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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Control of microphonics for a superconducting radio-frequency photo-injector cryomodule

A superconducting radio-frequency photo-injector cryomodule is being developed for the high-energy upgrade of the Linac Coherent Light Source (LCLS-II-HE). This effort is a collaboration between the Facility for Rare Isotope Beams at Michigan State University (MSU), Argonne National Laboratory, Helmholtz-Zentrum Dresden-Rossendorf, and SLAC National Accelerator Laboratory. The cryomodule features a 185.7 MHz superconducting quarter-wave resonator (QWR) designed to operate with an RF electric field of 30 MV/m at the photo-cathode. Mechanical vibrations must be controlled for operation with stable amplitude and phase. The first prototype cryomodule was cold-tested at MSU with a QWR, fundamental power coupler, tuner, and cathode stalk. In the cold test, we observed microphonics that made it difficult to control the RF phase at high gradient. The cryogenic circuit was identified as a likely culprit. This paper presents our studies of microphonics during the cryomodule cold test and follow-up investigations at room temperature. Our findings provided valuable feedback for modifications to the cryogenic circuit and a successful second cold test of the cryomodule.

Accelerator Physics↗
DOE OSTI2022

Preferred Spin Excitations in the Bilayer Iron-Based Superconductor $CaK(Fe_{0.96}Ni_{0.04})_4As_4$ with Spin-Vortex Crystal Order

Spin-orbit coupling (SOC) is a key to understand the magnetically driven superconductivity in iron-based superconductors, where both local and itinerant electrons are present and the orbital angular momentum is not completely quenched. Here, we report a neutron scattering study on the bilayer compound CaK(Fe 0.96 Ni 0.04 ) 4 As 4 with superconductivity coexisting with a noncollinear spin-vortex crystal magnetic order that preserves the tetragonal symmetry of the Fe-Fe plane. In the superconducting state, two spin resonance modes with odd and even L symmetries due to the bilayer coupling are found similar to the undoped compound CaKFe 4 As 4 but at lower energies. Polarization analysis reveals that the odd mode is c-axis polarized, and the low-energy spin anisotropy can persist to the paramagnetic phase at high temperature, which closely resembles other systems with in-plane collinear and c-axis biaxial magnetic orders. Overall, these results provide the missing piece of the puzzle on the SOC effect in iron-pnictide superconductors, and also establish a common picture of c-axis preferred magnetic excitations below T c regardless of the details of magnetic pattern or lattice symmetry.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Anisotropic effect of a magnetic field on the neutron spin resonance in FeSe

We use inelastic neutron scattering to study the effect of a magnetic field on the neutron spin resonance (E r = 3.6 meV) of superconducting FeSe (T c = 9 K). While a field aligned along the in-plane direction broadens and suppresses the resonance, a c-axis aligned field does so much more efficiently, consistent with the anisotropic field-induced suppression of the superfluid density from the heat capacity measurements. These results suggest that the resonance in FeSe is associated with the superconducting electrons arising from orbital selective quasiparticle excitations between the hole and electron Fermi surfaces.

36 MATERIALS SCIENCE↗
NASA NTRS1991

Superconducting Microwave Electronics at Lewis Research Center

Over the last three years, NASA Lewis Research Center has investigated the application of newly discovered high temperature superconductors to microwave electronics. Using thin films of YBa2Cu3O7-delta and Tl2Ca2Ba2Cu3Ox deposited on a variety of substrates, including strontium titanate, lanthanum gallate, lanthanum aluminate and magnesium oxide, a number of microwave circuits have been fabricated and evaluated. These include a cavity resonator at 60 GHz, microstrip resonators at 35 GHz, a superconducting antenna array at 35 GHz, a dielectric resonator at 9 GHz, and a microstrip filter at 5 GHz. Performance of some of these circuits as well as suggestions for other applications are reported.

