Spectral variation of blackbody radiation.
Simplified method for determining spectral variation of blackbody radiation in terms of temperature
RADIATION MEASUREMENT↗
SEARCH · Engineering Papers
Results for “Blackbody”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Fast response, blackbody furnace for temperatures up to 3000 deg k.
Inductively heated graphite furnace, having a source of blackbody radiation, for calibration of pyrometers up to 3,000 degrees k
PYROMETER↗
Theoretical relationship between equivalent blackbody temperatures and surface temperatures measured by the Nimbus High Resolution Infrared Radiometer
Theoretical relationship between equivalent blackbody temperatures and surface temperatures measured by Nimbus High Resolution Infrared Radiometer /HRIR/
RADIOMETER↗
Modified blackbody device emits high-density radiation
Modified device provides a versatile, precisely controllable source of blackbody radiation to calibrate radiometers used for spectrometric analysis of large rocket engine plumes.
Schumacher, P. E.↗
An improvement in blackbody cavity design
Setting the axis of the conical cavity at an angle to the axis of observation removes the imperfection at the apex of the cone from the direct observation area of the radiometer. Fillet no longer behaves as a nonuniformity in the blackbody.
Schmidt, R. M.↗
Patterns of equivalent blackbody temperature and reflectance of model clouds computed by changing radiometers field of view
Equivalent blackbody temperature and reflectance patterns of model clouds computed by changing radiometer field of view
Tecson, J. J.↗
Equivalent blackbody temperature of the top of a severe storm
An RB-57F high-altitude aircraft equipped with Wilde RC-8 cameras and an infrared spectrometer was used in the investigations. A storm was overflown over Graham, Texas, on April 29, 1970. In the experiment, the average radiometric temperature was determined to be very near the environmental temperature near the cloud tops. However, hot and cold regions in and near the updrafts and downdrafts were found to be significantly out of equilibrium. It is recommended that caution should be exercised in determining cloud top altitude from equivalent blackbody temperature.
Pitts, D. E.↗
Detection of anisotropy in the cosmic blackbody radiation
Anisotropy has been detected in the cosmic blackbody radiation with a 33-GHz (0.9 cm) twin-antenna Dicke radiometer flown to an altitude of 20 km aboard a U-2 aircraft. In data distributed over two-thirds of the Northern Hemisphere, an anisotropy is observed, which is well fitted by a first-order spherical harmonic with an amplitude of (3.5 plus or minus 0.6) x 10 to the -3rd deg K, and direction 11.0 plus or minus 0.6 h right ascension and 6 plus or minus 10 deg declination. This observation is readily interpreted as due to motion of the earth relative to the radiation with a velocity of 390 plus or minus 60 km/sec.
Smoot, G. F.↗
Laser-induced two-photon blackbody radiation in the vacuum ultraviolet
Experimental measurements of a new type of vacuum-ultraviolet radiation source are reported. It is shown that the maximum source brightness, within its narrow linewidth, is that of a blackbody at the temperature of a metastable storage level. The laser-induced emission at 569 A from a He glow discharge corresponded to a metastable temperature of 22,700 K and was over 100 times brighter than the 584-A He resonance line.
Zych, L. J.↗
Predicting tropical cyclone intensity using satellite measured equivalent blackbody temperatures of cloud tops
A regression technique was developed to forecast 24 hour changes of the maximum winds for weak (maximum winds less than or equal to 65 Kt) and strong (maximum winds greater than 65 Kt) tropical cyclones by utilizing satellite measured equivalent blackbody temperatures around the storm alone and together with the changes in maximum winds during the preceding 24 hours and the current maximum winds. Independent testing of these regression equations shows that the mean errors made by the equations are lower than the errors in forecasts made by the peristence techniques.
Gentry, R. C.↗
Effect of blackbody radiation on the threshold for two-electron photodetachment of H/-/
The threshold law of the titled process, which is of the same form as that for electron-impact ionization of H, can experimentally be contaminated by simultaneous single photodetachment and Rydberg excitation of the residual atom, followed by ionization of the Rydberg atom by (room-temperature) blackbody photons. This gives a signal indistinguishable from direct double photodetachment. The correction is here calculated and shown to be finite at the double photodetachment threshold, and to have, possibly, an implication about the form of the threshold law itself. However, at room temperature its contribution is found to be small as it pertains to a recently initiated experiment at the Los Alamos Meson Physics Facility for available energies greater than a millivolt above threshold. The temperature dependence of the correction is shown to be large (k/B/T) to the 7/2; thus at higher temperatures the effect may be observable.
