Studies of the Positron Lifetime and Doppler Broadening Annihilation Radiation of Polyvinyl Chloride Doped with Al2O3

2004 ◽  
Vol 445-446 ◽  
pp. 328-330 ◽  
Author(s):  
Hamdy F.M. Mohamed ◽  
E.E. Abdel-Hady ◽  
H.B. Alaa
Keyword(s):  
Polyvinyl Chloride ◽  
Positron Lifetime ◽  
Annihilation Radiation ◽  
Doppler Broadening

A Positron Study of Early Clustering in Al-Mg-Si Alloys

2014 ◽  
Vol 794-796 ◽  
pp. 33-38 ◽  
Author(s):  
Meng Liu ◽  
Jakub Čížek ◽  
Cynthia S.T. Chang ◽  
John Banhart
Keyword(s):  
Positron Lifetime ◽  
The Other ◽  
Annihilation Radiation ◽  
Doppler Broadening ◽  
Natural Ageing ◽  
Temperature Dependent ◽  
Continuous Growth ◽  
Positron Annihilation Lifetime ◽  
Vacancy Type Defect ◽  
Trapping Sites

Early stages of clustering in quenched Al-Mg-Si alloys during natural ageing were studied by positron annihilation lifetime spectroscopy utilizing its unique sensitivity to electron density differences in various atomic defects. Two different positron trapping sites could be identified, one related to a vacancy-type defect, the other to solute clusters. The first trap is deep, i.e. irreversibly traps positrons, the second shallow, from which positrons can escape, which creates the signature of a temperature-dependent positron lifetime. During the first 80 min of NA, the vacancy-related contribution decreases, while the solute clusters increasingly trap positrons, thus reflecting their continuous growth and power to trap positrons. Coincident Doppler broadening spectroscopy of the annihilation radiation shows that the annihilation sites are Si-rich after quenching but contain more Mg after 70 min.

scholarly journals Calculation of the Doppler broadening of the electron-positron annihilation radiation in defect-free bulk materials

2000 ◽  
Vol 61 (15) ◽  
pp. 10092-10099 ◽  
Author(s):  
V. J. Ghosh ◽  
M. Alatalo ◽  
P. Asoka-Kumar ◽  
B. Nielsen ◽  
K. G. Lynn ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Annihilation Radiation ◽  
Doppler Broadening ◽  
Bulk Materials ◽  
Electron Positron Annihilation ◽  
Electron Positron

Doppler broadening measurements of the electron-positron annihilation radiation in nanocrystalline ZrO2

2005 ◽  
Vol 40 (19) ◽  
pp. 5265-5268 ◽  
Author(s):  
M. Chakrabarti ◽  
D. Bhowmick ◽  
A. Sarkar ◽  
S. Chattopadhyay ◽  
S. Dechoudhury ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Annihilation Radiation ◽  
Doppler Broadening ◽  
Electron Positron Annihilation ◽  
Electron Positron

Evidence for Vacancy Clustering in Silicon Implanted Indium Phosphide

1992 ◽  
Vol 268 ◽  
Author(s):  
Peter J. Schultz ◽  
P.J. Simpson ◽  
U.G. Akano ◽  
I.V. Mitchell
Keyword(s):  
Room Temperature ◽  
Elevated Temperatures ◽  
Annihilation Radiation ◽  
Doppler Broadening ◽  
Lattice Order ◽  
Defect Reduction ◽  
Room Temperature Photoluminescence ◽  
Moderate Reduction ◽  
Vacancy Type Defect ◽  
Variable Energy

ABSTRACTDamage induced in InP wafers by ion implantation has been investigated using Doppler broadening of annihilation radiation from variable-energy positrons (VEP), Rutherford backscattering/channeling (RBS), and room temperature photoluminescence (PL). Si* ions were implanted at 600 keV incident energy to total fluences from 1011 to 1014 ions cm−2. Annealing at room temperature was monitored for ∼100 days, during which both VEP and RBS showed recovery of the crystal toward the pre–implanted condition. RBS measurements of samples annealed at elevated temperatures showed that full restoration of lattice order occurred at 375 K, but VEP data for isochronal annealing up to 720 K showed only a moderate reduction in the vacancy–type defect concentration with a significantly narrower lineshape, consistent with vacancy clustering. PL measurements for MOCVD grown InP layers annealed up to 1100 K after implantation also indicated only moderate defect reduction.

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