Effects of Local Heating and Premelting in the Terminal Part of the e+ Track
The terminal part of the e+ track (the positron blob) is formed during ionization slowing down and subsequent ion-electron recombinations produced by a positron. It releases up to 1 keV of energy, which is converted into heat within few picoseconds. If a bulk temperature of a medium is below, but close enough to its melting point, some region of a substance may melt, yielding a peculiar temperature dependence of the lifetime (LT) spectra. We have estimated properties of the molten region with a help of macroscopic heat con- duction equation and suggested a model describing temperature dependence of the ortho- positronium lifetime in frozen methanol, ethanol, butanol and water close to their melting points.
Jozef Krištiak, Jan Kuriplach and Pradeep K. Pujari
D. Zvezhinskiy et al., "Effects of Local Heating and Premelting in the Terminal Part of the e+ Track", Materials Science Forum, Vol. 733, pp. 15-18, 2013