Position-Resolved Positron Annihilation Lifetime Spectroscopy


Position-Resolved Positron Annihilation Lifetime Spectroscopy

Fiedler, F.; Anwand, W.; Butterling, M.; Cowan, T. E.; Enghardt, W.; Fritz, F.; Heidel, K.; Kempe, M.; Steudtner, T.; Wagner, A.

A method allowing for position-resolved positron lifetime spectroscopy studies in large volume samples will be presented. This technique was developed at the superconducting linear accelerator ELBE (Electron linac with high brilliance and low emittance) at the Helmholtz-Zentrum Dresden-Rossendorf, Germany. A beam of continuous 16 MeV electron bunches of about 5 ps temporal width and a repetition frequency of 26 MHz was used to generate bremsstrahlung preserving the sharp timing of the electron beam. Positrons produced in the target via pair production feature a sharp time stamp for lifetime studies. They decelerate quickly and annihilate in microscopic defects. This allows for high timing resolution and high signal to background ratios due to the coincident detection of two annihilation photons. Two commercially available Lutetium Oxyorthosilicate scintillator (LSO) detectors were employed to detect the annihilation photons. These LSO detectors are already clinically used in the SIEMENS Biograph PET Scanner. Each detector consists of a crystal matrix with 13 13 pixels and a total size of 52 mm 52 mm 20 mm. The total energy resolution was measured to be 5.1% (RMS) and the timing resolution is 225 ps (RMS). Experiments resulting in position resolved lifetime measurements will be presented.

Keywords: position-resolved positron life time spectroscopy; non-destructive material analysis

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  • Lecture (Conference)
    IEEE Nuclear Science Symposium and Medical Imaging Conference - NSS MIC 2012, 29.10.-03.11.2012, Anaheim, USA

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Publ.-Id: 18221