Nuclear Seminar - Ondrej Šauša, Helena Švajdlenková (22.4.2026)
Wednesday 22.4.2026 at 14:00, Lecture room F1/364
RNDr. Ondrej Šauša, CSc. (Institute of Physics SAS, KJCH PriF UK):
Fundamentals of Positron Annihilation Lifetime Spectroscopy (PALS)
Abstract:
The first part will present basic facts about positron annihilation in a material environment, about the formation of a bound state of an electron and a positron (positronium) in insulators and the use of positronium in the study of the free volume of porous materials. Experimental devices for measuring the lifetimes of positrons and positronium will be discussed, from simple coincidence scintillation systems to complicated devices such as slow positron beams and positron microscopes. Possible outputs from typical annihilation experiments will be shown, which provide unique information about the microstructure of the studied substances.
and
Ing. Helena Švajdlenková, PhD. (Polymer Institute SAS, KJCH PriF UK):
The use of PALS in polymer chemistry
Abstract:
In the second part, there will be a presentation of specific outputs from annihilation experiments in the field of polymer chemistry. Examples will include the study of the microstructure of dimethacrylates used in dental medicine, as well as the preparation of epoxides using frontal polymerization.