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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Micro pulse lidar

An eye safe, compact, solid state lidar for profiling atmospheric cloud and aerosol scattering has been demonstrated. The transmitter of the micropulse lidar is a diode pumped micro-J pulse energy, high repetition rate Nd:YLF laser. Eye safety is obtained through beam expansion. The receiver employs a photon counting solid state Geiger mode avalanche photodiode detector. Data acquisition is by a single card multichannel scaler. Daytime background induced quantum noise is controlled by a narrow receiver field-of-view and a narrow bandwidth temperature controlled interference filter. Dynamic range of the signal is limited by optical geometric signal compression. Signal simulations and initial atmospheric measurements indicate that systems built on the micropulse lidar concept are capable of detecting and profiling all significant cloud and aerosol scattering through the troposphere and into the stratosphere. The intended applications are scientific studies and environmental monitoring which require full time, unattended measurements of the cloud and aerosol height structure.

Spinhirne, James D.↗
DOE OSTI2020

Design of the DUNE APATF cryogenic system

Fermi National Accelerator Laboratory (FNAL) is developing the international Long- Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) to advance neutrino science. The flagship of the DUNE project consists of a large particle detector constructed one-mile (1.6 km) beneath the surface at the Sanford Underground Research Facility (SURF) in Lead, SD. The SURF detector is the largest of its type ever built and is comprised of four cryostats totaling 70,000 tons of liquid argon (LAr) to record neutrino interactions with unprecedented precision. Each cryostat houses a detector, the first includes 150 Anode Panel Assemblies (APA) submersed within 17,500 tons of LAr. Before installing 150 APA within the SURF detector they will be cryogenically cooled to nominally 90 K at the APA Test Facility (APATF) utilizing nitrogen flows. The APATF cryogenic system is entirely located one-mile underground at the SURF facility and includes nominally 13 kW of refrigeration at 80 K, cryogenic transfer lines, APA test cryostats, a cryogenic control system, and various control and pressure safety elements to ensure performance and safety requirements are achieved. The APATF preliminary design is in progress and major considerations include an efficient, costeffective mechanism to deliver the required refrigeration to the APATF underground, support of rigid testing intervals to support the DUNE operating schedule, temperature stability of the APA and electronics within cryostats, efficient cryogenic system operation to minimize heat leak and/or liquid nitrogen consumption, thermo-mechanical stability and flexibility of components, and pressure safety of the APATF cryogenic system. Installation and integration of the APATF cryogenic system within the footprint and to adjacent sub-systems is also discussed.

43 PARTICLE ACCELERATORS↗
DOE OSTI2026

Intelligent Experiments through Real-Time AI: Fast Data Processing and Autonomous Detector Control for High-Energy Nuclear Experiments

The aim of this project is to develop software and hardware for fast real-time data processing and autonomous detector control and calibration for the sPHENIX and the future EIC experiments. Below summarizes Georgia Tech team efforts in the past year: 1. We developed a real-time clustering algorithm and FPGA-based pipeline architecture for processing fired pixel data from ALPIDE sensors in sPHENIX experiments. Our Columnar Clustering Co-Design introduces a hardware-aware, stream-friendly approach that segments pixel data by column pairs using a Column Pair Clustering (CPC) strategy, followed by Cluster Stitching to merge adjacent subclusters. Implemented in Vitis HLS, the pipeline comprises five stages—read-in, subclustering, stitching, analysis, and write-out—connected by tagged HLS streams with custom end-of-event signaling for robust synchronization. We designed a pipelined dataflow model optimized for throughput, low latency, and minimal buffering, enabling scalable clustering across events of arbitrary size. Our system maintains spatial precision via center-of-mass and shape key extraction and efficiently handles edge cases such as fragmented or nested clusters. Compared against DBSCAN in both software and hardware, our approach demonstrates competitive performance under FPGA constraints. 2. We also conducted a comprehensive algorithm-to-hardware co-design of connected component analysis tailored for sPHENIX experiments, focusing on real-time, low-latency processing using FPGAs and High-Level Synthesis (HLS). Starting from a Python-based particle tracking pipeline, the team translated the core logic—graph traversal via DFS and Union-Find—into an HLS-compatible C++ model, replacing dynamic memory and recursion with static arrays and pipelined control flow. The final design includes a fully streamed and dataflow-compatible Union-Find kernel optimized across five iterations, incorporating loop pipelining, array partitioning, AXI/FIFO interface tuning, and function flattening. Experimental results show up to 14.8× speedup over the CPU baseline, reducing per-graph latency to 1.58 μs and demonstrating strong resource efficiency with only ~7k LUTs and zero BRAM usage. The design maintains functional correctness against the Python reference using a Python-based C-simulation framework and Mean Squared Error metrics. This work validates the potential of HLS-driven FPGA designs for edge-level HEP data acquisition, laying a scalable foundation for future integration with real-time detector pipelines and multi-graph processing systems.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Experimental validation of a high fidelity Monte Carlo neutron transport model of the MIT graphite exponential pile

