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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Zero-bias conductance peaks at zero applied magnetic field due to stray fields from integrated micromagnets in hybrid nanowire quantum dots

Many recipes for realizing topological superconductivity rely on broken time-reversal symmetry, which is often attained by applying a substantial external magnetic field. Alternatively, using magnetic materials can offer advantages through low-field operation and design flexibility on the nanoscale. Mechanisms for lifting spin degeneracy include exchange coupling, spin-dependent scattering, spin injection – all requiring direct contact between the bulk or induced superconductor and a magnetic material. Here, we implement locally broken time-reversal symmetry through dipolar coupling from nearby micromagnets to superconductor-semiconductor hybrid nanowire devices. Josephson supercurrent is hysteretic due to micromagnets switching. At or around zero external magnetic field, we observe an extended presence of Andreev bound states near zero voltage bias. We also show a zero-bias peak plateau of a non-quantized value. Our findings largely reproduce earlier results where similar effects were presented in the context of topological superconductivity in a homogeneous wire, and attributed to more exotic time-reversal breaking mechanisms [Nat. Phys. 17, 43 (2020)]. In contrast, our stray field profiles are not designed to create Majorana modes, and our data are compatible with a straightforward interpretation in terms of trivial states in quantum dots. At the same time, the use of micromagnets in hybrid superconductor-semiconductor devices shows promise for future experiments on topological superconductivity.

Jiang, Luyao [Univ. of Pittsburgh, PA (United Stat↗
DOE OSTI2023

Electro-optic transduction in silicon via gigahertz-frequency nanomechanics

Interfacing electronics with optical fiber networks is key to the long-distance transfer of classical and quantum information. Piezo-optomechanical transducers enable such interfaces by using gigahertz-frequency acoustic vibrations as mediators for converting microwave photons to optical photons via the combination of optomechanical and piezoelectric interactions. However, despite successful demonstrations, efficient quantum transduction remains out of reach due to the challenges associated with hybrid material integration and increased loss from piezoelectric materials when operating in the quantum regime. Here, we demonstrate an alternative approach in which we actuate 5-GHz phonons in a conventional silicon-on-insulator platform. In our experiment, microwave photons resonantly drive a phononic crystal oscillator via the electrostatic force realized in a charge-biased narrow-gap capacitor. The mechanical vibrations are subsequently transferred via a phonon waveguide to an optomechanical cavity, where they transform into optical photons in the sideband of a pump laser field. Operating at room temperature and atmospheric pressure, we measure a microwave-to-optical photon conversion efficiency of 1.72±0.14×10 −7 in a 3.3 MHz bandwidth. Our results mark a stepping stone towards quantum transduction with integrated devices made from crystalline silicon, which promise efficient high-bandwidth operation and integration with superconducting qubits. Additionally, the lack of need for piezoelectricity or other intrinsic nonlinearities makes our approach applicable to a wide range of materials for potential applications beyond quantum technologies.

42 ENGINEERING↗
DOE OSTI2015

SU-E-T-195: Commissioning the Neutron Production of a Varian TrueBeam Linac

Purpose: The purpose of this work is the characterization of a new Varian TrueBeam™ facility in terms of neutron production, in order to estimate neutron equivalent dose in organs during radiotherapy treatments. Methods: The existing methodology [1] was used with the reference SRAMnd detector, calibrated in terms of thermal neutron fluence at the reference field operated by PTB (Physikalisch-Technische-Bundesanstalt) at the GeNF (Geesthacht-Neutron-Facility) with the GKSS reactor FRG-1 [2]. Thermal neutron fluence for the 5 available possibilities was evaluated: 15 MV and 10&6 MV with and without Flattening Filter (FF and FFF, respectively). Irradiation conditions are as described in [3]. In addition, three different collimator-MLC configurations were studied for 15 MV: (a) collimator of 10×10 cm{sup 2} and MLC fully retracted (reference), (b) field sizes of 20×20 cm{sup 2} and 10×10 cm{sup 2} for collimator and MLC respectively, and (c) collimator and MLC aperture of 10×10 cm{sup 2}. Results: Thermal fluence rate at the “reference point” [3], as a consequence of the neutron production, obtained for (a) conformation in 15 MV is (1.45±0.11) x10{sup 4} n•cm{sup 2}/MU. Configurations (b) and (c) gave fluences of 96.6% and 97.8% of the reference (a). Neutron production decreases up to 8.6% and 5.7% for the 10 MV FF and FFF beams, respectively. Finally, it decreases up to 2.8% and 0.1% for the 6 MV FF and FFF modes, respectively. Conclusion: This work evaluates thermal neutron production of Varian TrueBeam™ system for organ equivalent dose estimation. The small difference in collimator-MLC configuration shows the universality of the methodology [3]. A decrease in this production is shown when decreasing energy from 15 to 10 MV and an almost negligible production was found for 6 MV. Moreover, a lower neutron contribution is observed for the FFF modes.[1]Phys Med Biol,2012;57:6167–6191.[2]Radiat Meas,2010;45:1513–1517.[3]Med Phys,2015;42:276–281.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2019

