Superconducting electronics often require high-density microwave interconnects capable of transporting signals between temperature stages with minimal loss, cross talk, and heat conduction. We report the design and fabrication of superconducting 53 wt% Nb-47 wt% Ti (Nb47Ti) FLexible coAXial ribbon cables (FLAX). The ten traces each consist of a ${\oslash}$ 0.076 mm NbTi inner conductor insulated with

The local thermal disturbance will produce a joule heat. When the joule heat is larger than the minimum quench energy (MQE), it will lead to the phenomenon of a quench. The same problem exists in stacked superconducting tapes. In this article, the defects in REBCO tapes were created using the bending method. The voltage and temperature traces were measured during the quench process. The quench characteristics

Bifilar coil is one of the most applicable structures used for resistive-type superconducting fault current limiter. However, the turn-to-turn (longitudinal) insulation of the bifilar coil under lightning and switching impulse is rather different from the conventional pancake coil. The longitudinal insulation is characterized as the distributed circuit of the coil under high-frequency excitation, and

The Bi-2212 round wire has a multifilamentary structure, and the use of numerical method to study ac loss of such multifilamentary superconducting wire requires a long calculation time and large memory. Adopting a homogenization method at low frequency to study the ac loss of multifilamentary structural wire/tape has been proven to have high enough accuracy and can save a lot of calculation time. With

Due to the excellent electromagnetic properties of superconductor materials, superconducting generators have higher efficiency, lower weight and volume than traditional rotating machines. However, it is difficult to simulate the electromagnetic behavior in the superconducting generator due to the nonlinear $E - J$ relationship. A numerical model based on the $T - A$ formulation and moving mesh method

For high temperature superconducting (HTS) dc cables, one key issue is the necessity of using polymer dielectrics with higher dielectric strength at cryogenic temperature in liquid nitrogen. Nanocomposites have played an important role in improving the dielectric properties of epoxy resin (EP). This article investigates on the dc breakdown strength and the surface potential behavior of the epoxy/Al

In this article, a stochastic finite-difference time-domain (S-FDTD) method is proposed for analyzing the influence of physical size uncertainty on the time-domain response of superconducting transmission lines. The formulations of the proposed method are, in detail, derived with the two-fluid model and London equation. A typical superconducting microstrip line is simulated to verify the effectiveness

The enhanced racetrack model coil and racetrack model magnet constitute the current R&D Nb $_3$ Sn magnets under development at CERN aiming to achieve dipole fields of 16–18 T, the design baseline of the Future Circular Collider. This article reports the mechanical behavior of their common support structure, which underwent three different levels of room-temperature preload (with the bladders and key

Iron-free twin-aperture superconducting quadrupole in the interaction region is a key technology to increase the luminosity of high-energy future colliders, such as the circular electron-positron collider that China will build in the next ten years with a center-of-mass energy of 240 GeV and a small crossing angle of 33 mrad in the interaction region. The final focusing quadrupole QD0, which is 2.2

The quench protection in high-temperature superconducting (HTS) magnets is a well-known issue. Therefore, it is fundamental to have reliable models available for the analysis of the quench propagation in such magnets. The quench propagation in an ENEA HTS cable-in-conduit conductor, developed for fusion applications with the particular reference to an insert for the central solenoid of the Italian

Superconductive passive transmission lines (PTL) are widely used for signal routing in large-scale rapid single flux quantum (RSFQ) circuits. Due to the imperfect matching of the transmission lines between the driver and receiver, single flux quantum (SFQ) pulses are partially reflected. The round trip propagation time of these reflections can coincide with the following SFQ pulse, resulting in a decrease

Nonlinear conductive composite insulation has been widely used to reduce nonuniformities in the local high electric field of high-voltage direct-current equipment. The silicon carbide (SiC)/epoxy resin composites with nonlinear conductivities have great potential applications in high temperature superconducting equipment. In this article, SiC/epoxy resin composites with different filler loading are

Modern space-based telescopes operating in the terahertz (THz) spectral range require highly reflecting and cryogenically cooled optics ensuring extremely low noise. The idea of using high-temperature superconductor YBa 2 Cu 3 O 7-δ as a telescope's mirror coating for providing low dissipation and high reflectivity of the surface for the subTHz frequency band has been explored. We are presenting here

A 10 kA high-temperature superconductor current lead (HTS-CL) using a double-tube stainless steel (SS) shunt has been designed, fabricated, and tested at Institute of plasma physics, Chinese Academy of Sciences (ASIPP). The current lead consists of 80 parallel the second generation HTS coated conductor with critical current of 220 A at 77 K in self-field, a double-tube SS shunt, and Cu connectors.