High-fidelity modeling and simulation were performed for the MIT graphite exponential pile (MGEP) using Monte Carlo neutron transport codes OpenMC and MCNP, and the results were validated by experimental data. The MGEP is being used as the test bed for the design of an autonomous control system for the pile's neutron flux distribution. The main contribution of this work is to generate the training data sets of neutron flux distributions with different locations of control rods that perturb the neutron flux profiles. First, code -to-code cross verification between OpenMC and MCNP was performed to ensure consistency of the numerical modeling within statistical uncertainties. To validate the accuracy of this high-fidelity model, a series of neutron flux measurements were conducted using a Helium-3 (He-3) neutron detector on a mobile platform that is placed inside the pile. Second, the neutron flux profiles were measured in four vertical layers of interest, and compared to the corresponding simulation results. The comparison results shows that the root mean square error is less than 2.5% in the two upper layers, and less than 4.5% in all four measured layers. Here the results validated the accuracy of the modeling and simulation. Finally, the relative change of the neutron flux profiles from moving control rods was analyzed, which identified the layer that has the best sensitivity regarding the control rods movements. Thus, this work identified and provided training data sets of both simulated and experimental neutron flux profiles in the most sensitive layer, paving the path forward to the real-time experimental demonstration of the autonomous control system.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS1997

Chaos: Understanding and Controlling Laser Instability

In order to characterize the behavior of tunable diode lasers (TDL), the first step in the project involved the redesign of the TDL system here at the University of Tennessee Molecular Systems Laboratory (UTMSL). Having made these changes it was next necessary to optimize the new optical system. This involved the fine adjustments to the optical components, particularly in the monochromator, to minimize the aberrations of coma and astigmatism and to assure that the energy from the beam is focused properly on the detector element. The next step involved the taking of preliminary data. We were then ready for the analysis of the preliminary data. This required the development of computer programs that use mathematical techniques to look for signatures of chaos. Commercial programs were also employed. We discovered some indication of high dimensional chaos, but were hampered by the low sample rate of 200 KSPS (kilosamples/sec) and even more by our sample size of 1024 (1K) data points. These limitations were expected and we added a high speed data acquisition board. We incorporated into the system a computer with a 40 MSPS (million samples/sec) data acquisition board. This board can also capture 64K of data points so that were then able to perform the more accurate tests for chaos. The results were dramatic and compelling, we had demonstrated that the lead salt diode laser had a chaotic frequency output. Having identified the chaotic character in our TDL data, we proceeded to stage two as outlined in our original proposal. This required the use of an Occasional Proportional Feedback (OPF) controller to facilitate the control and stabilization of the TDL system output. The controller was designed and fabricated at GSFC and debugged in our laboratories. After some trial and error efforts, we achieved chaos control of the frequency emissions of the laser. The two publications appended to this introduction detail the entire project and its results.

Blass, William E.↗
NASA NTRS1984

Characterization of CNRS Fizeau wedge laser tuner

A fringe detection and measurement system was constructed for use with the CNRS Fizeau wedge laser tuner, consisting of three circuit boards. The first board is a standard Reticon RC-100 B motherboard which is used to provide the timing, video processing, and housekeeping functions required by the Reticon RL-512 G photodiode array used in the system. The sampled and held video signal from the motherboard is processed by a second, custom fabricated circuit board which contains a high speed fringe detection and locating circuit. This board includes a dc level discriminator type fringe detector, a counter circuit to determine fringe center, a pulsed laser triggering circuit, and a control circuit to operate the shutter for the He-Ne reference laser beam. The fringe center information is supplied to the third board, a commercial single board computer, which governs the data collection process and interprets the results.

