English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The fraction of positronium (Ps) emitted from a surface of a germanium singlecrystal at high temperature is usually assumed to approach unity at zeropositron implantation energy. In the experiment, however, the determination ofthe absolute Ps fraction is not straight forward since recording a referencespectrum with $100\,\%$ Ps formation remains demanding. We use GEANT4-simulateddetector responses to $2\gamma$ and $3\gamma$ radiation sources mimickingpositron and Ps annihilation inside the (coincidence) Doppler-broadeningspectrometer at NEPOMUC, FRM II, in order to derive a reliable value for the Psfraction reemitted from a Ge(100) target heated close to its melting point.Analysis of the measured spectra by fitting the simulated spectra shows anabsolute value of $(72\,\pm{4})\,\%$ maximum Ps formation, contradicting the$100\,\%$ assumption.

Absolute fraction of emitted Ps determined by GEANT4 supported analysis of gamma spectra