The R&D of the central solenoid model coil (CSMC) is preparatory toward the final fabrication of the Chinese fusion engineering test reactor central solenoid coil. CSMC is being designed and partly fabricated in the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). During the process, new manufacturing technologies are developed and some design optimization is proposed. Based on the

We describe a novel use for superconducting flux pumping, namely a method for magnetizing a planar magnetic field source. The method is useful for many applications, but we illustrate it with the planar Penning trap with applications in quantum technology. A flux pumping mechanism and associated mathematical model are described. The method allows for complete control of the induced persistent current

Long standing data from niobium thin-film accelerating cavities will be revisited and analyzed by a modified London model of radio-frequency (RF) superconductivity. First, the applicability of this model is explored using the data of the Bardeen–Cooper–Schrieffer (BCS) surface resistance and its dependence on the RF magnetic field, temperature, and mean free path. Second, the RF losses from the trapped

In the last few years, the current density of Bi-2212 wires has been greatly improved by filament densify technologies. One further step toward applications in fusion magnets is to design a high current cable, which must overcome the drawbacks of Bi-2212 wires: brittleness and complex heat treatment process. In this article, react-and-wind flat cables are proposed. With react-and-wind technique, a

Present superconducting accelerators require a central refrigeration system and piping to distribute liquid helium and nitrogen. Stand-alone cryocooler-based systems are of significant interest both to scientific and industrial customers, as they allow applications at facilities where no cryogenic equipment and expertise exists, where it is undesirable to develop additional cryogenic systems, or where

To utilize wave energy, we propose a power take-off device mainly composed of a novel buoy and a high-temperature superconducting synchronous reluctance linear generator (HTS-SRLG). We describe the conceptual structure and function of the buoy, which makes use of seawater to provide more power to the HTS-SRLG. Then, we introduce the configuration and the key electrical design process of the HTS-SRLG

Dynamic resistance is essential to evaluate the performance of high-temperature superconducting (HTS) coated conductors, especially when applied in synchronous electric machines and HTS flux pumps. The analytical expression of dynamic resistance has been proposed and verified in many cases, and it appears that dynamic resistance R dyn is in a linear correlation with transport current It and the amplitude

Superconducting $\beta$ =1 quarter-wave geometry of 166.6 MHz has been proposed as main accelerating cavities for the high-energy photon source (HEPS) storage ring. HEPS is a 6-GeV kilometer-scale synchrotron light source promising ultralow emittance currently being constructed in Beijing. A proof-of-principle cavity has been previously in-house developed and vertical-tested achieving excellent cryogenic

Trapped-flux magnets made of stacks of superconducting tapes are an interesting and important alternative to the application of rare-earth permanent magnets and trapping flux in bulk superconductors. Many applications, such as electric motors, can require the complex shapes of magnetic elements to combat issues such as demagnetization during the operation. Therefore, a reliable production technique

The purpose of this article is to estimate the magnetic field dependent critical current density scaling relation of NbTi used in a superconducting wire. The estimation problem is set using a finite element method based forward model solving the critical current of a wire in external magnetic fields. A sensitivity analysis is carried out to reveal the uncertainties in the process. It is shown that

An approach to merge superconducting Josephson junction (JJ) devices with nanoscale Graphene devices in order to achieve high gain-bandwidth-product on the order of THz is proposed. While JJ-based devices have existed since nearly 1962, interfacing or interacting with them with standard electrical systems has been a challenge for several reasons, including operating temperature, switching speed, and

