scholarly journals Mixing of Al Into Uranium Silicides Reactor Fuels

1996 ◽  
Vol 439 ◽  
Author(s):  
Fu-Rong Ding ◽  
R. C. Birtcher ◽  
B. J. Kestel ◽  
P. M. Baldo
Keyword(s):  
Ion Beam ◽  
High Dose ◽  
Ion Beam Mixing ◽  
Dose Irradiation ◽  
Fuel Burn ◽  
Fission Gas ◽  
Mixing Rates ◽  
Radiation Induced ◽  
And Diffusion ◽  
Swelling Behaviors

AbstractSEM observations have shown that irradiation induced interaction of the aluminum cladding with uranium silicide reactor fuels strongly affects both fission gas and fuel swelling behaviors during fuel burn-up. We have used ion beam mixing, by 1.5 MeV Kr, to study this phenomena. RBS and the 27 A1( p, γ) 28 Si resonance nuclear reaction to was used to measure radiation induced mixing of Al into U3Si and U3Si2 after irradiation at 300γ;C.Initially U mixes into the Al layer and Al mixes into the U3 Si. At a low doses, the Al layer is converted into Ual4 type compound while near the interface the phase U(Al93 Si. 07 )3 grows. Under irradiation, Al diffuses out of the Ual4 surface layer, and the lower density ternary, which is stable under irradiation, is the final product. Al mixing into U3 Si2 is slower than in U3 Si, but after high dose irradiation the Al concentration extends much father into the bulk. In both systems Al mixing and diffusion is controlled by phase formation and growth. The Al mixing rates into the two alloys are similar to that of Al into pure uranium where similar aluminide phases are formed.

Diffusion of A Deposited GeSe Film in GaAs using Ion-Beam Mixing

1985 ◽  
Vol 45 ◽  
Author(s):  
N. J. Kepler ◽  
N. W. Cheung
Keyword(s):  
Integrated Circuits ◽  
Ohmic Contacts ◽  
Ion Beam ◽  
Threshold Temperature ◽  
Electrical Characteristics ◽  
Electrical Measurements ◽  
Furnace Annealing ◽  
Ion Beam Mixing ◽  
Heavily Doped ◽  
And Diffusion

ABSTRACTIon-beam mixing and rapid thermal annealing (RTA) techniques are used to form shallow and heavily-doped n+ layers in undoped GaAs. RTA reduces surface degradation and improves crystalline quality compared to lengthy thermal cycles, although furnace annealing producesidentical electrical characteristics. Ion-beam mixing has only a small effect on the diffusion of a deposited GeSe film, because the damage created by implantation is repaired during RTA before significant diffusion occurs. We define a threshold temperature representing the onset of significant electrical activation and/or diffusion, and propose a model relating the annealing, activation, and diffusion temperatures for the GeSe/GaAs system. RBS. SIMS, and electrical measurements show that extremely shallow layers with a sheet resistivity as low as 1480/El can be formed in GaAs by diffusion from a GeSe source. This technique has potential application to the formation of shallow ohmic contacts for GaAs integrated circuits.

Luminescence and radiation-induced color centers in anion-defective alumina crystals after high-dose irradiation

2016 ◽  
Vol 90 ◽  
pp. 90-93 ◽  
Author(s):  
V.S. Kortov ◽  
V.A. Pustovarov ◽  
S.V. Zvonarev ◽  
T.V. Shtang
Keyword(s):  
Color Centers ◽  
High Dose ◽  
Dose Irradiation ◽  
Radiation Induced

Formation of GaAs Ohmic Contacts by Using Ion Beam Mixing

1985 ◽  
Vol 54 ◽  
Author(s):  
S. Furukawa ◽  
T. Asano ◽  
T. Fukada ◽  
H. Ishiwara ◽  
K. Tsutsui
Keyword(s):  
Ohmic Contacts ◽  
Ion Beam ◽  
High Dose ◽  
Doped Semiconductors ◽  
Ion Beam Mixing ◽  
Mixing Effects ◽  
Annealing Step ◽  
Short Period ◽  
Constant Dose ◽  
Pt Films

