Effect of ultrasonic oscillatory stress on deformation luminescence of X-irradiated KCl:Eu2+KCl:Eu2+

Luminescence has been observed during deformation of X-irradiated alkali halide crystals. And also, it has been observed at fracture or under superimposition of ultrasonic oscillation. These phenomena are useful for studying the deformation of crystals. We have investigated luminescence during the deformation of X-irradiated KCl:Eu2+KCl:Eu2+ and under superimposition of oscillation.The luminescence intensity rapidly increases at the beginning of plastic deformation. The intensity roughly remains constant for a while and is then followed by gradual decreasing. The variation of luminescence intensity seems to correspond to the deformation stage of the crystal. The spectrum of deformation luminescence (DL) has a peak of 420 nm due to Eu2+Eu2+. Superimposition of oscillation during plastic deformation of crystals causes a decrease in stress along with additional luminescence (sonoluminescence, SL). The SL intensity also appears to correspond to the deformation stage. SL/DL is found to be proportional to stress decrement due to superimposition of ultrasonic oscillation irrespectively of strain. DL has been found to occur mainly at the intersection of slip bands.