Puget Sound Energy Glacier Energy Storage System: An Assessment of Battery Technical Performance

This report investigates the technical performance of the Glacier BESS facility, consisting of one 2 MW, 4 MWh BESS, based on a number of baseline and use case tests. Baseline tests were intended to assess the general technical capability of the BESS (e.g., stored energy capacity, ramp rate performance, ability to track varying charge/discharge commands, direct current (DC) battery internal resistance). Use case tests were used to examine the performance of the BESS while engaged in specific economic services (e.g., arbitrage, power factor correction). The project measured and/or calculated parameters that are important for understanding BESS performance when subjected to actual field operation for achieving economic benefits, e.g., round trip efficiency (RTE) with and without rest, with and without auxiliary loads, auxiliary power consumption, signal command tracking performance, temperature variations, parasitic power loss during power electronics switching during rest, and state of charge (SOC) excursions. These baseline and use case parameters were analyzed using recorded test results. In addition, the results and lessons presented herein are also beneficial for any task or effort that needs technical assessment on similar and different types of BESS based on field deployment results, since the assessment methodology remains the same.

25 ENERGY STORAGE↗
DOE OSTI2014

Next Generation Environmentally-Friendly Driving Feedback Systems Research and Development

The objective of this project is to design, develop, and demonstrate a next-generation, federal safety- and emission-complaint driving feedback system that can be deployed across the existing vehicle fleet and improve fleet average fuel efficiency by at least 2%. The project objective was achieved with the driving feedback system that encourages fuel-efficient vehicle travel and operation through: 1) Eco-Routing Navigation module that suggests the most fuel-efficient route from one stop to the next, 2) Eco-Driving Feedback module that provides sensible information, recommendation, and warning regarding fuel-efficient vehicle operation, and 3) Eco-Score and Eco-Rank module that provides a means for driving performance tracking, self-evaluation, and peer comparison. The system also collects and stores vehicle travel and operation data, which are used by Algorithm Updating module to customize the other modules for specific vehicles and adapts them to specific drivers over time. The driving feedback system was designed and developed as an aftermarket technology that can be retrofitted to vehicles in the existing fleet. It consists of a mobile application for smart devices running Android operating system, a vehicle on-board diagnostics connector, and a data server. While the system receives and utilizes real-time vehicle and engine data from the vehicle’s controller area network bus through the vehicle’s on-board diagnostic connector, it does not modify or interfere with the vehicle’s controller area network bus, and thus, is in compliance with federal safety and emission regulations. The driving feedback system was demonstrated and then installed on 45 vehicles from three different fleets for field operational test. These include 15 private vehicles of the general public, 15 pickup trucks of the California Department of Transportation that are assigned to individual employees for business use, and 15 shuttle buses of the Riverside Transit Agency that are used for paratransit service. Detailed vehicle travel and operation data including route taken, driving speed, acceleration, braking, and the corresponding fuel consumption, were collected both before and during the test period. The data analysis results show that the fleet average fuel efficiency improvements for the three fleets with the use of the driving feedback system are in the range of 2% to 9%. The economic viability of the driving feedback system is high. A fully deployed system would require capital investment in smart device ($150-$350) and on-board diagnostics connector ($50-$100) as well as paying operating costs for wireless data plan and subscription fees ($20-$30 per month) for connecting to the data server and receiving various system services. For individual consumers who already own a smart device (such as smartphone) and commercial fleets that already use some kind of telematics services, the costs for deploying this driving feedback system would be much lower.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2019

Shallow Embedded Strain Measurements and Analysis for a NbTi Superconducting Sextupole Coil During Cooling, Excitation, and Quench

