This article presents a novel high-temperature superconducting ultra-wideband filter with a 108% fractional bandwidth. A high-order ladder topology circuit is utilized in the proposed filter to ensure a deep out-of-band rejection. Superconducting quasi-lumped elements are applied to reduce the insertion loss brought by the high-order circuit. The proposed filter derives from a low-pass filter (LPF)

Better cryo-stability is mandatory for any superconducting (SC) feeders system of fusion devices as the large amount of the magnet-stored energy can be safely dumped via feeder path only. Magnesium diboride (MgB 2 ) as a feeder may provide an innovative solution in lieu of low temperature superconductor. It has a critical SC transition temperature ( TC ) of 39 K, ductile nature, and ease of availability

2G high-temperature superconducting (HTS) wires and YBCO-coated conductors perform better carrying current capability, which is potentially applied to the manufacture of HTS magnets. This article presents the experimental results of the pumping current for YBCO coils using a pulse-type magnetic flux pump in the conduction-cooling system and liquid nitrogen bath (LN 2 ) cryogenic environment. The optimization

An architecture of rapid single-flux-quantum logic circuits using clockless gates is proposed. Compared with a circuit composed of only clocked gates, a circuit using clockless gates includes fewer clocked gates, and therefore, a smaller clock distribution network. A circuit in the proposed architecture is constructed from pipeline stages. Each pipeline stage consists of a column of clocked gates and

The general-purpose circuit simulator analysis program for linear active circuits (APLAC) is not widely known within the superconductor circuit community, regardless of its built-in Josephson junction model and capability of modeling the superconductive phase transition with controlled sources. We review the use of APLAC to model, e.g., noisy dc SQUIDs and transition-edge sensors. Based on an APLAC

With the advances in superconductor detectors and single flux quantum (SFQ) logic circuits, megapixel imagers have become possible. Various detectors such as superconducting stripline detectors (SSLD), kinetic inductance detectors, nanowire single-photon detectors have quite matured in terms of speed and performance. However, scaling of the read-out electronics is still a challenge. We propose an SFQ

Heavy ion rotating gantries comprise large magnets to meet the requirement of high magnetic field. High-temperature superconductors (HTSs) are able to achieve notably higher current densities compared to copper conductors, and enable significant mass and size reduction. However, large yokes for magnetic field enhancement and shielding still make these gantries heavy and bulky. These yokes are made

High-field Nb 3 Sn dipoles generating more than 15 T are strongly required, whether it is for the future circular collider studies (CERN 16 T Development Program, CEA-CERN demonstrator) or for test stations (FRESCA2, HEPDipo). The use of magnets graded with different cables now becomes unavoidable to allow for more compact and cost-effective designs. This article presents a 2-D parametric study, which

Synchronous machines are under consideration for applications on electrically propelled planes. Attractive features of such machines include high efficiency, low mass, and volume. To achieve these features, both rotor excitation field and ac stator winding coils employ superconductors. The dc field winding on the rotor experiences little harmonic fields. However, the stator winding, subjected to a

Angular behaviors of critical current density J c and n -values at 77 K, 1 T were investigated in YBCO films with columnar defects (CDs) tilted at small angles to the ab -plane before and after the additional introduction of CDs at different angles, where CDs were installed by heavy-ion irradiations. The enhanced J c at B || ab by the initial irradiation at θ i = ±85° relative to the c -axis was reduced

Ionized jet deposition (IJD) is a pulse electron deposition method. It can be used for the preparation of thin films from a wide spectrum of materials on different substrates. The main benefits of IJD are high flexibility and a possibility to change many of the deposition parameters. Some of them even during the deposition such as acceleration voltage, working gas, substrate temperature, etc. The wide

In order to improve in-field J c values of GdBCO CCs fabricated by the reactive co-evaporation by deposition and reaction (RCE-DR) process with the nominal composition of Gd:Ba:Cu = 1:1:2.5, the Gd 2 O 3 particles trapped in the GdBCO superconducting matrix were refined by controlling the nucleation and growth temperature of Gd 2 O 3 in the liquid phase before the growth of GdBCO film at the same growth

