Positron spectroscopy based on an electron linac brings a new aspect of methodology for positron research. We planned to start the construction of a slow-positron facility in 1990, aiming to produce 'more than 2x10(9) e+/s slow positrons by utilizing a high-energy accelerator, the 2.5-GeV electron linac, as its primary beam source. One of the results of using a high-intensity pulsed positron beam was reported as a study of the origins of positronium emitted from SiO2. In parallel, the research and development of positron beams was also performed. In this article, results and status of this research and development are reported and discussed.