ABSTRACTIon beam mixing effects on metals and highly doped semiconductors on GaAs for formation of ohmic contacts have been studied. In this study, we have principally selected Pt as metal and Ge as semiconductors electrodes for GaAs. In Pt/GaAs system, we observed alloying phenomena induced by Si+, Ar+, Ge+ ion mixing effects. The amount of GaAs reacted with Pt was found to be proportional to the mass of the incident ions for constant dose. Concernig with the formation of ohmic contacts, only in the case of Si implantation through Pt films, the conversion from Schottky- to ohmic-contact was observed due to ion beam mixing effects. In Ge/GaAs system, we observad the solid state epitaxy for implanted Ge layer by the first annealing at 450°C in the two step annealing, but no activation of the implanted species. For activating implanted species, the second annealing at 800°C was effective. Concerning with the formation of ohmic contacts, we observed that the ohmic I-V characteristics for Ge/GaAs system could be obtainable when the following conditions were satisfied at the same time: 1) high dose implantation of As+ into Ge layer, 2) low dose implantation of Si into Ge/GaAs boundary and 3) relatively short period annealing in the second annealing step. From such study, it is concluded that ion beam mixing in conjunction with rapid annealing would be most promising for forming stable and reproducible ohmic contacts.

scholarly journals NF-E2-Related Factor 2 (Nrf2) Ameliorates Radiation-Induced Skin Injury

2021 ◽  
Vol 11 ◽  
Author(s):  
Jiao Xue ◽  
Chenxiao Yu ◽  
Yiting Tang ◽  
Wei Mo ◽  
Zhicheng Tang ◽  
...  
Keyword(s):  
Clinical Symptoms ◽  
Expression Profiles ◽  
Antioxidant Response ◽  
High Dose ◽  
Related Factor ◽  
Skin Injury ◽  
Skin Cells ◽  
Dose Irradiation ◽  
Radiation Induced

Radiation-induced skin injury (RISI) commonly occur in cancer patients who received radiotherapy and is one of the first clinical symptoms after suffering from nuclear exposure. Oxidative damage is the major causes of RISI. Nuclear factor erythroid 2-related factor 2 (Nrf2) is considered as a key mediator of the cellular antioxidant response. However, whether Nrf2 can alleviate RISI after high-dose irradiation remains unknown. In this study, we demonstrated that Nrf2-deficient (Nrf2-/-) mice were susceptible to high-dose irradiation and adenovirus-mediated overexpression of Nrf2 (ad-Nrf2) protected against radiation in skin cells. Overexpression of Nrf2 attenuated the severity of skin injury after high-dose electron beam irradiation. To uncover the mechanisms of Nrf2 involved in RISI, mRNA sequencing technology was performed to analyze the mRNA expression profiles of Ad-Nrf2 skin cells following radiation. The results revealed that a total of 127 genes were significantly changed, 55 genes were upregulated, and 72 genes were downregulated after Nrf2 overexpression. GSEA showed that Nrf2 was associated with positive regulation of genes involved in the reactive oxygen species pathway after radiation. Taken together, this study illustrated the role of Nrf2 in RISI and provided potentially strategies for ameliorating RISI.

Why does Hydrogen Loss Rate Correlate with How Strongly Hydrogen Inhibits Ion Beam Mixing?

1989 ◽  
Vol 157 ◽  
Author(s):  
R. E. Wistrom ◽  
P. Borgesen
Keyword(s):  
Loss Rate ◽  
Ion Beam ◽  
Ion Beam Mixing ◽  
Mixing Rates ◽  
Loss Rates

ABSTRACTPrevious studies have shown that the presence of hydrogen in multilayer samples containing Ti reduces ion beam mixing rates. The present study sought to determine why the magnitude of this effect depends on which metal is mixed into Ti and why it is correlated to the rate at which hydrogen leaves the sample during mixing. Hydrogen loss rates of multilayers were compared with those of bilayer samples designed to minimize the effect of mixing. For bilayers, hydrogen loss rates were smaller and did not depend on which metal was mixed into Ti in the same way that multilayer loss rates do. This suggests that hydrogen leaves the multilayer samples because it is bound less strongly in the mixed regions than in the Ti. The primary cause of hydrogen loss is mixing rather than ion beam induced desorption.

