scholarly journals Spectral Radiance of a Large-Area Integrating Sphere Source

1995 ◽  
Vol 100 (1) ◽  
pp. 37 ◽  
Author(s):  
J.H. Walker ◽  
A. Thompson
Keyword(s):  
Spectral Radiance ◽  
Integrating Sphere ◽  
Large Area

Computer modeling of a large-area integrating sphere uniform radiation source for calibration of satellite remote sensors

Optik ◽  
2011 ◽  
Vol 122 (13) ◽  
pp. 1143-1145 ◽  
Author(s):  
Yingwei He ◽  
Ping Li ◽  
Guojin Feng ◽  
Yu Wang ◽  
Zilong Liu ◽  
...  
Keyword(s):  
Computer Modeling ◽  
Radiation Source ◽  
Integrating Sphere ◽  
Large Area ◽  
Remote Sensors

Validation of spectral radiance assignments to integrating sphere radiance standards for the Advanced Baseline Imager

2014 ◽  
Author(s):  
B. C. Johnson ◽  
Stephen Maxwell ◽  
Eric Shirley ◽  
Kim Slack ◽  
Gary D. Graham
Keyword(s):  
Spectral Radiance ◽  
Integrating Sphere

scholarly journals Adjustable light source for low light level with nearly constant correlated color temperature

2022 ◽  
Vol 2149 (1) ◽  
pp. 012016
Author(s):  
Z F Wu ◽  
L Li ◽  
C H Dai ◽  
Y F Wang ◽  
Q T Cheng ◽  
...  
Keyword(s):  
Light Source ◽  
Spectral Distribution ◽  
Light Level ◽  
Color Temperature ◽  
Spectral Radiance ◽  
Integrating Sphere ◽  
Spectral Difference ◽  
Low Light ◽  
Light Levels ◽  
Variable Aperture

Abstract Low light level (LLL) calibration becomes more and more important since the rapid growth of remote sensing. The spectral radiance at normal higher light levels can be calibrated with good accuracy, while LLL spectral radiance cannot. If an adjustable light source can be designed at nearly constant correlated color temperature (CCT) covering several orders of magnitude, low light level spectral radiance can be obtained with the help of a photodetector. Whether or not the spectral distribution of an integrating sphere based light source is nearly constant is investigated. By adjusting the diameter of the variable aperture between the integrating sphere and tungsten lamp, the spectral radiance can be varied over 6 orders of magnitude. However, the relative spectrum in the red region increases notably when the spectral radiance is decreased to 1/100000. If the spectral radiance is decreased further, the spectral difference can be more than 300% and CCT decreases more than 250 K. By using baffles and another integrating sphere, low light level radiation source at nearly constant spectral distribution is obtained. The variation of CCT is less than 50 K over 6 orders of magnitude.

Simulation and Design on a New Uniform Radiation Source for Calibration of Satellite Remote Sensors

2012 ◽  
Vol 500 ◽  
pp. 574-578
Author(s):  
Ting Liang Guo ◽  
Guo Jin Feng ◽  
Yu Wang
Keyword(s):  
Radiation Source ◽  
Integrating Sphere ◽  
Complex Task ◽  
Large Area ◽  
Design Efficiency ◽  
Remote Sensors ◽  
Tracing Algorithm ◽  
Inner Light ◽  
Very High ◽  
Practical Measurement

High-precision calibration of space sensors is a complex task. For calibration, integrating sphere system is the main equipment to produce large area uniform radiation source. Such integrating spheres are usually very huge with large diameters, generally more than one meter. Furthermore, such a large integrating sphere costs very high. In order to reduce the size of integrating sphere and cost, the necessary pre-simulation is very necessary. In this paper, a new semi-integrating sphere with 1300mm diameter was designed by using of ray-tracing algorithm on different special structures to improve the design efficiency. The results showed that, 1. The output of semi-integrating sphere system is more sensitive to its inner light source location and the aperture. 2. The practical measurement of semi-integrating sphere is approaching to the simulation findings. Although the opening diameter of semi-integrating sphere reaches to 50% of the diameter of semi-integrating sphere, the output radiance uniformity is still larger than 95% and with better performance.

