X-Ray Images

Abstract

Experiment 23.1: Recording Dot Maps. (a) Adjustment of CRT recording dot. Various WDS iron x-ray images obtained with different settings of the CRT dot brightness reveal the subjective nature of the analog dot mapping procedure. A dim recording dot (Figure A23.1b) provides a very weak image even where the iron concentration is high and no information at all where the iron concentration is low. The optimum dot brightness image (Figure A23.1c) carries more information but the image is weak and noisy in the iron-poor regions because the total number of x-rays recorded in the 100-sec scan is inadequate to provide the necessary image statistics. Note that both characteristic and bremsstrahlung x-rays of the same energy are recorded since no background correction is applied in the analog WDS scan. The highest intensity dot produces an image (Figure A23.1d) in which the x-ray pulse locations are most easily evident, but the image is not satisfactory because blooming of the dot image causes a loss of resolution and contrast, obscuring fine scale details.