS) nested inner coils (insert) wound with SuperPower Inc. REBCO tapes and a low temperature superconducting (LTS) outer magnet (outsert) composed of five coi... View full abstract»

• ### Optical pulse-drive for the pulse-driven AC Josephson voltage standard

Publication Year: 2019, Page(s): 1
| | PDF (357 KB)

We developed an optical pulse-drive for the operation of the Josephson Arbitrary Waveform Synthesizer (JAWS) using a fast photodiode (PD) operated at 4 K, close to the JAWS chip. The optical pulses are transmitted to the PD by an easy-removable optical fiber attached to it. A bare lensed PD is mounted by flip-chip technique to a custom-made silicon-carrier chip. This carrier chip is equipped with ... View full abstract»

• ### Examination on High-Q NMR Transmit/Receiver Pickup Coils Made by $\rm YBa_{2}Cu_{3}O_{7-\delta}$ Thin Films

Publication Year: 2019, Page(s): 1
| | PDF (510 KB)

An important method to improve the sensitivity of a NMR system is to increase the quality factor (Q) of the pickup coils. In this study, we focus on the following three items. (1) Effect of the surface resistance $(R_s)$ of the YBCO films on the Q of the NMR pickup coil; (2) Relationship between coil line width and current flowing through coil: and (3) Effect of Si-io... View full abstract»

• ### Combined Circuit Model to Simulate Post-Quench Behaviors of No-Insulation HTS Coil

Publication Year: 2019, Page(s): 1
| | PDF (1450 KB)

This paper presents a "combined" circuit model to simulate non-linear behaviors of a no-insulation (NI) high temperature superconductor (HTS) coil. The key idea is a selective use of either the lumped circuit model or distributed depending on an operating condition. When the NI coil current is below its critical current, the radial leak currents through turn-to-turn contacts may be assumed to be u... View full abstract»

• ### Parametric Approach for Routing Power Nets and Passive Transmission Lines as Part of Digital Cells

Publication Year: 2019, Page(s): 1
| | PDF (1142 KB)

In design and layout of RSFQ circuits, multiple inde-pendent biases are often desired to provide flexibility in timings of critical paths. In absence of automated power routing, power nets are often included as part of the layout cells. Multiple variants of each cell need to be manually created to support different biasing configurations. The parametric approach for routing power nets provides the... View full abstract»

• ### A New Magnetic Levitation System with an Increased Levitation Force

Publication Year: 2019, Page(s): 1
| | PDF (511 KB)

A conventional configuration for levitating a vehicle consists of a magnetic guideway on the ground and superconductors in a cryostat located below the vehicle, at a few millimetres from the guideway. A problem is the limitation of the levitating force by the amplitude of the magnetic field generated by the guideway and the size of the superconductors. In addition, the levitating force is trans-mi... View full abstract»

• ### A Tabletop Persistent-Mode, Liquid Helium-Free 1.5-T MgB2 “Finger” MRI Magnet: Construction and Operation of a Prototype Magnet

Publication Year: 2019, Page(s): 1
| | PDF (481 KB)

This paper presents results of construction and operation of a persistent-mode, liquid-helium-free, small-scale prototype magnet for the development of a tabletop 1.5-T “finger” MRI system for osteoporosis screening. The prototype magnet, composed of 2 $MgB_{2}$ coils, one superconducting joint, and a persistent-current switch (PCS) built from a portion of one coil, w... View full abstract»

• ### Energy calibration of high-resolution X-ray TES microcalorimeters with 3 eV optical photons

Publication Year: 2019, Page(s): 1
| | PDF (972 KB)

With the improving energy resolution of transitionedge sensor (TES) based microcalorimeters, performance verification and calibration of these detectors has become increasingly challenging, especially in the energy range below 1 keV where fluorescent atomic X-ray lines have linewidths that are wider than the detector energy resolution and require impractically high statistics to determine the gain... View full abstract»

• ### Magnetic Measurements on the Prototype Magnets of the High-Order Correctors for HL-LHC

Publication Year: 2019, Page(s): 1
| | PDF (5967 KB)

The National Institute for Nuclear Physics (INFN) is developing, at the Laboratory of Accelerators and Applied Superconductivity (LASA Milan, Italy), five families of corrector magnets, from skew quadrupole up to dodecapole order, which will be installed in the interaction regions of the High-Luminosity LHC (HL-LHC). These magnets are based on a superferric design, which allows a relatively simple... View full abstract»

