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Results for “Kendall cavity radiometer”

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All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Special Pyrheliometer Shroud Development

To insure that the insolation values accurately represent the input power to a power conversion unit the field of view (FOV) of the concentrator aperture and the insolation radiometer must be the same. The calculations, implementation, and results of this approach are covered. Three instruments were used to measure the insolation: an Eppley Normal Incidence Radiometer (NIP) and two versions of the kendall cavity radiometer. The shrouds used to limit the FOV of the radiometers were designed to simulate the FOV of the PDC-1 concentrater with the cold water cavity calorimeter. This technique of matching the FOV of an insolation radiometer to the FOV of a specific concentrater and receiver aperture appears to be both practical and effective. The efficiency of a power conversion unit will be too low if the insolation is measured with a radiometer which has a FOV which is larger than the FOV of the concentrator.

Dennison, E. W.↗
NASA NTRS1978

Calibration standards and field instruments for the precision measurement of insolation

The paper describes the development of an absolute calibration standard for irradiance measurements. This field instrument, designated the Kendall Radiometer System Mark 3, is identical to the PACRAD (Primary Absolute Cavity Radiometer) except for a modification to ensure all weather operation. Two Mark 3 radiometers have been in operation at the JPL's Goldstone Deep Space Communications Complex for over two years and are continuing to provide data which are within plus or minus 1% of the absolute value. A calibration stability analysis is presented for the two instruments.

Reid, M. S.↗
NASA NTRS1977

Precision insolation measurement under field conditions

The paper describes a precision insolation instrument - the Mark 3 Kendall Radiometer - developed for field survey work and for use as a calibration transfer standard. The instrument, which can be used to make accurate measurements of solar irradiance, has a windowless black cavity receptor mounted in a massive heat sink and has equal sensitivity to ultraviolet, infrared, and visible radiation. Attention is given to a calibration stability analysis over two years of operation.

Reid, M. S.↗
NASA NTRS1967

Improved cavity-type absolute total-radiation radiometer

Conical cavity-type absolute radiometer measures the intensity of radiant energy to an accuracy of one to two percent in a vacuum of ten to the minus fifth torr or lower. There is a uniform response over the ultraviolet, visible, and infrared range, and it requires no calibration or comparison with a radiation standard.

Kendall, J. M., Sr.↗
NASA NTRS1977

Rocket calibration of the Nimbus 6 solar constant measurements

A sounding rocket experiment was performed in June 1976, in which the solar constant was observed simultaneously outside the earth's atmosphere by three types of absolute cavity radiometers (the Primary Absolute Cavity Radiometer and two Active Cavity Radiometers, Type IV) and duplicates of Nimbus 6 ERB/ESP (Earth Radiation Budget/Eclectic Satellite Pyrheliometer) solar channels. The preliminary average solar constant result from the cavity radiometers is 1367 W/sq m with an uncertainty of less than plus or minus 0.5% in SI units. The duplicate ERB channel 3 on the rocket gave a value of 1389 W/sq m, which agreed exactly with the Nimbus 6 ERB channel 3 measurement made simultaneously with the rocket flight.

Duncan, C. H.↗
NASA NTRS1977

Rocket calibration of the Nimbus 6 solar constant measurements

Total solar irradiance was observed simultaneously outside the earth's atmosphere by three types of absolute cavity radiometers and duplicates of four of the Nimbus 6 Earth Radiation Budget (ERB) solar channels in a June 1976 sounding rocket experiment. The preliminary average solar constant result from the cavity radiometers is 1367 Wm (-2) with an uncertainty of less than + or - 0.5% in S.I. units. The duplicate ERB channel 3 on the rocket gave a value of 1389 Wm (-2) which agreed exactly with the Nimbus 6 ERB channel 3 measurement made simultaneously with the rocket flight.

Duncan, C. H.↗
NASA NTRS1981

Radiometer for accurate (+ or - 1%) measurement of solar irradiance equal to 10,000 solar constants

The 10,000 solar constant radiometer was developed for the accurate (+ or - 1%) measurement of the irradiance produced in the image formed by a parabolic reflector or by a multiple mirror solar installation. This radiometer is water cooled, weighs about 1 kg, and is 5 cm (2 in.) in diameter by 10 cm (4 in.) long. A sting is provided for mounting the radiometer in the solar installation capable of measuring irradiances as high as 20,000 solar constants, the instrument is self calibrating. Its accuracy depends on the accurate determination of the cavity aperture, and absorptivity of the cavity, and accurate electrical measurements. The spectral response is flat over the entire spectrum from far UV to far IR. The radiometer responds to a measurement within 99.7% of the final value within 8 s. During a measurement of the 10,000 solar constant irradiance, the temperature rise of the water is about 20 C. The radiometer has perfect cosine response up to 60 deg off the radiometer axis.

Kendall, J. M., Sr.↗