Abstract
A positron pulsing system has been constructed for variable energy positron lifetime spectroscopy. The system consists of a reflection type chopper, a sub-harmonic prebuncher, and a double harmonic buncher. By operating the system with an intense slow positron beam generated by an electron linac, positron lifetime spectra have been successfully measured in an extended time range of more than 45 ns with a good time resolution (250 ps). Furthermore, Doppler broadening profiles of annihilation radiations can be obtained simultaneously with the lifetime measurements.