the use of [18f]-2-fdg has been increasing in recent years. this agent was originally used for evaluation of cns glucose uptake and pathologic conditions by positron emission tomography (pet). in view of increasing demand for this agent, its production has been started at cyclotron dept., nuclear research center for agriculture & medicine-karaj iran (nrcam). in this paper, [18f]-fdg synthes...

Abstract Experimental determinations of the detection efficiency for positrons impacting a channel electron multiplier with incident energies between 0–1400 eV are presented. A log-normal dependence energy is established and used to compute positron-to-positronium ratio as function positronium energy, required determining quantities involving positron rates. energy-dependence also observed in r...

Positron annihilation spectroscopy techniques are well established nuclear techniques with applications which nowadays range from structural investigations of materials to investigations of biological samples and medical imaging. They have extensively been used more than thirty years, but with constant improvements in measuring methods and with new applications, especially in investigations of ...

We report a target design which produced substantial gain in relativistic electron-positron pair production using high-intensity lasers and targets with large-scale micro-structures on their surface. Comparing to an unstructured target, selected Si microwire array yielded near 100% increase the laser-to-positron conversion efficiency 10 MeV average emitted positron energy under nominally same e...

Methodological possibilities of positron annihilation lifetime (PAL) spectroscopy applied to characterize different types of nanomaterials treated within three-term fitting procedure are critically reconsidered. In contrast to conventional three-term analysis based on admixed positron- and positronium-trapping modes, the process of nanostructurization is considered as substitutional positron-po...

A baseline design for the NLC positron source based on the existing SLC positron system is described. The proposed NLC source consists of a dedicated S-band electron accelerator, a conventional positron production and capture system utilizing a high-Z target and an adiabatic matching device, and an L-band positron linac. The invariant transverse acceptance of the capture system is 0.06 m⋅rad, e...

The variational method is applied to the low-energy positron scattering and annihilation problem. ultimate aim of investigation find a computationally economical way accounting for strong electron–positron correlations, including effect virtual positronium formation. study elastic s-wave from hydrogen atom. A generalized eigenvalue problem set up solved obtain positron–hydrogen phase shifts wit...

Positron scattering from atoms and molecules is studied at low values of incident positron energy. The experiments use a cold magnetized positron beam formed in a positron accumulator. A discussion of positron scattering in a magnetic ®eld is presented along with di€erential cross-sections (DCS) for positron±atom collisions and positron± molecule total vibrational excitation cross-sections. Abs...

Positron annihilation rates in many polyatomic molecular gases are anomalously high. Qualitatively, this can be explained by positron capture in vibrational Feshbach resonances, which can occur for molecules with positive positron affinities [Gribakin, Phys. Rev. A 61 (2000) 022720]. To verify this idea quantitatively, we examine the densities of vibrational excitation spectra of alkanes. To un...