Beta radiography
Description
A radiographic technique that uses a plane beta source to produce an image on a radiographic film. Since 1967, beta radiography has used a source plate composed of a thin polymethacrylate sheet labeled with radioactive carbon-14. This isotope emits pure beta particles of low energy (150 keV), which can penetrate a maximum of 10 inches of air, 0.3 mm of skin or a sheet of paper (Kushel). The technique is performed by first layering a sheet of film, emulsion side up, then the paper to be examine, covered with the beta plate. A glass weight or vacuum is applied to press the layers together and minimize air gaps which deteriorate the image quality. The image corresponds to the mass per unit area of the paper or material being examined. Thin layers of organic ink or paint usually do not appear on the radiograph but mineral ink or paint absorb the beta particles and so appear on the radiograph. Beta radiography produces high quality and high contrast images of watermarks and other texture characteristics of paper. Due to legal issues concerning the use of radioactive sources, electron transmission radiography is a possible substitution technique.
Synonyms and Related Terms
bêtagraphie (Fr.); Betaradiographie (Deut.); radiografia por particulas beta (Port.)
Additional Information
° D.Kushel, "Radiographic Methods Used in the Recording of Structure and Watermarks in Historic Papers"° H.Tomimasu, D.Kim, P.Luner, M.Suk, "Comparison of Four Paper Imaging techniques: Beta Radiography, Electrography, Light Transmission and Soft X-radiography" TAPPI Journal, 74(7):165-175, 1991.° Jean E. Brown, Richard Mulholland, "Using microfocus x-radiography and other techniques to create a digital watermark database." In book. Works of art on paper: books, documents and photographs: techniques and conservation: contributions to the Baltimore Congress, 2-6 September 2002. International Institute for Conservation of Historic and Artistic Works, Daniels, Vincent, Donnithorne, Alan, and Smith, Perry, Editors, 2002.
Authority
- G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971
- External source or communication Comment: Jean-Louis Boutaine, 20/06/2007
- A Glossary of Paper Conservation Terms, Margaret Ellis (ed.), Conservation Center of the Institute of Fine Arts, New York City, 1998
- External source or communication Comment: Jean-Louis Boutaine, 20/06/2007
- G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971