Related papers: Positronium Physics and Biomedical Applications
Positronium is the short-lived atom consisting of a bound electron-positron pair. In the triplet state, when the spins of both particles are parallel, radiative recombination lines will be emitted prior to annihilation. The existence of…
The Jagiellonian positron emission tomograph (J-PET) is a multi-purpose device built out of plastic scintillators. With large acceptance and high angular resolution, it is suitable for the studies of various phenomena such as discrete…
A simple method to compute QED bound state properties is presented, in which binding energy effects are treated non-perturbatively. It is shown that to take the effects of all ladder Coulomb photon exchanges into account, one can simply…
The energy levels of the muonium ($\mu^+ e^-$) atom, which consists of two ''point-like'' leptonic particles, can be calculated to very high accuracy in the framework of bound state Quantum Electrodynamics (QED), since there are no…
A maximum value for the magnetic field is determined, which provides the full compensation of the positronium rest mass by the binding energy in the maximum symmetry state and disappearance of the energy gap separating the electron-positron…
The positronium state in quartz is described by a linear superposition of two states: the first describing the free positron in the crystal and the second corresponding to a positronium Bloch wavefunction in the lattice. The condition for…
Within the last decade powerful methods have been developed to study surfaces using bright low-energy positron beams. These novel analysis tools exploit the unique properties of positron interaction with surfaces, which comprise the absence…
Positronium Lifetime Imaging (PLI) extends positron emission tomography by using the lifetime of positronium atoms as a probe of tissue molecular architecture. In this work, we report the first PLI measurements performed with $^{52}$Mn and…
A possibility of a verification of CPT-invariance of QED for bound states by example of muonium or antimuonium produced in reactions of scattering of electrons or positrons by nuclei is considered. The number of events of the muonium…
The present status of theoretical and experimental investigations of the decay rate of a positronium is considered. The increasing interest to this problem has been caused by the disagreement of the calculated value of $\Gamma_3 (o-Ps)$ and…
Positrons bind to molecules leading to vibrational excitation and spectacularly enhanced annihilation. Whilst positron binding energies have been measured via resonant annihilation spectra for $\sim$90 molecules in the past two decades, an…
One of the features of the triplet state of positronium (ortho-Positronium)atoms is its relatively longer lifetime when compared to the singlet states ofpositronium (para-Positronium) atoms. The most probable decay of ortho-Positronium is…
This chapter reviews the following items: 1. Energy deposition and track structure of fast positrons: ionization slowing down, number of ion-electron pairs, typical sizes, thermalization, electrostatic interaction between e+ and its blob,…
The Jagiellonian Positron Emission Tomograph (J-PET) is the first PET device built from plastic scintillators. It is a multi-purpose detector designed for medical imaging and for studies of properties of positronium atoms in porous matter…
Positronium atoms (Ps) are widely used as a probe to characterize voids or vacancies in non-metallic materials, where Ps annihilation lifetime is strongly modified by pickoff, depending on the size of the trapping cavity and on the…
In the framework of a scalar QFT, we evaluate the decay of an initial massive state into two massless particles through a triangle-shaped diagram in which virtual fields propagate. Under certain conditions, the decaying state can be seen as…
We present a precise theoretical prediction for the decay width of the bound state of two electrons and a positron (a negative positronium ion), Gamma(Ps^-) = 2.087 085(12)/ns. We include O(alpha^2) effects of hard virtual photons as well…
The Jagiellonian Positron Emission Tomograph (J-PET) is a detector for medical imaging of the whole human body as well as for physics studies involving detection of electron-positron annihilation into photons. J-PET has high angular and…
The excess energy emitted during the positronium (Ps) formation in condensed matter may be released as light. Spectroscopic analysis of this light can be a new method of studying the electronic properties of materials. We report the first…
A model-potential approach has been developed to study positron interactions with molecules. Binding energies and annihilation rates are calculated for positron bound states with a range of alkane molecules, including rings and isomers. The…