Radiation Damage of II, III, IV, V Pyrochlores - CaLnZrNbO7

2012 ◽  
Vol 1475 ◽  
Author(s):  
Karl R. Whittle ◽  
Massey de los Reyes ◽  
Yan Gao ◽  
Mark G. Blackford ◽  
Nestor J. Zaluzec ◽  
...  
Keyword(s):  
Radiation Damage ◽  
Cross Section ◽  
Critical Temperatures ◽  
User Facility

ABSTRACTPyrochlores based on the general composition CaLnZrNbO7 (where Ln = La, Nd, Sm, Gd and Ho) have been prepared, and irradiated through the crystalline-amorphous transition, with 1 MeV Kr ions at the IVEM-TANDEM user facility. The obtained critical temperatures show a decrease from La to Gd (∼680 K to ∼230 K), with Ho being resistant to amorphisation at 50K. The results suggest that the amorphisation cross section for these materials is directly related to the Ln component.

The Role of Sn, Zr and Hf in the Radiation Damage in II, III, IV and V Pyrochlores

2012 ◽  
Vol 1383 ◽  
Author(s):  
Karl R. Whittle ◽  
Massey de los Reyes ◽  
Mark G. Blackford ◽  
Nestor J. Zaluzec ◽  
Gregory R. Lumpkin
Keyword(s):  
Radiation Damage ◽  
Cross Section ◽  
Radiation Tolerance ◽  
User Facility

ABSTRACTCeramics based on the general compositions CaLnXNbO7 (where Ln = La, Nd and Sm, and X=Zr and Sn) have been prepared, and irradiated with 1 MeV Kr ions at the IVEM-TANDEM user facility. The radiation tolerance of these materials has been found to be less than Zr and Hf equivalents. The results also suggest that the amorphisation cross section for these materials is related to the Ln component, and is similar to those observed for Zr and Hf equivalents.

Studies of metaphase chromosomes in the scanning transmission x-ray microscope: Image fidelity, radiation damage and specimen preparation

1992 ◽  
Vol 50 (2) ◽  
pp. 1038-1039
Author(s):  
Shawn Williams ◽  
Xiaodong Zhang ◽  
Susan Lamm ◽  
Jack Van’t Hof
Keyword(s):  
Visible Light ◽  
Radiation Damage ◽  
Cross Section ◽  
Imaging Techniques ◽  
Dose Range ◽  
Specimen Preparation ◽  
X Rays ◽  
Metaphase Chromosomes ◽  
X Ray ◽  
Scanning Transmission

The Scanning Transmission X-ray Microscope (STXM) is well suited for investigating metaphase chromosome structure. The absorption cross-section of soft x-rays having energies between the carbon and oxygen K edges (284 - 531 eV) is 6 - 9.5 times greater for organic specimens than for water, which permits one to examine unstained, wet biological specimens with resolution superior to that attainable using visible light. The attenuation length of the x-rays is suitable for imaging micron thick specimens without sectioning. This large difference in cross-section yields good specimen contrast, so that fewer soft x-rays than electrons are required to image wet biological specimens at a given resolution. But most imaging techniques delivering better resolution than visible light produce radiation damage. Soft x-rays are known to be very effective in damaging biological specimens. The STXM is constructed to minimize specimen dose, but it is important to measure the actual damage induced as a function of dose in order to determine the dose range within which radiation damage does not compromise image quality.

Ion Beam Irradiation of Lanthanum Compounds in the Series La2O3-TiO2

2010 ◽  
Vol 1265 ◽  
Author(s):  
Karl Whittle ◽  
Mark Blackford ◽  
Robert Aughterson ◽  
Katherine L Smith ◽  
Gregory R Lumpkin ◽  
...  
Keyword(s):  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Inverse Correlation ◽  
Critical Temperatures ◽  
Voltage Electron ◽  
Local Environments ◽  
Two Systems ◽  
User Facility

AbstractThin crystals of La2O3, La2/3TiO3, La2TiO5, and La2Ti2O7 have been irradiated in situ using 1 MeV Kr2+ ions in the Intermediate Voltage Electron Microscope-Tandem User Facility (IVEM-Tandem), at the Argonne National Laboratory (ANL). We observed that La2O3 remained crystalline to a fluence greater than 3.1 × 1016 ions cm-2 at a temperature of 50 K. The four binary oxide compounds in the two systems were observed through the crystalline-amorphous transition as a function of ion fluence and temperature. Results from the ion irradiations give critical temperatures for amorphisation (Tc) of 840 K for La2Ti2O7, 865 K for La2/3TiO3, and 1027 K for La2TiO5. The Tc values observed in this study, together with previous data for TiO2, are discussed with reference to the phase diagrams for La2O3-TiO2 systems and the different local environments within the crystal structures. Results suggest an observable inverse correlation between Tc and melting temperature (Tm) in the two systems.

10.09: Critical temperatures of members with class 4 cross-section

ce/papers ◽  
2017 ◽  
Vol 1 (2-3) ◽  
pp. 2582-2591
Author(s):  
Élio Maia ◽  
Carlos Couto ◽  
Paulo Vila Real ◽  
Nuno Lopes
Keyword(s):  
Cross Section ◽  
Critical Temperatures

Spallation Radiation Damage Calculations and Database: Cross-Section Discrepancies between the Codes

2006 ◽  
Vol 3 (7) ◽  
pp. 13467 ◽  
Author(s):  
Wei Lu ◽  
MS Wechsler ◽  
PD Ferguson ◽  
EJ Pitcher ◽  
SW Dean
Keyword(s):  
Radiation Damage ◽  
Cross Section
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