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.

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.

Positron Beam Study of Co Doped ZnO Films Prepared by PLD

2008 ◽  
Vol 607 ◽  
pp. 102-104 ◽  
Author(s):  
Hong Feng Ren ◽  
Hui Min Weng ◽  
Bang Jiao Ye ◽  
Rong Dian Han ◽  
Hui Li ◽  
...  
Keyword(s):  
Diffusion Length ◽  
Effective Diffusion ◽  
Positron Beam ◽  
Zno Films ◽  
Defect Structures ◽  
X Ray Diffraction ◽  
Slow Positron ◽  
X Ray ◽  
Doped Zno ◽  
Co Doped

Slow positron beam are used to study defect structures in Co doped and undoped ZnO films prepared by Pulsed Laser Deposition (PLD) at 400°C, 600°C, 700°C on c-plane sapphire. Comparing with ZnO samples, Co doped ZnO samples have larger positron effective diffusion length (Leff), which change in different tendencies depending on the growth temperature. Crystal structures of the samples are investigated by X-ray diffraction (XRD) and wurtzite ZnO could be observed in Co doped samples.

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

POSITRON INTERACTION IN POLYMERS

2004 ◽  
Vol 19 (23) ◽  
pp. 3951-3959 ◽  
Author(s):  
CORINE BAS ◽  
N. DOMINIQUE ALBÉROLA ◽  
MARIE-FRANCE BARTHE ◽  
JÉRÉMIE De BAERDEMAEKER ◽  
CHARLES DAUWE
Keyword(s):  
Positron Annihilation ◽  
Chemical Structure ◽  
Positron Beam ◽  
Positron Annihilation Spectroscopy ◽  
Hole Size ◽  
Doppler Broadening ◽  
Positron Source ◽  
Positron Annihilation Lifetime ◽  
Doppler Broadening Spectra ◽  
Variable Energy

A series of dense copolyimide membranes was characterized using positron annihilation spectroscopy. The positron annihilation lifetime spectroscopy performed on film with a classical positron source gives informations on the positronium fraction formed and also on the hole size within the film. The Doppler broadening spectra (DBS) of the gamma annihilation rays coupled with a variable energy positron beam allow the microstructural analyses as a function of the film depth. Experimental data were also linked to the chemical structure of the polyimides. It was found that the presence of the fluorine atoms strongly affects the positron annihilitation process and especially the DBS responses.

scholarly journals Study of Microvoids in High-Rate a-Si:H Using Positron Annihilation

1997 ◽  
Vol 467 ◽  
Author(s):  
X. Zou ◽  
D. P. Webb ◽  
S. H. Lin ◽  
Y. W. Lam ◽  
Y. C. Chan ◽  
...  
Keyword(s):  
Thin Films ◽  
Positron Annihilation ◽  
Surface Region ◽  
Positron Beam ◽  
High Rate ◽  
Doppler Broadening ◽  
Slow Positron ◽  
Depth Profiles ◽  
Vacancy Type Defect ◽  
Low Rate

ABSTRACTIn this paper, we have carried out the positron annihilation measurement on high-rate and low-rate a-Si:H thin films deposited by PECVD. By means of the slow positron beam Doppler-broadening technique, the depth profiles of microvoids in a-Si:H have been determined. We have also studied the vacancy-type defect in the surface region in high-rate grown a-Si:H, making comparison between high-rate and low-rate a-Si:H. By plotting S and W parameters in the (S, W) plane, we have shown that the vacancies in all of the high-rate and low-rate deposited intrinsic samples, and in differently doped low-rate samples are of the same nature.

The SiO2/Si Interface Probed With Positrons

1987 ◽  
Vol 105 ◽  
Author(s):  
Bent Nielsen ◽  
K. G. Lynn ◽  
T. C. Leung ◽  
D. O. Welch ◽  
G. Rubloff
Keyword(s):  
Heat Treatment ◽  
Elevated Temperature ◽  
Positron Annihilation ◽  
Positron Beam ◽  
The State ◽  
Open Volume ◽  
Variable Energy ◽  
Thermally Grown

AbstractThe effects of the heat treatment of Si covered with a thermally-grown ˜50 nm overlayer of SiO2 were probed by means of measurements of positron annihilation characteristics obtained with a variable-energy positron beam. From measurements at elevated temperature (˜500°C) it was observed that positrons implanted overlapping the SiO2/Si interface decay from a state with properties distinctively different from the state in Si and in SiO2. The nature of the annihilation characteristics indicates the presence of open volume defects.

Positron spectroscopy of bulk and near-surface defects in semiconductors

1989 ◽  
Vol 67 (8) ◽  
pp. 813-817
Author(s):  
P. Hautojārvi
Keyword(s):  
Positron Annihilation ◽  
Positron Lifetime ◽  
Surface Defects ◽  
Positron Beam ◽  
Near Surface ◽  
Slow Positron ◽  
Positron Spectroscopy ◽  
Positron Lifetime Spectroscopy ◽  
Defects In Semiconductors ◽  
Ion Implanted

The use of positron annihilation to study defects in semiconductors is discussed. Positron-lifetime spectroscopy reveals As vacancies in as-grown GaAs and gives information on ionization levels. The vacancy profiles in ion-implanted Si are investigated by slow positron beam.

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