Results 261 to 270 of about 7,941,196 (306)
Some of the next articles are maybe not open access.
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
openaire +2 more sources
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
openaire +2 more sources
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 ...
openaire +2 more sources
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
openaire +2 more sources
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
openaire +2 more sources
Analysis of beam quality for the laser beams after spectral beam combining
Optik, 2010Abstract The beam quality of the laser beams after spectral beam combining (SBC) has been analyzed in this paper. Based on the propagation model of the spectral beam combining system, the expression for the output field of an individual beam passing through the spectral beam combining system with lens aberration has been given and the intensity ...
Yan Zhang, Bin Zhang
openaire +1 more source
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.
openaire +1 more source
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.
openaire +1 more source
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.
openaire +2 more sources
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
openaire +1 more source
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
openaire +1 more source