Abstract
Various mesoporous materials were investigated to choose the best material for experiments requiring high yield of long-lived positronium. We found that the fraction of 3\gamma annihilation determined using \gamma-ray energy spectra and positron annihilation lifetime spectra (PAL) changed from 20% to 25%. The 3gamma fraction and o-Ps formation probability in the polymer XAD-4 is found to be the largest. Elemental analysis performed using scanning electron microscop (SEM) equipped with energy-dispersive X-ray spectroscop EDS show high purity of the investigated materials.
Highlights
The Jagiellonian Positron Emission Tomography scanner (J-PET) has been recently built at the Jagiellonian University [1,2,3,4,5,6,7,8,9] using a novel approach proposed in references [10, 11]
~125 ps is ascribed to p-Ps decay, the one comes from positron free annihilation and three the longest lived with a lifetime above 1 ns – from o-Ps decay (Table 1)
In the case when only a few kinds of free volumes/pores exist in the material few components in PALS measurements come from o-Ps decay, the 3
Summary
The Jagiellonian Positron Emission Tomography scanner (J-PET) has been recently built at the Jagiellonian University [1,2,3,4,5,6,7,8,9] using a novel approach proposed in references [10, 11]. Samples were examined using PALS (Positron Annihilation Lifetime Spectroscopy) and gamma-ray spectroscopy. Samples were placed in the same vacuum chamber like in PALS measurements.
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