A digital coincidence Doppler broadening (CDB) spectrometer consisting of two HPGe detectors is assembled; the energy resolution of each detector is 1.1 keV at energies near the annihilation line. Two desktop applications for CDB spectra processing are developed. TLIST Processor converts two-dimensional CDB spectra into one-dimensional spectra. Another tool SW Calculator deconvolutes the experimental CDB spectra into contributions from positron annihilation with valence, core and conduction band electrons. The program estimates the energies of the corresponding electrons and evaluates S and W parameters of the CDB spectra.
Analysis of the o-Ps lifetimes concentration dependences in water-propanol mixtures (with and without CoCl_2 additive) shows that this mixture looks like an emulsion of alcohol micelles in water at propanol mole fractions 0.1-0.4.
We discuss some aspects important for interpretation of the Ps formation process in liquids and molecular media: (1) inhomogeneity of intratrack reactions and parameters of the e⁺ track, (2) final states of e⁺, its solvation in polar and nonpolar liquids, relation to e⁺ mobility, (3) quasi-neutrality of the e⁺ blob and its ambipolar outdiffusion, (4) appearance of the "in-blob" and "out-of-the-blob" positron fractions, and (5) electric field effect on Ps formation.
Investigation of the local heating effect at the terminal part of a fast positron track sheds light on the accumulation of defects in a frozen medium close to its melting point. Estimations of the formation energies of the structural defects which may trap the Ps atom as well as a contribution of these defects to the enthalpy of fusion are obtained.
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.