Microstructural and magnetic characterizations of YBa 2 Cu 3 O 7−δ nanowire fabric-like samples were performed. Fabric-like ceramic superconductors are nanoporous materials and can be applied, e.g., in magnetic shielding, since the porous morphology makes them extremely light-weight and effectively to be cooled. The samples were produced by the solution blow spinning (SBS) technique, starting from

The 1144 family of Iron Based Superconductors (IBSCs) is characterized by critical currents among the highest for single crystalline IBSCs. The synthesis of polycrystalline compounds is usually carried out through high temperature (T > 900 °C) processes. These methods, justified by a supposed thermodynamic instability of the 1144 phase at low temperature, are complicated by the presence of highly volatile

Internally oxidized Nb 3 Sn wires with artificial pinning centers (APC) have been developed by manufacturing a multifilament PIT-style wire, each filament consisting of a Nb-Ta-Zr alloy tube filled with a mixture of Sn, Cu, and oxide powders. During heat treatment, the oxide decomposes, and the oxygen goes into solid solution in the Nb alloy. Upon Sn diffusion into the Nb alloy, ZrO 2 nanoprecipitates

BaMO 3 (M = Zr, Hf) pinning centers introduced in REBa 2 Cu 3 O 7-x (REBCO and RE = rare earth) coated conductors yield superior performance in high magnetic fields. We present the critical current density Jc over a temperature range of 4.2–77 K and magnetic fields of 0–14 T ( B || c- axis), of 5-15 mol.% Zr- and Hf- added REBCO 4+ μm thick film tapes fabricated by advanced metal organic chemical vapor

Effective quench detection technologies are extremely important for protecting high temperature superconducting (HTS) applications. In recent years, an optical fiber encapsulated HTS tape (OF-tape) is proposed for quench detection by using distributed temperature sensing (DTS) technology. In this paper, an HTS coil (OF-coil) wound with a 39 m long OF-tape was prepared and energized by an AC overcurrent

Advanced metal organic chemical vapor deposition technique (A-MOCVD) was used to grow 4-5 μm thick REBa 2 Cu 3 O 7−δ (REBCO, RE = rare earth) films, doped with 5% and 15% Hf . Thick REBCO films doped with 5% Hf exhibit self-field critical current density ( Jc ) over 1.8 MA/cm 2 at 77 K and 3 MA/cm 2 at 65 K, 1.5 T. Increasing the Hf content to 15% resulted in Jc above 9 MA/cm 2 at 20 K, 9 T. The effect

Jelly-roll (JR) processed wires using metal thin foils as starting materials have excellent cold workability and drawability. We have successfully fabricated Nb/Al composite mono-core wires having 50 μm in outer diameter and over 400 meters in length. Furthermore, some of the wires were additionally drawn to 30 μm in outer diameter. It is known that the critical current density ( J c ) of Nb 3 Al synthesized

For extra-high-voltage high-temperature superconducting (HTS) cables, not only high electrical insulation performance but also low dielectric loss is required. Therefore, we focus on a porous synthetic paper with lower dielectric loss, e.g., Tyvek polyethylene nonwoven fabric, than that of polypropylene laminated paper (PPLP), which has been used for a conventional HTS cable insulation system. In this

High engineering critical current density ( JE of 1300 A/mm 2 at 4.2 K and 15 T) in Bi-2212 round wire has been achieved through a partial melt, overpressure heat treatment process. JE varies strongly with processing conditions, particularly the maximum heat treatment temperature ( T max ). Increasing T max results in longer time in the melt (defined as the time between when Bi-2212 melts on heating

The V-Ti alloys are promising materials as alternate to the commercial Nb-based superconductors for high current-high magnetic field applications. However, the critical current density ( J c ) of these alloys are somewhat low due to their low grain-boundary density. We show here that grain refinement of the V-Ti alloys and enhancement of the J c can be achieved by the addition of Gd into the system

