Positron annihilation spectroscopy is a powerful probe to investigate the interfaces in materials relevant for energy storage such as Li-ion batteries. The key interpretation of results positron implantation profile, which spatial function related characteristics forming battery. We provide models profile cathode battery coin cell. These are basis reliable visualization multilayer geometries an...

High-temperature positron two-dimensional angular correlation of annihilation radiation ~2D-ACAR! measurements have recently been succesfully applied to map parts of the Fermi surface of YBa2Cu3O72d . Using the same principle, we have been able to observe with a bulk sensitive method, the Fermi surface of Nd22xCe xCuO42d . Although positron trapping by defects and correlation effects are strong...

A method is proposed for detecting positron-atom bound states by observing enhanced positron annihilation due to electronic Feshbach resonances at electron-volt energies. The method is applicable to a range of open-shell transition-metal atoms which are likely to bind the positron: Fe, Co, Ni, Tc, Ru, Rh, Sn, Sb, Ta, W, Os, Ir, and Pt. Estimates of their binding energies are provided.

We have measured the momentum distribution of the electron-positron annihilating pair in diamond as a function of crystallographic orientation, using the Doppler broadening technique of positron annihilation spectroscopy. A 1% variation in the longitudinal projection of the momentum distribution was observed as the sample was rotated about the (110) axis. This anisotropic distribution shows an ...

Using idealized models of the accretion disk, we investigate effects induced by modified theories gravity on annihilation neutrino pair into electron-positron pairs ($\nu{\bar \nu}\to e^-e^+$), occurring near rotational axis. For have considered with temperature $T=constant$ and $T\propto r^{-1}$. In both cases, find that lead to an enhancement, up more than one order magnitude respect General ...

Low energy positron production and storage may be used to make and observe some interesting many-positron, many-electron systems both in vacuum and in the presence of ordinary matter. One of the most interesting possibilities is to make an annihilation photon laser. One might start on the path to this laser by creating a high density positron burst and forming a dense gas of positronium atoms w...

This paper is devoted to study many-body effects in the positron annihilation experiment, both electron−positron (e–p) and electron–electron (e–e) correlations. Various theories of the e–p interaction in real solids were used to verify them by comparing theoretical and experimental e–p momentum densities in Cu and Y. We show that the lattice potential has an essential influence on the e–p corre...

The electron-positron annihilation source in the Galactic center region has recently been observed with INTEGRAL/SPI, which shows that this 511 keV source is strong and its extension is consistent with the Galactic bulge geometry. The positron production rate, estimated to more than 10 43 per second, is very high and raises a challenging question about the nature of the Galactic positron source...

Positron range is one of the main physical effects limiting the spatial resolution of positron emission tomography (PET) images. If positrons travel inside a magnetic field, for instance inside a nuclear magnetic resonance (MR) tomograph, the mean range will be smaller but still significant. In this investigation we examined a method to correct for the positron range effect in iterative image r...

Positron Annihilation Spectroscopy is a valuable microscopic method to study radiation damage in nuclear reactor pressure vessel steels. At SCKoCEN, a new positron lifetime setup, suited to measure positron lifetimes in irradiated steel, is being constructed. The particularity of this setup is that the prompt count rate originating from the induced 60Co-activity in the steel is highly reduced. ...