Time-Resolved Luminescence Measurements on Up-Conversion Phosphors for Electron Beam Sterilization Monitoring

M. Reitzig, T. Härtling, M. Winkler, P.E. Powers, S. Derenko, O. Röder, J. Opitz
Fraunhofer Institute for Nondestructive Testing IZFP, Dresden Branch, DE

Keywords: wterilization, medical products, optical monitoring, luminescence, up-conversion

Summary:

We present recent investigations on time-resolved measurements on alterations in the temporal luminescence decay of up-conversion phosphors induced by electron beam treatment. As a consequence of the tight regulations concerning sterility in the food and medical sectors a reliable and nondestructive in situ evaluation of the sterilization process faces a huge demand. Our technique is based on placing a suitable marker material (based on rare-earth phosphors) inside or as a coating on the packaging material. Upon electron irradiation the marker material changes its luminescent properties as a function of applied energy dose. The energy dependence is verified by time-resolved measurements on different up-conversion materials.