Peter Willems obtained a Master of Physics at the University of Antwerp in 1980. Preparation of a Ph. D. Thesis was started at the dept. of Atomic and Molecular Physics of the same university and completed in April 1986. After military service and a brief interlude in the field of Metallurgy, he started his industrial career as a R&D project manager for Agfa Gevaert N.V in November 1988.

At Agfa, Peter Willems was the basic R&D anchor man for Non Destructive Testing until May 2006. He subsequently worked on X-ray detector systems such as new film systems, scintillators, storage phosphor based computed radiography, and direct radiography systems based on CCD, CMOS or amorphous silicon technology. His work mainly concerned application oriented feasibility studies to explore the edge of new and alternative technologies.

After Agfa NDT was acquired by General Electric, he became anchor man within Agfa for GE Inspection Technologies. In June 2006, Peter Willems started to work directly for GE as an independent consultant for film and computed radiography systems. From 1 April 2010 until 30 September 2011, he was guest scientist at the Radiology dept. of the Bundesanstalt für Materialforschung und –prüfung in Berlin.

Abstract

The search for digital radiographic technologies started in the seventies of last century.

When in 1973, Computed Tomography was introduced by Hounsfield for medical applications; the benefits of capturing radiographic images in digital form became obvious.

For industrial X-ray applications digital systems have been introduced since the mid-nineties. They have gained popularity in the NDT community, but they have not yet replaced industrial X-ray film.

Digital radiographic detectors need to meet the requirements of the specific NDT application where they will be used. This is expressed by the image quality parameters such as: spatial resolution, signal to noise ratio, contrast sensitivity, dynamic range and uniformity of response. But in order to be qualified as “fit for NDT” they also need to withstand the - sometimes harsh - environmental conditions in which industrial radiography takes place. And in order to be commercially viable, workflow performance (acquisition time, system throughput) and system price need to be in accordance.

This review aims at identifying the fundamental limitations of each technology for NDT applications. The key parameters for failure or success will be indicated. Also systems that did not make it to the medical market, but that may have interesting properties for NDT applications are discussed.