21 results on '"Boshra Afra"'
Search Results
2. Ion track annealing in quartz investigated by small angle X-ray scattering
- Author
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Patrick Kluth, Boshra Afra, Adrian Hawley, Matias Rodriguez, Christina Trautmann, and Daniel Schauries
- Subjects
Nuclear and High Energy Physics ,Crystallography ,Materials science ,Small-angle X-ray scattering ,Scattering ,Ion track ,Irradiation ,Small-angle scattering ,Instrumentation ,Molecular physics ,Isotropic etching ,Amorphous solid ,Ion - Abstract
We report on the reduction of cross-section and length of amorphous ion tracks embedded within crystalline quartz during thermal annealing. The ion tracks were created via Au ion irradiation with an energy of 2.2 GeV. The use of synchrotron-based small angle X-ray scattering (SAXS) allowed characterization of the latent tracks, without the need for chemical etching. Temperatures between 900 and 1000 °C were required to see a notable change in track size. The shrinkage in cross-section and length was found to be comparable for tracks aligned perpendicular and parallel to the c-axis.
- Published
- 2015
3. Size characterization of ion tracks in PET and PTFE using SAXS
- Author
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Matias Rodriguez, Christina Trautmann, Thomas Bierschenk, Stephen T. Mudie, Patrick Kluth, Boshra Afra, and Daniel Schauries
- Subjects
Nuclear and High Energy Physics ,chemistry.chemical_compound ,Swift heavy ion ,chemistry ,Small-angle X-ray scattering ,Ion track ,Polyethylene terephthalate ,Analytical chemistry ,Radius ,Irradiation ,Small-angle scattering ,Instrumentation ,Ion - Abstract
Ion tracks in polyethylene terephthalate (PET) and polytetrafluoroethylene (PTFE) were created by swift heavy ion irradiation and subsequently characterized using small angle X-ray scattering (SAXS). Due to their reduced density compared to the surrounding matrix, cylindrical geometry, and parallel orientation, ion tracks produce a characteristic scattering pattern which allows quantitative analysis of their radius with high precision. For ion tracks in PET thermal annealing led to a gradual fading with a decrease in density difference yet a simultaneous increase in ion track radius. Such an increase in radius is the direct opposite compared to temperature induced ion track shrinking in inorganic materials, and suggests a very different thermal response of the polymer.
- Published
- 2015
4. Structural analysis of simulated swift heavy ion tracks in quartz
- Author
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Szymon L. Daraszewicz, Aleksi A. Leino, Flyura Djurabekova, Kai Nordlund, Boshra Afra, Patrick Kluth, and Olli H. Pakarinen
- Subjects
Nuclear and High Energy Physics ,Swift heavy ion ,Scattering ,Chemistry ,Ion track ,Stopping power (particle radiation) ,Atomic physics ,Rutherford backscattering spectrometry ,Kinetic energy ,Channelling ,Instrumentation ,Ion - Abstract
Swift heavy ions (SHI), of specific kinetic energies in the excess of 1 MeV/u, can create cylindrical regions of structural transformation in SiO 2 targets, also known as SHI tracks. Recent measurements of the track cross-sections in α -quartz show significant and consistent discrepancies across different experimental techniques used. In particular, the track radii obtained from channelling experiments based on the Rutherford Backscattering Spectrometry (RBS-c) method increase monotonically with the electronic stopping power, whereas the track radii obtained from the Small Angle X-ray scattering (SAXS) saturate past a certain stopping power threshold. We perform a systematic study of the structure of the α -quartz tracks obtained from the molecular dynamics (MD) simulations incorporating a time-dependent energy deposition based on the inelastic thermal spike model, which allows us to discuss the possible origins of these experimental discrepancies.
- Published
- 2014
5. Effect of electronic energy loss on ion track formation in amorphous Ge
- Author
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Mark C Ridgway, Patrick Kluth, Matias Rodriguez, Boshra Afra, Christina Trautmann, Raquel Giulian, Stephen T. Mudie, and Thomas Bierschenk
- Subjects
Nuclear and High Energy Physics ,Materials science ,business.industry ,Ion track ,Synchrotron ,Charged particle ,law.invention ,Ion ,Amorphous solid ,Ion beam deposition ,Semiconductor ,Physics::Plasma Physics ,law ,Irradiation ,Atomic physics ,Nuclear Experiment ,business ,Instrumentation - Abstract
The formation of ion tracks was studied in amorphous Ge for irradiation with Au ions with energies of 89 MeV, 185 MeV and 2.19 GeV. Synchrotron based small-angle X-ray scattering revealed an underlying core–shell morphology of the ion tracks for all irradiation energies. While the ion track dimensions increase with the electronic energy loss for the lower irradiation energies, the ion track radius remains unchanged for the highest energy which indicates an effect of the projectile velocity on the process of ion track formation.