A convenient method to permanently adjust the operating frequency of a microstrip superconducting quantum interference device amplifier (MSA) was investigated. An optical laser cutter was used to ablate the input coil of an MSA, bonded to a printed circuit board (PCB), to increase the MSA's operational frequency. During the ablation process, the MSA did not have to be electrically or physically decoupled

Temperature-dependent current transfer properties of copper (Cu)- and iron (Fe)-sheathed magnesium diboride (MgB $_2$ ) superconducting wires are studied by the estimation of current transfer length (CTL) and the electric field for various cross-sectional area combinations of the superconducting core, barrier, and outer metallic sheath. The result indicates that the CTL values increase with increasing

Superconducting energy pipeline is a novel type of cotransmission system of electric power and fuel. As an indispensable part of the energy pipeline, the heat leakage and thermal performance of current leads are critical for the efficiency and safety of the system. In this article, a design method of current leads with given heat flux was proposed and used, which provides a new idea of lead optimization

Superconducting electronics are promising candidates for complementing semiconductor electronics. However, a comprehensive suite of superconducting design and simulation tools that is necessary to streamline and automate the design process is either nonexistent or very limited. Here, we describe Synopsys’ advances in the technology computer-aided design (TCAD) front for physics-based simulation of

In this article, we present a miniature solid nitrogen cooling system designed for high-transition temperature (high- ${T_\mathrm{C}}$ ) superconductor Josephson devices operating in the temperature range of 40–55 K. The system utilizes a small fiberglass Dewar and an external pump to solidify nitrogen in thermal contact with a circuit board insert. Our cooling tests of two different Dewars with 100 mL

The use of a high-Tc (HTS) rf-superconducting quantum interference device (SQUID) for inspecting the liquid component of lithium-ion (Li-ion) batteries is proposed. It is possible that a small amount of metal can become mixed in with components of Li-ion batteries during the manufacturing process and contaminate them, with a resultant fire risk, Thus, the development of a highly sensitive inspection

Thermal effect will greatly affect the engineering performance of high-temperature superconductors (HTSs) due to its strong dependence of electromagnetic parameters upon the local temperature. To advance the understanding of such thermal effects, a validated 3-D strong-coupled electromagnetic-thermal model for HTS bulk was established in commercial finite-element software COMSOL, which ensures the

Superconducting radio frequency (SRF) cavities are often limited by thermal quench, which is an excessive electromagnetic heating that occurs in the high magnetic field area and expands thereafter forcing the cavity to lose its superconducting state. In this article, we demonstrate how the quench phenomena can be modeled using a coupled electromagnetic thermal analysis. The proposed model takes into

Superconducting gas-insulated transmission line (S-GIL) concept for high-temperature superconducting (HTS) power cables was developed with practical designs that use tubular insulator spacers. The implications of spacer materials and designs were studied in terms of electric field enhancement and its role in limiting the maximum withstand voltage. Three different tubular insulator materials and two

To resist the alternating electromagnetic loads, the International Thermonuclear Experimental Reactor (ITER) correction coils are protected by a 20-mm-thick 316LN austenitic stainless steel case. According to the strict tolerance requirement of the case manufacture, laser welding was applied to enclosure welding of the cases with a 20-kW high-power laser for root pass and Tungsten Inert Gas welding

This article maps the magnetic field within a type-II superconductor of finite dimension that is magnetically flux-pinned. The measured field is lower in magnitude than anticipated from the frozen image model and changes shape dependent on the field-cooled image location. A proposed refined model more accurately reflects the measured field.

