Papers by Keyword: Positron Annihilation Lifetime (PAL)

Abstract: An interlaboratory comparison for positron annihilation lifetime (PAL) measurements for pure nickel and fused silica was performed. Based on the reported positron (for nickel) and positronium (for fused silica) lifetimes, the uncertainties in the PAL measurements were estimated.

Abstract: Cerium doped lutetium aluminium garnet (Lu3Al5O12:Ce, LuAG:Ce) displays particularly promising performance and has a great potential to be used in PET and SPECT. LuAG:Ce phosphors was synthesized with a simple sol-gel process. The structure was identified with XRD. Variations of luminescent properties and defects of LuAG:Ce phosphors with different heat-treatment temperatures and Ce3+-dope concentrations have been investigated, with the aid of emission spectra and positron annihilation lifetime measurements. The influence of defects on the luminescence properties was discussed.

Abstract: Positron annihilation lifetime spectroscopy (PALS) measurements were performed on polymer electrolyte membranes (PEMs) synthesized by radiation-induced graft polymerization of styrene into crosslinked-polytetrafluoroethylene (cPTFE) films and subsequent sulfonation. The base cPTFE and polystyrene grafted films were also measured as references. The cPTFE based PEM was found to have free-volume holes with different radius of 0.28-0.30 nm and 0.44-0.45 nm. The larger holes may be located in PTFE amorphous regions, while the smaller ones are considered to exist in both PTFE crystallites and poly(styrene sulfonic acid) grafts containing no water.