The present study deals with strain measurements and their numerical analysis for a niobium titanium wire wounded superconducting sextupole coil in a multi-field operation environment, including cooling down, excitation, and quench. Four low-temperature resistance strain gauges with designed compensation circuits were affixed directly on the surface of the superconducting wires but within glass fiber cloth. Before the sextuple coil’s test was carried out, for the purpose of reliability, based on the designed compensation circuit, some basic experiments were carried out during cooling down, excitation, and quench. The experimental results showed that the shallow embedded low-temperature resistance strain gauges were still highly reproducible with an error of 1% for a variable magnetic field and an error of 5% for a variable thermal field by executing various modes. It shows multi-stage strain monitoring is feasible for the superconducting sextupole. In addition, a numerical multiphysics model for the sextuple coil is also built from Maxwell’s equations and the equilibrium equations for mechanical and thermal deformation. A self-tested elastic modulus of NbTi/Cu stack with epoxy, which is cut from a NbTi/Cu sextupole prototype, at low temperature is used in this simulation. The numerical results have reasonable agreement with the experimental observations and show the multiphysics model with self-tested elastic modulus can be applied to analysis strain behaviors under complicated fields before superconducting magnet assembly. The present results will also provide some strain-measuring technology and multiphysics numerical analysis on an LTS/HTS superconducting magnet developed at the Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS).

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2016

Sellafield FGMSP Additional Sludge Retrievals A Significant Step in Decommissioning Part of the U.K.'s Nuclear Legacy - 16180

The First Generation Magnox Storage Pond (FGMSP) is an open-air pond on the Sellafield site (U.K.) constructed to receive and store spent nuclear fuel from the UK's fleet of Magnox reactors. Operations ceased in 1986, leaving a significant mobile (sludge from the corrosion of fuel cladding) and solids (fuel, fuel fragments and other debris) inventory. In December 2013, Westinghouse Electric Company and EnergySolutions proposed to create an Additional Sludge Retrieval (ASR) capability, with the aim of starting sustainable sludge transfer and hazard reduction as soon as possible. The ASR project team proposed a sludge retrievals concept based on the use of a self-propelled, remote controlled Floating Platform. The deployment system was derived from a Floating Platform concept developed by Westinghouse to support field operations in European nuclear power plants. The system was designed, manufactured and successfully tested in real scale conditions, and was installed and fully commissioned in March 2015. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Design of a Submillimeter Crack-Detection Tool for Si Photovoltaic Wafers Using Vicinal Illumination and Dark-Field Scattering

Micro-cracks in silicon solar cells reduce the mechanical strength of the wafer, and cause breakage during manufacturing, transportation and field operation. Therefore, there is a need to trace where micro-cracks initiate in the manufacturing line. As wafers become thinner, the critical crack length required for fracture significantly decreases for the same loading conditions. Currently, very few industry-standard tools can reliably detect sub-mm cracks, which will become more critical for thinner wafers. In this work, we demonstrate a technique to detect sub-mm cracks located at the edges of various multicrystalline silicon wafers and solar cells. The proposed technique, which is based on near-infrared dark-field imaging with vicinal laser illumination from the wafer edge, has several advantages over state-of-the-art optical transmission imaging and dark-field scattering techniques. Moreover, we adapt this technique to achieve the high-throughput requirement of in-line metrology, hence it can be used to detect sub-mm cracks in a manufacturing line. With a high-framerate linescan camera, this proposed crack technique is designed to theoretically achieve a scanning throughput of less than 1 second per wafer.

14 SOLAR ENERGY↗
DOE OSTI2019

Application of the PHDS Germanium Gamma-ray Imager (GeGI) in Facility Decontamination Assessment - 19471

