Electron transmission radiography

Description

A radiographic technique that uses secondary electrons emitted from a thin lead foil (100 to 250 micrometers) to produce an image of the examined object on a radiographic film. Electron transmission radiography is conducted by placing a flat object in intimate contact with the emulsion side of a single coated radiographic or photographic film. The lead foil intensifying screen is then placed on the other side of the object. A radiotransparent weight or vacuum is applied to press the layers together and minimize air gaps which deteriorate the image quality. A high energy industrial X-ray generator (200-400 kV) is used to irradiate the lead foil causing it to emit low energy electrons (through photoelectric effect and/or Compton effect) which in turn pass through the object and expose the film. The film is less sensitive to the high energy X-rays that pass through the object. This technique can be used when Beta radiography is not available.

Synonyms and Related Terms

electron radiography; radiographie par electrons secondaires (Fr.); Sekunderelektronenradiographie (Deut.); radiografia de electrões secundarios (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.

° C.Bridgman, "The Radiography of Paper" Studies in Conservation, 10(1):8-17, 1965.

° D. Schnitger, "Radiographie mit Elektronen aus Metallverstärkerfolien - Darstellung der Radiographie mit Fotoelektronen aus Metallverstärkerfolien als zerstörungsfreies Prüfverfahren für dünne organische Werkstoffe. Forschungsbericht 103, BAM Berlin, ISBN 3-88314-328-6