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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

A space simulation test chamber development for the investigation of radiometric properties of materials

The design, fabrication, and preliminary utilization of a thermal vacuum space simulation facility are discussed. The facility was required to perform studies on the thermal radiation properties of materials. A test chamber was designed to provide high pumping speed, low pressure, a low photon level radiation background (via high emissivity, coated, finned cryopanels), internal heat sources for rapid warmup, and rotary and linear motion of the irradiated materials specimen. The radiation detection system consists of two wideband infrared photoconductive detectors, their cryogenic coolers, a cryogenic-cooled blackbody source, and a cryogenic-cooled optical radiation modulator.

Enlow, D. L.↗
NASA NTRS1989

Measurements of very low-sidelobe conical horn antennas

A description is given of conical corrugated-horn antennas that were designed for millimeter-wave radiometers with a 7 degree field of view, namely the Differential Microwave Radiometers (DMRs) that will measure the large-angular-scale anisotropy of the cosmic background radiation that is generally thought to be the remnant of the primeval explosion, the Big Bang. The DMRs will be part of the Cosmic Background Explorer (COBE) satellite. Measured test results for three radiometers at 31.4, 53, and 90 GHz are reported along with those of a circular polarization orthomode transducer designed and characterized at 31.4 GHz. The measurement techniques and facilities are described, including an outdoor far-field facility where measurements down to levels 90 dB below the main beam maximum were achieved. The goal of achieving very low-sidelobe antennas with good symmetry has been demonstrated.

Toral, Marco A.↗
NASA NTRS2005

Optical vector receiver operating near the quantum limit

An optical receiver concept or binary signals with performance approaching the quantum limit at low average signal background photons has been devised by Dolinar, however this receiver requires ideal optical combining and complicated real-time shaping of the local field, hence tends to be difficult to implement at high data rates. A simpler nulling receiver that approaches the quantum limit without complex optical processing, suitable for high-rate operation has been suggested earlier by Kennedy. Here we formulate a vector receiver concept that incorporates the Kennedy receiver together with a physical beamsplitter, but also utilizes the reflected signal component to improve signal detection. It is found that augmenting the Kennedy receiver with classical coherent detection at the auxiliary beamsplitter output, and optimally processing the vector observations, always improves on the performance of the Kennedy receiver alone, significantly so at low average photon rates. This is precisely the region of operation where modern codes approach channel capacity. It is also shown that the addition of background radiation has little effect on the performance of the coherent receiver component, suggesting a viable approach for near quantum-limited performance in high background environments

Lau, Chi-Wung↗
NASA NTRS1972

Optical radiation from regions downstream of mercury bombardment thrusters

A 0.5 meter focal length, plane grating monochromator was used to measure the radiance of spectral radiation emanating from regions downstream of a mercury bombardment thruster. The wavelength range investigated was 2800 A. This radiation was due primarily to the radiative decay of excited mercury atoms exhausted from the thruster. Radiance values ranged from 10 to the minus 11th power to 10 to the minus 9th power W/sq cm sr, varying with wavelength. For resonant radiation, the spectral radiance may exceed 10 to the minus 8th power W/sq cm sr. From such radiance measurements, it was concluded that the thruster background radiation should not interfere with the control functions of a star tracker viewing through the thruster exhaust, provided that the tracker is designed to operate with a sufficiently small field of view.

Milder, N. L.↗
NASA NTRS1983

Background sources in optical communications

The characterization and measurement of background radiation relevant to optical communications system performance is addressed. The necessary optical receiver parameters are described, and radiometric concepts required for the calculation of collected background power are developed. The most important components of optical background power are discussed, and their contribution to the total collected background power in various communications scenarios is examined.

Vilnrotter, V. A.↗
NASA NTRS2006

Active Solid State Dosimetry for Lunar EVA

The primary threat to astronauts from space radiation is high-energy charged particles, such as electrons, protons, alpha and heavier particles, originating from galactic cosmic radiation (GCR), solar particle events (SPEs) and trapped radiation belts in Earth orbit. There is also the added threat of secondary neutrons generated as the space radiation interacts with atmosphere, soil and structural materials.[1] For Lunar exploration missions, the habitats and transfer vehicles are expected to provide shielding from standard background radiation. Unfortunately, the Lunar Extravehicular Activity (EVA) suit is not expected to afford such shielding. Astronauts need to be aware of potentially hazardous conditions in their immediate area on EVA before a health and hardware risk arises. These conditions would include fluctuations of the local radiation field due to changes in the space radiation field and unknown variations in the local surface composition. Should undue exposure occur, knowledge of the dynamic intensity conditions during the exposure will allow more precise diagnostic assessment of the potential health risk to the exposed individual.[2]

