Compton, effect

Spectral Gamma Ray Log. This log makes use of a very efficient tool that records the individual response to the different radioactive minerals. These minerals include potassium-40 and the elements in the uranium family as well as those in the thorium family. The GR spectrum emitted by each element is made up of easily identifiable lines. As the result of the Compton effect, the counter records a continuous spectrum. The presence of potassium, uranium and thorium can be quantitatively evaluated only with the help of a computer that calculates in real time the amounts present. The counter consists of a crystal optically coupled to a photomultiplier. The radiation level is measured in several energy windows. 

In modified scattering, the resulting increase in wavelength (Compton effect) is evidence that the x-ray photon acting as a corpuscle has been scattered by colliding with an electron to which it has lost momentum in the process. The Compton effect is not at present of practical importance in analytical chemistry. 

Absorption Coefficient—Fractional absorption of the energy of an unscattered beam of x- or gamma-radiation per unit thickness (linear absorption coefficient), per unit mass (mass absorption coefficient), or per atom (atomic absorption coefficient) of absorber, due to transfer of energy to the absorber. The total absorption coefficient is the sum of individual energy absorption processes (see Compton Effect, Photoelectric Effect, and Pair Production). 

Compton Effect—An attenuation process observed for x- or gamma radiation in which an incident photon interacts with an orbital electron of an atom to produce a recoil electron and a scattered photon whose energy is less than the incident photon. 

The Compton effect, in which the photon is scattered with significantly lower energy by a medium electron, which is then ejected with the energy differential. 

The excellent, high-resolution y- and X-ray spectra which can be obtained from semiconductor detectors make the detectors very important in modern instruments. A typical spectrum is shown in Figure 10.11(b) which may be compared with the much broader peaks from a scintillation detector (Figure 10.11(a)). The spectra are not immune from the problem of Compton scattering (p. 461) but a good quality modem detector will have a photopeak to Compton peak ratio of 50 1 or better. Computer-aided spectrum analysis also serves to reduce the interference from the Compton effect. 

Inelastic photon scattering processes are also possible. In 1928, the Indian scientist C. V. Raman (who won the Nobel Prize in 1930) demonstrated a type of inelastic scattering that had already been predicted by A. Smekal in 1923. This type of scattering gave rise to a new type of spectroscopy, Raman spectroscopy, in which the light is inelastically scattered by a substance. This effect is in some ways similar to the Compton effect, which occurs as a result of the inelastic scattering of electromagnetic radiation by free electrons. 

When y radiation hits an electron, it is deviated from its original trajectory and, losing energy, changes its frequency. The increase in frequency consequent upon anelastic scattering is only a function of the angle between incident and deflected rays and does not depend on the energy of the incident radiation. The importance of this fact, known as the Compton effect, increases as the atomic number of the element decreases. 

Complexes, see also specific type in solution, structures, see X-ray diffraction n-Complexes, 4 178-184 Complex formation constant, outersphere, 43 46, 55 electrovalent interaction in, 3 269-270 Compressibility coefficient of activation, 42 9 Comproportionation constants, class II mixed-valence complexes, 41 290-292 Comproportionation equilibrium, 41 280-281 Compton effect, 3 172 Conantokins, calcium binding, 46 470-471 Concanavalin A, 36 61, 46 308 Concensus motif, 47 451 Concentration-proportional titrations of poly-metalates, 19 250, 251, 254 Condensation... 

The Compton effect A photon is characterized not only by its energy, E = Hco but also by a momentum, p. The latter may be evaluated directly by using the relativistic expression for the energy of a particle in terms of its rest mass, m, and momentum, p, namely... 

Fig. 2.4 The scattering of a photon by a stationary electron in the Compton effect.

Now we will briefly indicate the problems that can be usefully treated with the above geometric theory of the hydrogen atom." In many applications, such as the theory of the Compton effect in a bound electron and in the inelastic matter theory of atoms it is a question of determining the norm of the projection of a given function on the subspace of Hilbert space determined by the principal quanmni number nJ This norm is defined by the sum... 

Electromagnetic waves behave like particles in photoelectric effect, Compton effect and phenomena of absorption and emission. The quantum of energy, E=Av, is called a photon. Photons travel with the speed of light c, and possess a momentum hv/c. 

The interpretation given above is simplified, since fluorescence is not the only process that allows the atom to lose its excess energy. Other phenomena such as Rayleigh scattering (elastic scattering) and the Compton effect (inelastic scattering with release of Compton electrons) can complicate the X-ray emission spectrum. 

Compton effect. A small fraction of the primary X-ray excitation beam is scattered in the form of radiation whose wavelength depends on the angle of observation. This radiation is superimposed on the X-ray fluorescence spectrum. The shift in angstroms between the two wavelengths (excitation and Compton) is given by ... 

Compton effect, 246 Conductance, 70 Conductivity, 70 Confirmation analysis, 210 Cooley, 171... 

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