Generation of X-rays

Materials Characterization Yang Leng 2008 John Wiley Sons (Asia) Pte Ltd 

Ka2 and Kfi are the three strongest characteristic X-rays are used for diffraction radiation. The wavelength difference between Ka and Ka2 are so small that they are not always resolved as separate radiation. For example, wavelengths generated by a copper target are approximately the following. 

We often simply call Ka 1 and Ka2 radiations the Ka doublet. The K doublet is the most widely used monochromatic X-rays for diffraction work. Table 2.1 lists the commonly used Ka doublet, of which the wavelength is an average of Ka and Ka2. 

Anode Material Atomic Number Xa(nm) Critical Excitation Potential (keV) Optimum Voltage (kV) 

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Physically the generation of X-rays is often a secondary process preceded hy the ionization of an atom. There are, therefore, several possihilities of X-ray generation depending on the type of the exciting medium - neutrals or charged particles such as electrons and ions and high-energy photons, i. e. X-rays themselves. 

An accurate measure of the radius and the mass of an individual neutron star will be of fundamental importance to discriminate between different models for the equation of state of dense hadronic matter. Unfortunately such a crucial information is still not available. A decisive step in such a direction has been done thanks to the instruments on board of the last generation of X-ray satellites. These are providing a large amount of fresh and accurate observational data, which are giving us the possibility to extract very tight constraints on the radius and the mass for some compact stars. 

Fukuda Y, Akahane Y, Aoyama M, Inoue N, Ueda H, Kishimoto Y, Yamakawa K, Faenov AYa, Magunov AI, Pikuz TA, Skobelev IYu, Boldarev AS, Abdallah Jr. J, Csanak G, Boldarev AS, Gasilov VA (2004a) Generation of X rays and energetic ions from super intense laser irradiation of micron-sized Ar clusters. Laser Part. Beams 22 215-220... 

Energy-dispersive X-ray analysis consists of generation of X-rays characteristic of the elements when an electron beam impinges on the sample. By using this technique a rapid analysis of the elements present in the sample can be done with detection limits of the order of 0.1 wt %. A typical spectrum obtained in the analysis of deposits within a crack in pipe in a petrochemical plant is shown in Figure 2.30. 

X-ray. Another result of the electron beam striking the specimen in SEM is the generation of X-rays characteristic of elements present. Figure 2 shows an incident electron striking an atom and ejecting an orbital electron. The vacancy... 

Three successive generations of X-ray point detectors have been developed, namely,... 

Figure 4.3. Three generations of X-ray light sources at DESY, Hamburg DORIS, the small traditional synchrotron (partially enhanced by wigglers). PETRA III, the synchrotron light source of the near future. FLASH, a EEL test facility for the next generation of synchrotron light...

The accelerator is used as radiation source in the development of new dosimetry systems (physical and chemical) and in the characterization of existing dosimeters in different conditions (a water cooled tantalum converter is used for the generation of X-ray and there is the possibility of controlling the temperature of small samples under irradiation). In Table I the technical specifications of the accelerator are reported. 

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