Wrbanek, John D.↗
DOE OSTI2025

External Radiation and Magnetic-Field Effects on the Coherence and Stability of Transmon Qubits

Superconducting transmon qubits are a central building block of modern quantum computing architectures, yet their coherence properties remain sensitive to external influences that can limit performance or introduce temporal instabilities. In this talk, I will discuss two experimental studies aimed at quantifying these effects. First, I will examine how ionizing radiation impacts qubit relaxation. Using the same transmon device operated at two locations with dramatically different radiation backgrounds—the above-ground SQMS facility at Fermilab (USA) and the deep-underground Gran Sasso Laboratory (Italy)—we observe a higher rate of radiation-induced decay events above ground, even though intrinsic noise remains the dominant source of single-shot errors. I will also discuss the detection efficiency of a radiation detector made using such a device. Second, I will present results on how small magnetic fields, applied either during cooldown or at millikelvin temperatures, influence device stability. We find that fixed-frequency transmons maintain robust coherence up to approximately 600 mG of trapped out-of-plane field, and that controlled application of magnetic field can reduce temporal fluctuations in T1. Together, these studies provide insight into how external environments shape transmon coherence and offer potential pathways for improving qubit stability in scalable quantum processors.

Roy, Tanay [Fermilab]↗
NASA NTRS1963

NASA Facility for the Study of Space Radiation Effects

Space particulate radiation from the Van Allen belts, solar flares, galactic cosmic, and manmade sources have energies and fluxes which are capable of producing damage in space mission payloads. NASA - Langley Research Center, Hampton, Virginia, has initiated the construction of a ground-based Space Radiation Effects Laboratory which simulates most of the space particulate energy spectrum and which can be used in a radiation research program for minimizing or eliminating deleterious radiation effects. A 600-megaelectronvolt synchrocyclotron of variable energy and electron accelerators from 1 to 10 megaelectronvolts will be included in the laboratory for accelerated testing. The plan of the proposed test areas reflects the latest advances in the state of the art as it pertains to the engineering and basic experimental requirements in flexibility, radiation background levels, shielding, and isolation. The laboratory operational plan permits three Virginia institutions of higher learning to cooperate with the Langley Research Center in carrying out radiation programs.

RADIATION EFFECT↗
NASA NTRS1995

A new Fabry-Perot spectrometer for observations of diffuse near-infrared line emission

We describe a new Fabry-Perot spectrometer that is optimized for the detection of extended, low-surface-brightness line emission from 1.4 to 2.4 microns. The instrument combines high throughput and high sensitivity, yet limits the background radiation falling on the detector. The instrument has a single 20 sec - 200 sec beam and a resolving power lambda/delta(lambda) approximately 2500. The system is background shot-noise limited in the K window and limited by a combination of read noise, dark-current shot noise, and fluctuations in the OH airglow lines in the H window. We present sample data of some of the lowest-surface-brightness H2 line emission in the near infrared obtained to date.

Luhman, M. L.↗
NASA NTRS1998

Issues in the reconstruction of environmental doses on the basis of thermoluminescence measurements in the Techa riverside

The potential of thermoluminescence measurements of bricks from the contaminated area of the Techa river valley, Southern Urals, Russia, for reconstructing external exposures of affected population groups has been studied. Thermoluminescence dating of background samples was used to evaluate the age of old buildings available on the river banks. The anthropogenic gamma dose accrued in exposed samples is determined by subtracting the natural radiation background dose for the corresponding age from the accumulated dose measured by thermoluminescence. For a site in the upper Techa river region, where the levels of external exposures were extremely high, the depth-dose distribution in bricks and the dependence of accidental dose on the height of the sampling position were determined. For the same site, Monte Carlo simulations of radiation transport were performed for different source configurations corresponding to the situation before and after the construction of a reservoir on the river and evacuation of the population in 1956. A comparison of the results provides an understanding of the features of the measured depth-dose distributions and height dependencies in terms of the source configurations and shows that bricks from the higher sampling positions are likely to have accrued a larger fraction of anthropogenic dose from the time before the construction of the reservoir. The applicability of the thermoluminescent dosimetry method to environmental dose reconstruction in the middle Techa region, where the external exposure was relatively low, was also investigated.