• ### A Novel HTS Flux-Switching Transverse-Flux Machine with Partitioned Stator

Publication Year: 2019, Page(s): 1
| | PDF (714 KB)

This paper proposes and analyzes a novel high-temperature superconducting (HTS) flux-switching transverse-flux (HTS-FSTF) machine with partitioned stator, which keeps the merits of stator-excitation HTS machine with static seals. The key is to adopt the axial partitioned stator structure to realize the independent partition arrangement of armature windings and HTS-excitation windings, as well as a... View full abstract»

• ### Measuring changes in inductance with microstrip resonators

Publication Year: 2019, Page(s): 1
| | PDF (1019 KB)

We measure the frequency dependence of a niobium microstrip resonator as a function of temperature from 1.4 to 8.4 K. In a two micron wide half-wave resonator, we find the frequency of resonance changes by a factor of 7 over this temperature range. From the resonant frequencies, we extract inductance per unit length, characteristic impedance, and propagation velocity (group velocity). We discuss h... View full abstract»

• ### Single-Flux-Quantum based Event-Driven Encoder for Large-Pixel Superconducting Nanowire Single-Photon Detector Array

Publication Year: 2019, Page(s): 1
| | PDF (1313 KB)

We propose a single-flux-quantum (SFQ) based eventdriven encoder for a large-pixel superconducting nanowire singlephoton detector (SSPD) array with a row-column readout architecture. The designed SFQ encoder can acquire time-tagged address data with a high time resolution. To apply 32 × 32 pixel SSPD system with a row-column architecture, the SFQ encoder is equipped with two 32-channel input ports... View full abstract»

• ### Transparency of planar interfaces in superconductors: a critical-state analysis

Publication Year: 2019, Page(s): 1
| | PDF (1022 KB)

The problem of determining the transparency of current flow through a planar interface connecting two superconducting parts, being bulks, tapes or films, is analyzed within the critical-state model. An exact relation between the magnetic moment of a sample containing such an interface and its transparency is de-rived for rectangular specimens in fully developed Bean critical states. The result can... View full abstract»

• ### Longitudinal Magnetic Field Effects on $\rm (Y,Gd)Ba_{2}Cu_{3}O_{7-\delta}$ Coated Conductors with $\rm BaHfO_{3}$ Nanoparticles Fabricated by UTOC-MOD Process

Publication Year: 2019, Page(s): 1
| | PDF (710 KB)

To clarify the effects of longitudinal magnetic field (LMF) on $\rm Y_{0.77}Gd_{0.23}Ba_{2}Cu_{3}O_{7-\delta}$ coated conductors fabricated by the TFA-MOD method with the ultra-thin-once-coating process (UTOC-MOD (Y,Gd)BCO-CCs), and to understand the contributions of $BaHfO_{3}$ nanoparticles (BHO-NPs) to this, we investigated the critica... View full abstract»

• ### New inspection method of soldering region at room temperature for ITER TF Termination

Publication Year: 2019, Page(s): 1
| | PDF (479 KB)

For inter-double-pancake (DP) joints of ITER TF coil termination, it is required to achieve sufficiently low joint resistance (RJ), as 3 $n\Omega$, to reduce Joule heating during operation with a background field of 2 T and nominal current of 68 kA. If RJ value is measured directly, a large cryostat is required to cool down huge mass and size of TF coil during RJ meas... View full abstract»

• ### Design and development of a compact 1 GHz (23.5 T)-class NMR magnet with Bi-2223 inner coils

Publication Year: 2019, Page(s): 1
| | PDF (1871 KB)

The design and development for a compact 1 GHz (23.5 T)-class NMR magnet are presented. The magnet uses inner coils wound with Ni alloy-reinforced Bi-2223 conductors in combination with LTS outer coils. The series-connected coils are operated in a power supply-driven mode. The total magnet size is very com-pact, and is comparable to that of a currently commercialized 600 MHz (14.1 T) NMR magnet. T... View full abstract»

• ### Computation of the magnetization of type II superconductors for potential beam screen coatings of the Future Circular Collider

Publication Year: 2019, Page(s): 1
| | PDF (6927 KB)

