Development of a pulsed positron microbeam

Maekawa, Masaki; Kawasuso, Atsuo

We have developed the positron microbeam apparatus. With the present equipment, the Doppler broadening measurement is possible. In order to collect more information about vacancy-type defects, it is necessary to perform positron annihilation lifetime spectroscopy measurement. For this purpose, the beam pulsing section inserting in the existing beam line was developed. This consists of a coaxial cylinder type pre-buncher, a deflection type chopper, and a resonator type buncher. When pulsing system was operated, it was confirmed that a pulsed beam with the pulse width of 140ps can be formed and that PALS measurement is possible.