NASA Discipline Radiation Health↗
NASA NTRS1981

Intergalactic shells at large redshift

The intergalactic shells produced by galactic explosions at large redshift, whose interiors cool by inverse Compton scattering off the cosmic background radiation, have a characteristic angular size of about 1 arcmin at peak brightness. At z values lower than 2, the shells typically have a radius of 0.5 Mpc, a velocity of about 50 km/sec, a metal abundance of about 0.0001 of cosmic values, and strong radiation in H I(Lyman-alpha), He II 304 A, and the IR fine-structure lines of C II and Si II. The predicted extragalactic background emission from many shells, strongly peaked toward the UV, sets an upper limit to the number of exploding sources at z values of about 10. Shell absorption lines of H I, C II, Si II, and Fe II, which may be seen at more recent epochs in quasar spectra, may probe otherwise invisible explosions in the early universe.

Shull, J. M.↗
NASA NTRS1990

Performance of bismuth germanate active shielding on a balloon flight over Antarctica

The GRAD (Gamma-Ray Advanced Detector) gamma-ray spectrometer was flown on a balloon at an altitude of 36.6 km over Antarctica on January 8-10, 1988, where it was used to make observations of SN 1987A. The performance of the bismuth germanate (BGO) active shielding in the near-space environment over Antarctica is examined. The promised effectiveness of this shielding in the suppression of unwanted background has been demonstrated. The BGO-shielded GRAD spectrometer detected gamma-ray lines with fluxes of 0.002/sq cm sec from SN 1987A in a radiation background approximately a factor of 4 more intense than that over Alice Springs, Australia. This level of sensitivity indicates that BGO is at least as effective as CsI when used as active shielding. Isomerism is common, both in the bismuth and germanium regions of the nuclear chart, but is found to be less of a problem for background suppression in the latter region than in the former.

Rester, A. C.↗
NASA NTRS1991

The diffuse infrared background - COBE and other observations

The Diffuse Infrared Background Experiment (DIRBE) on the Cosmic Background Explorer (COBE) satellite is designed to conduct a sensitive search for an isotropic cosmic infrared background radiation over the spectral range from 1 to 300 micrometers. The cumulative emissions of pregalactic, protogalactic, and evolving galactic systems are expected to be recorded in this background. The DIRBE instrument, a 10 spectral band absolute photometer with an 0.7 deg field of view, maps the full sky with high redundancy at solar elongation angles ranging from 64 to 124 degrees to facilitate separation of interplanetary, Galactic, and extragalactic sources of emission. Initial sky maps show the expected character of the foreground emissions, with relative minima at wavelengths of 3.4 micrometers and longward of 100 micrometers. Extensive modelling of the foregrounds, just beginning, will be required to isolate the extragalactic component. In this paper, we summarize the status of diffuse infrared background observations from the DIRBE, and compare preliminary results with those of recent rocket and satellite instruments.

Hauser, M. G.↗
DOE OSTI2026

Development of a broadband hard x-ray radiography platform for pulsed-power experiments

In this article, we develop and demonstrate a broadband hard x-ray radiography platform at the Zebra Pulsed Power Laboratory that integrates point-projection radiography, bremsstrahlung measurements, and hard x-ray pinhole imaging, designed to diagnose current-driven, cylindrically compressed matter. Initial laser-pulsed-power coupled experiments revealed that intense background radiation generated during 1 MA Zebra current shots overwhelmed laser-produced hard x-rays, obscuring radiographic images. Using combined spectral and spatial diagnostics, we identify energetic electrons accelerated by return currents as the dominant source of background hard x-rays, with electron energies inferred to be 3–4 MeV based on Monte Carlo simulations, and demonstrate mitigation through modifications to the radiation shielding and return-current configuration. The diagnostic platform was validated using a wire-pinch hard x-ray source, allowing radiographs of static 1-mm-diameter aluminum wires to be obtained while simultaneously measuring x-ray source spectra and spatial emission distributions within a single shot. Measured wire transmission profiles were quantitatively reconstructed using radiation transport simulations that incorporate an experimentally inferred two-temperature exponential x-ray spectrum from bremsstrahlung signal analysis and spatially distributed emission sources identified by pinhole imaging. Agreement between measured and simulated transmission profiles demonstrates the validity of the radiographic and x-ray source characterization approach, establishing this diagnostic platform as a promising tool for diagnosing magnetically driven, high-density plasmas relevant to warm dense matter and inertial fusion energy research.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS2001

Neutron environments on the Martian surface

Radiation is a primary concern in the planning of a manned mission to Mars. Recent studies using NASA Langley Research Center's HZETRN space radiation transport code show that the low energy neutron fluence on the Martian surface is larger than previously expected. The upper atmosphere of Mars is exposed to a background radiation field made up of a large number of protons during a solar particle event and mixture of light and heavy ions caused by galactic cosmic rays at other times. In either case, these charged ions interact with the carbon and oxygen atoms of the Martian atmosphere through ionization and nuclear collisions producing secondary ions and neutrons which then interact with the atmospheric atoms in a similar manner. In the past, only these downward moving particles have been counted in evaluating the neutron energy spectrum on the surface. Recent enhancements in the HZETRN code allow for the additional evaluation of those neutrons created within the Martian regolith through the same types of nuclear reactions, which rise to the surface. New calculations using this improved HZETRN code show that these upward moving neutrons contribute significantly to the overall neutron spectrum for energies less than 10 MeV.

