Results 211 to 220 of about 442,874 (245)
Some of the next articles are maybe not open access.
Positron-reemission-microscope study of positron implantation and diffusion
Physical Review B, 1991The results of high-resolution laterally resolved measurements of positron implantation and diffusion are presented. High-magnification (4400\ifmmode\times\else\texttimes\fi{}), transmission-mode positron-reemission-microscopic images of a compound sample, which inhibited positron implantation in a well-defined region, were taken for positron ...
, Brandes, , Canter, , Mills
openaire +2 more sources
Positron trapping model including spatial diffusion of the positron
Physical Review B, 1985The trapping model for the annihilation rate of positrons implanted in solids has been combined with a diffusion model for the spatial motion of the implanted positrons prior to annihilation. Results are given for a simple system having traps only at the surface of a sample and allowing no detrapping, and for a general case where both effects are ...
, Frieze, , Lynn, , Welch
openaire +2 more sources
Zeitschrift für Naturforschung A, 2019
Propagation of nonlinear and supernonlinear positron-acoustic periodic waves is examined in an electron-positron-ion plasma composed of static positive ions, mobile cold positrons, and q-nonextensive electrons and hot positrons. Employing the phase plane
Jharna Tamang, A. Saha
semanticscholar +1 more source
Propagation of nonlinear and supernonlinear positron-acoustic periodic waves is examined in an electron-positron-ion plasma composed of static positive ions, mobile cold positrons, and q-nonextensive electrons and hot positrons. Employing the phase plane
Jharna Tamang, A. Saha
semanticscholar +1 more source
Physical Review B, 1985
Positron diffusion in Si(100) and Si(111) has been studied using a variable-energy positron beam. The positron diffusion coefficient is found to be ${D}_{+}$=2.7\ifmmode\pm\else\textpm\fi{}0.3 ${\mathrm{cm}}^{2}$/sec using a Makhov-type positron implantation profile, which is demonstrated to fit the data more reliably than the more commonly applied ...
Nielsen, B. +3 more
openaire +2 more sources
Positron diffusion in Si(100) and Si(111) has been studied using a variable-energy positron beam. The positron diffusion coefficient is found to be ${D}_{+}$=2.7\ifmmode\pm\else\textpm\fi{}0.3 ${\mathrm{cm}}^{2}$/sec using a Makhov-type positron implantation profile, which is demonstrated to fit the data more reliably than the more commonly applied ...
Nielsen, B. +3 more
openaire +2 more sources
Positron sources and positron beams
Proceedings of the International School of Physics “Enrico Fermi”In the last decades, a large variety of low-energy positron beams has been built based on β+sources. However, the available maximum intensity of laboratory beams is limited to about 107moderated positrons per second. For this reason, several setups have been developed at large-scale facilities such as electron accelerators and research reactors in
openaire +1 more source
Radiation Physics and Chemistry (1977), 1984
One of the most exciting new techniques introduced in the last ten years is positron emission tomography (PET). PET provides quantitative, three-dimensional images for the study of specific biochemical and physiological processes in the human body.
Y L, Yamamoto +4 more
openaire +2 more sources
One of the most exciting new techniques introduced in the last ten years is positron emission tomography (PET). PET provides quantitative, three-dimensional images for the study of specific biochemical and physiological processes in the human body.
Y L, Yamamoto +4 more
openaire +2 more sources
Positron Lifetime in Mordenitel
Crystal Research and Technology, 1988AbstractPositron lifetime spectra have been measured for mordenite pure and impregnated with various amounts of metallic gold being highly dispersed. The change of annihilation characteristics (in comparison to those corresponding to the pure mordenite), resulting both from the presence of gold particles in the zeolite matrix and the way of treatment ...
J. Ch. Abbé, M. Dębowska
openaire +1 more source
Psychiatric Clinics of North America, 1986
PET is a unique tool for the direct in vivo evaluation of physiologic processes within discrete areas of the brain. Thus far, its application to the study of schizophrenia has served to confirm the subtleties of this illness. However, PET does promise to increase our knowledge of the neurochemical anatomy of the normal and abnormal mind with respect to
R M, Cohen, W E, Semple, M, Gross
openaire +2 more sources
PET is a unique tool for the direct in vivo evaluation of physiologic processes within discrete areas of the brain. Thus far, its application to the study of schizophrenia has served to confirm the subtleties of this illness. However, PET does promise to increase our knowledge of the neurochemical anatomy of the normal and abnormal mind with respect to
R M, Cohen, W E, Semple, M, Gross
openaire +2 more sources
Positron Polarons and Positron Trapping by Defects in LiF
Journal of the Physical Society of Japan, 1975The momentum distribution of annihilation photon pairs in LiF observed at 293 K was found to be slightly broader than that at 89 K. Assuming that the positrons are thermalized and annihilate mainly in the polaron states, the broadening was analyzed in terms of their effective mass.
Kunio Fujiwara +3 more
openaire +1 more source
Mobility of positrons in polyethylene
Physical Review B, 1986We have measured the positron drift velocity versus electric field in polyethylene by observing the Doppler shift of the annihilation photons. We find that the average positron mobility computed using the internal electric field (dielectric constant =2.26) is \ensuremath{\mu}=10.3\ifmmode\pm\else\textpm\fi{}1.5 ${\mathrm{cm}}^{2}$ ${\mathrm{V ...
, Mills +3 more
openaire +2 more sources