Using the Filters


Once the automatic count has been completed, click on the Area filter to open the Track Filters window. The upper (black) histogram should show a significant peak associated with features that are single tracks, and often a peak of smaller (mostly non-track) features ranging down to the minimum cutoff. Select the Mode and ensure that this is near the peak (usually slightly to the right) for the single track features. Check that this gives reasonable results on the grain images in terms of identifying single, double or multiple tracks. The objective is to ensure that multiple tracks are correctly identified as far as possible, although this area correction is not perfect. As necessary, adjust the modal area by moving the slider underneath the histogram, while watching the result on the image overlay. When this is set to the optimum value, select the Minimum track area and adjust the slider to get rid of unwanted small, non-track features, recognising that this will be a compromise between removing unwanted features and excluding some small track features.

A variety of other filters are available that can be selected from the drop down menu to further define the limits of identified features that are classified as fission tracks. These are the Circularity, Feret-Max, Feret-Min (essentially the maximum and minimum diameters,) and Aspect ratio of the maximum to minimum diameters. These can all be adjusted in the same way as for the Area filter but in most cases these are much less useful than the etch-pit area and are seldom needed to refine the automatic count. They can be useful however to show the characteristics of the track etch pits identified.