In-Situ Study of Radiation Damage in V2os Induced by Low Energy Electrons

1989 ◽  
Vol 157 ◽  
Author(s):  
R. Ai ◽  
H.-J. Fan ◽  
P.C. Stair ◽  
L.D. Marks
Keyword(s):  
Radiation Damage ◽  
Photoelectron Spectroscopy ◽  
High Resolution Electron Microscopy ◽  
Electron Radiation ◽  
Enhanced Diffusion ◽  
Radiation Enhanced Diffusion ◽  
Resolution Electron ◽  
Low Energy Electrons

ABSTRACTRadiation damage in V2Os induced by electrons in the energy range 0-3 keV has been studied by high resolution electron microscopy, X-ray photoelectron spectroscopy and mass spectrometry. Different phase transformations were observed when V205 was irradiated by electrons of different energies. The damage kinetics and the role of electron radiation enhanced diffusion were investigated. It was found that nucleation and growth of lower oxides was driven by electron radiation enhanced diffusion.

Possible applications of fraunhofer holography in high resolution electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 222-223 ◽  
Author(s):  
N. Bonnet ◽  
M. Troyon ◽  
P. Gallion
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Transfer Function ◽  
Radiation Damage ◽  
High Resolution Electron Microscopy ◽  
Far Field ◽  
Field Region ◽  
Crystalline Materials ◽  
Resolution Electron ◽  
The Ideal

Two main problems in high resolution electron microscopy are first, the existence of gaps in the transfer function, and then the difficulty to find complex amplitude of the diffracted wawe from registered intensity. The solution of this second problem is in most cases only intended by the realization of several micrographs in different conditions (defocusing distance, illuminating angle, complementary objective apertures…) which can lead to severe problems of contamination or radiation damage for certain specimens.Fraunhofer holography can in principle solve both problems stated above (1,2). The microscope objective is strongly defocused (far-field region) so that the two diffracted beams do not interfere. The ideal transfer function after reconstruction is then unity and the twin image do not overlap on the reconstructed one.We show some applications of the method and results of preliminary tests.Possible application to the study of cavitiesSmall voids (or gas-filled bubbles) created by irradiation in crystalline materials can be observed near the Scherzer focus, but it is then difficult to extract other informations than the approximated size.

Anisotropic radiation damage of potassium tetracyano platinate (KCP)

1978 ◽  
Vol 36 (1) ◽  
pp. 392-393
Author(s):  
N. Uyeda ◽  
E. J. Kirkland ◽  
B. M. Siegel
Keyword(s):  
Electron Diffraction ◽  
Radiation Damage ◽  
Structural Changes ◽  
High Resolution Electron Microscopy ◽  
Radiation Sensitivity ◽  
Resolution Electron ◽  
Damage Process ◽  
Diffraction Patterns ◽  
Fading Rate

The direct observation of structural change by high resolution electron microscopy will be essential for the better understanding of the damage process and its mechanism. However, this approach still involves some difficulty in quantitative interpretation mostly being due to the quality of obtained images. Electron diffraction, using crystalline specimens, has been the method most frequently applied to obtain a comparison of radiation sensitivity of various materials on the quantitative base. If a series of single crystal patterns are obtained the fading rate of reflections during the damage process give good comparative measures. The electron diffraction patterns also render useful information concerning the structural changes in the crystal. In the present work, the radiation damage of potassium tetracyano-platinate was dealt with on the basis two dimensional observation of fading rates of diffraction spots. KCP is known as an ionic crystal which possesses “one dimensional” electronic properties and it would be of great interest to know if radiation damage proceeds in a strongly asymmetric manner.

Fine structure and properties of defects in naturally occurring silicates and oxides

1990 ◽  
Vol 48 (4) ◽  
pp. 460-461
Author(s):  
David R. Veblen
Keyword(s):  
Chemical Reactions ◽  
High Resolution Electron Microscopy ◽  
Extended Defects ◽  
Single Chain ◽  
Naturally Occurring ◽  
Resolution Electron ◽  
Fine Structures ◽  
Image Simulations ◽  
Similar Crystal Structure

