scholarly journals Structural and Optical Modifications in the BaO-ZnO-LiF-B2O3-Yb2O3 Glass System after γ-Irradiation

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6955
Author(s):  
Nimitha S. Prabhu ◽  
Hiriyur Mallaiah Somashekarappa ◽  
M. I. Sayyed ◽  
Hamid Osman ◽  
Sultan Alamri ◽  
...  
Keyword(s):  
Trap Depth ◽  
Structural Rearrangement ◽  
Glass System ◽  
Γ Irradiation ◽  
Oxygen Hole ◽  
Spin Resonance ◽  
Before And After ◽  
Radiation Induced ◽  
The Fourier Transform ◽  
Induced Defects

A Yb3+-doped borate glass system was examined for the structural and optical modifications after γ-irradiation. Among the studied 10BaO-20ZnO-20LiF-(50-x)B2O3-xYb2O3 (x = 0.1, 0.5, 0.7, and 1.0 mol%) glasses, the 10BaO-20ZnO-20LiF-49.9B2O3-0.1Yb2O3 glass showed the highest thermoluminescence intensity, trap density, and trap depth. The glass was irradiated with the optimum γ-dose of 1 kGy towards the analysis of radiation-induced defects. The amorphous nature was preserved before and after irradiation. The glass density slightly increased after irradiation. The structural rearrangement was evident from the Fourier transform infrared spectroscopy by the appearance and disappearance of some bonds after γ-irradiation. The transformation of [BO4] units into [BO3] units and non-bridging oxygens was deduced. The color of the glass darkened after irradiation and the optical absorption intensity enhanced between 250 and 700 nm. The optical bandgap reduced and Urbach energy increased upon γ-dose exposure. The electron spin resonance of the irradiated glass exhibited two signals at g = 2.0167 and g = 1.9938, corresponding to the non-bridging oxygen hole center and Boron E’-center, respectively.

Radiation-induced defects in montebrasite: An electron paramagnetic resonance study of O – hole and Ti3+ electron centers

2020 ◽  
Vol 105 (7) ◽  
pp. 1051-1059
Author(s):  
José R. Toledo ◽  
Raphaela de Oliveira ◽  
Lorena N. Dias ◽  
Mário L.C. Chaves ◽  
Joachim Karfunkel ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Electron Irradiation ◽  
Color Centers ◽  
Hydroxyl Groups ◽  
Γ Irradiation ◽  
Paramagnetic Resonance ◽  
Radiation Induced ◽  
Induced Defects ◽  
Electron Paramagnetic ◽  
Hole Centers

Abstract Montebrasite is a lithium aluminum phosphate mineral with the chemical formula LiAlPO4(Fx,OH1–x) and considered a rare gemstone material when exhibiting good crystallinity. In general, montebrasite is colorless, sometimes pale yellow or pale blue. Many minerals that do not have colors contain hydroxyl ions in their crystal structures and can develop color centers after ionization or particle irradiation, examples of which are topaz, quartz, and tourmaline. The color centers in these minerals are often related to O− hole centers, where the color is produced by bound small polarons inducing absorption bands in the near UV to the visible spectral range. In this work, colorless montebrasite specimens from Minas Gerais state, Brazil, were investigated by electron paramagnetic resonance (EPR) for radiation-induced defects and color centers. Although γ irradiation (up to a total dose of 1 MGy) did not visibly modify color, a 10 MeV electron irradiation (80 MGy) induced a pale greenish-blue color. Using EPR, O− hole centers were identified in both γ- or electron-irradiated montebrasite samples showing superhyperfine interactions with two nearly equivalent 27Al nuclei. In addition, two different Ti3+ electron centers were also observed. From the γ irradiation dose dependency and thermal stability experiments, it is concluded that production of O− hole centers is limited by simultaneous creation of Ti3+ electron centers located between two equivalent hydroxyl groups. In contrast, the concentration of O− hole centers can be strongly increased by high-dose electron irradiation independent of the type of Ti3+ electron centers. From detailed analysis of the EPR angular rotation patterns, microscopic models for the O− hole and Ti3+ electron centers are presented, as well as their role in the formation of color centers discussed and compared to other minerals.

