Optimization specifier for the Source_adapt component.
Author: Kristian Nielsen
This components works together with the Source_adapt component, and
is used to define the criteria for selecting which neutrons are
considered "good" in the adaptive algorithm. The name of the
associated Source_adapt component in the instrument definition is
given as parameter. The component is special in that its position
does not matter; all neutrons that have not been absorbed prior to
the component are considered "good".