scholarly journals Positron spur structure emulated by variable energy slow positron beam

1993 ◽  
Vol 03 (C4) ◽  
pp. 131-133
Author(s):  
Y. ITO ◽  
H. ABE ◽  
Y. TABATA
Keyword(s):  
Positron Beam ◽  
Slow Positron ◽  
Variable Energy

Isochronal annealing studies on 1.1 MeV Fe ion irradiated RAFM steel using variable energy slow positron beam

2017 ◽  
Author(s):  
Renjith Ramachandran ◽  
C. David ◽  
R. Rajaraman ◽  
S. Abhaya ◽  
B. K. Panigrahi ◽  
...  
Keyword(s):  
Positron Beam ◽  
Isochronal Annealing ◽  
Slow Positron ◽  
Rafm Steel ◽  
Variable Energy

scholarly journals Sintering of zirconia-based nanomaterials studied by variable-energy slow-positron beam

2014 ◽  
Vol 505 ◽  
pp. 012020 ◽  
Author(s):  
I Prochazka ◽  
J Cizek ◽  
O Melikhova ◽  
W Anwand ◽  
G Brauer ◽  
...  
Keyword(s):  
Positron Beam ◽  
Slow Positron ◽  
Variable Energy

Effect of Sintering on Defects in Yttria Stabilised Zirconia

2012 ◽  
Vol 733 ◽  
pp. 236-239 ◽  
Author(s):  
Ivan Procházka ◽  
Jakub Čížek ◽  
Oksana Melikhova ◽  
Wolfgang Anwand ◽  
Gerhard Brauer ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Subsurface Layer ◽  
Positron Beam ◽  
Annihilation Radiation ◽  
Strong Suppression ◽  
Slow Positron ◽  
Open Volume ◽  
Zirconia Nanopowders ◽  
Variable Energy

A variable energy slow positron beam was utilised to investigate depth dependent effects of sintering on the tetragonal yttria stabilised zirconia nanopowders. Positron implantation was combined with the determination of Doppler broadened profiles of annihilation radiation. The results are consistent with recent positron lifetime data showing that sintering at elevated temperatures leads to a disappearance of pores and a significant grain growth, which is demonstrated by a strong suppression of positronium formation and a substantial decrease in concentration of open volume defects at triple points, respectively, with increasing sintering temperature. An existence of a subsurface layer of a relatively high content of defects was shown in sintered samples and tentatively attributed to arise from a diffusion of open volume defects from the sample interior toward the surface or from a sintering-induced surface modification.

scholarly journals A new approach to near-surface positron annihilation analysis of ion irradiated ferritic alloys

2021 ◽  
Author(s):  
Vladimir Krsjak ◽  
Petr Hruška ◽  
Jarmila Degmova ◽  
Stanislav Sojak ◽  
Pavol Noga ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Ion Beam ◽  
Positron Beam ◽  
Ion Beam Irradiation ◽  
Near Surface ◽  
Slow Positron ◽  
New Approach ◽  
Ferritic Alloys ◽  
Positron Annihilation Lifetime ◽  
Variable Energy

The present work provides an innovative approach to the near-surface slow-positron-beam (SPB) study of structural materials exposed to ion-beam irradiation. This approach enables the use of variable-energy positron annihilation lifetime...

scholarly journals Slow positron beam at the JINR, Dubna

Nukleonika ◽  
2015 ◽  
Vol 60 (4) ◽  
pp. 725-728 ◽  
Author(s):  
Paweł Horodek ◽  
Andrey G. Kobets ◽  
Igor N. Meshkov ◽  
Alexey A. Sidorin ◽  
Oleg S. Orlov
Keyword(s):  
Diffusion Length ◽  
Nuclear Research ◽  
Positron Beam ◽  
Positron Annihilation Spectroscopy ◽  
Low Energy ◽  
Positron Energy ◽  
Slow Positron ◽  
Tungsten Foil ◽  
Sample Chamber ◽  
Variable Energy

Abstract The Low Energy Positron Toroidal Accumulator (LEPTA) at the Joint Institute for Nuclear Research (JINR) proposed for generation of positronium in flight has been adopted for positron annihilation spectroscopy (PAS). The positron injector generates continuous slow positron beam with positron energy range between 50 eV and 35 keV. The radioactive 22Na isotope is used. In distinction to popular tungsten foil, here the solid neon is used as moderator. It allows to obtain the beam intensity of about 105 e+/s width energy spectrum characterized by full width at half maximum (FWHM) of 3.4 eV and a tail to lower energies of about 30 eV. The paper covers the characteristic of variable energy positron beam at the LEPTA facility: parameters, the rule of moderation, scheme of injector, and transportation of positrons into the sample chamber. Recent status of the project and its development in the field of PAS is discussed. As an example, the measurement of the positron diffusion length in pure iron is demonstrated.

