Generation ofE’ centers and oxygen hole centers in synthetic silica glasses by γ irradiation

1993 ◽  
Vol 48 (5) ◽  
pp. 3116-3123 ◽  
Author(s):  
H. Imai ◽  
K. Arai ◽  
J. Isoya ◽  
H. Hosono ◽  
Y. Abe ◽  
...  
Keyword(s):  
Γ Irradiation ◽  
Silica Glasses ◽  
Oxygen Hole ◽  
Hole Centers

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.

New Phosphorus Oxygen Hole Center in Γ-Irradiated SiO2:P2O5 Optical Fiber

1985 ◽  
Vol 61 ◽  
Author(s):  
H. Kawazoe ◽  
M. Kohketsu ◽  
Y. Watanabe ◽  
K. Shibuya ◽  
K. Muta
Keyword(s):  
Optical Absorption ◽  
Optical Fiber ◽  
Room Temperature ◽  
Hole Center ◽  
Paramagnetic Centers ◽  
Γ Irradiation ◽  
Electron Center ◽  
Oxygen Hole ◽  
New Type ◽  
Hole Centers

ABSTRACTThe formation of paramagnetic centers upon γ-irradiation was examined for the silica based waveguides doped with P2O5 by using ESR and optical absorption. The centers inherent in SiO2 glasses such as Si-E′ and OHC were found to be replaced with P-related centers such as phosphorus oxygen hole centers and phosphorus electron center by introducing a small amount of P2O5. New type of POHC was detected especially in the glass with [P2O5] of 1.3 mol % at 77K, which was assumed to be a precursor of the POHC stable at room temperature. The correlation between γ-induced loss-increase and the formation of these defects was examined.

Erratum: Generation ofE′centers and oxygen hole centers in synthetic silica glasses byγirradiation

1994 ◽  
Vol 49 (5) ◽  
pp. 3691-3691 ◽  
Author(s):  
H. Imai ◽  
K. Arai ◽  
J. Isoya ◽  
H. Hosono ◽  
Y. Abe ◽  
...  
Keyword(s):  
Silica Glasses ◽  
Oxygen Hole ◽  
Hole Centers

The Effect of Electron Irradiation on the Structure of Sodium Aluminum-Iron Phosphate Glasses

MRS Advances ◽  
2016 ◽  
Vol 1 (63-64) ◽  
pp. 4227-4232 ◽  
Author(s):  
S.V. Stefanovsky ◽  
O.I. Stefanovsky ◽  
M.I Kadyko ◽  
V.A. Zhachkin ◽  
L.D. Bogomolova
Keyword(s):  
Room Temperature ◽  
Structural Evolution ◽  
Iron Phosphate ◽  
Esr Spectra ◽  
Phosphate Glasses ◽  
Water Molecules ◽  
Oxygen Hole ◽  
Bending Modes ◽  
Iron Phosphate Glasses ◽  
Hole Centers

ABSTRACTGlasses of the series (mol.%) 40 Na2O, (20-x) Al2O3, x Fe2O3, 40 P2O5 were irradiated with 8 MeV electrons to doses equivalent of 0.1, 0.5, and 1.0 MGy and characterized by FTIR spectroscopy and ESR at room temperature. FTIR spectra of all the glasses consist of strong bands due to O-P-O stretching modes in (PO4)3- and (P2O7)4- units at 1000-1200 cm-1, P-O-P stretching modes at 900-950 cm-1 (νas) and 700-750 cm-1 (νs), and bending modes in the PO4 units. The wavenumber range lower 800 cm-1 has some contribution due to stretching modes in MO4 and MO6 (M = Al, Fe) units. Moreover the bands at 3300-3700 cm-1 and 1550-1650 cm-1 due to stretching and bending modes in both absorbed and structurally bound H2O molecules were present. As irradiation dose increases the bands due to stretching and bending modes in water molecules and M-O-H bonds become stronger and are split. No essential changes with increasing dose were observed within the spectral range of stretching modes of the O-P-O and P-O-P bonds. Irradiation yields phosphorus-oxygen hole centers - PO42- (D5) and PO42- (D6), and PO32- ion-radicals (D2) observable in ESR spectra of low-Fe glasses. At x>5 their responses are overlapped with strong broad line due to Fe(III). On the whole, with the increase in iron content the glass structural evolution decrease.

Nonuniform distribution of oxygen hole centers in silica optical fibers

1993 ◽  
Vol 63 (25) ◽  
pp. 3440-3442 ◽  
Author(s):  
S. Kannan ◽  
M. E. Fineman ◽  
J. Li ◽  
G. H. Sigel
Keyword(s):  
Optical Fibers ◽  
Nonuniform Distribution ◽  
Oxygen Hole ◽  
Hole Centers

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.

scholarly journals Change of silica luminescence due to fast hydrogen ion bombardment

Nukleonika ◽  
2015 ◽  
Vol 60 (2) ◽  
pp. 289-292 ◽  
Author(s):  
Vitaliy P. Zhurenko ◽  
Oganes V. Kalantaryan ◽  
Sergiy I. Kononenko
Keyword(s):  
Extended Period ◽  
Implantation Dose ◽  
Visible Range ◽  
Blue Band ◽  
Dose Accumulation ◽  
Oxygen Hole ◽  
Mathematical Processing ◽  
Luminescent Radiation ◽  
Luminescent Spectra ◽  
Hole Centers

AbstractThis paper deals with the luminescence of silica (KV-type) induced by beam of hydrogen ions with the energy of 210 keV per nucleon. An average implantation dose of up to 3.5 × 1021cm−3(5 × 1010Gy) was accumulated during irradiation over an extended period. The luminescent spectra consisted of the blue band (maximum at 456 nm) and the red band (650 nm) in the visible range. It was shown that increase in the absorption dose had an effect on the silica luminescence. It was found that the most significant changes in the spectrum occurred during the dose accumulation in the region of 550–700 nm. The shape of the spectrum of the luminescent radiation in this wavelength range was affected both by the oxygen deficient centres (blue band) and non-bridging oxygen hole centers (red band). Mathematical processing of the experimental spectra permitted to identify contributions to the luminescent radiation coming from both types of defects.

Defect Induced by Heated Treatment in Silica Fiber Material

2011 ◽  
Vol 304 ◽  
pp. 160-164
Author(s):  
Zhong Yin Xiao ◽  
Wen Yun Luo ◽  
Jian Xiang Wen ◽  
Jian Zhong Yin ◽  
Ting Yun Wang
Keyword(s):  
Thermal Treatment ◽  
Treatment Process ◽  
Defect Formation ◽  
Fiber Material ◽  
Nonbridging Oxygen ◽  
Pure Silica ◽  
Conversion Frequency ◽  
Oxygen Hole ◽  
Strained Bonds ◽  
Hole Centers

In this paper, defect induced by heated treatment in silica is studied. The formation process of defect is analyzed by the thermodynamic model. The results show that defect can be produced by thermal treatment process. The concentration of defect can be affected by many factors. The defect formation induced by heated treatment is related to the initial precursors. To pure silica glass, the precursors mainly come from the strained bonds of network. It can produce centers and nonbridging oxygen hole centers (NBOHCs). These defects are also related to the temperature of heated treatment and the conversion frequency between precursors and defects. The changes of defect concentration with temperature and conversion frequency are also discussed in detail.

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