Temkin, A.↗
Low background spectral response of 30-130-micron detectors from blackbody measurements
Low background far infrared detector responsivity and low background spectral response calibrations can be performed simultaneously with a cooled, temperature-swept blackbody. This makes the use of a cooled, low background spectrometer unnecessary in many applications. Calibrations of a beryllium-doped germanium detector showing unwanted 100-micron response, and of a gallium-doped germanium detector, are described.
Moore, W. J.↗
Irradiance from stars based on blackbody theory
A computer program which calculates a theoretical backbody curve for a star when given only the star's temperature and visual magnitude is presented. The program was written to produce approximate stellar spectra to be used in the design of the Space Telescope Fine Guidance System (FGS). In addition to the blackbody curve, the program calculates the number of photons tht would be received by the Space Telescope per 25 MSEC interval in wavelength increments of 0.2 microns. The equations used for the computations work best for stars that emit primarily in the range of near infrared to ultraviolet.
Jacobs, W. A.↗
A blackbody-pumped CO2-N2 transfer laser
A compact blackbody-pumped CO2-N2 transfer laser was constructed and the significant operating parameters were investigated. Lasing was achieved at 10.6 microns by passing preheated N2 through a 1.5-mm-diameter nozzle to a laser cavity where the N2 was mixed with CO2 and He. An intrinsic efficiency of 0.7 percent was achieved for an oven temperature of 1473 K and N2 oven pressure of 440 torr. The optimum laser cavity consisted of a back mirror with maximum reflectivity and an output mirror with 97.5-percent reflectivity. The optimum gas mixture was 1CO2/.5He/6N2. The variation of laser output was measured as a function of oven temperature, nozzle diameter, N2 oven pressure, He and CO2 partial pressures, nozzle-to-oven separation, laser cell temperature, and output laser mirror reflectivity. With these parameters optimized, outputs approaching 1.4 watts were achieved.
Deyoung, R. J.↗
A cryogenic blackbody for millimeter wavelengths
The present cryogenic blackbody reference, or 'cold load', for mm-wavelength radiation has an emissivity of more than 0.99 over a two-octave wavelength range and can be used as a calibrating standard for sensitive IR photometers. The transmittance spectrum obtained indicates that wave impedance and index do not vary significantly over the 80-360 GHz range.
Peterson, J. B.↗
Anisotropy of the cosmic blackbody radiation
The universe is filled with thermal radiation having a current temperature of 2.75 K. Originating in the very early universe, this radiation furnishes strong evidence that the Big Bang cosmology best describes our expanding universe from an incredibly hot, compacted early stage until now. The model can be used to extrapolate our physics backward in time to predict events whose effects might be observable in the 2.75 K radiation today. The spectrum and isotropy are being studied with sophisticated microwave radiometers on the ground, in balloons, and in satellites. The results are as predicted by the simple theory: the spectrum is that of a blackbody (to a few percent) and the radiation is isotropic (to 0.01 percent) except for a local effect due to our motion through the radiation. However, a problem is emerging. Primordial fluctuations in the mass density, which later became the great clusters of galaxies that we see today, should have left an imprint on the 2.75 K radiation - bumpiness on the sky at angular scales of about 10 arc minutes. They have not been seen.
Wilkinson, D. T.↗
Miniature high stability high temperature space rated blackbody radiance source
This paper presents the design and test performance of a conical cavity type blackbody radiance source that will meet the requirements of the Halogen Occultation Experiment on the NASA Upper Atmospheric Research Satellite program. The thrust of this design effort was to minimize the heat losses, in order to keep the power usage under 7.5 watts, and to minimize the amount of silica in the materials. Silica in the presence of the platinum heater winding used in this design would cause the platinum to erode, changing the operating temperature set-point. The design required the development of fabrication techniques which would provide very small, close tolerance parts from extremely difficult-to-machine materials. Also, a space rated ceramic core and unique, low thermal conductance, ceramic-to-metal joint was developed, tested and incorporated in this design. The completed flight qualification hardware has undergone performance, environmental and life testing. The design configuration and test results are discussed in detail.
Jones, J. A.↗
Studies of blackbody-pumped lasers
Laser action was achieved in a large-scale pulsed system and meaningful experiments were carried out in the axial flow facility to understand the physics of solar-pumped lasers. Studies of the variation of laser mixture composition were done for mixtures of CO2 and N2O additions. Theoretical analysis and modeling of the system were also performed based on a model including radiative pumping, diffusion and wall deactivation, and vibrational energy transfer between two optically active species. Qualitative agreement between predictions in the parameter variation and the experimental results were obtained with CO and N2O mixtures. Several experimental studies were performed to quantify the properties of carbon monoxide as absorber and storage of energy in the blackbody pumped system.
Christiansen, W. H.↗