Rotating anode generators

Other techniques utilize various types of radiation for the investigation of polymer surfaces (Fig. 2). X-ray photoelectron spectroscopy (XPS) has been known in surface analysis for approximately 23 years and is widely applied for the analysis of the chemical composition of polymer surfaces. It is more commonly referred to as electron spectroscopy for chemical analysis (ESCA) [22]. It is a very widespread technique for surface analysis since a wide range of information can be obtained. The surface is exposed to monochromatic X-rays from e.g. a rotating anode generator or a synchrotron source and the energy spectrum of electrons emitted... 

As will become apparent, it is important to place the photographic plate as close to the specimen as possible. With rotating anode generators, care should be taken not to allow the full power of the beam to fall on the plate when stationary as this leads to an unsightly overexposed vertical line on the topograph. The presence of a horizontal stripe on the recorded topograph is often due to the presence of a second reciprocal lattice point lying on the Ewald sphere. It can be removed by a small rotation of the crystal about the diffraction vector as if to take a stereo pair. 

Figure 5.2 Cut-through diagram of a rotating-anode generator.

The X-ray source may be a conventional sealed tube or rotating anode generator or bending magnet synchrotron radiation and more recently the exploitation of multipole insertion devices such as wigglers and undulators represent great gains in source intensity. 

The types of radiations that are used in structural crystallography are mainly x-rays, neutrons, and electrons. The use of electrons is still difficult for structure determination but can be a useful tool for the detection of structural transitions (see Section X). White or monochromatic x-ray beams can conveniently be obtained from sealed tubes, rotating anode generators, or synchrotron sources [5], with relative flux magnitudes on the order of 1, 10, >100, respectively. The first two x-ray sources are continuous and are generally designed to produce almost monochromatic beams, while synchrotron radiation is pulsed and white. Neutron sources are comparatively much weaker and are either continuous (nuclear reactor) or pulsed (spallation source [6]). 

Figure 16-30. XRD of a thin (200 nm) film of Ooct-OPV5, vacuum-deposited on glass. Left as-deposited right annealed for 5 min at 120°C (9-2 d scanning in symmetrical reflection mode on a Ri-gaku horizontal diffractometer, with Ni-monochromatized CuKa radiation (2 = 1.5418 A) Rigaku RU200B rotating-anode generator operated at 40 kV, 40 mA).

Recently, these studies have led to the production of laboratory diffractometers. Stachs and his collaborators [STA 00], for example, bnilt a device eqnipped with a rotating anode generator and a cylindrical two-dimensional imaging plate detector. The maximum size of these detectors, currently the largest on the market, is close to 30 cm in diameter. Despite this size, the measnrement of diffraction peaks corresponding to relatively small interplanar distances can only be achieved, with this type of device, if the incident beam s wavelength is small. These anthors used the Ka radiation of a silver anode tnbe. However, this choice leads to a significant overlap of the peaks. Other authors performed the same type of measurements with... 

More sophisticated experiments involve a rotating anode generator and a... 

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