In-flight annihilation correction for 511 keV photon spectrometryG.F. Steyn, S.G. Dolley, F. Szelecsényi, Z. Kovács, N.P. van der Meulen and C. VermeulenEPJ Web Conf., 146 (2017) 08010DOI: https://doi.org/10.1051/epjconf/201714608010