Presenter Information

W. Anthony D. Friedman, BP America

Location

Brunswick, ME

Start Date

1-1-1992 12:00 AM

Description

In an ideal microfocus X-ray tube all the radiation would emanate from a single point, typically 10µm or less in diameter. The intensity would also be independent of angle within the cone beam that is defined by apertures within the tube. Such a tube would have high resolution due to the small spot size, and the uniform distribution of X-ray photons on the detector plane would make it useful for measuring density variations in flat samples such as ceramic modulus of rupture (MOR) bend test bars. Koenigsberg and Cotter [1] have shown that there are additional sources of X-rays in microfocus tubes that create anomalous shadows in images of MOR bars, making it difficult to assess their uniformity. They demonstrated that the secondary sources can be eliminated by placing a tungsten aperture in the tube [2]. While this cured the problem of anomalous shadows, it did not determine the cause of the secondary source. In this work, a pinhole camera is used to determine the shape and size of the secondary sources, enabling the structures that scattered the primary X-rays to be identified.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

11A

Chapter

Chapter 1: Fundamentals of Standard Techniques

Section

X-Ray and Computed Radiography

Pages

347-354

DOI

10.1007/978-1-4615-3344-3_43

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Unfocused Source of X-Rays in a Microfocus X-Ray Tube

Brunswick, ME

In an ideal microfocus X-ray tube all the radiation would emanate from a single point, typically 10µm or less in diameter. The intensity would also be independent of angle within the cone beam that is defined by apertures within the tube. Such a tube would have high resolution due to the small spot size, and the uniform distribution of X-ray photons on the detector plane would make it useful for measuring density variations in flat samples such as ceramic modulus of rupture (MOR) bend test bars. Koenigsberg and Cotter [1] have shown that there are additional sources of X-rays in microfocus tubes that create anomalous shadows in images of MOR bars, making it difficult to assess their uniformity. They demonstrated that the secondary sources can be eliminated by placing a tungsten aperture in the tube [2]. While this cured the problem of anomalous shadows, it did not determine the cause of the secondary source. In this work, a pinhole camera is used to determine the shape and size of the secondary sources, enabling the structures that scattered the primary X-rays to be identified.