As part of a site wide investigation, U.S. EPA Region 5 had to assess the nature and extent of contamination in a former radioactive source manufacturing facility. This work involved verification of the radioisotope expected, ensuring no other radioisotopes were present, and quantification of the activity and areal extent of contamination throughout the facility. The device used to support this assessment work was the Germanium Gamma-ray Imager (GeGI) manufactured by PHDS Co. of Knoxville, Tennessee. GeGI is a germanium-semiconductor imaging detector system that provides identification, location, and quantification of radioactive materials within its field of view. GeGI provides the highest fidelity radiological assay information including the best gamma-ray energy resolution and spatial localization of any existing technology, including gamma-ray energy resolution of ∼0.3% full-width half-max (FWHM) at 662 keV and angular location resolution ∼ +/-1 degree. The GeGI is a mechanically cooled, portable system well-suited to field operations. PHDS Co. also provided on-site support during assessment operations and performed subsequent data analysis. Gamma-ray spectral data and associated images were collected with GeGI in six primary areas of the facility having significant residual contamination. A total of 61 gamma-ray spectrum/image sets were collected over the course of three working days (22 Compton images and 39 Pinhole/Compton images). During data collection, Compton imaging was used as the means by which to identify and prioritize hotspots. After contaminated regions were identified via Compton imaging, short-distance Pinhole spectrum/image sets were collected for additional analysis. All of the spectrum/image sets were analyzed to determine the radioisotope distribution within the GeGI field of view, as well as to provide an estimate of the activity associated with each hotspot. It was determined that the nature of residual contamination present was distributed across specific areas of elevated activity, where in some areas there was significant accumulation of contaminated material. It was also determined that no discrete sources of high-activity were present, as would be expected in the case of radioactive material product intended for sealed source manufacture. Results included the activity of residual contamination for each of the areas assessed, and an estimate of the physical area over which that contamination was distributed. It was anticipated by EPA that if decontamination were to be performed that it would involve some type of concrete scabbling or other means of physical removal of contaminated material. The GeGI data could be used to estimate the areal extent (square footage) of concrete removal that would be required for decontamination. Using the activity estimate data from the GeGI along with an estimated depth of concrete removal, planning could be performed for decontamination work (equipment and personnel), waste collection, packaging, transportation, and disposal, along with an associated cost estimate. With regard to health and safety, use of the GeGI reduced the radiation dose to the EPA R5 staff performing the assessment work. The GeGI is a non-destructive device that supports assessment of radioactively contaminated areas and sources from a distance, reducing the need for close contact to radiation, and the time necessary for personnel to operate near such hazards. Use of the GeGI in this facility assessment was our first attempt to apply this technology in what proved to be a quick and efficient decontamination assessment method. The GeGI can assess the nature and extent of residual contamination in a facility, first by quickly identifying the areas of elevated activity, followed by refined measurement and assessment of those elevated areas. The GeGI data can then be used to develop planning and a cost estimate of required decontamination and waste management activities. Since it's a non-destructive gamma identification and imaging device, it can reduce the distance of workers from radioactive sources and the dose incurred from assessment work. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

Degradation of Fuel Cell Membrane Electrode Assemblies from Buses Operated More than 25,000 h

This study investigates the performance losses and degradation of proton-exchange-membrane fuel-cell stacks taken from the Alameda Contra Costa Transit District (AC Transit) bus system (Alameda and Contra Costa counties, California, United States) that were operated for over 25,000 h. Here, we focus on the origin of differences in electrochemical performance between beginning-of-life (BOL) and end-of-life states as well as diagnostic data acquired during the lifetime of the buses. In doing so, we employ in- and ex- situ characterization methods such as polarization curves, electrochemical impedance spectroscopy, electron microscopy, and X-ray characterization. Uniform degradation of the catalyst layer including Pt agglomeration/migration and electrode thinning was observed in all of the post-teardown measurements compared to BOL materials resulting from years of field operation. Despite these changes, the measured post-teardown performance suggests a sufficient output for the expected load, which indicate factors other than degradation of the membrane-electrode assemblies (MEAs) are likely responsible for the decommissioning of the stacks. The findings indicate that these MEA materials can enable long lifetime in fuel-cell vehicles, if the MEAs are not subjected to adverse operating conditions. The results also highlight the need for more in-vehicle diagnostics to maximize the lifetime of fuel cell vehicle (FCV) powerplants.

25 ENERGY STORAGE↗
DOE OSTI2018

High-precision control of tracked field robots in the presence of unknown traction coefficients

Accurate steering through crop rows that avoids crop damage is one of the most important tasks for agricultural robots utilized in various field operations, such as monitoring, mechanical weeding, or spraying. In practice, varying soil conditions can result in off-track navigation due to unknown traction coefficients so that it can cause crop damage. To address this problem, this work presents the development, application, and experimental results of a real-time receding horizon estimation and control (RHEC) framework applied to a fully autonomous mobile robotic platform to increase its steering accuracy. Recent advances in cheap and fast microprocessors, as well as advances in solution methods for nonlinear optimization problems, have made nonlinear receding horizon control (RHC) and receding horizon estimation (RHE) methods suitable for field robots that require high-frequency (milliseconds) updates. A real-time RHEC framework is developed and applied to a fully autonomous mobile robotic platform designed by the authors for in-field phenotyping applications in sorghum fields. Nonlinear RHE is used to estimate constrained states and parameters, and nonlinear RHC is designed based on an adaptive system model that contains time-varying parameters. The capabilities of the real-time RHEC framework are verified experimentally, and the results show an accurate tracking performance on a bumpy and wet soil field. Finally, the mean values of the Euclidean error and required computation time of the RHEC framework are equal to 0.0423 m and 0.88 ms, respectively.