Source record↗
NASA NTRS1984

Spartan - Space at low-cost

Mission profiles and objectives of the Spartan Shuttle payload are described. Spartan was designed to provide extended observations normally carried out for only a few minutes using sounding rockets. The payload will be placed in co-orbit with the Orbiter by the RMS arm and controlled by a ground-based researcher or by an on-board program. Spartan features minimal battery power, batteries, and control systems and no redundancy. Thermal control is added because the flights last 100-1000 times as long as those on sounding rockets. Data are recorded by an on-board tape recorder and operations are controlled by an on-board microprocessor. Spartan 1 will carry a star-pointer and X-ray detectors for high energy astrophysics experiments. Spartan 2 will gather solar physics data in the form of temperatures of hydrogen gas and ions and electrons. Particle densities will also be monitored and a 43 cm solar telescope will produce UV and white light solar coronagraphs. UV spectroscopy of stars, clouds and galaxies will be performed by the Spartan 3 payload.

Source record↗
NASA NTRS1961

Predicted Performance of On-Off Systems for Precise Satellite Attitude Control

An investigation has been made of the use of on-off reaction jets for precision attitude control of a satellite. Since a symmetrical vehicle is assumed, only single-axis control needs to be considered. The responses to initial disturbances and also limit-cycle characteristics for several systems have been evaluated. Calculated results indicate that realistic values of settling time and fuel consumption for the example considered can be obtained. The performance of a given system depends on the characteristics of the error detector used. In cases where the detector output was saturated for a relatively low error input, the settling time deteriorated when a lead network was used to provide damping. This deterioration could be eliminated if a separate rate signal to produce vehicle rate limiting were available. As an alternate approach, two systems were investigated which used a timed sequence of torques and could operate with a detector output of very small linear range. Although the performance of these systems was poorer than that of the lead network system without detector saturation, the performance was better than that of the lead network system with low values of detector saturation. The effects on limit-cycle characteristics of hysteresis, lead network constants, dead zone, and thrust time delays were also investigated.

Brown, Stuart C.↗
NASA NTRS2002

Commercial-Off-The-Shelf Microelectromechanical Systems (MEMS) Flow-Measurement Probes Fabricated And Assembled

As an alternative to conventional tubing instrumentation for measuring airflow, designers and technicians at the NASA Glenn Research Center have been fabricating packaging components and assembling a set of unique probes using commercial-off-the-shelf microelectromechanical systems (MEMS) integrated circuits (computer chips). Using MEMS as an alternative has some compelling advantages over standard measurement devices. Sensor technologies have matured through high-production usage in industries such as automotive and aircraft manufacturers. Currently, MEMS are the choice in applications such as tire pressure monitors, altimeters, pneumatic controls, cable leak detectors, and consumer appliances. Conventional instrumentation uses tubing buried in the model aerodynamic surfaces or wind tunnel walls. The measurements are made when pressure is introduced at the tube opening. The pressure then must travel the tubing for lengths ranging from 20 to hundreds of feet before reaching an electronic signal conditioner. This condition causes a considerable amount of damping and requires measurements to be made only after the test rig has reached steady-state operation. The electronic MEMS pressure sensor is able to take readings continuously under dynamic states in nearly real time. The use of stainless steel tubing for pressure measurements requires many tubes to be cleaned, cut to length, carefully installed, and delicately deburred and spliced for use. A cluster of a few hundred 1/16-in.- (0.0625-in.-) diameter tubes (not uncommon in research testing facilities) can be several inches in diameter and may weigh enough to require two men to handle. Replacing hard tubing with electronic chips can eliminate much of the bulk. Each sensor would fit on the tip of the 1/16-in. tubing with room to spare. The P592 piezoresistive silicon pressure sensor (Lucas NovaSensor, Fremont, CA) was chosen for this project because of its cost, availability, and tolerance to extreme ambient conditions. The chip is 1 mm square by 0.6 mm thick (0.039 by 0.023 in.) with 0.12-mm (0.005-in.) wire connection tabs. Three MEMS chips were used to build the first type of flow-angularity probe. This MEMS probe will be demonstrated as an alternative to a standard tube type "Cobra Probe" now used routinely in wind tunnel and aeronautical hardware applications. The response time and accuracy would allow the probe to be translated on an actuator across a flow field, yielding precision dynamic measurements not possible with conventional instrumentation. The low profile, the minimal power requirement, the rugged construction, and the moderate cost all contribute to making MEMS sensors the enticing choice instrument in future research measurement needs. The MEMS probe efforts are a continuation of work initiated by Brian Willis, without whose foresight and efforts this project would never have been realized. This task was funded through cooperation with the NASA Electronic Parts and Packaging (NEPP) program at the Jet Propulsion Laboratory.

