Ion Irradiation Effects on Ho2+xTi2-xO7-x/2 (x=0, 0.4 and 0.67)

2012 ◽  
Vol 512-515 ◽  
pp. 643-647
Author(s):  
Yu Hong Li ◽  
Yong Qiang Wang ◽  
Juan Wen ◽  
Valdez A. James ◽  
Kurt E. Sickafus
Keyword(s):  
Phase Diagram ◽  
Ion Irradiation ◽  
Incident Angle ◽  
Ion Beam ◽  
National Laboratory ◽  
Grazing Incidence ◽  
Phase Transformation Temperature ◽  
Synthesis Methods ◽  
Threshold Fluence ◽  
Β Phase

We recently synthesized different composition polycrystalline Ho2+xTi2-xO7-x/2 (x=0, 0.4 and 0.67), which is derivative fluorite compounds known as and pyrochlore phases in Ho3O2-TiO2 phase diagram by using conventional solid state synthesis methods. The samples were irradiated with 400 keV Ne2+ ions at cryogenic temperature (~77 K), using the Danfysik ion accelerator at the Ion Beam Materials Laboratory (IBML) of Los Alamos National Laboratory (LANL). The irradiation fluences in the experiments ranged from 5×1014-5×1015ions/cm2. An order-to-disorder (O-D) transformation was observed for α, β and pyrochlore phases, as determined using grazing incidence X-ray diffraction (GIXRD) at an incident angle of 0.25°. The O-D transformation threshold fluence for α phase was found to be noticeably lower than those for β phase and pyrochlore, and the O-D transformation threshold fluence for β phase was the highest. The O-D transformation threshold fluence was found to be coherent with the phase transformation temperature in the Ho3O2-TiO2temperature-composition (T-C) phase diagram.

Electron and ion irradiation-induced dissolution of mechanical twins in the intermetalic U3Si: An in situ HVEM study

1989 ◽  
Vol 47 ◽  
pp. 652-653
Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher
Keyword(s):  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
Mechanical Twinning ◽  
In Situ Experiments

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.

Amorphization Kinetics of Zr (Cr,Fe)2 Under Ion Irradiation

1992 ◽  
Vol 279 ◽  
Author(s):  
A. T. Motta ◽  
L. M. Howe ◽  
P. R. Okamoto
Keyword(s):  
Neutron Irradiation ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Matrix Interface ◽  
Thin Foils ◽  
Intermetallic Precipitates ◽  
Kinetics Of

ABSTRACTThin foils of Zircaloy-4 were irradiated with 350 KeV 40Ar ions in the dual ion beam/HVEM facility at Argonne National Laboratory at 300 – 650 K. The irradiation-induced araorphization of the intermetallic precipitates Zr (Cr, Fe)2 and Zr2 (Ni, Fe) was studied in situ. For Zr (Cr,Fe)2 precipitates the dose-to-amorphization was found to increase exponentially with temperature, with a critical temperature of about 650 K. The amorphization morphology was shown to be homogeneous, with no preferential site for nucleation, in contrast to neutron-irradiation amorphization which started at the precipitate-matrix interface. For Zr2 (Ni,Fe) precipitates it was found that amorphization occurred at 550 K and 600 K, whereas in neutron irradiation no amorphization has been observed at those temperatures. The results are discussed in the context of the previous experimental results of neutron and electron irradiation and likely amorphization mechanisms are proposed.

scholarly journals Effects of the Surface on Displacement Cascades Produced by Heavy-Ion Irradiation of Ni3Al and Cu3Au

1996 ◽  
Vol 439 ◽  
Author(s):  
S. Müller ◽  
M. L. Jenkins ◽  
C. Abromeit ◽  
H. Wollenberger
Keyword(s):  
Ion Irradiation ◽  
Incident Angle ◽  
Ion Beam ◽  
Heavy Ion ◽  
Small Population ◽  
Dislocation Loops ◽  
Near Surface ◽  
Ion Energy ◽  
Heavy Ion Irradiation ◽  
Transmission Electron

AbstractStereo transmission electron microscopy has been used to characterise the distribution in depth of disordered zones and associated dislocation loops in the ordered alloys Ni3Al and Cu3Au after heavy ion irradiation, most extensively for Ni3Al irradiated with 50 keV Ta+ ions at a temperature of 573 K. The Cu3Au specimen was irradiated with 50 keV Ni+ ions at an incident angle of 45° at a temperature of 373 K. In Ni3Al the defect yield, i.e. the probability for a disordered zone to contain a loop was found to be strongly dependent on the depth of the zone in the foil, varying from about 0.7 for near-surface zones to about 0.2 in the bulk. The sizes and shapes of disordered zones were only weakly dependent on depth, except for a small population of zones very near the surface which were strongly elongated parallel to the incident ion beam. In Cu3Au the surface had a smaller but still significant effect on the defect yield. The dependence of the tranverse disordered zone diameter d on ion energy E for Ta+ irradiation of NiA was found to follow a relationship d = k1, E1/α with k, = 2.4 ± 0.4 and α = 3.3 ± 0.4. A similar relationship with the same value of α is valid for a wide variety of incident ion/target combinations found in the literature.

