Polarized β emitters for NMR probes

The physical principles of atomic and nuclear polarization by the tilted-foil interaction as applied to the production of polarized emitters for NMR probes are discussed.     

The solvophobic effect in simple fluid mixtures

The “solvophobic” effect is the tendency of solute particles to cluster as the attractive interaction between solvent particles is strengthened. The potentials of mean force in the hypernetted chain approximation have been obtained for a simple fluid mixture consisting of two hard spheres immersed in a hard core/Yukawa tail solvent. The results clearly exhibit features attributable to the “solvophobic” effect.     

Hyperfine interactions of polarized β-emitting12B and12N in Si,Ge, and GaP

Using a nuclear reaction, the polarized short-lived -emitters¹²B and¹²N were implanted into Si, Ge, and GaP crystals. Hyperfine fields were studied via both NMR techniques and an external magnetic holding field H_ext on-off techniques in an H_ext range 0–8 kG and a temperature range 100–1000 K. No significant NMR signal was observed between 2 and 30 MHz for¹²N in Si and Ge despite maintenance of 60% polarization at T100 K and H_ext>4 kG, whereas for¹²B in Si at T>800 K almost full polarization was found at the Larmor frequency.     

Hyperfine interactions of Rn and Ra implanted into Fe,Al, Cd and Bi metals

The interactions on radon and radium nuclei implanted into metals have been studied by means of α-γ angular correlations. The influence of source preparation and of surface oxide layers have been studied in sources prepared by evaporation and isotope separator implantation. The interactions in iron are found to have contributions from static magnetic fields as well as static quadrupole interactions. The magnetic fields for radon and radium in iron were determined to be +920±85 kOe and −380±35 kOe, respectively. The theoretical models used to describe the perturbations due to mixed interactions and their importance in internal field determinations are discussed.     

Beam-foil polarization for in-beam nuclear-polarization studies

The physical principles of atomic and nuclear polarization by grazing-incidence collisions (scattering) and by the tilted-foil interaction (transmission) are introduced. The formation in-flight of bound atomic systems of antiprotons and polarized light nuclei, polarized by beam-foil techniques at threshold energies, are discussed.     

On the phenomenological theory of diffusion

A phenomenological theory of diffusion is given along the lines of the treatment of De Groot and Mazur¹). Simple relations between the diffusion matrices of the various kinds of composition variables are established. In linear approximation all kinds of composition variables obey Fick's second law. The special role of the mean volume velocity is discussed and attention is given to Onsager coefficients and mobilities (friction coefficients).     

Atomic and nuclear polarization by beam-foil spectroscopy

Induction of atomic and nuclear polarization by grazing-incidence collisions (scattering) and by the tilted-foil interaction (transmission) is discussed. By direct observation of asymmetric Β decay, the foil can become a practical nuclear polarizer.     

Antihydrogen synthesis: A progress report

The main suggested routes for atomic antihydrogen ( ) formation will be reviewed in a pedestrian fashion. These are the following reactions: , and (iii) . The present status of the projects related to these reactions, as well as the projects' experimental scope, will also be discussed or referred to. Some speculations will be made regarding the physics that can be yielded by an antihydrogen probe.