A new positron lifetime spectrometer using a fast digital oscilloscope and BaF2 scintillators H.Saito.*,Y.Nagashima2,T.Kurihara,T.Hyodo Institute of Physics,Graduate School of Arts and Sciences,University of Tokyo,3-8-1 Komaba Meguro-ku,Tokyo,153-8902 Japan Institute of Materials Structure Science,High Energy Accelerator Research Organization(KEK).1-1.O-ho,Tsukuba-shi,Ibaragi. 305-0801 Japan Nuclear Instruments and Methods in Physics Research A 487(2002)612-617 e