Crystallization of nano-size thallous oxide during ion irradiation of Tl-Ba-Ca-Cu-O high-temperature superconductors

1995 ◽  
Vol 53 ◽  
pp. 214-215
Author(s):  
P. P. Newcomer ◽  
L. M. Wang ◽  
M. L. Miller ◽  
R. C. Ewing
Keyword(s):  
High Temperature ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Temperature Superconductors ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Planetary Science ◽  
University Of New Mexico ◽  
The University ◽  
Nano Size

The Tl-Ba-Ca-Cu-O class of type-II high temperature superconductors (HTS) have Tc's as high as 125K. Although they have good critical current values, when a field is applied the weak pinning and consequent flow of magnetic vortices are a major impediment to the usefulness of these materials. Ion irradiation has been shown to enhance the pinning. High quality single crystals, as determined with x-ray precession and HRTEM, with sharp HTS Meissner signals, were irradiated with 1.5 MeV Kr+ and Xe+ ions using the HVEM-Tandem facility at Argonne National Laboratory. Ion beam microstructural modification was studied in-situ using electron diffraction and after irradiation using HRTEM and nano-beam EDS on Tl-1212 and Tl-2212 (numbers designate the stoichiometry Tl-Ba- Ca-Cu-O) single-crystal HTS. After irradiation, microstructure was studied using the JEOL 2010 in the Earth and Planetary Science Department at the University of New Mexico in order to characterize the resulting irradiation-induced nano-size precipitates.

Radiation-induced disordering and amorphization—An in situ HVEM study of uranium silicide with comparison to natural processes in zirconolite

1990 ◽  
Vol 48 (4) ◽  
pp. 534-535
Author(s):  
R. C. Birtcher ◽  
L. M. Wang ◽  
C. W. Allen ◽  
R. C. Ewing
Keyword(s):  
Electron Irradiation ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
In Situ Tem ◽  
In Situ Experiments

We present here results of in situ TEM diffraction observations of the response of U3Si and U3Si2 when subjected to 1 MeV electron irradiation or to 1.5 MeV Kr ion irradiation, and observations of damage occuring in natural zirconolite. High energy electron irradiation or energetic heavy ion irradiation were performed in situ at the HVEM-Tandem User Facility at Argonne National Laboratory. In this Facility, a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter have been interfaced to a 1.2 MeV AEI high voltage electron microscope. This allows a wide variety of in situ experiments to be performed with simultaneous ion irradiation and conventional transmission electron microscopy. During the electron irradiation, the electron beam was focused to a diameter of about 2 μ.m at the specimen thin area. The ion beam was approximately 2 mm in diameter and was uniform over the entire specimen. With the specimen mounted in a heating holder, the temperature increase indicated by the furnace thermocouple during the ion irradiation was typically 8 °K.

In sito Ion Beam Analysis of Radiation Damage Kinetics in MgTiO3 Single Crystals at 170-470 K

1995 ◽  
Vol 396 ◽  
Author(s):  
Ning Yu ◽  
Jeremy N. Mitchell ◽  
Kurt E. Sickafus ◽  
Michael Nastasi
Keyword(s):  
Radiation Damage ◽  
Single Crystals ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Los Alamos National Laboratory ◽  
Beam Analysis ◽  
Radiation Resistant ◽  
Threshold Doses

AbstractRadiation damage kinetics in synthetic MgTiO3 (geikielite) single crystals have been studied using the in situ ion beam facility at Los Alamos National Laboratory. The geikielite samples were irradiated at temperatures of 170, 300, and 470 K with 400 keV xenon ions and the radiation damage was sequentially measured with Rutherford backscattering using a 2 MeV He ion beam along a channeling direction. Threshold doses of 1 and 5×1015 Xe/cm2 were determined for the crystalline-to-amorphous transformation induced by Xe ion irradiation at 170 and 300 K, respectively. However, geikielite retained its crystallinity up to a dose of 2.5x1016 Xe/cm2 at the irradiation temperature of 470 K. This study has shown that MgTiO3, which has a corundum derivative structure, is another radiation resistant material that has the potential for use in radiation environments.

scholarly journals Plant Mutation Breeding with Heavy Ion Irradiation at IMP

2016 ◽  
Vol 8 (5) ◽  
pp. 34 ◽  
Author(s):  
Xicun Dong ◽  
Xia Yan ◽  
Wenjian Li
Keyword(s):  
Ion Irradiation ◽  
Biological Effects ◽  
Ion Beam ◽  
National Laboratory ◽  
Heavy Ion ◽  
Mutation Breeding ◽  
High Yield ◽  
Early Maturity ◽  
Heavy Ion Irradiation ◽  
Heavy Ion Beam

<p>The Heavy Ion Research Facility in Lanzhou (HIRFL) is one of the ion-beam acceleration facilities intensively used at IMP, founded as national laboratory and opened for user in world from 1992. Since then, a lot of experiments irradiated by heavy ion beam have been carried out in the HIRFL, including plant mutation breeding. In this review, the biological effects induced by heavy ions and their corresponding mechanisms were reported from the point of view of cytological, morphological and molecular levels. To date, a large number of mutants were isolated using heavy ion irradiation IMP, such as early maturity, flower color and shape, high yield and disease resistant. In conclusion, heavy ion beam irradiation is an efficient mutagen and has significant phenotypic variations in plant. Our research will be further focused on transformation of scientific and technological achievements and mutagenic mechanism of heavy ion beam on high plant at the molecular level in the recent future.</p>

