1. A radiation detection system comprising: a scintillator configured to detect sample events associated with an unknown sample; a guard detector subsystem configured to detect active guard events; one or more processors adapted to: count coincident events that are the sample events and the active guard events detected coincidently in one or more energy regions and count non-coincident events that are the sample events detected when the active guard events are not coincidently detected; and for each energy region calculate a compensation guard count based on the count of coincident events and a predetermined guard efficiency value associated with the energy region, calculate a correction value that is based on the compensation guard count and the counts of coincident events and the count of non-coincident events, and correct the count of non-coincident events corresponding to the energy region based on the calculated correction value to produce corrected sample event counts.