Which energy level is associated with the photopeak of Cs-137?

The photopeak for Cs-137 corresponds to an energy level of 662 keV. This energy level is significant because it represents the primary gamma emission produced when Cs-137 undergoes radioactive decay. Cs-137 decays through beta decay into Ba-137m, which then emits gamma radiation as it stabilizes. The 662 keV photon is the most prominent gamma photon emitted during this decay process and is used frequently in both clinical and radiological applications for calibration and quality assurance of imaging systems. Understanding this energy level aids in accurately identifying and quantifying the presence of Cs-137 in various environments, which is crucial in both medical imaging and radiation safety.