Development of gamma ray-induced positron annihilation spectroscopy at UVSOR-III

Taira, Yoshitaka*; Sugita, Kento*; Okano, Yasuaki*; Hirade, Tetsuya  

Positron annihilation spectroscopy is a powerful analytical method that can measure vacant defects in crystals and microvoids in insulating materials. UVSOR-III is developing gamma-ray-induced positron annihilation spectroscopy using ultrashort pulse gamma rays. Specifically, we have succeeded in positron annihilation lifetime (PAL) measurement and positron age-momentum correlation (AMOC) measurement. PAL has succeeded in directly measuring the spectrum of only the sample. In addition, AMOC also succeeded in observing the positron annihilation only in the samples, which shows the different momentum distribution for the different defect states. At present, coincidence Doppler broadening (COB) measurement is also available, and a CDB spectrum with only positron annihilation from the sample will be obtained by the newly developed analysis program.