- Published
- 2014
6. SAXS and TEM investigation of ion tracks in neodymium-doped yttrium aluminium garnet
- Author
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Feng Chen, Christina Trautmann, Boshra Afra, Patrick Kluth, Thomas Bierschenk, Weixing Li, Stephen T. Mudie, Rodney C. Ewing, Matias Rodriguez, and Daniel Schauries
- Subjects
Aluminium oxides ,Nuclear and High Energy Physics ,Materials science ,Dopant ,Small-angle X-ray scattering ,Ion track ,Analytical chemistry ,chemistry.chemical_element ,Neodymium ,Amorphous solid ,Ion ,Crystallography ,chemistry.chemical_compound ,chemistry ,Yttrium aluminium garnet ,Instrumentation - Abstract
Neodymium-doped yttrium aluminium garnet (Nd:Y3Al5O12 or Nd:YAG) crystals were irradiated with 2.2 GeV 197Au ions. Ion track formation was investigated using synchrotron based small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). Cylindrical ion tracks consisted of an amorphous core with sharp boundaries within the crystalline matrix. The SAXS results, modelled as long cylindrical tracks, provided a constant track density that is 0.6 ± 0.3% different to that of the surrounding matrix. The average track radii determined by both techniques were in excellent agreement, 4.4 ± 0.1 nm from SAXS and 4.4 ± 0.5 nm from TEM. A comparison with previous results of ion tracks in YAG indicates that the track radius is not affected by the presence of 1 mol% Nd dopant.
- Published
- 2014
7. The shape of ion tracks in natural apatite
- Author
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Weixing Li, Patrick Kluth, Maik Lang, Matias Rodriguez, Boshra Afra, Thomas Bierschenk, Rodney C. Ewing, Daniel Schauries, and Christina Trautmann
- Subjects
Nuclear and High Energy Physics ,Materials science ,Scattering ,Small-angle X-ray scattering ,Ion track ,Track (disk drive) ,Mineralogy ,Radius ,Apatite ,Ion ,visual_art ,visual_art.visual_art_medium ,Irradiation ,Atomic physics ,Instrumentation - Abstract
Small angle X-ray scattering measurements were performed on natural apatite of different thickness irradiated with 2.2 GeV Au swift heavy ions. The evolution of the track radius along the full ion track length was estimated by considering the electronic energy loss and the velocity of the ions. The shape of the track is nearly cylindrical, slightly widening with a maximum diameter approximately 30 μm before the ions come to rest, followed by a rapid narrowing towards the end within a cigar-like contour. Measurements of average ion track radii in samples of different thicknesses, i.e. containing different sections of the tracks are in good agreement with the shape estimate.
- Published
- 2014
8. Annealing behaviour of ion tracks in olivine, apatite and britholite
- Author
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Boshra Afra, Maik Lang, Patrick Kluth, Christina Trautmann, Rodney C. Ewing, Matias Rodriguez, William J. Weber, Nigel Kirby, and Thomas Bierschenk
- Subjects
Nuclear and High Energy Physics ,Materials science ,Olivine ,Annealing (metallurgy) ,Ion track ,Analytical chemistry ,Mineralogy ,engineering.material ,Apatite ,Silicate minerals ,visual_art ,X-ray crystallography ,visual_art.visual_art_medium ,engineering ,Phosphate minerals ,Small-angle scattering ,Instrumentation - Abstract
Ion tracks were created in olivine from San Carlos, Arizona (95% Mg2SiO4), apatite (Ca5(PO4)3(F,Cl,O)) from Durango, Mexico, and synthetic silicates with the apatite structure: Nd8Sr2(SiO4)6O2 and Nd8Ca2(SiO4)6O2 using 1.6 and 2.2 GeV Au ions. The morphology and annealing behaviour of the tracks were investigated by means of synchrotron based small angle X-ray scattering in combination with ex situ annealing. Tracks in olivine annealed above ∼400 °C undergo a significant change in track radius due to recrystallisation of the damage tracks. At temperatures higher than 620 °C, the scattering images indicate fragmentation of the track cylinders into smaller subsections. Ion tracks were annealed at elevated temperatures up to 400 °C in the Durango and Ca-britholite, and up to 560 °C in Sr-britholite. While there was a significant change in the track radii in the Durango apatite, tracks in the two synthetic samples remained almost unchanged.
- Published
- 2014
9. Temperature dependence of ion track formation in quartz and apatite
- Author
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Flyura Djurabekova, Daniel Severin, Kai Nordlund, Markus Bender, Olli H. Pakarinen, Daniel Schauries, Maik Lang, S. Botis, Matias Rodriguez, Nigel Kirby, Christina Trautmann, Boshra Afra, Weixing Li, Patrick Kluth, and Rodney C. Ewing
- Subjects
Materials science ,Annealing (metallurgy) ,Ion track ,Fluorapatite ,Analytical chemistry ,Mineralogy ,02 engineering and technology ,Radius ,021001 nanoscience & nanotechnology ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Apatite ,Ion ,visual_art ,0103 physical sciences ,visual_art.visual_art_medium ,Irradiation ,010306 general physics ,0210 nano-technology ,Quartz - Abstract
Ion tracks were created in natural quartz and fluorapatite from Durango, Mexico, by irradiation with 2.2 GeV Au ions at elevated temperatures of up to 913 K. The track radii were analysed using small-angle X-ray scattering, revealing an increase in the ion track radius of approximately 0.1 nm per 100 K increase in irradiation temperature. Molecular dynamics simulations and thermal spike calculations are in good agreement with these values and indicate that the increase in track radii at elevated irradiation temperatures is due to a lower energy required to reach melting of the material. The post-irradiation annealing behaviour studied for apatite remained unchanged.