Effect of γ-Irradiation on the Mechanical Properties of Al-Cu Alloy

2006 ◽  
Vol 251-252 ◽  
pp. 105-110 ◽  
Author(s):  
M. Abo-Elsoud ◽  
H. Ismail
Keyword(s):  
Quantitative Information ◽  
Irradiation Effect ◽  
Γ Irradiation ◽  
Cu Content ◽  
Cu Alloy ◽  
Hardness Tests ◽  
Radiation Induced ◽  
Induced Defects ◽  
Aging Hardening ◽  
Kinetics Of

SEM observations and Vickers-hardness tests were performed to identify the irradiation effects. γ- irradiation effect during the aging hardening process can be explained depending on the composition of the alloy and is used to derive quantitative information on the kinetics of the transformation precipitates. Increasing the Cu content of an Al-Cu alloy can improve the aging hardness. The present results of hardness behavior with SEM observations of surveillance specimens at different doses suggest that the radiation-induced defects are probably complex valance-solute clusters. These clusters act as nuclei for the precipitation of θ-Al2Cu type. This can be effectively utilized to study the systematic of nucleation of precipitates at vacancy-type defects. γ-irradiation probably play the key role in defects responsible for material strengthening and embrittlement.

EFFECT OF γ-IRRADIATION ON THE MECHANICAL PROPERTIES OF AL–CU ALLOY

2006 ◽  
Vol 13 (06) ◽  
pp. 773-777 ◽  
Author(s):  
M. ABO-ELSOUD ◽  
H. ISMAIL ◽  
MAGED S. SOBHY
Keyword(s):  
Quantitative Information ◽  
Irradiation Effect ◽  
Γ Irradiation ◽  
Cu Content ◽  
Cu Alloy ◽  
Hardness Tests ◽  
Radiation Induced ◽  
Induced Defects ◽  
Aging Hardening ◽  
Kinetics Of

SEM observations and Vickers hardness tests were performed to identify the irradiation effects. γ-irradiation effect during the aging hardening process can be explained depending on the composition of the alloy and is used to derive quantitative information on the kinetics of the transformation precipitates. Increasing the Cu content of an Al – Cu alloy can improve the aging hardness. The present results of the hardness behavior, with SEM observations of surveillance specimens at different doses, suggest that the radiation-induced defects are probably complex valence-solute clusters. These clusters act as nuclei for the precipitation of θ- Al 2 Cu type. This can be effectively utilized to study the systematics of nucleation of precipitates at vacancy-type defects. γ-irradiation probably plays the key role in defects responsible for material strengthening and embrittlement.

Thermally reversible γ-ray-induced redox reaction between substitutional iron and aluminum impurity centers in a silica glass

2001 ◽  
Vol 16 (1) ◽  
pp. 127-131 ◽  
Author(s):  
Radhaballabh Debnath
Keyword(s):  
Silica Glass ◽  
Γ Irradiation ◽  
Paramagnetic Resonance ◽  
Hole Trapping ◽  
Oxygen Hole ◽  
Before And After ◽  
Impurity Centers ◽  
Spin Resonances ◽  
Electron Paramagnetic ◽  
Hole Centers

The magnetic properties of the substitutional iron and aluminum impurity centers in a sintered Vycor silica glass were studied before and after 1.1–1.3 MeV γ irradiation. Observation of two overlapping spin resonances (g ∼ 4.20–4.28) in the spectra of both the irradiated and preirradiated glasses indicated the existence of two types of tetra coordinated substitutional iron centers of the [FeO4−/Na+]0 type. The intensity of these electron-paramagnetic resonance (EPR) signals decreased upon g irradiation of the glass with concomitant generation of aluminum hole center [AlO4]0, which was manifested by the occurrence of a new six-line EPR signal with g 4 2.009, while thermal annealing of these aluminum oxygen hole centers restores the intensity of the iron centers almost to their preirradiation level. This result suggests that if not the whole, a major fraction of the electrons released in the process of g-ray-induced hole trapping at the Al site are captured by the substitutional iron centers. The electron traps, thus formed, are quite stable and can be deactivated by thermal stimulation.

scholarly journals Features of Radiation-Defect Annealing in n-Ge Single Crystals Irradiated with High-Energy Electrons

2019 ◽  
Vol 64 (2) ◽  
pp. 151
Author(s):  
S. V. Luniov ◽  
A. I. Zimych ◽  
M. V. Khvyshchun ◽  
V. T. Maslyuk ◽  
I. G. Megela
Keyword(s):  
Single Crystals ◽  
High Energy ◽  
Measured Temperature ◽  
Hall Constant ◽  
Defect Annealing ◽  
Before And After ◽  
Temperature Dependences ◽  
Radiation Induced ◽  
Disordered Crystal ◽  
Induced Defects

