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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Design and performance of a magnetic bottle electron spectrometer for high-energy photoelectron spectroscopy

We describe the design and performance of a magnetic bottle electron spectrometer (MBES) for high-energy electron spectroscopy. Our design features a 2 m long electron drift tube and electrostatic retardation lens, achieving sub-electronvolt (eV) electron kinetic energy resolution for high energy (several hundred eV) electrons with a close to 4π collection solid angle. A segmented anode electron detector enables the simultaneous collection of photoelectron spectra in high resolution and high collection efficiency modes. This versatile instrument is installed at the time-resolved molecular and optical sciences instrument at the Linac Coherent Light Source x-ray free-electron laser (XFEL). In this paper, we demonstrate its high resolution, collection efficiency, and spatial selectivity in measurements where it is coupled to an XFEL source. These combined characteristics are designed to enable high-resolution time-resolved measurements using x-ray photoelectron, absorption, and Auger–Meitner spectroscopy. We also describe the pervasive artifact in MBES time-of-flight spectra that arises from a periodic modulation in electron collection efficiency and present a robust analysis procedure for its removal.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1991

Designs for surge immunity in critical electronic facilities

In recent years, Federal Aviation Administration (FAA) embarked on a program replacing older tube type electronic equipment with newer solid state equipment. This replacement program dramatically increased the susceptibility of the FAA's facilities to lightning related damages. The proposal is presented of techniques which may be employed to lessen the susceptibility of new FAA electronic facility designs to failures resulting from lightning related surges and transients as well as direct strikes. The general concept espoused is one of a consistent system approach employing both perimeter and internal protection. It compares the technique presently employed to reduce electronic noise with other techniques which reduce noise while lowering susceptibility to lightning related damage. It is anticipated that these techniques will be employed in the design of an Air Traffic Control Tower in a high isokeraunic area. This facility would be subjected to rigorous monitoring over a multi-year period to provide quantitative data hopefully supporting the advantage of this design.

Roberts, Edward F., Jr.↗
NASA NTRS2004

Communications Transceivers for Venus Surface Missions

The high temperature of the surface of Venus poses many difficulties. Previous Venus landers have only operated for short durations before succumbing to the heat. NASA Glenn Research Center conducted a study on communications for long duration Venus surface missions. I report the findings in this presentation. Current technology allows production of communications transceivers that can operate on the surface of Venus, at temperatures above 450 C and pressures of over 90 atmospheres. While these transceivers would have to be relatively simple, without much of the advanced signal processing often used in modern transceivers, since current and near future integrated circuits cannot operate at such high temperatures, the transceivers will be able to meet the requirements of proposed Venus Surface mission. The communication bands of interest are High Frequency or Very High Frequency (HFNHF) for communication between Venus surface and airborne probes (including surface to surface and air to air), and Ultra High Frequency (UHF) to Microwave bands for communication to orbiters. For HFNHF, transceivers could use existing vacuum tube technology. The packaging of the vacuum tubes may need modification, but the internal operating structure already operates at high temperatures. Using metal vacuum structures instead of glass, allows operation at high pressure. Wide bandgap transistors and diodes may be able to replace some of the thermionic components. VHF communications would be useful for line-of- sight operations, while HF would be useful for short-wave type communications using the Venusian ionosphere. UHF and microwave communications use magnetically focused thermionic devices, such as traveling wave tubes (TWTs), magnetron (M-type) amplifiers, and klystrons for high power amplifiers, and backward wave oscillators (BWOs) and reflex klystrons for oscillators. Permanent magnets are already in use in industry that can operate at 500 C. These magnets could focus electron beam tubes on the surface of Venus. While microwave windows will need to be designed for the high pressure, diamond windows have already been demonstrated, so high-pressure microwave windows can be designed and built. Thus, all of these devices could be useful for Venus surface missions. Current electronic power conditioners to supply the high voltages used in these microwave devices cannot operate at high temperatures, but earlier electronic power conditioners that used vacuum tubes can be modified to work at high temperature. Evaluating the various devices in this study, the M-type traveling wave tube (where a traveling wave structure is used in a crossed-field device, similar to the Amplitron used on the Apollo missions) stood out for the high power amplifier since it requires a single high voltage, simplifying the power supply design. Since the receiver amplifier is a low power amplifier, the loss of efficiency in linear beam devices without a depressed collector (and thus needing a single high voltage) is not important; a low noise TWT is a possible solution. Before solid-state microwave amplifiers were available, such TWTs were built with a 1-2 dB noise figure. A microwave triode or transistor made from a wide bandgap material may be preferable, if available. Much of the development work needed for Venusian communication devices will need to focus on the packaging of the devices, and their connections, but the technology is available to build transceivers that can operate on the surface of Venus indefinitely.

Force, Dale A.↗
NASA NTRS1981

Automatic arc welding of propulsion system tubing in close proximity to sensitive electronic devices

The planned final assembly of the Galileo spacecraft propulsion system tubing, which involves welding in close proximity to sensitive electronics, raised significant concerns about the effects of electromagnetic coupling of weld energy on CMOS and other sensitive integrated circuits. A test program was established to assess the potential of an orbital arc welder and an RF-induction brazing machine to damage sensitive electronic equipment. Test parameters were varied to assess the effectiveness of typical transient suppression practices such as grounding, bonding, and shielding. A technique was developed to calibrate the hazard levels at the victim-circuit location; this technique is described along with the results and conclusions of the test program.