This work reports the longitudinal thermal conductivity, κ, of Ag- and Cu/Ag-sheathed Ba 1-x K x Fe 2 As 2 conductors. Our investigation has been carried out between 4 K and 80 K with magnetic fields up to 19 T. In the case of Ag-sheathed tapes, the thermal conductivity reaches maximum values of ∼80 Wm −1 K −1 and is weakly dependent on the field. The use of Cu/Ag in the place of Ag allows increasing

Triaxial HTS AC power cables, that incorporates three HTS phases wound around a single core within a single cable is considering the optimal solution for low and medium voltages. Such a design permits to save expensive HTS conductor and to increase the power density transmitted. It is difficult to increase the transmission capacity of a triaxial cable by increasing its operating voltage and therefore

The achievement of low-resistance connection in REB 2 C 3 O 7-z (REBCO, RE = Y, Gd) coated conductors (CCs) has become one of the strategic factors for magnet applications. In this letter, we fabricated low-resistivity ( Rsj = 4.9 nΩ·cm 2 ) Ag-diffusion joints of REBCO CC by improving the interface connection of the Ag stabilizer. The effective contact area at the interface between two Ag stabilizers

We investigated the hardware implementation of an area-efficient superconducting lookup table (LUT) based on a single flux quantum (SFQ) logic by using a newly proposed small memory cell. The memory cell is composed of a nondestructive read-out (NDRO) flip-flop with input circuits that convert the input dc current to an SFQ pulse signal. The datum can be written to the selected memory cell in the 2-D

A method for modeling the superconducting state of an inhomogeneous film is proposed. The superconducting properties are changed by varying Ginzburg–Landau (GL) parameters over the film thickness. A system of 1-D equations was found using the standard minimization of the modified GL-free energy functional to describe the superconducting state of the inhomogeneous plate. Using the proposed method, the

In the framework of a design study for a post-LHC 100 TeV circular hadron collider, namely FCC-hh, high-gradient Nb 3 Sn lattice quadrupoles were investigated, following closely the specifications from the optic layout of that machine. After several iterations, a baseline design of the main quadrupole was selected and, then, included in the FCC-hh Conceptual Design Report. The article deals with the

High-temperature superconducting (HTS) cable has the merits of high capacity and small volume in the normal operation condition. However, the fault current, which could be 10–30 times of the nominal current, gives a great challenge to its thermal stability. Due to the overcurrent, the HTS tapes will quench to resistive state and result in generating large amount of heat, which may degrade or even damage

Superconducting 499.8-MHz radio frequency (rf) cavities have been proposed for the High Energy Photon Source (HEPS), a 6-GeV diffraction-limited synchrotron light source currently under construction in Beijing. Being an active third-harmonic system, two cavities shall provide 3.5-MV rf voltage and 400 kW of beam power to enable a complex rf gymnastics required by a novel injection scheme. Adopting

In the process of power compensation of the superconducting magnetic energy storage system (SMES) in the power grid, the existence of ac loss and eddy current loss will cause the magnet to heat up, and temperature rise is the main factor limiting the power output capability of SMES. This article proposes a state assessment method (SAM) that considers the temperature rise of the magnet. This method

Adiabatic quantum-flux-parametron (AQFP) logic is an energy-efficient superconductor logic family. In this article, we design binary counters, namely an up counter, a down counter, and an up/down counter, based on AQFP logic. These binary counters are T-flip-flop-based and count logic 1s in the input signal that is synchronized with excitation currents, which clock the counters. The internal state

Electrical machines with high-temperature superconducting (HTS) armature windings can benefit from high power density and efficiency. Furthermore, by using permanent magnets (PM) on the rotor, the cryogenic system can be significantly simplified compared with the fully superconducting (SC) machines or the machines with SC field windings. Compared with the conventional electrical machines, the performance

The second-generation high-temperature superconducting tapes (2G-HTS) such as the REBCO coated conductors are known for their strong mechanical properties and high current carrying capacity with low ac losses compared with first-generation HTS tapes as well as low-temperature superconductors. Therefore, they seem to be good candidates to assemble coils for superconducting rotating electric machines

Corrections were made to finanical support information for the above named paper.