Warner, Joseph D.↗
DOE OSTI2025

Beyond-Hubbard Pairing in a Cuprate Ladder

The Hubbard model is believed to capture the essential physics of cuprate superconductors. However, recent theoretical studies suggest that it fails to reproduce a robust and homogeneous superconducting ground state. Here, using resonant inelastic x-ray scattering and density matrix renormalization group calculations, we show that magnetic excitations in the prototypical cuprate ladder Sr 14 Cu 24 O 41 are inconsistent with those of a simple Hubbard model. The magnetic response of hole carriers, contributing to an emergent branch of spin-flip excitations, is strongly suppressed. This effect is the consequence of strong d -wavelike pairing, enhanced by nearly an order of magnitude through a large nearest-neighbor attractive interaction and persisting up to at least 260 K. The close connection between the physics of cuprate ladders and that of the two-dimensional compounds suggests that such an enhanced hole pairing may be a universal feature of superconducting cuprates. Published by the American Physical Society 2025

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Bidirectional Multiphoton Communication between Remote Superconducting Nodes

Quantum communication test beds provide a useful resource for experimentally investigating a variety of communication protocols. Here we demonstrate a superconducting circuit test bed with bidirectional multiphoton state transfer capability using time -domain shaped wave packets. Further, the system we use to achieve this comprises two remote nodes, each including a tunable superconducting transmon qubit and a tunable microwave -frequency resonator, linked by a 2 m-long superconducting coplanar waveguide, which serves as a transmission line. We transfer both individual and superposition Fock states between the two remote nodes, and additionally show that this bidirectional state transfer can be done simultaneously, as well as being used to entangle elements in the two nodes.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Facility upgrade for superheavy-element research at RIKEN

The RIKEN Nishina Center (RNC) executed an accelerator upgrade project for the heavy-ion linac (called RILAC). A superconducting RIKEN linear accelerator (SRILAC) and a new superconducting electron-cyclotron-resonance ion source (SC-ECRIS) to boost the final energy and intensity were constructed, aimed at synthesizing a new superheavy element, 119, through a hot fusion reaction. The project included the construction of a gas-filled recoil ion separator (GARIS-III) suitable for detecting the residues of the hot-fusion reaction. To avoid research interruption during the SRILAC construction period (2017–2019) and gain experience in hot-fusion reaction processes, GARIS-II located in the GARIS experimental hall in LINAC building was moved to the E6 experimental hall in Nishina building. Certain exploratory measurements were performed employing the beams accelerated by RILAC2 and the RIKEN ring cyclotron (RRC), which is a part of the existing accelerator complex of the radioactive isotope beam factory (RIBF). Further, commissioning experiments with the upgraded facility (SRILAC and GARIS-III) were performed. The upgrade project and its commissioning results are chronologically described in this article.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Design of an ultra-low mode volume piezo-optomechanical quantum transducer

Coherent transduction of quantum states from the microwave to the optical domain can play a key role in quantum networking and distributed quantum computing. We present the design of a piezo-optomechanical device formed in a hybrid lithium niobate on silicon platform, that is suitable for microwave-to-optical quantum transduction. Our design is based on acoustic hybridization of an ultra-low mode volume piezoacoustic cavity with an optomechanical crystal cavity. The strong piezoelectric nature of lithium niobate allows us to mediate transduction via an acoustic mode which only minimally interacts with the lithium niobate, and is predominantly silicon-like, with very low electrical and acoustic loss. We estimate that this transducer can realize an intrinsic conversion efficiency of up to 35% with <0.5 added noise quanta when resonantly coupled to a superconducting transmon qubit and operated in pulsed mode at 10 kHz repetition rate. The performance improvement gained in such hybrid lithium niobate-silicon transducers make them suitable for heralded entanglement of qubits between superconducting quantum processors connected by optical fiber links.