NASA Center LaRC↗
DOE OSTI2026

Detector Characterization for SuperCDMS Commissioning

Super Cryogenic Dark Matter Search (SuperCDMS) SNOLAB is a next generation direct detection experiment search ing for low mass dark matter using cryogenic germanium and silicon detectors operated at millikelvin temperatures. As the experiment begins its first commissioning data taking, establishing that the detectors respond to energy deposits in a stable, predictable way is a prerequisite for any future physics analysis. This work presents a study of detector stability for four SuperCDMS SNOLAB detectors, det 7 and det 15 (germanium), and det 11 and det 14 (silicon), using two data sets taken during early commissioning: dedicated Barium-133 calibration runs, which provide a known gamma ray energy reference at 356 keV, and low background runs, which record whatever background radiation the detectors see with no external source present. The Ba-133 data do not show a distinct, well localized line at the expected energy, and the low background data show a baseline that drifts and oscillates over time rather than remaining flat. This baseline instability appears consistently across multiple channels rather than being confined to one, suggesting a shared, detector wide cause rather than a single faulty channel. Together, these observations point to the detectors’ cryogenic support system as the likely source of the instability, since small temperature fluctuations introduced during normal operation of the cooling system could plausibly couple into the exquisitely temperature sensitive detectors. These results inform the ongoing commissioning effort by narrowing down where instability in the current data is originating from.

O'Hanlon, Viktoria M. [Skidmore Coll.; Fermilab]↗
DOE OSTI2026

Detector Characterization for SuperCDMS Commissioning

Super Cryogenic Dark Matter Search (SuperCDMS) SNOLAB is a next generation direct detection experiment search ing for low mass dark matter using cryogenic germanium and silicon detectors operated at millikelvin temperatures. As the experiment begins its first commissioning data taking, establishing that the detectors respond to energy deposits in a stable, predictable way is a prerequisite for any future physics analysis. This work presents a study of detector stability for four SuperCDMS SNOLAB detectors, det 7 and det 15 (germanium), and det 11 and det 14 (silicon), using two data sets taken during early commissioning: dedicated Barium-133 calibration runs, which provide a known gamma ray energy reference at 356 keV, and low background runs, which record whatever background radiation the detectors see with no external source present. The Ba-133 data do not show a distinct, well localized line at the expected energy, and the low background data show a baseline that drifts and oscillates over time rather than remaining flat. This baseline instability appears consistently across multiple channels rather than being confined to one, suggesting a shared, detector wide cause rather than a single faulty channel. Together, these observations point to the detectors’ cryogenic support system as the likely source of the instability, since small temperature fluctuations introduced during normal operation of the cooling system could plausibly couple into the exquisitely temperature sensitive detectors. These results inform the ongoing commissioning effort by narrowing down where instability in the current data is originating from.

O'Hanlon, Viktoria M. [Skidmore Coll.; Fermilab]↗
NASA NTRS1980

Baffle design for earth radiation rejection in the Cryogenic Limb-Scanning Interferometer/Radiometer

The Cryogenic Limb-Scanning Interferometer/Radiometer (CLIR) is being developed to observe infrared emissions of the earth's upper atmosphere from space. The earth's surface is an extended source of intense background radiation with a small angular separation from the desired scene. The CLIR employs an off-axis Gregorian Telescope whose primary mirror and baffles are cooled by an open-cycle cryogen system. A system of specular annular baffles has been developed to minimize both stray light problems and cryogen consumption by retro-mapping the aperture into itself. Each off-axis ray which enters the aperture and strikes the specular baffle surface is reflected so that it passes out of the aperture and is not absorbed on a cryogenic surface. The specular baffle which lies closest to the aperture is an ellipsoid whose foci trace out the circular aperture on revolution about the axis. Its theoretical 'ray trace' efficiency is 100 percent. A subsequent baffle has an elliptical cross section whose near focus traces out the central hole in the ellipsoidal baffle and whose far focus traces out the aperture. Its theoretical efficiency is about 90 percent. These baffles reduce the earth radiation heat load on the cryogenic cooler by an order of magnitude, changing it from the dominant cause of cryogen consumption to a relatively small effect. An aperture shield is also desirable to reduce cryogen consumption, stray light, and contamination.

Bremer, J. C.↗