Design, simulation and performance of a slow positron beam with secondary electron tagging for positron annihilation lifetime spectroscopy

作者：Marinov H; Djourelov N^*; Nedelec P; Petrov L

来源：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment , 2013, 729: 569-575.

DOI：10.1010/j.nima.2013.03.045

• Positron beam
• Secondary electrons
• Backscattering
• Positron lifetime

A positron annihilation lifetime spectrometer using a magnetically guided continuous positron beam and the signal nom secondary electrons (SE) emitted nom the sample is presented. The positron and secondary electrons trajectories as well as the physics of SE were simulated using GEANT4 program. A special attention was paid to the consequences of positron backscattering, in particular on the shape of the lifetime spectrum. A very good agreement was obtained between simulation and measurements concerning the time resolution (similar to 300-400 ps FWHM) for the studied range of incident positron energies. Due to the complex shape of the resolution function, the present design of the spectrometer is not suited to study of short lifetimes, but can be used for depth profiling porosimetry of materials with Ps formation with the an excellent peak to background raLio of similar to 10(5).

• 出版日期2013-11-21