If you would like to evaluate different detector layouts, there are two ways this is typically done.  The first is to simply use the enable/disable function on detectors.  Enabling and disabling a detector is as simply is clicking on the enable/disable check box in the detector list. This allows you to exclude detectors from analysis without having to delete the data.  This way if you find your new design is unacceptable you can easily revert to the previous one.  The other option is to create a copy of the study and modify the copied study.  You can copy a study from the study list page of the Project Manager application.