A radiation detector can include a logic element configured to determine a depth of interaction based on a decay time corresponding to a radiation event and a constituent concentration profile of a radiation-sensing member. In another aspect, a method of detecting radiation can include determining a depth of interaction based on a decay time corresponding to a radiation event and a constituent concentration profile of a radiation-sensing member. The radiation detector and method can be useful in applications where depth of interaction is significant. The radiation-sensing member may include a variety of different materials, and is particularly well suited for alkali metal halides.