Positron annihilation spectroscopy, when combined with highquality supporting modeling of positron states and annihilation in matter, is a powerful tool for detailed defect identification of vacancy-type defects in semiconductors and oxides. Here we demonstrate that the Doppler broadening of the positron annihilation radiation is a very sensitive means for observing the oxygen environment aroun...

Microstructure hierarchical model considering the free-volume elements at the level of interacting crystallites (non-spherical approximation) and the agglomerates of these crystallites (spherical approximation) was developed to describe free-volume evolution in mechanochemically milled As4S4/ZnS composites employing positron annihilation spectroscopy in a lifetime measuring mode. Positron lifet...

This paper is a review of low-energy positron interactions with atoms and molecules. Processes of interest include elastic scattering, electronic and vibrational excitation, ionization, positronium formation and annihilation. An overview is presented of the currently available theoretical and experimental techniques to study these phenomena, including the use of trap-based positron beam sources...

It is well known that positrons can live long enough to form complexes with atoms. The theoretical study of these complexes is important to interpret experimental data from both positron scattering by atoms and molecules and positron annihilation spectroscopy. There are typically two different kinds of positron complexes. In one of them a positron attaches to a neutral or ionic atom or molecule...

Multiple myeloma causes major morbidity resulting from osteolytic lesions that can be detected by metastatic bone surveys. Magnetic resonance imaging and positron emission tomography can detect bone marrow focal lesions long before development of osteolytic lesions. Using data from patients enrolled in Total Therapy 3 for newly diagnosed myeloma (n=303), we analyzed associations of these imagin...

Cathode materials are crucial to improved battery performance, in part because there are not yet materials that can maintain high power and stable cycling with a capacity comparable to that of anode materials. Our parameter-free, gradient-corrected model for electron-positron correlations predicts that spectroscopies based on positron annihilation can be deployed to study the effect of lithium ...

Absolute measurements are presented for the positron-impact cross sections for positronium formation, direct ionization, and total ionization of the diatomic molecules N2, CO, and O2, in the range of energies from threshold to 90 eV. Cross sections for the electronic excitation of the a 1 and a 1 state in N2 and the A 1 state in CO near threshold are also presented. The experiment uses a cold, ...

We treat in detail positron production from the decay of radioactive nuclei produced in nuclear reactions of accelerated 3He. Because of their large cross sections and low threshold energies, these reactions can significantly contribute to positron production in solar flares with accelerated-particle compositions enriched in 3He. The addition of these 3He reactions extends earlier calculations ...

The zero-range potential model is used to investigate positron collisions and annihilation with molecules. The Kr2 dimer is considered as an example. It is shown that (i) although positrons do not bind to individual Kr atoms, they do form bound states with Kr2. (ii) A sequence of vibrationally excited states of the positron–molecule complex extends into the positron continuum, where it manifest...

background: mesial temporal lobe epilepsy (tle) is a remediable epileptic syndrome. about 40% of patients continue to have seizures after standard temporal lobectomy. it has been suggested that some of these patients could actually suffer from a more complex epileptogenic network. because a few papers have been dedicated to this topic, we decided to write an article updating this theme. methods...