Digital positron lifetime spectrometer for measurements of radioactive materials

Abstract

A digital positron lifetime spectrometer for the measurements of 2 GBq level radioactive materials has been constructed and successfully tested. The equipment consists of a state-of-the-art digital oscilloscope and three movable scintillation detectors operating in triple-coincidence mode. The time resolution of 188 ps full-width at half-maximum (FWHM) is achieved for the positron lifetime measurements of radioactive specimens. Also by comparison of measurements of well-known material with and without high 60 Co background radiation the ability to measure radioactive specimens is proved. In this paper the performance, construction, installation, optimization and calibration of the setup is reported.

Influence of different chemical elements on irradiation-induced hardening embrittlement of RPV steels

“…The resolution of the setup was constantly checked to be about 175 ps, while the source contribution was set to 15% with a single lifetime of 393 ps. More detailed information about the experimental setup is given in [23,25]. All measurements were performed at room temperature using a 22 Na positron source, with a strength of 2 MBq, wrapped in Kapton foils.…”

Coincidence time resolution investigation of BaF2-based H6610 detectors for a digital positron annihilation lifetime spectrometer

“…Time resolution is considered as one of the key parameters to evaluate the characteristics of a PAL spectrometer. Numerous efforts have been made to improve the time resolution of PAL spectrometers over the past twenty years [15][16][17][18][19][20][21][22][23][24][25][26]. The tendency is to develop digital PAL spectrometers in which analog electric modules are substituted by fast digitizers.…”

Positron annihilation study of neutron irradiated model alloys and of a reactor pressure vessel steel

“…The main lifetime used within this paper has been measured, but it is very close to the calculated value (s m = I 1 Â s 1 + I 2 Â s 2 ). More detailed information about the experimental setup is given by Jardin et al [18,20]. Here, it has been shown that for our setup, the lifetime measured in non-irradiated pure Fe samples corresponds to (107.57 ± 0.38) ps.…”