The construction and successive first operation of a slow positron beam at The Hebrew University of Israel are reported here. The beam follows a traditional design, using a 22Na source, and a Tungsten moderator. It is designed to allow a combined measurement of Doppler-Broadening (DB), sample conductivity, and sample in-situ cooling, with the flexibility to add more detection options in the future. The beam energy varies between 0.03 keV and 30 keV. The detection system consists of two high-purity Germanium detectors, facing each other, allowing coincidence DB measurements. Event readout is done using a state-of-the-art compact desktop system. The beam has been successfully tested by using it to characterize annealed Copper (Cu) samples. Three samples were measured at various energies (0.5 keV–16.5 keV), one before any treatment and two annealed at 250 °C and 500 °C. The results, fitted using VEPFIT, show consistent behavior with previous measurements.
|Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
|Published - Jan 2024
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- Compact DAQ
- Doppler Broadening
- Positron annihilation spectroscopy
- Slow positron beam