| ABSTRACT: | EVALUATION OF NEW DIGITAL DETECTORS FOR HIGH RESOLUTION
RADIOGRAPHY
Valérie Kaftandjian1, and Bernard Munier2
1 INSA-CNDRI, Bât St Exupéry, Villeurbanne Cedex, France; 2 THALES Electron Devices,
Centr’Alp, Moirans, France
Film radiography is still in use in a number of industries, due to the high spatial resolution obtained,
which allows detecting very small defects. However, new generations of digital detectors become
more and more competitive towards film, in terms of contrast resolution and sensitivity. Even if the
spatial resolution of films remains better, the digital detectors have good contrast performance and
high grey-level dynamic range, which has already proved good defect sensitivities for some
applications. However, it is impossible to say in an absolute manner « this detector is better than
film ». For each application, it is necessary to optimise the acquisition conditions in order to get the
required image quality.
In the actual study, two digital detectors were investigated : an amorphous silicon flat panel and a TDI
multilinear detector. Emphasis is put on the sensitivity to small defects (typically 50 ?m) of high
contrast. The wire-type IQI sensitivity was selected as a main image quality parameter, and spatial
resolution was also assessed by the bar/space pattern method. Particularities of both detectors are
emphasized. The aim was not to compare one against the other but to enhance the potentialities of
each, with respect to film radiography. Acquisition conditions were thus optimised for each detector,
because their physical characteristics towards X-rays absorption are not similar.
Abstract WCNDT – November 2003
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