4.3 Industrial applications

λ ¼

Use of Gamma Radiation Techniques in Peaceful Applications

4. Application field

Figure 2.

114

industry and preservation of cultural heritage.

• Time decline of radioactivity

• Radiation emission

• Sensitivity of detection

4.1 Medical physics applications

The properties used for these various applications are:

Relationship between the linear attenuation coefficient and the HVL for a soft tissue.

ð<sup>∞</sup> 0

ð<sup>∞</sup> 0 e �<sup>μ</sup>xdx

intensity in a narrow beam is reduced to 1/e (or 0.37) of its original value.

xe�<sup>μ</sup>xdx

where μ is the linear attenuation coefficient and x is the absorber thickness. N.B: The relaxation length is the thickness of a shield for which the photon

Apart from the use of nuclear energy for the supply of electricity, the applications of radioactivity are numerous in many areas: medical physics, earth sciences,

The major application of radiation in medicine is radiotherapy and/or treatment by ionizing radiation. A few months after the discovery of X-rays, there is over a century, it has become clear that biological action radiation could be used in the

¼ 1 μ

(8)

• Elaboration of materials: Irradiation causes, under certain conditions, chemical reactions that allow the development of more resistant materials, more lightweight, capable of superior performance.

#### 4.4 Gamma rays spectrometry

The development of γ-spectrometry began with the development of nuclear sciences and technology to meet the needs for the control, characterization and analysis of radioactive materials. This measurement technics exploits a fundamental property observed for unstable nuclei: the emission of radiation from the process of nuclear decay. It is thus known as non-destructive because it respects the integrity of the object to be analyzed [4].

The interest in γ spectrometry has continued to grow over the years, both from a point of view metrological and a point of view applications. This development was made possible by a better understanding of the process of photon interaction with matter, and especially by the appearance of semiconductor detectors in the 1960s. Spectrometry γ then became a powerful tool for studying decay patterns. It is now used in a wide variety of sectors (for example: dating, climatology, astrophysics, medicine) and in virtually all stages of the fuel cycle.

Photon spectrometry is a commonly used nuclear measurement technique to identify and quantify gamma emitting radionuclides in a sample. It is nondestructive and does not require specific sample preparation. Conventional spectrometers are designed around semiconductor detectors, usually with high purity germanium (hyper-pure germanium).

The radionuclides measured by this method emit gamma photons of specific energies and their interactions with the detector depend on several variables (geometry or conditioning: physical shape of the object, density, measured quantity, container type, emission energy, size, shape, nature of the detector, etc.).
