Authors:

David Fry

,

Uwe Ewert

,

C. Gollwitzer

,

E. Neuser

,

J. Selling

Publication:

Materials Evaluation, Volume 70, Issue 8

Publication Date: 1 August 2012Testing Method:

Radiographic Testing

Measurement of microfocus spot size can be important for several reasons: assuring quality during the manufacture of microfocus tubes; tracking performance and stability of microfocus tubes; determining maximum possible magnification for an inspection (especially important for digital radiography where the native spatial resolution of the digital system is inadequate for the application); and contributing to the total unsharpness from the focal spot alone. A theoretical analysis of microfocus spot determination using radiographic techniques is performed, and limits on precision are determined. This is followed by examples of measurements and calculation of focal spot size from those measurements. Measured data are then presented to show the practical application of the technique.

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