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Flight calibration source development
An important element in monitoring the sensitivity of flight instrumentation throughout a flight is a reliable reference. Tungsten filament quartz halogen and deuterium UV sources were tested for this purpose. All three types were obtained from available commercial supplies and were tested against various mission requirements, particularly long term stability characteristics. Stability tests were made before and after thermal vacuum and vibration tests.
Cryogenic Blackbody-Radiation Calibration Source
Operating temperatures range from ambient down to minus 100 degrees C. V-grooved front face of source body blackened and recessed in black sleeve. Semiairtight chamber that houses source purged with dry nitrogen gas to prevent formation of dew or frost at low operating temperature.
Wavelength Calibration Sources for Extreme Precision Radial Velocity Detection of Exoplanets
No abstract provided
A Multi-source Calibrated GOES Dataset and Solar Radiation Environment Model Update
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A Multi-source Calibrated GOES Dataset and Solar Radiation Environment Model Update
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Non-radioisotopic gamma-ray calibration source for radiation detection instruments
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A 136 MHz ground station calibration using celestial noise sources
Calibration technique using celestial radio sources for 136 MHz satellite ground station
DSN 70-meter antenna microwave optics design and performance improvements. Part 2: Comparison with measurements
The measured Deep Space Network (DSN) 70-meter antenna performance at S- and X-bands is compared with the design expectations. A discussion of natural radio-source calibration standards is given. New estimates of DSN 64-meter antenna performance are given, based on improved values of calibration source flux and size correction. A comparison of the 64- and 70-meter performances shows that average S-band peak gain improvement is 1.94 dB, compared with a design expectation of 1.77 dB. At X-band, the average peak gain improvement is 2.12 dB, compared with the (coincidentally similar) design expectation of 1.77 dB. The average measured 70-meter S-band peak gain exceeds the nominal design-expected gain by 0.02 dB; the average measured 70-meter X-band peak gain is 0.14 dB below the nominal design-expected gain.
Radio Frequency Plasma Discharge Lamps for Use as Stable Calibration Light Sources
Stable high radiance in visible and near-ultraviolet wavelengths is desirable for radiometric calibration sources. In this work, newly available electrodeless radio-frequency (RF) driven plasma light sources were combined with research grade, low-noise power supplies and coupled to an integrating sphere to produce a uniform radiance source. The stock light sources consist of a 28 VDC power supply, RF driver, and a resonant RF cavity. The RF cavity includes a small bulb with a fill gas that is ionized by the electric field and emits light. This assembly is known as the emitter. The RF driver supplies a source of RF energy to the emitter. In commercial form, embedded electronics within the RF driver perform a continual optimization routine to maximize energy transfer to the emitter. This optimization routine continually varies the light output sinusoidally by approximately 2% over a several-second period. Modifying to eliminate this optimization eliminates the sinusoidal variation but allows the output to slowly drift over time. This drift can be minimized by allowing sufficient warm-up time to achieve thermal equilibrium. It was also found that supplying the RF driver with a low-noise source of DC electrical power improves the stability of the lamp output. Finally, coupling the light into an integrating sphere reduces the effect of spatial fluctuations, and decreases noise at the output port of the sphere.
Uniform, variable light sources for instrument calibration.
Light sources with uniform variable luminance field designed for calibrating cameras used in space exploration
Uniform variable light sources for instrument calibration
Light sources design with variable uniform luminance for space exploration cameras calibration
An upgraded frequency-selectable laser source (FLS) calibrator for CMB bandpass characterization
One of the biggest challenges for Cosmic Microwave Background (CMB) experiments comes from the uncertainty in instrument bandpass calibration. Uncertainties in bandpass can limit foreground removal and spectral fitting, which are critical for inflationary and galaxy cluster measurements. CMB experiments currently use Fourier Transform Spectrometers (FTSes) to measure instrument bandpasses. However, FTS systems are currently systematics-limited, so significant improvements in bandpass measurements require novel calibrators. To this end, we developed a Frequency-selectable Laser Source (FLS) calibrator, which uses a laser with adjustable frequency coupled to a system that allows for laser power attenuation. Following initial testing with the first FLS prototype, we developed an upgraded version of the calibrator with improved performance. We present the upgrades to the FLS calibrator, the characterization of the upgraded calibrator and new laser source, and plans for testing with microwave instruments in the field.
Infrared thermometry in high temperature materials processing: influence of liquid water and steam
Here, the capability of four infrared thermometry techniques (2-colour and 1-colour pyrometers, Pyrolaser and IR camera) was evaluated with respect to the impact of water or steam in the line of sight to determine temperature from two heat sources (blackbody calibration source and steel block inside the furnace). The influence of liquid water on the temperature readings was minimal when using 2-colour pyrometry due to comparable absorption coefficients of water for the measured wavelengths. The signals measured using both the Pyrolaser and the 1-colour pyrometer were decreased due to the partial absorption and resulted in an apparent temperature lower than the actual. Water readily absorbed the IR signal in the range of the IR camera operation, resulting in no signal whenever liquid water was present in the line of sight. Steam caused the most deviation and fluctuation of temperature readings for all techniques due to the large level of light scattering in addition to the absorption of the radiant energy. A technique was developed to determine the transmissivity (apparent emissivity) when water or steam is in the line of sight of measurement. An approximate correction to the measurements based on Planck’s law is discussed for both 2-colour and 1-colour pyrometers.
RF ion mass spectrometer calibration ion source system Final report, Oct. 1964 - Mar. 1968
Plasma-ion source system for ground calibration of Bennett RF ion mass spectrometer
Thermal calibration target
Blackbody source calibrates the response of a medium resolution infrared radiometer used on a meteorological satellite. This approach controls the temperature of a thermal calibrating device over a wide range without the need for controlling a liquid nitrogen input to the device. The availability of liquid nitrogen achieves the required thermal control.
Noise Source for Calibrating a Microwave Polarimeter
A correlated-noise source has been developed for use in calibrating an airborne or spaceborne Earth-observing correlation microwave polarimeter that operates in a in a pass band that includes a nominal frequency of 10.7 GHz. Deviations from ideal behavior of the hardware of correlation polarimeters are such as to decorrelate the signals measured by such an instrument. A correlated-noise source provides known input signals, measurements of which can be processed to estimate and correct for the decorrelation effect.