Light source multiple

In recent years, high-resolution x-ray diffraction has become a powerful method for studying layered strnctnres, films, interfaces, and surfaces. X-ray reflectivity involves the measurement of the angnlar dependence of the intensity of the x-ray beam reflected by planar interfaces. If there are multiple interfaces, interference between the reflected x-rays at the interfaces prodnces a series of minima and maxima, which allow determination of the thickness of the film. More detailed information about the film can be obtained by fitting the reflectivity curve to a model of the electron density profile. Usually, x-ray reflectivity scans are performed with a synchrotron light source. As with ellipsometry, x-ray reflectivity provides good vertical resolution [14,20] but poor lateral resolution, which is limited by the size of the probing beam, usually several tens of micrometers. 

Most optical spectral measurements, where the measurement of multiple wavelengths is required, will feature some type of polychromatic or broadband light source. There are a few exceptions here, such as tunable laser sources and source arrays. In such instances, the source is effectively "monochromatic at a given point in time. These sources are covered separately under monochromatic sources. 

In the photochemical procedure, addition product can be minimized in keeping the relative NBS concentration as small as possible. In addition, substrate concentrations should be optimized with regard to the exitance of the chosen light source to avoid secondary recombination reactions. Under these conditions 4-bromomethyl-5-methyl-l,3-dioxol-2-one can be prepared with only minor impurities (bromine addition and multiple allylic bromination reactions (Eq. 23)) [34]. 

Most optical spectral measurements, where the measurement of multiple wavelengths is required, will feature some type of polychromatic or broadband light source. There are a... 

If we have multiple point light sources, we need to add the components from the different light sources. Let be the radiance given off by light source i, then the radiance L(Ny) given off by the patch in the direction of the viewer is... 

---