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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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Comment on “Quality of paraxial electromagnetic beams”
Applied Optics, 2008We comment on a recent paper by Seshadri [Appl. Opt.45, 5335 (2006)]APOPAI0003-693510.1364/AO.45.005335. In the cited work the author utilized the so-named Felsen method in order to derive the full wave expression of a scalar Bessel-Gauss field, propagating in free space, originated from an assigned input distribution on the source plane z = 0.
Omar, El Gawhary, Sergio, Severini
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Experimental validation of beam quality correction factors for proton beams
Physics in Medicine and Biology, 2015This paper presents a method to experimentally validate the beam quality correction factors (kQ) tabulated in IAEA TRS-398 for proton beams and to determine the kQ of non-tabulated ionization chambers (based on the already tabulated values). The method is based exclusively on ionometry and it consists in comparing the reading of two ionization chambers
Gomà, Carles +3 more
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Beam-quality measurement of a focused high-order harmonic beam
Optics Letters, 1998Using a multilayer spherical mirror, we focus the high-order harmonic radiation produced near 55 nm by the nonlinear interaction of an intense femtosecond laser pulse and a xenon gas jet. The focused XUV beam is characterized by a knife-edge technique in the focal region and by far-field imaging.
L, Le Déroff, P, Salières, B, Carré
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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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Effect of turbulence on the beam quality of apertured partially coherent beams
Journal of the Optical Society of America A, 2008The effects of turbulence on the beam quality of apertured partially coherent beams have been studied both analytically and numerically. Taking the Gaussian Schell-model (GSM) beam as a typical example of partially coherent beams, closed-form expressions for the average intensity, mean-squared beam width, power in the bucket, beta parameter, and Strehl
Xiaoling, Ji, Guangming, Ji
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Equivalent spectra as a measure of beam quality
Medical Physics, 1986The concept of the equivalent spectrum (Seq) is introduced, where Seq is defined as an idealized energy spectrum which results in identical attenuation properties as the actual spectrum of a given x‐ray tube. Seq is described by two parameters, the equivalent aluminum filtration Aleq and the equivalent kilovoltage kVeq, which are evaluated iteratively ...
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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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1983
The ability to control dose in terms of absolute value, repeatability from wafer to wafer, and uniformity across a wafer is the most important characteristic of any implanter.
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The ability to control dose in terms of absolute value, repeatability from wafer to wafer, and uniformity across a wafer is the most important characteristic of any implanter.
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The dependence of radiographic mottle on beam quality
American Journal of Roentgenology, 1976The dependence of radiographic mottle on beam quality has been studied for a variety of film/screen combinations. The measurement technique consisted of scanning the radiographs with a microdenitometer; the analogue signal from the microdesitometer was gated and recorded with a multichannel analyzer.
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