42 ENGINEERING↗
DOE OSTI2021

Ir-192 radioisotope replacement with a hand-portable 1 MeV Ku-band electron linear accelerator

Although linear accelerators are used in many security, industrial and medical applications, the existing technologies are too large and expensive for several critical applications such as radioactive source replacement, field radiography and mobile cargo scanners. Here, one of the main requirements for these sources is to be highly portable to allow field operation. In response to this problem, RadiaBeam has designed a hand-portable 1 MeV X-ray source, scalable to higher energies, based on Ku-band split electron linac, that can be used for Ir-192 radioisotope replacement. In this paper, we present its multiphysics and engineering design studies, as well as an accelerating structure prototype along with RF measurements.

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

Effects of Simultaneous Static and Traveling Magnetic Fields on the Molten Steel Flow in a Continuous Casting Mold

The drawback of steel fluid flow phenomena for a continuous casting mold under an electromagnetic stirrer with a traveling magnetic field is the resulting severe meniscus fluctuations due to the high-velocity and excessive downward flow in the casting direction. This can result in slab surface defects due to mold flux or inclusion entrainment. To inhibit these defects in the as-cast steel products, the implementation of braking forces using static magnetic fields in combination with a traveling magnetic field was studied in the current study. The numerical results of the fluid flow in the mold under a combined traveling and static magnetic field operation show not only 50 pct lower downward flow speed, but also more enhanced rotational flow to improve washing effects. The numerical results were validated in commercial-scale operations. The results suggest the optimized range of the ratio between the traveling and static magnetic flux densities is 65 to 75 pct to ensure steel quality improvements; this range maintains a balance between the fluid forces from the jet flow and the magnetic forces in the mold.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Trace-gas sensing using the compliance voltage of an external cavity quantum cascade laser

Quantum cascade lasers (QCLs) are increasingly being used to detect, identify, and measure levels of trace gases in the air. External cavity QCLs (ECQCLs) provide a broadly-tunable infrared source to measure absorption spectra of chemicals and provide high detection sensitivity and identification confidence. Applications include detecting chemical warfare agents and toxic industrial chemicals, monitoring building air quality, measuring greenhouse gases for atmospheric research, monitoring and controlling industrial processes, analyzing chemicals in exhaled breath for medical diagnostics, and many more. Compact, portable trace gas sensors enable in-field operation in a wide range of platforms, including handheld units for use by first responders, fixed installations for monitoring air quality, and lightweight sensors for deployment in unmanned aerial vehicles (UAVs). We present experimental demonstration of a new chemical sensing technique based on intracavity absorption in an external cavity quantum cascade laser (ECQCL). This new technique eliminates the need for an infrared photodetector and gas cell by detecting the intracavity absorption spectrum in the compliance voltage of the laser device itself. To demonstrate and characterize the technique, we measure infrared absorption spectra of chemicals including water vapor and Freon-134a. Sub-ppm detection limits in one second are achieved, with the potential for increased sensitivity after further optimization. The technique enables development of handheld, high-sensitivity, and high-accuracy trace gas sensors for in-field use.

infrared spectroscopy, quantum cascade laser, trac↗
DOE OSTI2018

Geomechanical Characterization and Modeling of the Newark Basin

To ensure long-term safety and containment during geologic carbon sequestration operations, understanding reservoir and cap rock behavior under increased pressure conditions is essential. In particular, the risk of induced seismicity has recently emerged as one of the largest concerns for geologic carbon sequestration and other injection operations. Little observational data are available about induced seismicity risks from carbon dioxide injection. However, an increasing number of earthquakes in the continental United States and worldwide are being attributed to human activities that involve other types of underground injection. Analysis of these events suggests that the net injected volume is one of the key factors, and a prolonged injection of large volumes of carbon dioxide is projected to have high potential for triggering similar seismic events. Increased pore pressure may activate an existing critically stressed discontinuity by reducing its frictional resistance to slip, and cause cap rock failure. Even when facture slip does not produce large seismic events felt by humans or cause visible damage, it can increase formation permeability and compromise cap rock integrity, thus increasing the risk of leakage. The Geomechanical Properties of Mesozoic Basins project performed unique research in the Newark Basin by combining detailed laboratory characterization and rock core testing with novel field operations performed on wireline to measure in-situ stress conditions.

