Instead of constructing a full multi-dimensional look-up-table as a model to find the critical dimension or other parameters in scatterometry, regression or other optimized estimation methods are employed starting from a \u201cbest guess\u201d value of the parameter. The filtration mechanism has a filter member in which water with suspended solids in it is forced through the filter member to clean the water. One or more separation charges isare arranged adjacent to each warhead effect jacket that when actuated cause removel of one or more said warhead effect jacket.