Image vidicon

An X-ray image of a test object is converted by a X-ray TV unit (4), and complete video-signal from it is supplied to specialized computer (5). For conversion of X-ray images series X-ray vidicons LI-444 and LI-473 can be used or experimental X-ray vidicons of the same dimensions with a Be input window [2] sensitive to soft X-radiation developed in Introscopy Institute. >. ... 

Application of experimental devices allows to perform NDT of products, made out of materials of low density (Al-Mg - alloys, Be, plastics) with high defectoscopic sensitivity up to 0,5 %. Inch-size X-ray vidicons used complete with microfocal X-ray tubes and X-ray image enlargement method allow to obtain resolution up to SO pairs of lines per mm. 

The use of experimental X-ray vidicons, original technique of X-raying and computer image processing allowed to improve basic parameters of XTVI and to achieve higher defectoscopic sensitivity and greater thickness of X-rayed materials and products. 

The main detectors used in AES today are photomultiplier tubes (PMTs), photodiode arrays (PDAs), charge-coupled devices (CCDs), and vidicons, image dissectors, and charge-injection detectors (CIDs). An innovative CCD detector for AES has been described [147]. New developments are the array detector AES. With modem multichannel echelle spectral analysers it is possible to analyse any luminous event (flash, spark, laser-induced plasma, discharge) instantly. Considering the complexity of emission spectra, the importance of spectral resolution cannot be overemphasised. Table 8.25 shows some typical spectral emission lines of some common elements. Atomic plasma emission sources can act as chromatographic detectors, e.g. GC-AED (see Chapter 4). 

The results obtained hitherto are of interest e.g. for color television, for medically important IR vidicons 3>, and for the construction of storage vidicons. Further systematic studies should test as many dyes as possible for possible use in television image reproduction6 ). 

There are two methods for digitizing the microscopic image formed by the vidicon camera the real-time digitizing with a fast A/D converter, usually in the... 

As an attractive alternative to the vidicon the array of elements can be connected directly to individual voltage detectors on a silicon integrated circuit (usually referred to as a ROIC read-out integrated circuit ) via solder bumps . The resulting signals can then be electronically processed to yield a picture in the standard way. Fig. 7.13 shows a section through part of such an imaging array. 

Because vidicon imagers and particularly the silicon vidicon with its various image-intensified derivatives are much more readily available and their behavior and performance are better controlled (even if not always fully understood), a brief description of their principles of operation may be necessary if their spectrometric performance (and that of other imagers as well) is to be properly and intelligently interpreted. 

Microseconds to nanoseconds As previously mentioned, gated intensified vidicons can provide temporal resolutions as low as 40 nsec. New intensifiers, e.g., microchannel plates, may extend this range to 1-5 nsec or less. However, by far, the most useful tool for ns to ps spectroscopy is the streak camera, i.e., an ultra-rapid temporal-to-spatial electronic image sweeper (16). Streak cameras convert an optical signal, e.g., a spectrum, into... 

In contrast to the image dissector, which measures the photon flux, the vidicon is an integrating device, where the target serves as a memory buffer, storing information until the scanning electron beam reads and erases it. 

Switch-Board Optics. The preceding discussion has summarized the various approaches which have been taken to achieve a practical spectrometer for SMA. The direct reader, the vidicon detector, and the development of image device/echelle systems... 

Figure 3. Three-dimensional representations of the spectrum from a mercury pen lamp recorded with an image dissector and a silicon target vidicon (30)...

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