We present time-domain electrical measurements and simulations of the quantized voltage pulses that are generated from series-connected Josephson junction (JJ) arrays. The transmission delay of the JJ array can lead to a broadening of the net output pulse, depending on the direction of the output pulse propagation relative to the input bias pulse. To demonstrate this, we compare time-domain measurements

Readout of a large, spacecraft-based array of superconducting transition-edge sensors (TESs) requires careful management of the layout area and power dissipation of the cryogenic-circuit components. We present three optimizations of our time- (TDM) and code-division-multiplexing (CDM) systems for the X-ray Integral Field Unit (X-IFU), a several-thousand-pixel-TES array for the planned Athena-satellite

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

We present experimental and numerical studies on a method to mitigate screening current-induced field (SCF) for NI REBCO coil. The SCF is the major field error to incorporate a REBCO insert for a high field LTS/HTS magnet. The field-shaking technique is going to be used to mitigate the SCF of 800-MHz REBCO insert magnet (H800) for MIT 1.3-GHz LTS/HTS NMR magnet (1.3 G). The field-shaking using 500-MHz

Time-division multiplexing (TDM) is the backup readout technology for the X-ray Integral Field Unit (X-IFU), a 3,168-pixel X-ray transition-edge sensor (TES) array that will provide imaging spectroscopy for ESA's Athena satellite mission. X-0IFU design studies are considering readout with a multiplexing factor of up to 40. We present data showing 40-row TDM readout (32 TES rows + 8 repeats of the last

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 MgB2 coils, one superconducting joint, and a persistent-current switch (PCS) built from a portion of one coil, was wound with a one continuous ~80-m

We present assembly and test results of a 3-nested-coil 800-MHz (18.8 T) REBCO insert (H800) for the MIT 1.3 GHz LTS/HTS NMR magnet currently under completion. Each of the three H800 coils is a stack of no-insulation (NI) REBCO double-pancake coils (DPs). The innermost 8.7-T Coil 1 (26 DPs) was completed by mid-2016; the middle 5.6-T Coil 2 (32 DPs) was complet-ed in mid-2017; while the outermost 4

We present a design study of a liquid-helium (LHe)-free 23.5-T, ϕ25-mm RT-bore REBCO magnet for high-resolution 1-GHz microcoil nuclear magnetic resonance (NMR) spectroscopy. A microcoil NMR magnet is compact and thus its cost will be less by nearly an order of magnitude than that of the standard NMR magnet, and placeable on a bench, thereby resulting in a large saving in space. In addition, LHe-free

We present post-quench analyses of the MIT 800-MHz REBCO insert magnet (H800), unexpectedly quenched during operation in March 2018, and design study of a new 800-MHz HTS insert (H800N). The as-wound H800 was supposed to contribute 18.7 T and, with an LTS background magnet (L500), produce 30.5 T corresponding to a proton resonance frequency of 1.3 GHz. The H800 was operated at 4.2 K in liquid helium

The MIT 1.3-GHz LTS/HTS NMR magnet is currently under development. The unique features of this magnet include a 3-nested formation for an 800-MHz REBCO insert (H800) and the no-insulation (NI) winding technique for H800 coils. Because when it is driven to the normal state, an NI REBCO magnet will respond electromagnetically, thermally, and mechanically that may result in permanent magnet damage, analysis

Strategies are explored to reduce the electromagnetic simulation time of electrically large superconducting transmission line structures while retaining model accuracy. The complex surface reactance of an infinite thin-film superconducting sheet is evaluated with the BCS (Bardeen-Cooper-Schrieffer) theory and used as an input to model the phase velocity and characteristic impedance of finite width

In this paper we present design, construction, and preliminary results of a proof-of-concept prototype of high-temperature superconductor (HTS) shim coils operated at 77 K and energized, for the first time among all shim coils, by a flux pump, here called digital flux injector (DFI). Although the prototype shims were wound with 2-mm wide REBCO tape, and DFI with Bi2223 and REBCO tapes, the HTS Z1 and

In 2005 the Committee on Opportunities in High Magnetic Fields (COHMAG) issued a challenge to develop a 30 T high-resolution NMR magnet. In response, the National High Magnetic Field Laboratory (NHMFL) is investigating all three commercially available high-temperature superconductors (HTS) including REBCO, Bi-2212 and most recently, a reinforced Bi-2223 conductor supplied by Sumitomo Electric, designated

We present design and test results for a thermally-activated persistent-current switch (PCS) applied to a double pancake (DP) coil (151 mm ID, 172 mm OD), wound, using the no-insulation (NI) technique, from a 120-m long, 76-μm thick, 6-mm wide REBCO tape. For the experiments reported in this paper, the NI DP assembly was immersed in a volume of solid nitrogen (SN2), cooled to a base temperature of