58 GEOSCIENCES↗
DOE OSTI2019

Hysteresis and degaussing of H1 dipole magnets

Hysteresis was observed in the H1 dipole magnets in CBETA SX line. This study is the first step in order to understand and mitigate the effects this has on field reproducibility. Ansys Maxwell 19.2 was used to model the MS1DIP05 magnet with a hysteretic core. The parameter space for a degaussing procedure using the trim coils was explored. It was found that significant degaussing can be obtained with a decaying ringing waveform of magnitudes above 10 A, so long as the frequency ƒ and decay constant w were chosen such that ƒ >> w. The circuit properties of the magnet were simulated and explored using a sinusoidal voltage input. It was found that for low frequencies ƒ << 1 Hz, the magnet behaves as a series LR circuit with R = (28.3 ± 0.5) mΩ and L = (5.7 ± 0.1) mH. At higher frequencies, hysteretic effects become significant, and resistance becomes proportional to the frequency due to hysteretic losses. A drop and saturation in inductance for higher frequencies was observed in the simulation data. Numerical instabilities were found for excitations below small voltages V < 50 mV. Experimental results on degaussing and current corrections were collected with Hall probe measurements. Good qualitative agreement with simulation results was found, but due to B-H curve details quantitative comparisons were inaccurate. Two procedures, MaxOp and MaxNull, were designed to produce repeatable operating field values to within 0.1 G.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Activation Energy for Solder Bond Degradation: Thermal Cycling of Field-aged Modules at Multiple Upper Temperatures

The reliability of solder joints in the solar cell metallization-interconnect system influences the lifetime of photovoltaic modules. Two field-aged modules-one with Sn 62 Pb 36 Ag 2 solder at the solder joints (Solarex MSX 60), and the other with the standard Sn 60 Pb 40 solder (Siemens M55)-were subjected to a modified thermal cycling (TC) test of IEC 61215. Three sections in each module were maintained at 85 degrees C, 95 degrees C, and 105 degrees C during the 15-minute high temperature dwell time. Current equivalent to the module short-circuit current was injected through the module when the chamber temperature was above 25 degrees C to simulate regular field operation. This novel approach aims to induce thermomechanical fatigue (TMF) at the solder joints and intermetallic compound (IMC) formation at the metal/solder interfaces. The activation energy (E a ) for solder bond degradation was calculated based on the series resistance (R s ) increase in TC testing rather than power drop to avoid the effect of confounding variables. Module-level R s increase in MSX 60 module after TC800 cycles and in M55 module after TC400 cycles was 1.22% and 183.7%, respectively. The E a determined for the module with 2wt% Ag is 0.24 eV and for that with the standard solder is 0.27 eV. The solder bond degradation seems to have been driven by TMF rather than IMC formation for both modules.

14 SOLAR ENERGY↗
DOE OSTI2023

Experimental Limit on Nonlinear State-Dependent Terms in Quantum Theory

Linear time evolution is one of the fundamental postulates of quantum theory. Past theoretical attempts to introduce nonlinearity into quantum evolution have violated causality. However, a recent theory has introduced nonlinear state-dependent terms in quantum field theory, preserving causality [D. E. Kaplan and S. Rajendran, Phys. Rev. D 105, 055002 (2022)]. We report the results of an experiment that searches for such terms. Our approach, inspired by the Everett many-worlds interpretation of quantum theory, correlates a binary macroscopic classical voltage with the outcome of a projective measurement of a quantum bit, prepared in a coherent superposition state. Measurement results are recorded in a bit string, which is used to control a voltage switch. Presence of a nonzero voltage reading in cases of no applied voltage is the experimental signature of a nonlinear state-dependent shift of the electromagnetic field operator. We implement blinded measurement and data analysis with three control bit strings. Control of systematic effects is realized by producing one of the control bit strings with a classical random-bit generator. The other two bit strings are generated by measurements performed on a superconducting qubit in an IBM Quantum processor and on a N 15 nuclear spin in a nitrogen-vacancy center in diamond. Our measurements find no evidence for electromagnetic quantum state-dependent nonlinearity. We set a bound on the parameter that quantifies this nonlinearity | ε γ | < 4.7 × 10 - 11 , at 90% confidence level.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