Redding, Chip↗
NASA NTRS1984

Microwave ice accretion meter

A system for indicating ice thickness and rate of ice thickness growth on surfaces is disclosed. The region to be monitored for ice accretion is provided with a resonant surface waveguide which is mounted flush, below the surface being monitored. A controlled oscillator provides microwave energy via a feed point at a controllable frequency. A detector is coupled to the surface waveguide and is responsive to electrical energy. A measuring device indicates the frequency deviation of the controlled oscillator from a quiescent frequency. A control means is provided to control the frequency of oscillation of the controlled oscillator. In a first, open-loop embodiment, the control means is a shaft operated by an operator. In a second, closed-loop embodiment, the control means is a processor which effects automatic control.

Magenheim, Bertram↗
NASA NTRS1995

Application of New Technology to Future Celestial Trackers

New developments in image sensors and optical materials have opened the door to dramatic mass and power reductions in celestial tracker designs. The rapid development of active pixel sensors (APS) has provided a new detector choice offering high on-chip integration of support circuitry at reduced power consumption. Silicon-Carbide (Si-C) optics are one of the new developments in low-mass optical components. We describe the celestial tracker needs of an Autonomous Feature and Star Tracking (AFAST) system designed for autonomous spacecraft control. Details of a low mass celestial tracker, based on a low power APS array and optimized for an AFAST system, are discussed.

active↗
DOE OSTI2020

Wireless Instrumented RB Experiment Preliminary Design and Analysis

The ability to deploy new nuclear fuels for current or future reactor concepts requires carefully designed experiments to generate data to support fuel qualification. Ideally these experiments would include state of-the-art sensing to maximize the amount of in situ data that can be collected during operation. Furthermore, advanced reactor systems can take advantage of integrated in-core sensing technologies to maximize fuel utilization, reduce unnecessary conservativism in design margins, and improve operator’s understanding of limiting peaking factors. Before any novel sensing technologies can be readily adopted for nuclear applications, they must first demonstrate acceptable performance in test reactors. This report summarizes the preliminary design and analysis of the most highly instrumented irradiation experiment ever performed in the removable beryllium (RB) positions of the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). The Wireless Instrumented RB Experiment 2021 (WIRE-21) will test a wide range of sensors including wireless sensors being developed by Westinghouse Electric Company (WEC) that could provide in situ measurements of peak fuel temperatures and fuel rod pressurization due to fission gas release. The ability to wirelessly transmit a signal through the fuel rod’s cladding is critical to improving fuel monitoring capabilities without requiring signal penetrations through the cladding pressure boundary, which would significantly impact fuel fabrication, handling, and operation. Other sensors that will be tested in WIRE-21 include an array of thermocouples, self-powered neutron detectors (SPNDs), and spatially distributed fiber-optic temperature sensors. More generally, WIRE-21 will establish a flexible irradiation vehicle design to allow accelerated, economical testing of advanced sensor technologies while leveraging the extremely high neutron flux that is available in HFIR. This report summarizes the mechanical design for WIRE-21, the experimental test matrix, initial neutronic and thermal design analyses, and the active monitoring and control system enhancements necessary to support testing of advanced sensor technologies. The containment for WIRE-21 is similar to previous RB irradiation vehicles but includes a few modifications, most notably the use of integrated compression seals to pass a larger number of sensor leads through the experiment’s pressure boundary. In addition to the sensor leads, inert gas lines are passed into the experiment to enable active temperature control and the ability to pneumatically actuate a bellows-driven pressure sensor. WIRE-21 is targeting temperatures (300–350°C) and neutron fluence levels (~10 22 n/cm 2 ) relevant to light water reactors (LWRs), but the flexible design of the experiment vehicle allows much higher operating temperatures (>1,100°C). Neutronic calculations determine the neutron flux conditions as well as the nuclear heating within the experiments. These results are used as inputs to detailed thermal finite element calculations, which are required to evaluate the complex, three-dimensional heat transfer that occurs within WEC’s wireless sensor enclosures. Initial results show that the temperatures of the sensors’ enclosures and the metal bellows can be operated near the temperature range of LWR coolants and cladding while simultaneously increasing the temperature of a surrogate fuel material to values in the range of 800–1200°C to simulate centerline fuel temperatures during LWR operation.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1981

Development of a CCD array as an imaging detector for advanced X-ray astrophysics facilities

The development of a charge coupled device (CCD) X-ray imager for a large aperture, high angular resolution X-ray telescope is discussed. Existing CCDs were surveyed and three candidate concepts were identified. An electronic camera control and computer interface, including software to drive a Fairchild 211 CCD, is described. In addition a vacuum mounting and cooling system is discussed. Performance data for the various components are given.

