What is the decay time of NaI (Tl) scintillator?

The decay time of NaI(Tl) scintillator is approximately 230 nanoseconds. This value refers to the time it takes for the emitted light signal from the scintillator after being excited by ionizing radiation to fall to a certain fraction of its maximum intensity, typically around 1/e of its peak value.

NaI(Tl) is a widely used scintillation crystal in radiation detection and imaging systems, including PET scanners, due to its favorable properties such as high light yield and good energy resolution. The relatively quick decay time allows for effective signal processing and helps in achieving better timing resolution in imaging applications.

The other options reflect decay times from different materials or scintillators, which have longer or shorter decay characteristics compared to NaI(Tl). This specificity in decay time is critical in the context of PET imaging to enhance image quality and allow for accurate timing in event detection.