Design of The Ghent Pulsed Variable Energy Slow Positron Beam

2001 ◽  
Vol 363-365 ◽  
pp. 655-657 ◽  
Author(s):  
Jérémie De Baerdemaeker ◽  
N. Balcaen ◽  
Charles Dauwe
Keyword(s):  
Positron Beam ◽  
Slow Positron ◽  
Variable Energy

Slow Positron Beam Probe for the ZnO/Silicone under Proton Irradiation

2008 ◽  
Vol 607 ◽  
pp. 108-110
Author(s):  
Ying Ping Hao ◽  
Hui Min Weng ◽  
Chun Dong Li ◽  
Wei Feng Guo ◽  
Jian Dang Liu ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Crosslink Density ◽  
Proton Irradiation ◽  
Diffusion Length ◽  
Effective Diffusion ◽  
Positron Beam ◽  
Coating System ◽  
Slow Positron ◽  
Silicone Coating ◽  
Variable Energy

The degradation of ZnO/Silicone coating system under 90keV proton irradiation varying from 5×1014cm-2 to 1×1016cm-2, was studied by slow positron annihilation spectrum. Effective diffusion length calculated by Variable energy positron fit (VEPFIT) shows a dramatically break in a dose of 1×1015cm-2. It is ascribed to the increase of crosslink density and decrease of free volume and hole during the proton irradiation. Furthermore, positron has shown a satisfying sensitivity in detecting the nano-scale defect on ZnO/Silicone system.

Vacancy-Type Defects in Ion-Implanted Si Studied By Slow Positron Beam

1987 ◽  
Vol 104 ◽  
Author(s):  
P. Hautojdärvi ◽  
P. Huttunen ◽  
J. Mäkinen ◽  
E. Punkka ◽  
A. Vehanen
Keyword(s):  
Laser Annealing ◽  
Positron Beam ◽  
Amorphous Layer ◽  
Slow Positron ◽  
Clear Separation ◽  
Layer Effect ◽  
Variable Energy ◽  
Ion Implanted

ABSTRACTVariable-energy positron beam studies have been made on ion implanted silicon. After 35, 60 and 100 keV H+ implantation a clear separation between vacancy and H atom distributions was found. In 100 keV As+ and P+ implanted Si the damaged layer extends to 300 and 400 nm, respectively, far beyond the the range of implanted atoms and the amorphous layer. Effect of thermal and laser annealing is also discussed.

Characterization of Epitaxial CoSi2 Film Growth on Si(100) by Slow Positron Beam

1993 ◽  
Vol 320 ◽  
Author(s):  
Ping Liu ◽  
Chenglu Lin ◽  
Zuyao Zhou ◽  
Huiming Weng ◽  
Bingzong Li ◽  
...  
Keyword(s):  
Film Growth ◽  
Positron Beam ◽  
Direct Reaction ◽  
Slow Positron ◽  
S Parameter ◽  
Different Depths ◽  
Ternary Reaction ◽  
Line Shape Parameter ◽  
Variable Energy

ABSTRACTA slow positron beam was used to investigate the solid state reaction of Co/Si and Co/Ti/Si. Variable-energy (0-20 keV) positrons were implanted into samples at different depths. The Doppler broadening of the annihilation -y-ray energy spectra, measured at a number of different incident positron energies were characterized a line-shape parameter “5”. It was found that the measured S parameters were sensitive to thin film reaction and crystalline characteristics. In particular, the S parameter of epitaxial CoSi2 formed by the ternary reaction was quit different from that of the polycrystalline CoSi2 formed by direct reaction of Co with Si.

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