Coloration of Ce-doped Multicomponent Silicate Glasses by Electron Irradiation

ABSTRACTElectron irradiation-induced modifications in two glasses, K2O – SiO2 and Au doped Na2O – B2O3 – SiO2, were observed in electron microscope. The products of modifications were “nano-particle” like contrasts in transmission electron microscopy (TEM) images, which can be easily confused with real nano-particles and phase separation. The driving force for the modifications in the glasses is the tendency of elimination of non-bridging oxygen (NBO) through the removal of cations. The phase separation into cation rich and poor region is their nature under electron irradiation. Therefore, it is absolutely essential to record in situ frames when the TEM images are used to provide microstructure information of glasses. Additionally, charging effects in glasses have also been discussed.

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Fundamentals of high-energy electron-irradiation-induced modifications of silicate glasses

Physical Review B ◽

10.1103/physrevb.68.064207 ◽

2003 ◽

Vol 68 (6) ◽

Cited By ~ 44

Author(s):

Nan Jiang ◽

Jianrong Qiu ◽

Adam Ellison ◽

John Silcox

Keyword(s):

Electron Irradiation ◽

High Energy ◽

Energy Electron ◽

Silicate Glasses ◽

High Energy Electron

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Direct observations of radiation-enhanced transformations in glass

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075543 ◽

1983 ◽

Vol 41 ◽

pp. 354-355

Author(s):

J. F. DeNatale ◽

D. G. Howitt

Keyword(s):

Glass Matrix ◽

Diffusion Mechanism ◽

Bubble Formation ◽

Silicate Glasses ◽

Phase Decomposition ◽

Direct Observations ◽

Thin Foils ◽

Oxygen Bubble ◽

Electron Energy Loss ◽

Kinetics Of

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.

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Evaluation of single-electron movies of glutamine synthetase molecules

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075191 ◽

1983 ◽

Vol 41 ◽

pp. 280-281

Author(s):

W. Kunath ◽

E. Zeitler ◽

M. Kessel

Keyword(s):

Electron Microscope ◽

Glutamine Synthetase ◽

Electron Irradiation ◽

Structural Damage ◽

Structural Changes ◽

Single Electron ◽

Continuous Series ◽

Digital Recording ◽

Recording Device ◽

Low Exposure

The features of digital recording of a continuous series (movie) of singleelectron TV frames are reported. The technique is used to investigate structural changes in negatively stained glutamine synthetase molecules (GS) during electron irradiation and, as an ultimate goal, to look for the molecules' “undamaged” structure, say, after a 1 e/Å2 dose.The TV frame of fig. la shows an image of 5 glutamine synthetase molecules exposed to 1/150 e/Å2. Every single electron is recorded as a unit signal in a 256 ×256 field. The extremely low exposure of a single TV frame as dictated by the single-electron recording device including the electron microscope requires accumulation of 150 TV frames into one frame (fig. lb) thus achieving a reasonable compromise between the conflicting aspects of exposure time per frame of 3 sec. vs. object drift of less than 1 Å, and exposure per frame of 1 e/Å2 vs. rate of structural damage.

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Radiation-Induced Precipitation at Thin Foil Surfaces in Ni-Be Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100055217 ◽

1982 ◽

Vol 40 ◽

pp. 598-599

Author(s):

T. Mukai ◽

T. E. Mitchell

Keyword(s):

Electron Microscopy ◽

High Voltage ◽

Electron Irradiation ◽

High Vacuum ◽

Thin Foil ◽

Homogeneous Precipitation ◽

High Voltage Electron Microscopy ◽

Voltage Electron ◽

High Voltage Electron ◽

Radiation Induced

Radiation-induced homogeneous precipitation in Ni-Be alloys was recently observed by high voltage electron microscopy. A coupling of interstitial flux with solute Be atoms is responsible for the precipitation. The present investigation further shows that precipitation is also induced at thin foil surfaces by electron irradiation under a high vacuum.

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Void-Lattice Formation in Natural Fluorite by Electron Irradiation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100093031 ◽

1976 ◽

Vol 34 ◽

pp. 614-615 ◽

Cited By ~ 1

Author(s):

L.E. Murr

Keyword(s):

Electron Microscope ◽

Electron Irradiation ◽

Heavy Ion ◽

High Energy ◽

Stoichiometric Ratio ◽

Direct Observations ◽

Transmission Electron ◽

Anion Vacancies ◽

Cation And Anion Vacancies ◽

Lattice Formation

The production of void lattices in metals as a result of displacement damage associated with high energy and heavy ion bombardment is now well documented. More recently, Murr has shown that a void lattice can be developed in natural (colored) fluorites observed in the transmission electron microscope. These were the first observations of a void lattice in an irradiated nonmetal, and the first, direct observations of color-center aggregates. Clinard, et al. have also recently observed a void lattice (described as a high density of aligned "pores") in neutron irradiated Al2O3 and Y2O3. In this latter work, itwas pointed out that in order that a cavity be formed,a near-stoichiometric ratio of cation and anion vacancies must aggregate. It was reasoned that two other alternatives to explain the pores were cation metal colloids and highpressure anion gas bubbles.Evans has proposed that void lattices result from the presence of a pre-existing impurity lattice, and predicted that the formation of a void lattice should restrict swelling in irradiated materials because it represents a state of saturation.

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