PALS System with CRM Materials for Biomedical Studies - experimental data

Objective and method: Positron annihilation lifetime spectroscopy (PALS) is a powerful technique in material science that allows the investigation of the properties and behavior of positrons in various materials. PALS can be used to investigate solid structures at the nanometer scale and enable the use of positronium properties as an additional diagnostic parameter. Here we present results from calibration of the PALS system with certificated reference materials (CRM). Materials: Source of 22Na covered with layer of Kapton film, and after that parafilm from both sides was used in all experiments. Certified materials of No_5602-a (polycarbonate) and No_5601-a (fused silica) were used to ascertain if parameters were correctly identified. Results: In an experiment three lifetime components were correctly identified. All of those components will always be present in the data in further experiments on biological samples. Lifetime components consist of: 196 ps for annihilations in AI an aluminium cover of the chamber, 386 ps for annihilations in thesource and in the Kapton foil, 463 ps for reactions with parafilm.