Lumsden, J. M.↗
NASA NTRS1995

Imaging Magnetometer

Imaging magnetometer proposed for scientific, industrial, or military use in detecting underground structures containing magnetic materials and underground machines generating and/or altering magnetic fields. Includes electron-beam tube integrated with phosphor-coated charge-coupled device (CCD). Images formed by magnetic deflection of electron beam. Locations, magnitudes, and directions of identifiable features of magnetic field examined to extract data on locations, sizes, and types of magnetically detected objects.

Moynihan, Philip I.↗
NASA NTRS1977

Application of an electron beam facility for heat transfer measurements in capillary tubes

A unique method was developed for the determination of heat transfer coefficients for water flowing through capillary tubes using a rastered electron beam heater. Heat flux levels of 150 and 500 watts/sq cm were provided on the top surface of four square tubes. Temperature gradient along the tube length and mass flow rates versus pressure drop were measured.

Lunde, A. R.↗
NASA NTRS1986

Technology for Television

A project being conducted by Varian Associates, Inc. and Lewis Research Center would allow a Ultrahigh Frequency (UHF) TV station to save 50% of its electricity cost. Because UHF stations need substantially more transmitter power, an amplifying device was needed. In the early 1970's Dr. Henry Kosmahl of Lewis had developed a radiowave amplifier to improve satellite transmission. He later worked with modifying klystron transmitters, electronic vacuum tubes used to generate and amplify UHF frequencies. If Dr. Kosmahl's multistage depressed collector or MDC can be incorporated into the klystron, the magnetic field shapes of electron beams can be changed to aid the energy recovery function of the MDC.

Source record↗
NASA NTRS1978

Ion tracking in an electrostatic potential distribution

An ion tracking system utilizing a single detector was designed to resolve two dimensional potential distributions in a vacuum. The ion detector consisted of a continuous dynode electron multiplier tube mounted behind a series of aperture plates. The detector was located on a track below a wedge shaped structure used to produce the desired potential distribution. A 150 volt electron beam aimed at selected regions, ionized the residual gas in the chamber. The ions were ejected from their source points by electrostatic forces causing them to drift downward toward the detector. Measurements of particle energy, detector position, and entry angle of the incoming particle flux were used to initialize a computer trajectory-tracing program. The program assumes a known theoretically calculated potential distribution near the wedge for computation of particle trajectories, providing a basis for evaluating the data. Special attention was given to characterization of the ion detector.

Ross, D. P.↗
DOE OSTI2025

Corrosion Resistance of an AlCeMg/Stainless-Steel Reactive Bond

A major issue for metal components in many industries is corrosion as it can substantially reduce their lifetime. This issue is especially problematic for materials used in heat exchanger applications. Al–Ce–Mg alloys, which exhibit corrosion resistance and can reactively bond with other metals, may be a viable solution to this problem. This investigation studied the corrosion behavior of Al–2Ce–6Mg (atomic percent)/stainless-steel (SS) reactive bond interfaces after full immersion in nitric, sulfuric, formic, and mixed acid for 267 h. This particular Al–Ce–Mg alloy was chosen due to its good castability. The results of scanning electron microscope characterization showed that reactive bond formations repeatedly occurred throughout the length of the casting in the as-cut samples and that these formations maintained a secure bonding between the alloy and the stainless-steel tubes. Transmission electron microscopy results showed that there was a clear compositional and microstructural transition across the reactive bond. The results of the immersion tests indicated that the nitric, sulfuric, and the mixed acid did not have an observably negative effect on the reactive bond structure. As for the sample exposed to formic acid only, noticable changes were seen in both the microstructural appearance and the elemental profile across the bond, suggesting that oxide formation occurred.

Brechtl, Jamieson [ORNL] (ORCID:0000000217394283)↗
NASA NTRS1986

Calculation of secondary electron trajectories in multistage depressed collectors for microwave amplifiers

Computational procedures are reported for treating power losses due to secondary electrons in multistage depressed collectors (MDC) for traveling wave tubes (TWT) and other O-type electron tubes. The MDC is modeled with an advanced, multidimensional computer program. Representative beams of secondary electrons are then injected at the points of impact of the primary beams. Separate programs are used to calculate representative beams of high-energy primary electron beams and of low-energy true secondaries. The recomputation of the MDC model including the true secondary beam allows determination of the secondary emission losses, and, if necessary, redesign of the MDC to improve performance. Recomputation of the MDC model including the primary beams is used to check on possible backstreaming from the MDC to the RF interaction structure of the tube. A comparison with experimentally measured values of TWT and MDC efficiencies is made.

Force, Dale A.↗
NASA NTRS1972

Removal of a glowing spot from an image tube using laser radiation.

A troublesome problem with the Kron electronograph has been the presence of a white glowing spot on the glass wall of the tube adjacent to the focus electrode. The procedure followed to eliminate the spot was to operate in the dark and apply voltage only to the focused electrode. Ruby laser radiation was unfocused, and its position was shifted on the electrode between laser shots until an effect was observed. This technique for removing the glowing spot should be applicable to other electronic image tubes.

Gurski, T. R.↗