The isothermal annealing of n-Ge single crystals irradiated with 10-MeV electrons to the fluence Φ = 5 × 1015 cm−2 has been studied. On the basis of the measured temperature dependences of the Hall constant and by solving the electroneutrality equations, the concentrations of radiation-induced defects (A-centers) in irradiated n-Ge single crystals are calculated both before and after the annealing. An anomalous increase of the Hall constant is found, when the irradiated n-Ge single crystals were annealed at Tan = 403 K for up to 3 h. The annealing at the temperature Tan = 393 K for 1 h gave rise to the np conversion in the researched crystals. The revealed effects can be explained by the concentration growth of A-centers owing to the generation of vacancies at the annealing of disordered crystal regions.

Electron Spin Resonance of Radiation-Induced Defects in Potassium Azide

1962 ◽  
Vol 125 (2) ◽  
pp. 451-453 ◽  
Author(s):  
D. W. Wylie ◽  
A. J. Shuskus ◽  
C. G. Young ◽  
O. R. Gilliam ◽  
Paul W. Levy
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Spin Resonance ◽  
Radiation Induced ◽  
Potassium Azide ◽  
Induced Defects

ELECTRON SPIN RESONANCE STUDIES OF THE RADIATION-INDUCED ADDITION OF HBr TO C2H4 IN THE SOLID STATE

1960 ◽  
Vol 38 (5) ◽  
pp. 689-696 ◽  
Author(s):  
F. W. Mitchell ◽  
B. C. Green ◽  
J. W. T. Spinks
Keyword(s):  
Electron Spin Resonance ◽  
Reaction Mechanism ◽  
Solid State ◽  
Liquid Nitrogen ◽  
Electron Spin ◽  
Reaction Intermediates ◽  
Γ Irradiation ◽  
Solid Mixture ◽  
Spin Resonance ◽  
Radiation Induced

Electron spin resonance measurements at 77 °K have been used to study the hydrobromination of ethylene induced by γ irradiation of the solid mixture at liquid nitrogen temperatures. The evidence resulting from these studies has given valuable information regarding the reaction intermediates and has been used in formulating a likely reaction mechanism.

An examination of the radiation-induced defects and thermoluminescence characteristics of Sm2O3 doped BaO–ZnO–LiF–B2O3 glass system for γ-dosimetry application

2021 ◽  
Vol 118 ◽  
pp. 111252
Author(s):  
Nimitha S. Prabhu ◽  
K. Sharmila ◽  
Swaroop Kumaraswamy ◽  
H.M. Somashekarappa ◽  
M.I. Sayyed ◽  
...  
Keyword(s):  
Glass System ◽  
Radiation Induced ◽  
Induced Defects ◽  
B2o3 Glass

Radiation Induced Effects on Properties of Semiconducting Nanomaterials

2015 ◽  
Vol 239 ◽  
pp. 1-36 ◽  
Author(s):  
S.K. Tripathi ◽  
Jagdish Kaur ◽  
R. Ridhi ◽  
Kriti Sharma ◽  
Ramneek Kaur
Keyword(s):  
Heavy Ion ◽  
Irradiation Effect ◽  
Defect States ◽  
Γ Irradiation ◽  
Beneficial Effects ◽  
Radiation Induced ◽  
Induced Changes ◽  
Induced Defects ◽  
The Impact ◽  
Irradiation Induced Defects

The irradiation of nanomaterials with energetic particles has significant effects on the properties of target materials. In addition to the well-known detrimental effects of irradiations, they have also some beneficial effects on the properties of nanomaterials. Irradiation effect can change the morphology of the materials in a controlled manner and tailor their mechanical, structural, optical and electrical properties. Irradiation induced modifications in the properties of nanomaterials can be exploited for many useful applications. With the aim of getting better performance of electronic devices, it is necessary to discuss the irradiation induced changes in the nanomaterials. In order to improve the irradiation hardness of electronic components, it is also crucial to have a fundamental understanding of the impact of the irradiation on the defect states and transport properties of the host material. In the present article, we review some recent advances on the irradiation induced effects on the properties of semiconducting nanomaterials. We have reviewed the effect of different types of irradiations which includes γ-irradiation, electron beam irradiation, laser irradiation, swift heavy ion irradiations, thermal induced, and optical induced irradiations, etc. on the various properties of semiconducting nanomaterials. In addition, the irradiation induced defects are also discussed.

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