In this paper, we present experimental results, of a small-model study, from which we plan to develop and apply a full-scale field-shaking system to reduce the screening current-induced field (SCF) in the 800-MHz HTS Insert (H800) of the MIT 1.3-GHz LTS/HTS NMR magnet (1.3G) currently under construction-the H800 is composed of 3 nested coils, each a stack of no-insulation (NI) REBCO double-pancakes

We present construction and test results of Coils 2 and 3 of a 3-coil 800-MHz REBCO insert (H800) for the MIT 1.3 GHz LTS/HTS NMR magnet currently under construction. Each of three H800 coils (Coils 1-3) is a stack of no-insulation REBCO double pancakes (DPs). The innermost 8.67-T Coil 1 (26 DPs) was completed in 2016; the middle 5.64-T Coil 2 (32 DPs) has been wound, assembled, and tested; and for

In this paper we present two design options for a tabletop liquid-helium-free, persistent-mode 1.5-T/90-mm MgB2 "finger" MRI magnet for osteoporosis screening. Both designs, one with and the other without an iron yoke, satisfy the following criteria: 1) 1.5-T center field with a 90-mm room-temperature bore for a finger to be placed at the magnet center; 2) spatial field homogeneity of <5 ppm over a

Nuclear Magnetic Resonance (NMR) probes based on High Temperature Superconducting (HTS) resonators have demonstrated significant gains in detection sensitivity. However, the widespread acceptance of this technology has been limited by some unresolved issues including the mechanical unreliability of the moveable inductive loops used to adjust tuning and matching. In order to improve reliability, we

This paper focuses on the construction and test results of Coil 2 that is part of a trio of nested coils composing the REBCO 800 MHz insert. Upon its completion, the REBCO 800 MHz insert will be placed in the bore of a 500 MHz low temperature superconducting (LTS) NMR magnet (L500) to form the MIT 1.3 GHz high-resolution NMR magnet. Coil 2 is a stack of 32 double pancake (DP) coils wound with 6-mm

A 1.3-GHz/54-mm LTS/HTS NMR magnet, assembled with a 3-coil (Coils 1-3) 800-MHz HTS insert in a 500-MHz LTS NMR magnet, is under construction. The innermost HTS insert Coil 1 has a stack of 26 no-insulation (NI) double pancake (DP) coils wound of 6-mm wide and 75-μm thick REBCO tapes. In order to keep the hoop strains on REBCO tape < 0.6% at an operating current Iop of 250 A and in a field of 30.5

Standard in-situ type MgB2 strands manufactured by Hyper Tech Inc have 19 - 36 subelements, a monel outer sheath, and a Cu interfilamentary matrix. Typical transport Jc s of the strands are 2×105 A/cm2 with n-values of 20 - 30 at 4.2 K and 5 T. This work introduces two new MgB2 conductor designs. First, a new class of MgB2 strand is designed for magnetic resonance imaging applications. This type has

We are developing superconducting transition-edge sensor (TES) microcalorimeter focal planes for versatility in meeting specifications of X-ray imaging spectrometers including high count-rate, high energy resolution, and large field-of-view. In particular, a focal plane composed of two sub-arrays: one of fine-pitch, high count-rate devices and the other of slower, larger pixels with similar energy

We describe the implementation of new commercial pulse-bias electronics that have enabled an improvement in the generation of quantum-accurate waveforms both with and without low-frequency compensation biases. We have used these electronics to apply a multilevel pulse bias to the Josephson arbitrary waveform synthesizer and have generated, for the first time, a quantum-accurate bipolar sinusoidal waveform

Bi2Sr2CaCu2Ox (Bi-2212) conductor is the only high temperature superconductor manufactured as a round wire and is a very promising conductor for very high field applications. One of the key design parameters of Bi-2212 wire is its filament size, which has been previously reported to affect the critical current density (Jc ) and ac losses. Work with 1 bar heat treatment showed that the optimal filament