Low Damage Smoothing of Magnetic Materials using Oblique Irradiation of Gas Cluster Ion Beam

2004 ◽  
Vol 843 ◽  
Author(s):  
Shigeru Kakuta ◽  
Shinji Sasaki ◽  
Kenji Furusawa ◽  
Toshio Seki ◽  
Takaaki Aoki ◽  
...  
Keyword(s):  
Magnetic Materials ◽  
Incident Angle ◽  
Ion Beam ◽  
Grazing Incidence ◽  
Native Oxide ◽  
Surface Roughening ◽  
Component Ratio ◽  
Angle Of Incidence ◽  
Cluster Ion ◽  
Gas Cluster Ion Beam

ABSTRACTOblique irradiation using a gas cluster ion beam (GCIB) has been studied in order to achieve low-damage smoothing of magnetic materials. We investigated how the surface morphology and surface roughness depended on the angle of incidence. Quite smooth surfaces could be obtained using both normal and grazing-incidence irradiation. At incident angles larger than 45?, periodic ripples were formed. The orientation of the ripples changed from perpendicular to parallel with respect to the GCIB when the incident angle exceeded a critical value. Surface roughening resulting from the formation of ripples was observed at incident angles between 45° and 65°. Fluctuations in the Ni/Fe component ratio and the intermixing of oxygen from the native oxide were evaluated. As the angle of incidence increased, both the thickness of the layer in which the component ratio was fluctuating and the depth of oxygen intermixing decreased. As a result, it was determined that low-damage smoothing of magnetic materials could be performed by using grazing-incidence irradiation from a GCIB.

Irradiation-induced grain growth in gold and copper: In situ HVEM studies at 75-300 K

1989 ◽  
Vol 47 ◽  
pp. 644-645
Author(s):  
Charles W. Allen
Keyword(s):  
Grain Growth ◽  
Ion Irradiation ◽  
Boundary Migration ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Average Grain Size ◽  
Growth Phenomenon ◽  
In Situ Experiments

When thin polycrystalline films of Au, Cu and various other materials are subjected to energetic ion irradiation, the average grain size increases even at cryogenic temperatures. As is the case with many ion beam processes, this phenomenon of ion irradiation induced grain growth exhibits only a very mild temperature dependence. This contribution is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction. A series of in situ ion and/or electron irradiation experiments is being performed at the HVEM-Tandem Facility at Argonne which have shown clearly for fine grained Au films that two mechanisms for growth are operative for the ion beam case: grain boundary migration as in normal thermal grain growth and grain coalescence which is similar in appearance to recrystallization by subgrain coalescence. Especially in the case of Au for which ion-induced growth is relatively rapid, such in situ experiments also demonstrate the importance of dislocation activity which is a consequence of the collision cascade damage associated with ion irradiation. Existing theories for irradiation-induced grain growth assume that growth occurs by boundary migration and that only point defects generated at grain boundaries are responsible for the growth phenomenon.

Ion-Induced Amorphization of Murataite

2002 ◽  
Vol 713 ◽  
Author(s):  
Jie Lian ◽  
Sergey V. Yudintsev ◽  
Sergey V. Stefanovsky ◽  
Olga I. Kirjanova ◽  
Rodney C. Ewing
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Pyrochlore Structure ◽  
Fluorite Structure ◽  
In Situ Tem ◽  
Cell Parameters ◽  
Unit Cells ◽  
Radiation Resistant

ABSTRACTMurataite A4B2C7O22-x, where A = Na+, Ca2+, REE3+, An3+/4+; B = Mn2+/3+, Zn2+; C = Ti4+, Fe3+, Al3+; 0≤x≤1, is an isometric, derivative of the fluorite-structure. Murataite is potentially suitable as a phase for the immobilization of rare earth (REE) and actinide elements (An). Murataite structures with three-(3C), five-(5C), and eight-fold (8C) multiples of the fluorite unit cell parameters have been identified. Radiation-induced amorphization of murataite has been investigated by 1 MeV Kr+ ion irradiation of three ceramic samples produced by melting in a resistive furnace and a cold crucible at 1400-1600 °C. The 1 MeV Kr+ ion irradiations were performed at room temperature using IVEM-Tandem Facility at Argonne National Laboratory. Radiation damage was observed by in-situ TEM. Initially, the irradiation caused disordering of the murataite structure. Murataite was rendered fully amorphous at a dose of (1.7∼1.9)Á1018 ion/m2. The pyrochlore structure phase (2C) is more radiation resistant to ion irradiation-induced amorphization than the murataite structure. Combining results on murataite with those pyrochlore and fluorite, a generally increasing trend in the susceptibility to ion beam damage is found in the fluorite-related structures as a function of the increasing multiples of the fluorite unit cells.

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