Gamma-induced Positron Lifetime and Age-Momentum Correlation Measurements (AMOC) of water at temperatures between 20° C and 90° C

The Gamma-induced Positron Spectroscopy (GiPS) facility at ELBE (Helmholtz-Zentrum Dresden-Rossendorf) is ideally suited to measure extended volume sample materials like liquids with an information depth of several mm in an appropriate time [1]. Moreover, GiPS allows for studying positron lifetimes and positron momentum within the same experiment and thus allows for realizing Age-Momentum Correlation (AMOC) experiments within a fraction of time needed with conventional setups.

There are still questions about the microscopic structure of liquid water and the behavior of water inside membranes and at boundaries is under vivid investigation.
AMOC experiments revealing additional information about the local environment at the instance of pick-off positron annihilation of o-Ps were performed for water at temperatures between 20°C and 90°C to verify recently reported observations of periodic quantum beats in the AMOC spectra, caused by spin conversion of o-Ps [2]. The radiation effect caused by the use of bremsstrahlung for positron production was also investigated.

Different analysing methods for these spectra with high statistic and quality will be presented. Also the application of common theory for positronium formation and chemical reactions in water will be discussed.