[en] We are developing a low energy, microscopically focused, pulsed positron beam for defect analysis by positron lifetime spectroscopy to provide a new defect analysis capability at the 10¹⁰ e⁺s^-l beam at the Lawrence Livermore National Laboratory electron linac. When completed, the pulsed positron microprobe will enable defect specific, 3-dimensional maps of defect concentrations with sub-micron resolution of defect location. By coupling these data with first principles calculations of defect specific positron lifetimes and positron implantation profiles we will both map the identity and concentration of defect distributions