Remote Raman Efficiencies and Cross-Sections of Organic and Inorganic Chemicals

2016 ◽  
Vol 71 (5) ◽  
pp. 1025-1038 ◽  
Author(s):  
Tayro E. Acosta-Maeda ◽  
Anupam K. Misra ◽  
John N. Porter ◽  
David E. Bates ◽  
Shiv K. Sharma
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Fused Silica ◽  
Spectral Radiance ◽  
Integrating Sphere ◽  
Organic Liquids ◽  
Experimental Conditions ◽  
Phosphate Ions ◽  
The University ◽  
532 Nm

We determined Raman cross-sections of various organic liquids and inorganic polyatomic ions in aqueous solutions with a 532 nm pulsed laser using remote Raman systems developed at the University of Hawaii. Using a calibrated integrating sphere as a light source, we converted the intensity counts in the spectrum of the light from the integrating sphere measured with UH remote Raman instrument to spectral radiance. From these data, a response function of the remote Raman instrument was obtained. With the intensity-calibrated instrument, we collected remote Raman data from a standard 1 mm path length fused silica spectrophotometer cell filled with cyclohexane. The measured value of the differential Raman cross-section for the 801 cm−1 vibrational mode of cyclohexane is 4.55 × 10−30 cm2 sr−1 molecule−1 when excited by a 532 nm laser, in good agreement with the values reported in the literature. Using the measured cyclohexane Raman cross-section as a reference and relative Raman mode intensities of the various ions and organic liquids, we calculated the Raman cross-sections of the strongest Raman lines of nitrate, sulfate, carbonate, phosphate ions, and organic liquids by maintaining same experimental conditions for remote Raman detection. These relative Raman cross-section values will be useful for estimating detection capabilities of remote Raman systems for planetary exploration.

scholarly journals Radiometric calibration of the in-flight blackbody calibration system of the GLORIA interferometer

2013 ◽  
Vol 6 (3) ◽  
pp. 5251-5295 ◽  
Author(s):  
C. Monte ◽  
B. Gutschwager ◽  
A. Adibekyan ◽  
M. Kehrt ◽  
A. Ebersoldt ◽  
...  
Keyword(s):  
Standard Uncertainty ◽  
Spectral Radiance ◽  
Radiometric Calibration ◽  
Calibration System ◽  
Large Area ◽  
Traceability Chain ◽  
3 Dimensional ◽  
Long Term Stability ◽  
Short And Long Term ◽  
Airborne Imaging

Abstract. GLORIA is an airborne, imaging, infrared Fourier transform spectrometer that applies the limb-imaging technique to perform trace gas and temperature measurements in the Earth's atmosphere with 3-dimensional resolution. To ensure the traceability of these measurements to the International Temperature Scale and thereby to an absolute radiance scale, GLORIA carries an on-board calibration system. It basically consists of two identical large area and high emissivity infrared radiators, which can be continuously and independently operated at two adjustable temperatures in a range from −50 °C to 0 °C during flight. Here we describe the radiometric and thermometric characterization and calibration of the in-flight calibration system at the Reduced Background Calibration Facility of the Physikalisch-Technische Bundesanstalt with a standard uncertainty of less than 100 mK. Extensive investigations of the system concerning its absolute radiation temperature and spectral radiance, its temperature homogeneity and its short- and long-term stability are discussed. The traceability chain of these measurements is presented.

scholarly journals Radiometric calibration of the in-flight blackbody calibration system of the GLORIA interferometer

2014 ◽  
Vol 7 (1) ◽  
pp. 13-27 ◽  
Author(s):  
C. Monte ◽  
B. Gutschwager ◽  
A. Adibekyan ◽  
M. Kehrt ◽  
A. Ebersoldt ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Standard Uncertainty ◽  
Spectral Radiance ◽  
Radiometric Calibration ◽  
Calibration System ◽  
Large Area ◽  
Traceability Chain ◽  
Long Term Stability ◽  
Short And Long Term ◽  
Airborne Imaging

Abstract. GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) is an airborne, imaging, infrared Fourier transform spectrometer that applies the limb-imaging technique to perform trace gas and temperature measurements in the Earth's atmosphere with three-dimensional resolution. To ensure the traceability of these measurements to the International Temperature Scale and thereby to an absolute radiance scale, GLORIA carries an on-board calibration system. Basically, it consists of two identical large-area and high-emissivity infrared radiators, which can be continuously and independently operated at two adjustable temperatures in a range from −50 °C to 0 °C during flight. Here we describe the radiometric and thermometric characterization and calibration of the in-flight calibration system at the Reduced Background Calibration Facility of the Physikalisch-Technische Bundesanstalt. This was performed with a standard uncertainty of less than 110 mK. Extensive investigations of the system concerning its absolute radiation temperature and spectral radiance, its temperature homogeneity and its short- and long-term stability are discussed. The traceability chain of these measurements is presented.

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