Compton scattered radiation

Fig. 6. Schematic illustration of the relationships of the original y-ray and the scattered radiations for Compton scattering where E is the energy of the incident photon, E is the energy of the recoiling electron, and E is the energy of the scattered photon.

Thus, the contribution of coherent and non-coherent (Compton) scattering in attenuation of primary radiation and fluorescence increase in comparison with the solid samples. 

Detection limits for various elements by TXRF on Si wafers are shown in Fig. 4.13. Synchrotron radiation (SR) enables bright and horizontally polarized X-ray excitation of narrow collimation that reduces the Compton scatter of silicon. Recent developments in the field of SR-TXRF and extreme ultra violet (EUV) lithography nurture our hope for improved sensitivity down to the range of less than 10 atoms cm ... 

We are interested in the transmission of y-quanta through the absorber as a function of the Doppler velocity. The radiation is attenuated by resonant absorption, in as much as emission and absorption lines are overlapping, but also by mass absorption due to photo effect and Compton scattering. Therefore, the number Tt E2)AE of recoilless y-quanta with energies EXo E + AE traversing the absorber is given by... 

Scattered radiation. In a transmission experiment, the Mossbauer sample emits a substantial amount of scattered radiation, originating from XRF and Compton scattering, but also y-radiation emitted by the Mossbauer nuclei upon de-excitation of the excited state after resonant absorption. Since scattering occurs in 4ti solid angle, the y-detector should not be positioned too close to the absorber so as not to collect too much of this unwanted scattered radiation. The corresponding pulses may not only uimecessarily overload the detector and increase the counting dead time, but they may also affect the y-discrimination in the SCA and increase the nonresonant background noise. 

The thickness of a Mossbauer sample affects not only the strength of the Mossbauer signal but also the intensity of the radiation arriving at the detector because the y-rays are inherently attenuated by the sample because of nonresonant mass absorption caused by the photo effect and Compton scattering as mentioned earlier. The counting rate C in the detector decreases exponentially with the density of the absorber,... 

In a typical Compton scattering experiment with unpolarized radiation, the cross section is expressed as... 

It is well known that the energy profiles of Compton scattered X-rays in solids provide a lot of important information about the electronic structures [1], The application of the Compton scattering method to high pressure has attracted a lot of attention since the extremely intense X-rays was obtained from a synchrotron radiation (SR) source. Lithium with three electrons per atom (one conduction electron and two core electrons) is the most elementary metal available for both theoretical and experimental studies. Until now there have been a lot of works not only at ambient pressure but also at high pressure because its electronic state is approximated by free electron model (FEM) [2, 3]. In the present work we report the result of the measurement of the Compton profile of Li at high pressure and pressure dependence of the Fermi momentum by using SR. 

Experimental chemists are rarely concerned with quantum effects and it s not unusual to find them ignoring this fundamental theory altogether. Even when an effort is made to explore the topic more deeply traditional quantum phenomena like black-body radiation, Compton scattering and even the photoelectric effect may appear to be of somewhat limited importance. Experimentalists who rely on spectroscopic measurements get by with interpretations based on a few simple semi-classical rules, and without ever appreciating the deep significance of quantum theory. Maybe there is a problem with the rigorous mathematical formulation of quantum theory and too little emphasis on quantum effects routinely encountered in chemistry. 

Schrodinger s equation is widely known as a wave equation and the quantum formalism developed on the basis thereof is called wave mechanics. This terminology reflects historical developments in the theory of matter following various conjectures and experimental demonstration that matter and radiation alike, both exhibit wave-like and particle-like behaviour under appropriate conditions. The synthesis of quantum theory and a wave model was first achieved by De Broglie. By analogy with the dual character of light as revealed by the photoelectric effect and the incoherent Compton scattering... 

The EMD is closely related to intensities obtained from Compton scattering experiments, in which the obtained distribution depends on the incident wavelength and the scattering angle. The intensity of the scattered radiation is proportional to the theoretically obtained Compton profile given by the equation... 

Work on the structure of crystals and fibers was not the only way in which Mark made use of x-rays. With several collaborators, he reported the results of a number of significant investigations of the physics of x-rays in 1926 and 1927. With Ehrenberg he reported studies of the index of refraction of x-rays, and with Leo Szilard studies verifying the linear polarization of x-rays scattered from electrons at 90. An investigation of the width of x-ray lines was carried out by Mark and Ehrenberg, and Mark and Kallmann reported work on the properties of Compton-scattered x-radiation and on the theory of the dispersion and scattering of x-rays. 

Figure 26 shows the spectra from four explosive samples and as well as nonthreat materials. These spectra exhibit strong peaks slightly below 59 and 69 keV, which are unrelated to coherent scatter. These peaks arise from incoherent (Compton) scatter of fluorescent radiation at 59 and 69keV, which is produced from tungsten anodes. Scatter off water shows no apparent CXRS peaks. The four explosive samples clearly show characteristics peaks, which differentiate them from the non-threat materials and from each other. HeuristicaUy, the location and relative amplitudes of these peaks provide an effective means for detecting explosives. 

We will consider four key experiments which led to the unravelling of the classical world view, namely black-body radiation, the photoelectric effect, Compton scattering, and electron diffraction. 

The acronym kerma for kinetic energy released in absorbing material has been used to conceptually connect the energy deposited by ionizing radiation with the radiation field. It is defined to include the kinetic energy, which is locally absorbed from products of interaction with the particular medium such as Compton electrons, photoelectrons, and pah production while excluding the energy, which is not locally absorbed, from Compton-scattered photons, characteristic fluorescence radiation, and annihilation photons. The kerma is defined as ... 

Fig. 11.11. Intensity of the X-ray radiation generated by all-optical Compton scattering using a 30 fs, 820 nm, 10 Hz and 1 J laser system...

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