Fast intrinsic luminescence of RbI and KI crystals excited by X-ray synchrotron radiation

Luminescence spectra and decay kinetics of the fast intrinsic luminescence of RbI and KI crystals at temperatures of 80 and 300 K have been measured with pulsed X-ray synchrotron radiation (SR) excitation. K the emission spectra show the well-known fast emission bands centered at 3.84 eV in RbI and at 4.15 eV in KI. At room temperature subnanosecond (∼ 100 ps) emission bands with non-exponential decay kinetics are observed at 3.7 eV in RbI and at 4.0 eV in KI. These two bands may be associated with high temperature fast intrinsic luminescence of CsI.