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High temperature superconducting (HTS) coils have been designed for various applications such as magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR), and superconducting magnetic energy storage (SMES). Typically, the coils are in kilojoule range and have solenoid structure. These are mostly optimized with MATLAB and electromagnetic analysis using finite element method (FEM) software

This article evaluates the novel design approach of a 3 MW partially superconducting synchronous machine for electric aircraft propulsion. Its special feature is the application of an electromagnetic Halbach array for the field excitation to reduce the back yoke weight and thereby increase the overall output power density. The electromagnetic Halbach array is obtained by reproducing a permanent magnet

REBCO coated conductors are very promising for various HTS power applications. However, a detailed knowledge about their quench characteristics is crucial for developing effective quench detection methods. This article experimentally and numerically analyzed the quench propagation characteristics of REBCO coated conductors impregnated with different epoxy. The quench parameters, including minimum quench

Reversible logic gates were previously implemented in superconducting circuits as adiabatic-reversible gates, which are powered with a sufficiently slow clock. In contrast, we are studying ballistic-reversible gates, where fluxons serve to both encode the information and power the gates. No power is applied to the gate apart from the energy of the input fluxons, and the two possible flux polarities

In this article, present the first detailed study of cascade switching in superconducting photon number resolving detectors. The detectors were made in the form of four parallel nanowires, coupled with the single-mode optical fiber and mounted into a closed-cycle refrigerator with a temperature of 2.1 K. We found out the value of additional false pulses ( N cas.sw. ) appearing due to cascade switching

Using a 2-D/3-D mixed electrothermal model, the quench behavior of an YBa 2 Cu 3 O 7-δ (YBCO) pancake magnet is investigated for operating temperature 30–65 K. From many simulations, it is found when the hot spot temperature T peak rises to the range [120 K, 300 K], both T peak and the normal zone length L NZ behave like exponential functions of the longitudinal normal zone propagation velocity (NZPV)

The A-V formulation based iterative algorithm method (IAM), developed at Paul Scherrer Institute, shows excellent performance in modeling the critical state magnetization-current in the ReBCO tape stacks after field-cooling magnetization. This article upgrades the function of the IAM, making it realistic to take into account the widely used E – J power law, as well as to model the magnetization-current

Fast detection of quench in high-temperature superconductors (HTS) is essential for the application of HTS magnets due to the low normal zone propagation velocity (NZPV). In this work, quench measurement of single-HTS wires has been carried out at 80 K through gas cooling. We use both electrical and thermoelectric methods to verify the ability of fiber Bragg grating (FBG) sensors to be applied to quench

This article presents a numerical model based on the definition of the scalar and vector potentials to calculate the ac losses generated in a high-temperature superconductor coated conductor tape by an ac transport current and by an ac external magnetic field applied with a generic orientation. The material characteristics of the different layers of a reference tape are included in the model equations

REBCO cable-in-conduit conductors at the level of tens of kiloamperes are being developed for application in fusion magnets. One important aspect to study is their performance in the case of a quench event. A conductor should survive from such an event without over design; therefore, they should be properly optimized. Using a simulation model developed based on THEA code, we studied the parameters

A 4.7 T compact superconducting magnet system for active shielding animal magnetic resonance imaging scanner was designed in this work. The resulting magnet consists of nine coaxial coils symmetrical about the z -axis. The innermost main coils and outermost shielding coils were made up of six inner coils with the positive current direction and three outer coils with the negative current direction,

The H-formulation, used abundantly for the simulation of high-temperature superconductors, has shown to be a very versatile and easily implementable way of modeling electromagnetic phenomena involving superconducting materials. However, the simulation of a full vector field in current-free domains unnecessarily adds degrees of freedom to the model, thereby increasing computation times. In this contribution