Schwartz, D. A.↗
NASA NTRS1984

MOSAIC

The Mosaicked Optical Self-scanned Array Imaging Camera (MOSAIC), is a 50 sq cm active area detector system encompassing 5.76 million picture elements. This camera is being developed for use in astronomical instrumentation requiring the use of large area imaging detectors with high resolution photon counting capability in the space ultraviolet. This paper gives a descriptive outline of the MOSAIC camera system including: the 100 mm diameter microchannel plate intensifier, the 3 x 3 array of 800 x 800 pixel charge coupled devices, the signal processing and buffer storage subsystem, the electronic support and control subsystem, and the data processing subsystem. Performance characteristics of the camera and its subsystems are presented, based on system analysis.

Williams, J. T.↗
NASA NTRS1993

Dynamic test results for the CASES ground experiment

The Controls, Astrophysics, and Structures Experiment in Space (CASES) Ground Test Facility (GTF) has been developed at Marshall Space Flight Center (MSFC) to provide a facility for the investigation of Controls/Structures Interaction (CSI) phenomena, to support ground testing of a potential shuttle-based CASES flight experiment, and to perform limited boom deployment and retraction dynamics studies. The primary objectives of the ground experiment are to investigate CSI on a test article representative of a Large Space Structure (LSS); provide a platform for Guest Investigators (GI's) to conduct CSI studies; to test and evaluate LSS control methodologies, system identification (ID) techniques, failure mode analysis; and to compare ground test predictions and flight results. The proposed CASES flight experiment consists of a 32 meter deployable/retractable boom at the end of which is an occulting plate. The control objective of the experiment is to maintain alignment of the tip plate (occulter) with a detector located at the base of the boom in the orbiter bay. The tip plate is pointed towards a star, the sun, or the galactic center to collect high-energy X-rays emitted by these sources. The tip plate, boom, and detector comprise a Fourier telescope. The occulting holes in the tip plate are approximately one millimeter in diameter making the alignment requirements quite stringent. Control authority is provided by bidirectional linear thrusters located at the boom tip and Angular Momentum Exchange Devices (AMED's) located at mid-boom and at the tip. The experiment embodies a number of CSI control problems including vibration suppression, pointing a long flexible structure, and disturbance rejection. The CASES GTF is representative of the proposed flight experiment with identical control objectives.

Bukley, Angelia P.↗
NASA NTRS1993

Micro pulse laser radar

An eye safe, compact, solid state lidar for profiling atmospheric cloud and aerosol scattering is disclosed. The transmitter of the micro pulse lidar is a diode pumped micro-J pulse energy, high repetition rate Nd:YLF laser. Eye safety is obtained through beam expansion. The receiver employs a photon counting solid state Geiger mode avalanche photodiode detector. Data acquisition is by a single card multichannel scaler. Daytime background induced quantum noise is controlled by a narrow receiver field-of-view and a narrow bandwidth temperature controlled interference filter. Dynamic range of the signal is limited to optical geometric signal compression. Signal simulations and initial atmospheric measurements indicate that micropulse lider systems are capable of detecting and profiling all significant cloud and aerosol scattering through the troposphere and into the stratosphere. The intended applications are scientific studies and environmental monitoring which require full time, unattended measurements of the cloud and aerosol height structure.

Spinhirne, James D.↗
NASA NTRS1998

An Investigation of the Largest Flares in Active Cool Star Binaries with ALEXIS

After a long delay due to the initial problems with the ALEXIS attitude control, the heroic efforts on the part of the ALEXIS satellite team enabled us to carry out this survey. However, the combination of the higher than expected and variable background in the ALEXIS detectors, and the lower throughput of the ALEXIS telescopes resulted in no convincing detections of large flares from the active binary systems. In addition, vignetting-corrected effective exposure times from the ALEXIS aspect solution were not available prior to the end of this contract; therefore, we were unable to convert upper limits measured in ALEXIS counts to the equivalent.

Stern, Robert A.↗