X-ray

Description

High energy radiation (from some keV to 110 keV) with very short wavelengths (0.001 - 10 nm). X-rays were discovered by Wilhelm Conrad Röntgen in 1895. They can pass through materials, ionize gases, and expose photographic film. X-rays can be produced by X-ray tubes associated with high voltage generators, or synchrotrons or radioactive sealed sourcesThe depth of penetration of x-rays through a material depends on there energy & of the atomic number & density of the material. The more frequent use of x-rays in museums consists in non destructive examination of artefacts like easel paintings, sculptures, ceramics, archaeological objects... by radiography. This permits to caracterise density variations in composite materials, to examine differences in painting pigments, to visualise sculpture structures ... Radiographs of paper and other low thickness & density materials are made with soft X-rays. X-rays are also used in analytical equipment (see X-ray diffraction and x-ray fluorescence) for the determination of cristalline structure and elemental compositions.

Synonyms and Related Terms

x-rays; xray; x-radiation, Roentgen ray

Risks

Overexposure or cumulative exposure can damage or destroy cells and tissue structures & so can induce illnesses like radiodermite, cancer,....

Resources and Citations

• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971

• G.G. Hawley, The Condensed Chemical Dictionary, Reinhold Publishing, New York, 6th ed., 1961

• Art and Architecture Thesaurus Online, http://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000