Extended defects and interfaces control many processes in rock-forming minerals, from chemical reactions to rock deformation. In many cases, it is not the average structure of a defect or interface that is most important, but rather the structure of defect terminations or offsets in an interface. One of the major thrusts of high-resolution electron microscopy in the earth sciences has been to identify the role of defect fine structures in reactions and to determine the structures of such features. This paper will review studies using HREM and image simulations to determine the structures of defects in silicate and oxide minerals and present several examples of the role of defects in mineral chemical reactions. In some cases, the geological occurrence can be used to constrain the diffusional properties of defects.The simplest reactions in minerals involve exsolution (precipitation) of one mineral from another with a similar crystal structure, and pyroxenes (single-chain silicates) provide a good example. Although conventional TEM studies have led to a basic understanding of this sort of phase separation in pyroxenes via spinodal decomposition or nucleation and growth, HREM has provided a much more detailed appreciation of the processes involved.

scholarly journals In situ monitoring of the influence of water on DNA radiation damage by near-ambient pressure X-ray photoelectron spectroscopy

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Marc Benjamin Hahn ◽  
Paul M. Dietrich ◽  
Jörg Radnik
Keyword(s):  
Dna Damage ◽  
Radiation Damage ◽  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
In Situ Monitoring ◽  
Strong Increase ◽  
Oh Radicals ◽  
Strand Breaks ◽  
X Ray

AbstractIonizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further.

Incorporation and Role of Nitrogen During Oxynitridation of Silicon Studied by Photoelectron Spectroscopy

1999 ◽  
Vol 567 ◽  
Author(s):  
Masayuki Suzuki ◽  
Yoji Saito
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Oxide Films ◽  
Silicon Surfaces ◽  
Gaseous Mixtures ◽  
X Ray ◽  
Initial Stage ◽  
Thermal Stability Of

ABSTRACTWe tried direct oxynitridation of silicon surfaces by remote-plasma-exited nitrogen and oxygen gaseous mixtures at 700°C in a high vacuum. The oxynitrided surfaces were investigated with in-situ X-ray photoelectron spectroscopy. With increase of the oxynitridation time, the surface density of nitrogen gradually increases, but that of oxygen shows nearly saturation behavior after the rapid increase in the initial stage. We also annealed the grown oxynitride and oxide films to investigate the role of the contained nitrogen. The desorption rate of oxygen from the oxynitride films is much less than that from oxide films. We confirmed that nitrogen stabilizes the thermal stability of these oxynitride films.

Measuring Radiation Enhanced Diffusion Through in situ Ion Radiation Induced Sintering of Oxide Nanoparticles

2021 ◽  
Author(s):  
Nathan J. Madden ◽  
Samuel A. Briggs ◽  
Diana Perales ◽  
Timothy J. Boyle ◽  
Khalid Hattar ◽  
...  
Keyword(s):  
Oxide Nanoparticles ◽  
Enhanced Diffusion ◽  
Radiation Enhanced Diffusion ◽  
Radiation Induced

Insight into the Formation of Ultrafine Nanostructures in Bulk Amorphous Zr54.5 Ti7.5Al10Cu20Ni8

2001 ◽  
Vol 703 ◽  
Author(s):  
André Heinemann ◽  
Helmut Hermann ◽  
Albrecht Wiedenmann ◽  
Norbert Mattern ◽  
Uta Kühn ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Volume Fraction ◽  
High Volume ◽  
High Resolution Electron Microscopy ◽  
Scattering Data ◽  
Scanning Calorimetry ◽  
Enhanced Diffusion ◽  
Resolution Electron ◽  
The Mean ◽  
Interparticle Interference

ABSTRACTBulk amorphous Zr54.5 Ti7.5Al10Cu20Ni8 is investigated by means of smal-angle neutron scattering (SANS), differential-scanning calorimetry (DSC), high-resolution electron microscopy (HREM) and other methods. The formation of ultrafine nanostructures in the glassy phase is observed and explained by a new model. Structura fluctuations of randomly distributed partialy ordered domains grow during annealing just below the glass transition temperature by local re-ordering. During anneaing the DSC gives evidence for a increasing volume fraction of the localy ordered domains. At high volume fractions of impinging domains a percolation threshold on the interconnected domain boundaries occurs and enhanced diffusion becomes possible. At that stage SANS measurements lead to satistically significant scattering data. The SANS signals are anayzed in terms of a model taking into account spherica particles surrounded by diffusion zones and interparticle interference effects. The mean radius of the nanocrystaline particles is determined to 1 nm and the mean thickness of the depletion zone is 2 nm. The upper limit for the volume fraction after annealing at 653 K for 4hours is about 20 %. Electron microscopy confirms the size and shows that the particle are crystaline.

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