A new timed slow positron beam

This is the authors' abstract. We don't add key points for this paper.

A simple method of producing a timed beam of variable energy positrons has been developed which utilizes secondary electrons liberated by beta + impact on a positron moderator to generate the timing pick-off. The slow positron flux has been timed with an efficiency greater than 20% and with a signal-to-background level much higher than that encountered in traditional thin plastic scintillator techniques.