Radiation, interaction with matter

There are three significant possible effects when radiation interacts with matter (5,6). First, the radiation can interact with the nucleus and induce radioactivity as in the case of neutrons. Second, displacement of atoms can occur. This has happened in a number of uranium- and thorium-containing minerals over geological periods. The outstanding example is zircon, which can contain over 10% Th and 2% U. The internal bombardment from these materials and their decay products over geological periods produces low or metamict zircon, where the disorder gives an amorphous state having a low density. 

In 1900 Max Planck proposed a solution to the problem of black-body radiation described above. He suggested that when electromagnetic radiation interacts with matter, energy can only be absorbed or emitted in certain discrete amounts, called quanta. Planck s theory will not be described here, as it is highly technical. In any case, Planck s proposal was timid compared with the theory that followed. He supposed that quanta were only important in absorption and emission of radiation, but that otherwise the wave theory did not need to be modified. It was Einstein who took a more radical step in 1905 (the year in which he published his first paper on the theory of relativity and on several other unrelated topics). Einstein s analysis of the photoelectric effect is crucial, and has led to a complete change in the way we think of light and other radiation. 

When electromagnetic radiation interacts with matter it causes the electron density in the material to oscillate at the same frequency as the incident light. Since the interaction of light and matter is a time-resolved process involving many photons, it should not be a surprise that the oscillation produced by... 

Beta radiation interacts with matter in three different ways ... 

The book starts with a chapter describing the occurrence of radioactive nuclides in nature, followed by chapters on man-modified and man-made radioactivity. The big challenge has always been the measurement of radioactivity. New detection methods are still being developed nowadays, all based on the physics of radiation interaction with matter. 

All the instruments for the detection and measurement of radioactivity are based on the physical processes of radiation interaction with matter. The understanding of these processes has led to the development of many types of radiation detectors. The methods used for the measurement of radionuclide concentrations in various matrices are numerous. Some are better then others, but the best is always a combination of several techniques. 

Indirectly ionizing radiations include some types of electromagnetic radiations and neutrons. These radiations interact with matter by giving rise to secondary radiation which is ionizing. Indirectly ionizing radiations lose energy by collisions with electrons, or atomic nuclei, and the charged particles thus set in motion interact in turn with the orbital electrons or nuclei. 

When radiation interacts with matter, the energy involved is much higher than the bond energy of the molecules. Intuitively one would thus expect all chemical bonds to be... 

The changes that take place when radiation interacts with matter (such as photographic film) provide the basis of operation for various radiation detection devices. 

Very detailed information about structure is obtained from investigations in which electromagnetic radiation interacts with matter. An important area of study, known as spectroscopy, is concerned mainly with the extent to which substances absorb radiation at various wavelengths. The information obtained through spectroscopy has contributed greatly to our understanding of chemical structure and is particularly important in biology. 

Radiation interacts with matter through the effects of the electric field vector on the electron distributions in molecules. Absorption of radiation involves raising a system from one energy level to a higher level by the absorption of a quantum of energy (a photon). Elastic scattering of radiaLion involves no such quantum jumps and can be discussed in classical terms. ... 

There are three ways in which ionizing (electromagnetic) radiation interacts with matter, viz. 

How does Electromagnetic Radiation interact with Matter ... 

FIGURE 1.9 The relative importance of various processes of y-radiation interaction with matter. 

Nikjoo, H. Uehara, S. Ewfietzoglou, D. (Eds.). 2012. Radiation Interactions with Matter, CRC Press, Boca Raton, EL, 544 pp. 

Time elapsed between the state of interaction of the primary radiation, whatever it is, and the state of full acquisition of the energy by the bulk of the material is long enough to affect the thermodynamic (TD) properties of the substance but too short to be detected easily. Some scientists may look at the interaction of radiation with matter as a single event interaction as in the atomic level. That is not a real situation, for example, if the radiation interaction with matter is considered as a single event, bond breakage of organic material should be random. What happened in practice is that specific portions of the molecule are affected by radiation, which is related to the TD of the interaction. 

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