Results 241 to 250 of about 882,775 (293)
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Optics Communications, 1976
Abstract The homogeneity of various types of self-sustained TEA laser discharges in CO 2 -N 2 -He mixtures has been investigated. It is shown that the double Rogowski uv-preionized configuration is the most suitable for the attainment of high quality laser emission. In such systems refractive index variations are delayed for the longest period.
Dufour, M., Egger, H., Seelig, W.
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Abstract The homogeneity of various types of self-sustained TEA laser discharges in CO 2 -N 2 -He mixtures has been investigated. It is shown that the double Rogowski uv-preionized configuration is the most suitable for the attainment of high quality laser emission. In such systems refractive index variations are delayed for the longest period.
Dufour, M., Egger, H., Seelig, W.
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Beam quality measurements using digitized laser beam images
Applied Optics, 1989A method is described for measuring various laser beam characteristics with modest experimental complexity by digital processing of the near and far field images. Gaussian spot sizes, peak intensities, and spatial distributions of the images are easily found. Far field beam focusability is determined by computationally applying apertures of circular or
M D, Duncan, R, Mahon
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Photon beam quality specification by narrow-beam transmission measurements
Physics in Medicine and Biology, 1994Radiation quality specifications in megavoltage photon beams are usually based on depth-dose measurements performed under reference conditions. Stopping-power ratios and various correction factors are then related to parameters such as TPR(10)20, which are extracted from depth-dose measurements. Stopping-power ratio determinations based on this concept
H, Nyström, M, Karlsson
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Quality of paraxial electromagnetic beams
Applied Optics, 2006The full wave theory of focused waves is developed and the radiation intensity distribution is determined. In the appropriate limit, the full wave theory correctly reproduces the paraxial beams. The limitations of paraxial beam theories are discussed. The method of treatment of full waves is presented with reference to the scalar Bessel-Gauss beam and ...
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Checking diagnostic X-ray beam quality
The British Journal of Radiology, 1968Abstract A radiographic method is described for comparing the effective kilovoltage and inherent nitration of diagnostic X-ray machines. The apparatus consists of a modified Xray cassette covered by a sheet of lead perforated with two rows of holes; one row is associated with a strip of slow intensifying screen and provides a reference exposure, the ...
G M, Ardran, H E, Crooks
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Quality improvement of partially polarized beams
Applied Optics, 2001Improvement of the beam-quality parameter of partially polarized beams is investigated. We focus on the use of a Mach-Zehnder-type interferometric arrangement with crossed polarizers. The analysis has been carried out within the framework of the intensity moment formalism. Conditions are given under which the beam-quality parameter is optimized.
J M, Movilla +2 more
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Laser beam quality characterization
SPIE Proceedings, 1998The demands on the quality of laser beams are becoming much greater. Traditional methods of measuring laser intensity profile such as burn spots, mode burns, and viewing the reflected beam, are woefully inadequate for today's applications. The increasingly high quality of lasers is to a large extent due to the availability of electronic beam profile ...
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Longitudinal beam quality monitoring
2020Reliable monitoring of the longitudinal beam quality is essential for a safe and effcient operation of any high intensity accelerator. The definition of beam quality criteria vary from one machine to the other, depending on the beam and machine parameters.
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Method to evaluate beam quality of Gaussian beams with aberrations
Applied Optics, 2012Zernike polynomials are commonly used to describe the aberration of light beams, and the beam quality of Gaussian beams with aberrations can be deduced when the order of Zernike polynomials is limited. In this paper, Hermite polynomials are utilized to reconstruct the aberrations of Gaussian beams.
Yuntao, Qiu +5 more
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BNCT Beam Quality Maximization
2001The Beam Shaping Assembly (BSA) optimization code SWAN is applied for establishing (1) the maximum attainable beam quality dependence on the BSA thickness; (2) the tradeoff between the maximum attainable beam quality and the dose-equivalent delivered, per source neutron, to the tumor; (3) the sensitivity of the above characteristics to the BSA ...
E. Greenspan, Y. Karni
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