Chiappina, Piero↗
DOE OSTI2026

CHARACTERIZING AND CONTROLLING RECOVERY AND RECRYSTALLIZATION IN NIOBIUM FOR IMPROVED SRF CAVITY PERFORMANCE

Crystal defects, such as dislocations and low-angle boundaries, provide sources of magnetic flux trapping in the Nb materials used for superconducting radio frequency (SRF) resonating cavities. Improving the performance of SRF cavities, as measured through the quality factor, requires reducing these defects. SRF cavity production involves deformation processing, such as rolling and forming, and strategic annealing heat treatments. The resulting microstructures can be recovered, recrystallized, or both. Because recovery leaves many defects that can trap flux, recrystallization should improve cavity performance. Thus, processing schedules that produce complete recrystallization without excessive grain growth need to be designed. Solutions to this problem require understanding physical metallurgy and differentiating between recovered and recrystallized regions of microstructure. Backscattered electron microscopy techniques are applied to this end. We demonstrate that the conditions required to produce fully recrystallized microstructures depend on Nb impurity content, suggesting that processing schedules may need to be adjusted by material heat or lot. We also demonstrate that processing can be used to control growth of recrystallized grains to maintain mechanical strength in fully recrystallized materials. Forming cavities from cold-rolled Nb sheet material may provide strategic new routes to obtain microstructures that improve SRF cavity performance.

Taleff, E. [The University of Texas at Austin]↗
DOE OSTI2024

Cold Test Results of Pre-Production PIP-II SSR2 Cavities with High-Power Coupler in the Fermilab Spoke Test Cryostat

As part of the PIP-II project at Fermilab, a pre-production cryomodule featuring 325 MHz Single Spoke Resonator type 2 (SSR2) superconducting RF cavities is under construction. These SSR2 cavities are fabricated by industry partners and undergo initial cold testing at our collaborating institution, IJCLab in France, utilizing low-power coupler. Subsequently, the cavities are subjected to final qualification at Fermilab, complete with tuner and high-power coupler assemblies. This paper provides an overview of the ongoing efforts dedicated to high-power testing of jacketed SSR2 cavities in the Spoke Test Cryostat (STC) at Fermilab. Performance parameters obtained from these tests are presented, offering valuable insights into the cavities operational characteristics and readiness for integration into the PIP-II cryomodule.

Sukhanov, A.↗
NASA NTRS2016

Design Overview of the DM Radio Pathfinder Experiment

We introduce the DM Radio, a dual search for axion and hidden photon dark matter using a tunable superconducting lumped-element resonator. We discuss the prototype DM Radio Pathfinder experiment, which will probe hidden photons in the 500 peV (100 kHz)-50 neV (10 MHz) mass range. We detail the design of the various components: the LC resonant detector, the resonant frequency tuning procedure, the differential SQUID readout circuit, the shielding, and the cryogenic mounting structure. We present the current status of the pathfinder experiment and illustrate it's potential science reach in the context of the larger experimental program.

axion↗
DOE OSTI2020

Quantum coherent devices with reduced energy dissipation

The disclosed technology can be used to increase lifetimes of quantum coherent devices such as qubits including transmons and xmons and to reduce the losses in resonators. Energy stored in superconducting devices can be lost by emission of phonons that couple to the environment. Defects in one or more materials in the quantum coherent device can cause the coupling to phonons. Patterning one or more of the layers creates a phononic bandgap that reduces or eliminates the emission of the phonons to the environment. The energy then couples back to the quantum coherent device.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Cold Test Results of Pre-Production PIP-II SSR2 Cavities with High-Power Couplers in the Fermilab Spoke Test Cryostat

As part of the PIP-II project at Fermilab, a pre-production cryomodule featuring 325 MHz Single Spoke Resonator type 2 (SSR2) superconducting RF cavities is under construction. These SSR2 cavities are fabricated by industry partners and undergo initial cold testing at our collaborating institution, IJCLab in France, utilizing low-power coupler. Subsequently, the cavities are subjected to final qualification at Fermilab, complete with tuner and high-power coupler assemblies. This paper provides an overview of the ongoing efforts dedicated to high-power testing of jacketed SSR2 cavities in the Spoke Test Cryostat (STC) at Fermilab. Performance parameters obtained from these tests are presented, offering valuable insights into the cavities operational characteristics and readiness for integration into the PIP-II cryomodule.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

