Question

It takes on average 3 eV to liberate an electron-hole pair in a Ge detector (100 times less than for NaI). How will the FWHM compare with that for a NaI detector?

Answer 1

The resolution of NaI and Ge detectors are measured in terms of Full-width half maxima(FWHM). This is very helpful in separating two adjacent energy peaks and in the clear identification of nuclides. FWHM is much smaller in Ge detector compared to the NaI detector, which gives better resolution for nuclide identification compared with NaI detector. The FWHM depends on the emitted radiation but also on the detector's diameter and thickness. The Ge detector has low FHWM compared to the NaI detector, it is more efficient in detecting the nuclides with lower energy. The NaI detector has large detector area which increases the probability of detecting the radiation and gives better sensitivity in detecting nuclides with higher energy. The FWHM of Ge detector offers the resolution of detecting two very closely located energy points and has ability to detect a mixture of nuclear material.