This filter is specifically designed for spot analyses were, because of side-wall ablation effects, data collected towards the end of an ablation will be influenced by data collected at the start of an ablation.
This filter provides a means to exclude all material 'down-hole' of the first excluded contaminant.
For example, to continue the example from the filters-defrag Filter, you may end up with a selection that looks like this:
In the first ablation of this example, the defragmentation filter has left four data regions selected. Because of down-hole effects, data in the second, third and fourth regions will be influenced by the material ablated at the start of the sample. If there is a contaminant at the start of the sample, this contaminant will also have a minor influence on these regions, and they should be excluded. This can be done using the Down-Hole Exclusion filter:
This filter is particularly useful if, for example, there is a significant contaminated region in the middle of an ablation, but threshold filters do not effectively exclude the post-contaminant region.