A Broadband Mechanically Tuned Superconducting Cavity Design Suitable for the Fermilab Main Injector

Radio Frequency superconductivity has been a mainstay of accelerator science for decades. However, its benefits have yet to be applied to proton synchrotrons with demanding tuning requirements. For example, the Main Injector (MI), Fermilab's high-energy proton synchrotron, currently utilizes 20+ ferrite-loaded cavities for a targeted 1.2 s acceleration cycle. Harnessing the extremely high gradients associated with superconductivity, the required number of cavities could be reduced by an order of magnitude, dramatically lowering operational power requirements even with cryogenic considerations. Additionally, the current plans for the Fermilab accelerator complex evolution initiative involve almost doubling the number of cavities in MI if the same designs are to be used, further highlighting the potential benefits of superconductivity. These advantages are attractive, but to date, no tunable superconducting cavity suitable for MI has been proposed due to the incompatibility of conventional broadband tuning methods with superconductivity. Here, we present a tunable superconducting cavity concept capable of record-breaking performance. Tuning will be accomplished by using high-speed linear actuators to vary the insertion depth of metallic plungers into the cavity volume. This tuning concept is theoretically viable with currently available technology and will be fully compatible with a superconducting cavity.

43 PARTICLE ACCELERATORS↗
DOE OSTI2026

Tantalum alloy–based resonators for quantum information systems

Utilizing tantalum (Ta) in superconducting circuits has led to significant improvements, such as high qubit lifetime (T 1 ) and quality factors in both qubits and resonators, suggesting that material optimization plays an important role in the development of superconducting circuits. Thus we here explore superconducting gap engineering in Ta-based devices as a powerful strategy for expanding the range of suitable host materials. By alloying 20 atomic percent (at.%) hafnium into Ta thin films, we achieve a superconducting transition temperature (T c ) of 6.09 K as observed in direct current (DC) transport measurements, reflecting an increase in the superconducting gap. We systematically vary deposition conditions to control film orientation and transport properties of Ta-Hf alloy thin films. We then confirm the enhancement in T c via microwave measurements at millikelvin temperatures. We verify the ~40 increase in T c relative to bare Ta devices, while the loss contributions from two-level systems and quasi-particles remain unchanged in the low temperature regime. These findings emphasize the promise of material engineering in superconducting circuits and point to many potential material candidates for further exploration.

Ta-Hf alloy thin films↗
DOE OSTI2020

Impact of nematicity on the relationship between antiferromagnetic fluctuations and superconductivity in FeSe 0.91 S 0.09 under pressure

The sulfur-substituted FeSe system, FeSe 1 - x S x , provides a versatile platform for studying the relationship among nematicity, antiferromagnetism, and superconductivity. Herein, by nuclear magnetic resonance (NMR) and resistivity measurements up to 4.73 GPa on FeSe 0.91 S 0.09 , we established the pressure- ( p -) temperature ( T ) phase diagram in which the nematic state is suppressed with pressure showing a nematic quantum phase transition (QPT) around p = 0.5 GPa , two superconductivity (SC) regions separated by the QPT appear, and antiferromagnetic (AFM) phase emerges above ~ 3.3 GPa . From the NMR results up to 2.1 GPa, AFM fluctuations are revealed to be characterized by the stripe-type wave vector which remains the same for the two SC regions. Furthermore, the electronic state is discovered to change in character from non-Fermi liquid to Fermi liquid around the nematic QPT and persists up to ~ 2.1 GPa . In addition, although the AFM fluctuations correlate with T c in both SC states, demonstrating the importance of the AFM fluctuations for the appearance of SC in the system, we found that, when nematic order is absent, T c is strongly correlated with the AFM fluctuations whereas T c weakly depends on the AFM fluctuations when nematic order is present. Our findings on FeSe 0.91 S 0.09 were shown to be applied to the whole FeSe 1 - x S x system and offer an insight into the relationship between AFM fluctuations and SC in Fe-based superconductors.

36 MATERIALS SCIENCE↗