This article presents a semianalytical modeling approach for ac losses computation in high-temperature superconducting (HTS) stacks and coils near ferromagnetic parts. The Brandt's model is combined with the equivalent current model to take into account of the proximity of ferromagnetic materials with finite relative permeability. Large stacks of HTS tapes are considered. A homogenization is applied

We report on the response of a monolithic high $\mathrm{T_{c}}$ transition-edge bolometer to about 3 mmWave for the first time. The detector structure consisting of 400-nm $\mathrm{YBa_{2}Cu_{3}O_{7-x}}$ (YBCO) film on buffered yttria stabilized zirconia substrate without any coupled antenna, shows bolometric type responsivity to the 3-mmWave radiation at its transition temperature. The YBCO thin film

Magnetic field monitoring devices are essential for studying and operating high-temperature superconducting (HTS) magnets. Apart from conventional Hall sensor, passive optical fiber sensor is also an option for magnetic field monitoring. In this article, we proposed a novel access based on yttrium iron garnet magneto-optic (YM) sensor, which is one kind of optical fiber sensors, to measure magnetic

A compact superconducting magnet was constructed for low-energy nuclear physics experiments at the RAON heavy-ion accelerator facility. Conduction-cooled Helmholtz coils with a radius of 40 cm generate a uniform magnetic field of up to 1.51 T at a current of 71 A. The magnet has two crossing beam windows that allows the beam to pass either parallel (solenoid mode) or perpendicular (dipole mode) to

The short-circuit fault current on the dc side affects the operation safety of the multiterminal flexible HVdc (MTDC) transmission system seriously. The resistance-type superconducting fault current limiter (RSFCL) has received extensive attention in limiting the dc impact current because it has a fast response speed and zero impedance at a steady state. At present, there are so many works on the simulations

It is of great industrial interest and academic importance to investigate current harmonics impacts on AC losses of superconductors, especially in large-scale power devices. However, only effect of amplitude of in-phase current harmonics on AC loss has been studied in the works of literature. We numerically characterized nonsinusoidal AC loss of superconducting tape carrying harmonic currents with

This article presents a theoretical investigation of a resistive superconducting fault current limiter (R-SFCL) operating in a medium-voltage network. The considered power system presents a high level of fault current as well as a high transient recovery voltage. The simulation result shows that the R-SFCL not only limits the fault current to a desirable value, but also improves transient recovery

The second-generation high-temperature superconductor REBCO is one of the most valuable candidates that meet the requirements of future magnetic confinement fusion device. Quench behavior of an improved high-current REBCO composite conductor is simulated by a 1-D finite element method. Indium-tin alloy foil placed in the gap between stabilizer, jacket, and superconducting tape stacks can significantly

This article reports a study to identify optimal synthesis parameters for a pure boron precursor prepared following a patented process developed at CNR-SPIN laboratories, performed in the framework of a collaboration between CNR-SPIN and CERN. Boron is a precursor that plays a crucial role in the MgB 2 wire manufacturing, as a consequence, the synthesis parameters of the superconducting phase have

AC loss from Roebel cables with high-temperature superconducting strands are comparatively less, and they possess large current carrying capacity since they have a transposed structure. However, the strands should be strong enough to withstand various types of external loads during their operation. The present work simulates the performance of the Roebel strand against an external tensile load using

High-temperature superconducting (HTS) power equipment and tests at present require operating temperatures higher than the liquid nitrogen (LN 2 ). LN 2 is an important cryogenic refrigerant and liquid insulation material, which is widely used in HTS equipment. Although pressurized LN 2 can achieve temperatures higher than 77 K, it requires the use of sealed pressure vessels. Thus, a liquid cryogen

This article presents a superconducting material based planar broadband 3-way Wilkinson power divider which can be used in the Josephson quantum voltage device for the voltage standards. The 3-way Wilkinson power divider aims to improve the integration of Josephson voltage device compared to the commonly used 2-way power divider. A two-stage λ /4 section on each branch is used to increase the bandwidth