Window transmissivity

Electrospray 4 ZnSe window Transmission with FTIR 1 10 157... 

Online liquid-liquid 200 ZnSe window Transmission with FTIR 30 0.2 164... 

Makeup/pneumatic 2 ZnSe window Transmission with FTIR 20 0.02 166... 

Figure 7.25 Examples of spectral sensitivities of a photodiode (a) and of two types of photomultipliers (b). The window transmissions are shown as q (silica) and g (optical glass). Horizontal axes, A in nm/100 vertical axes,

Checks for possible sensitivity changes (due to window transmission) were made during the course of the data acquisition. The maximum sensitivity variation observed over a one hour period of lean engine operation was 2.4 percent change in the mean value. 

Adapted input window and screen substrate allowing transmission of low energy X-rays. For very low energy (typically below 30 keV) a thin Be window is used. Such a window in combination with a Be screen substrate will make possible imaging down to 3 keV. 

Figure Bl.24.17. An example of scanning transmission ion microscopy (STIM) measurements of a human oral cancer cell. The different images indicate different windows in the energy of transmitted helium ions as indicated in the figure. White indicate areas of high counts. The teclmique offers a thickness scan through the sample, and, in this case, the cell walls of one specific cell can be seen in the areas dominated by thicker structures (data from C A Pineda, National Accelerator Centre, Fame, South Africa).

For an air/glass interface, tan 0b = n, the refractive index of glass. In a gas laser, the light must be reflected back and forth between mirrors and through the gas container hundreds of times. Each time the beam passes through the cavity, it must pass through transparent windows at the ends of the gas container (Figure 18.10b), and it is clearly important that this transmission be as efficient as possible. 

By placing these windows in a plane set at the Brewster angle with respect to the Ught beam, maximum transmission is assured (minimum reflection). The above considerations regarding polarization of refracted and reflected beams must be modified for nontransparent media such as metals, for which there is little polarization of a reflected beam. 

Transmission Fourier Transform Infrared Spectroscopy. The most straightforward method for the acquisition of in spectra of surface layers is standard transmission spectroscopy (35,36). This approach can only be used for samples which are partially in transparent or which can be diluted with an in transparent medium such as KBr and pressed into a transmissive pellet. The extent to which the in spectral region (typically ca 600 4000 cm ) is available for study depends on the in absorption characteristics of the soHd support material. Transmission ftir spectroscopy is most often used to study surface species on metal oxides. These soHds leave reasonably large spectral windows within which the spectral behavior of the surface species can be viewed. 

Eig. 4. Transmission profile for a siUca-based glass fiber. Region A represents electronic transitions B, the transmission window and C, molecular vibrations. Point LL is the lowest loss observed in an optical fiber. Absorption profiles for (-) OH and ( ) Fe are also shown. See text. 

Optical Properties. The high refractive index (2.42 at 589.3 nm) and dispersion (0.044) are the basis for the brilliance and fire of a properly cut gemstone. The optical transmission out to 10.6 p.m for Type Ila diamonds makes possible windows for CO2 lasers and for devices such as were in the... 

Figure 3 Curves showing the ebsorption of the window meterials at low energy for a standard Be window and a low-Z window. The high-energy region shows the transmission of X rays through 3 mm and 5 mm thick Si (Li) crystals. Most detectors can be represented by a combination of one of the low-energy curves and one of the high-energy curves.

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