B and C band excitation and emission spectra in KI:Tl

We present the excitation spectra of KI:T1 measured in the region of the B and C absorption bands at several emission wavelengths and at 20 K, 80 K and 300 K. An accurate analysis of these spectra shows new properties of the excitation spectra, that we relate to the non radiative relaxation of the excited electrons towards the luminescent states.