Results 271 to 280 of about 239,845 (311)
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1983
There are a variety of mechanisms which change the refractive index of the medium in which the pulse propagates. These changes in the refractive index may lead to a distortion of the wave-front of the pulse, thereby increasing the energy losses of the beam and deteriorating its focusibility.
Günter Brederlow +2 more
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There are a variety of mechanisms which change the refractive index of the medium in which the pulse propagates. These changes in the refractive index may lead to a distortion of the wave-front of the pulse, thereby increasing the energy losses of the beam and deteriorating its focusibility.
Günter Brederlow +2 more
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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 C +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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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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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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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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Matrix formulation of the beam quality of the Hermite-Gaussian beam
Laser Physics, 2009Based on the M 2-parameter of Hermite-Gaussian beam, we deduced the matrix formulation of the beam quality for nonsymmetric two-dimensional Hermite-Gaussian beam, which at an arbitrary azimyth angle α. And coupled beam radius square, coupled M 2-parameter also have been introduced.
W. Li +6 more
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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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Laser beam quality, entropy and the limits of beam shaping
Optics Communications, 1996Abstract The paper presents a thermodynamical and quantum-statistical analysis of the electromagnetic field with the aim of deriving the entropy of partially coherent thermal and laser beams. Together with the second law of thermodynamics the knowledge of the entropy allows the discussion of the limits of beam shaping.
Th. Graf, J.E. Balmer
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The beam quality of nonparaxial Hermite-sine-Gaussian beam
Optics Communications, 2008Abstract Based on the theory of the second intensity moment of nonparaxial scalar beam and the method of angular spectrum, the expressions for the far-field divergence angle, waist width and M2 factor of nonparaxial Hermite-sine-Gaussian (HSiG) beams are derived.
Peihong Ding +3 more
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