Results 161 to 170 of about 260,823 (197)

Positron binding: A positron-density viewpoint

Physical Review A, 1994
The binding of a single positron to a many-electron system (in the field of a fixed nuclear configuration) is viewed in terms of positron and electron densities. Following the treatments due to Levy and co-workers [Phys. Rev. A 32, 2010 (1985); 30, 2745 (1984)], certain general integral conditions and also an exact differential equation for the ...
Tunna Baruah, Rajeev K. Pathak, Anjali Kshirsagar, Rajendra R. Zope   +3 more
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Positron-atom and positron-molecule collisions

Physics Reports, 1982
Abstract The scattering of positrons by atoms and molecules is reviewed. The recent development of monoenergetic slow positron beams and their applications to the measurement of cross sections for positrons interacting in various gases are discussed briefly.
A S Ghosh, Puspajit Mandal, N. C. Sil
openaire   +2 more sources

Positron emission tomography

Clinical Physics and Physiological Measurement, 1988
While positron emission tomography (PET) represents the most advanced methodology using radiotracers, it is subject to two main constraints. The first is the physical accuracy with which the regional distribution, time course and concentration of the tracer can be determined. This is principally a function of the instrumentation.
Joel S. Karp, Gerd Muehllehner
openaire   +9 more sources

Positrons at CEBAF

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1993
Abstract It is estimated that about 2.5 × 1010 slow positrons per second might be produced if 1.0 mA of 400 MeV electrons were incident on target. This estimate and some problems of target design are discussed. The electron beam structure is 1–2 ps pulses with a repitition rate of 7.5 MHz which is appropriate for a free electron laser (FEL) which is ...
Lester D. Hulett, W. J. Kossler, A. J. Greer   +2 more
openaire   +3 more sources