%T Detection of low-energy charged particles by channel electron multipliers %O Published by IOP Publishing Ltd on behalf of Sissa Medialab. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence (http://creativecommons.org/licenses/by/4.0). Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. %X Experimental determinations of the detection efficiency for positrons impacting a channel electron multiplier with incident energies between 0–1400 eV are presented. A log-normal dependence with energy is established and used to compute the positron-to-positronium detection efficiency ratio as a function of positronium energy, as required for determining quantities involving the ratio of positron and positronium rates. A log-normal energy-dependence is also observed in results of previous work with electrons, protons and ions. %L discovery10158097 %V 17 %A DM Newson %A M Shipman %A SJ Brawley %A R Kadokura %A TJ Babij %A D Cooke %A DE Leslie %A G Laricchia %A . . %J Journal of Instrumentation %I Institute of Physics %D 2022