Radiation-Induced Muscle Damage in Rats after Fractionated High-Dose Irradiation

1998 ◽  
Vol 149 (5) ◽  
pp. 482 ◽  
Author(s):  
Hsue-Yin Hsu ◽  
Chee-Yin Chai ◽  
Moon-Sing Lee
Keyword(s):  
Muscle Damage ◽  
High Dose ◽  
Dose Irradiation ◽  
Radiation Induced

Temperature Dependence of Ion Beam Mixing in Al

1981 ◽  
Vol 7 ◽  
Author(s):  
S.T. Picraux ◽  
D. M. Follstaedt ◽  
J. Delafond
Keyword(s):  
Low Temperatures ◽  
Driving Forces ◽  
Ion Beam ◽  
Slow Motion ◽  
Ion Beam Mixing ◽  
Depth Profiles ◽  
Mixing Rates ◽  
Atomic Mixing ◽  
Concentration Depth Profiles

ABSTRACTThe atomic mixing of evaporated Al/Sb films and of Al/Ag films on Al<110> crystal substrates by 400 keV Xe ion beams has been investigated. Concentration depth profiles were measured in situ by 1.5 MeV He scattering as a function of Xe fluence from 2 to 32×1015 Xe/cm2. The initial mixing rates are similar at 85 and 300 K; mixing proceeds by rapid motion of Al (≈15 Al/Xe) into and uniformly through the thickness of the Sb film and by a slow motion of Sb (≈0.5 Sb/Xe) into the Al<110> substrate. More rapid Sb mixing into Al occurs for polycrystalline Al. The rate for Al into Sb slows at concentrations approaching the stable AlSb phase. Appreciably higher rates of Sb mixing into Al (2.2 to 2.8 Sb/Xe) occur at 575 K. Mixing rates for the highly soluble system, Al/Ag, are compared to the nearly insoluble Al/Sb at 85 and 300 K. Appreciably higher rates are found for Ag than for Sb, suggesting the influence of chemical driving forces even at these low temperatures.

scholarly journals Nano-structuring, surface and bulk modification with a focused helium ion beam

2012 ◽  
Vol 3 ◽  
pp. 579-585 ◽  
Author(s):  
Daniel Fox ◽  
Yanhui Chen ◽  
Colm C Faulkner ◽  
Hongzhou Zhang
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
High Dose ◽  
Modification Process ◽  
Dose Irradiation ◽  
Probe Size ◽  
Helium Ion ◽  
High Incidence ◽  
High Level ◽  
Irradiation Process

We investigate the ability of a focused helium ion beam to selectively modify and mill materials. The sub nanometer probe size of the helium ion microscope used provides lateral control not previously available for helium ion irradiation experiments. At high incidence angles the helium ions were found to remove surface material from a silicon lamella leaving the subsurface structure intact for further analysis. Surface roughness and contaminants were both reduced by the irradiation process. Fabrication is also realized with a high level of patterning acuity. Implantation of helium beneath the surface of the sample is visualized in cross section allowing direct observation of the extended effects of high dose irradiation. The effect of the irradiation on the crystal structure of the material is presented. Applications of the sample modification process are presented and further prospects discussed.

SIMS investigations of titanium profiles in LiNbO3 produced by ion beam mixing and diffusion

1989 ◽  
Vol 333 (4-5) ◽  
pp. 485-487 ◽  
Author(s):  
T. Bremer ◽  
D. Kollewe ◽  
H. Koschmieder ◽  
W. Heiland
Keyword(s):  
Ion Beam ◽  
Ion Beam Mixing ◽  
And Diffusion
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