High temperature superconductor coatings have been proposed for the reduction of the beam coupling impedance for the future circular collider's hadron-hadron (FCC-hh) option. These coatings are however prone to hysteretic magnetization due to the ramp of the external magnet field. We present a mathematical formulation and implementation of Bean's model, which is a simplified, phenomenological mode... View full abstract»

• ### Field Measurement and Analysis of a 3 T 66 mm No-Insulation HTS NMR Magnet with Screening Current and Manufacturing Uncertainty Considered

Publication Year: 2019, Page(s): 1
| | PDF (925 KB)

This paper reports calculation and measurement of magnetic fields from a 3 T 66 mm room-temperature bore No-Insulation (NI) high temperature superconductor (HTS) nuclear magnetic resonance (NMR) magnet with screening current and manufacturing uncertainty taken into account. The magnet reached its full field of 3 T under a conduction-cooling environment at 17 K. In experiment, axial magnetic fields... View full abstract»

• ### Rotational superconducting gravitational wave detectors based on Cooper-pair electronic transducers

Publication Year: 2019, Page(s): 1
| | PDF (434 KB)

We report here on experimental and theoretical de-velopments of a new method for gravitational wave (GW) detec-tion. It is based on two principal steps: 1) conversion of the GW action into rotational motion and 2) conversion of the rotational motion into an electric current. The ability to detect extremely tiny currents empowers this approach. Preliminary experiments con-firm the theoretical expec... View full abstract»

• ### Software tools for flux trapping and magnetic field analysis in superconducting circuits

Publication Year: 2019, Page(s): 1
| | PDF (878 KB)

We have recently developed and reported methods with which to analyze the effects of external magnetic field and flux trapping on superconducting electronic circuits. Here, we show how the methods can be turned into tools and discuss verification of the analysis results. We present robust and repeatable post-layout verification methods and show examples of magnetic field and flux trap-ping analysi... View full abstract»

• ### 3-D Mechanical Modelling of 20 T Clover Leaf Ends Coils - Good Practices and Lessons Learned

Publication Year: 2019, Page(s): 1
| | PDF (8006 KB)

Very high electromagnetic forces are generated in the superconducting coils of high field accelerator magnets. The cables, which are used to wind the coils, can withstand limited pressure levels and strains generated during the powering without degradation. To protect the cables from mechanical damage, reliable prediction of strain and stress inside the coil is paramount for designing suitable sup... View full abstract»

• ### Superconducting longitudinal gradient bend for the Swiss Light Source upgrade: thermo-mechanical study

Publication Year: 2019, Page(s): 1
| | PDF (3942 KB)

Newer generation circular light sources shall radiate at even higher brightness, requiring a reduction of their emittance. Furthermore, high energy photons are needed for research in materials science, biology and chemistry. These requirements can be met using superconducting longitudinal gradient bend magnets, foreseen for the upgrade of the Swiss Light Source (SLS2). The design of this kind of m... View full abstract»

• ### Commercial Design and Operating Characteristics of a 300 kW Superconducting Induction Heater (SIH) based on HTS Magnets

Publication Year: 2019, Page(s): 1
| | PDF (1549 KB)

Supercoil Co., Ltd. has commercialized a 300-k W-high-Tc-based superconducting induction heater (SIH). Supercoil has many patents related to the SIH as well as technologies to maintain thermal stability and reliability in the operation of a high-Tc superconducting magnet against uneven quench through the metal insulation winding method. Here, two high temperature superconducting (HTS) magnets were... View full abstract»

• ### Mechanical analysis of the collaring process of the 11T dipole magnet

Publication Year: 2019, Page(s): 1
| | PDF (902 KB)

As part of the LHC accelerator upgrades foreseen by the HL-LHC project, the CERN 11 T program is aimed at replacing standard LHC Nb-Ti main dipole magnets, operating with a bore field of 8.3 T, with pairs of shorter Nb3Sn dipole magnets with a bore field of 11 T and the same total integrated field, thus providing space for additional collimators in the Dispersion Suppressor region. At the time of ... View full abstract»

## Aims & Scope

IEEE Transactions on Applied Superconductivity contains articles on the applications of superconductivity and other relevant technology.

Full Aims & Scope

## Meet Our Editors

Editor-in-Chief
Alexander Polasek
Electrical Energy Research Center (Cepel)

polasek@cepel.br