scholarly journals Angular resolution in VCSEL radiant intensity distribution measurements

2021 ◽  
Vol 18 (3) ◽  
pp. 58-61
Author(s):  
Günther Leschhorn ◽  
Thomas Attenberger ◽  
Tobias Schneider
Keyword(s):  
Intensity Distribution ◽  
Angular Resolution ◽  
Radiant Intensity

Spatial Distribution of Radiant Intensity from Primary Sources for Atomic Absorption Spectrometry. Part I: Hollow Cathode Lamps

1995 ◽  
Vol 49 (4) ◽  
pp. 413-424 ◽  
Author(s):  
Albert Kh. Gilmutdinov ◽  
Bernard Radziuk ◽  
Michael Sperling ◽  
Bernhard Welz ◽  
Konstantin Yu. Nagulin
Keyword(s):  
Spatial Distribution ◽  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Intensity Distribution ◽  
Hollow Cathode ◽  
Imaging System ◽  
Absorption Spectrometry ◽  
Operating Conditions ◽  
Radiant Intensity ◽  
Warm Up

The spatial distribution of radiant intensity from hollow cathode lamps used as radiation sources in atomic absorption spectrometry is investigated with a digital photodiode array imaging system. Intensity distribution over the cross section of each lamp is measured for both atomic and ionic lines of the analyte and the filler gas. The shape of the distribution is strongly dependent on the hollow cathode diameter. In small cathodes the distribution has the shape of a paraboloid with maximum intensity at the hollow cathode axis for all of the recorded lines. The intensity distributions of lines emitted from large cathodes are nonparaboloid and in some cases have a minimum at the cathode axis and a maximum concentric to the cathode walls. It is shown that the intensity distribution for a given lamp has practically the same shape for all currents applied. Data on the evolution of the intensity distribution during warm-up of the lamps and under various operating conditions are presented.

The Relationship of the Radiant Intensity Distribution of Focal Spots to Resolution

Radiology ◽  
1974 ◽  
Vol 111 (2) ◽  
pp. 427-431 ◽  
Author(s):  
Hyman Bernstein ◽  
R. Thomas Bergeron ◽  
David J. Klein
Keyword(s):  
Intensity Distribution ◽  
Radiant Intensity ◽  
Relationship Of ◽  
The Relationship

Design of a uniform irradiance source based on light emitting diodes

2021 ◽  
pp. 147715352110010
Author(s):  
E Rojas Villafañe ◽  
A Valor ◽  
JM de la Rosa ◽  
D Fabila-Bustos ◽  
S Stolik
Keyword(s):  
Intensity Distribution ◽  
Theoretical Calculations ◽  
Light Emitting Diode ◽  
Simulation Method ◽  
Diode Array ◽  
Light Sources ◽  
Uniform Illumination ◽  
Radiant Intensity ◽  
Light Emitting ◽  
Simulation Results

Many applications in various fields require uniform illumination from light sources, for example, in medical imaging in the biophotonics area. In this work, the design and application of an annular light-emitting diode array capable of producing a homogeneous irradiance pattern is presented. As part of the design process, software that allows the simulation of the irradiance pattern as a function of the LED’s radiant intensity distribution, and the position and inclination angle of the LEDs, was developed and validated. Based on the simulation results, a source that produces homogeneous illumination over an area of 20 mm in diameter, where the lowest irradiance is more than 94% of the maximum irradiance, was constructed and tested in real conditions. The simulation method and theoretical calculations on which the array is based can be applied to the design of sources for other applications where a homogeneous irradiance is required.

Mapping the Galactic Free-Free Foreground via Interstellar Hα Emission

2005 ◽  
Vol 201 ◽  
pp. 116-125
Author(s):  
R. J. Reynolds ◽  
L. M. Haffner
Keyword(s):  
Intensity Distribution ◽  
Angular Resolution ◽  
Galactic Latitude ◽  
Dust Grains ◽  
High Galactic Latitude ◽  
Spectral Fitting ◽  
Fitting Procedures ◽  
Hα Emission

Recently completed Hα surveys of large portions of the sky can be used to create maps of the free-free intensity distribution at high Galactic latitude that are independent of the spectral fits to the CMB data. This provides an opportunity to test the accuracy of the spectral fitting procedures and to search for other sources of Galactic forground contamination that could be confused spectrally with the free-free, such as spinning dust grains. The Wisconsin Hα Mapper (WHAM) survey has sampled the sky north of declination −30° at about one degree angular resolution and has revealed that, except for a few isolated regions of enhanced emission, δTff (30 GHz) ≲ 30 μK at Galactic latitudes near 15°, decreasing to δTff(30 GHz) ≲ 4 μK at latitudes above 50°. Also in progress are Hα surveys that sample the sky at higher angular resolution.

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