- Published
- 2013
10. Effect of doping on the radiation response of conductive Nb–SrTiO3
- Author
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Boshra Afra, Daniel Severin, Jiaming Zhang, Patrick Kluth, Weixing Li, Rodney C. Ewing, Nikita Medvedev, Maik Lang, Matias Rodriguez, Michael Sorokin, Markus Bender, and Christina Trautmann
- Subjects
Nuclear and High Energy Physics ,Electron density ,Materials science ,Condensed matter physics ,Small-angle X-ray scattering ,Ion track ,Doping ,Ion ,Condensed Matter::Materials Science ,Crystallography ,Impurity ,Electrical resistivity and conductivity ,Transmission electron microscopy ,Instrumentation - Abstract
Based on the Coulomb spike model, track formation depends strongly on the electrical resistivity of a material, and ion tracks form only in insulating materials. However, there are no systemic studies of the effect of resistivity on the track formation in materials, such as SrTiO 3 (STO), where with the addition of low concentrations of Nb, the resistivity dramatically decreases covering the entire electronic regime from an insulating to conducting material. In this study, high energy (8.6 MeV/u) ion-induced track formation in STO was characterized by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) techniques as a function of Nb-doping concentrations. Contrary to the Coulomb spike model’s predictions, the Nb-doping had no evident influence on track formation, as confirmed by both TEM and SAXS. This may be the result of the low electron density in the bulk material or the minor effect of the Nb-doping on the bonding in the material. In situ TEM studies of low energy (1 MeV Kr 2+ ) ion irradiations show that the low concentration doping has a minor influence on the crystalline-to-amorphous transformation as a result of subtle structural variations of incorporated impurity atoms.
- Published
- 2013
11. Shape manipulation of ion irradiated Ag nanoparticles embedded in lithium niobate
- Author
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Mark C Ridgway, Rainer Thomae, M.K. Moodley, Krish Bharuth-Ram, Matias Rodriguez, Jura Rensberg, Steffen Wolf, Boshra Afra, F. D. Smit, Carsten Ronning, Andreas Johannes, Shakeeb Bin Hasan, Thomas Bierschenk, R. Neveling, Carsten Rockstuhl, Complex Photonic Systems, and Faculty of Science and Technology
- Subjects
Materials science ,Ion beam ,Lithium niobate ,Nanoparticle ,Physics::Optics ,Bioengineering ,02 engineering and technology ,01 natural sciences ,Molecular physics ,Silver nanoparticle ,Ion ,chemistry.chemical_compound ,Optics ,METIS-318194 ,0103 physical sciences ,General Materials Science ,Electrical and Electronic Engineering ,010302 applied physics ,business.industry ,Mechanical Engineering ,Ion track ,General Chemistry ,021001 nanoscience & nanotechnology ,chemistry ,IR-101651 ,Mechanics of Materials ,Extinction (optical mineralogy) ,Particle size ,0210 nano-technology ,business - Abstract
Spherical silver nanoparticles were prepared by means of ion beam synthesis in lithium niobate. The embedded nanoparticles were then irradiated with energetic (84)Kr and (197)Au ions, resulting in different electronic energy losses between 8.1 and 27.5 keV nm(-1) in the top layer of the samples. Due to the high electronic energy losses of the irradiating ions, molten ion tracks are formed inside the lithium niobate in which the elongated Ag nanoparticles are formed. This process is strongly dependent on the initial particle size and leads to a broad aspect ratio distribution. Extinction spectra of the samples feature the extinction maximum with shoulders on either side. While the maximum is caused by numerous remaining spherical nanoparticles, the shoulders can be attributed to elongated particles. The latter could be verified by COMSOL simulations. The extinction spectra are thus a superposition of the spectra of all individual particles.
- Published
- 2016
12. SAXS study of ion tracks in San Carlos olivine and Durango apatite
- Author
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Patrick Kluth, Maik Lang, Boshra Afra, Christina Trautmann, Matias Rodriguez, Nigel Kirby, and Rodney C. Ewing
- Subjects
Nuclear and High Energy Physics ,Materials science ,Olivine ,Annealing (metallurgy) ,Ion track ,Analytical chemistry ,Mineralogy ,engineering.material ,Apatite ,Ion ,Silicate minerals ,visual_art ,X-ray crystallography ,engineering ,visual_art.visual_art_medium ,Phosphate minerals ,Instrumentation - Abstract
Ion tracks were generated in crystalline San Carlos olivine (Mg,Fe) 2 SiO 4 and Durango apatite Ca 10 (PO 4 ) 6 F 2 using different heavy ions ( 58 Ni, 101 Ru, 129 Xe, 197 Au, and 238 U) with energies ranging between 185 MeV and 2.6 GeV. The tracks and their annealing behavior were studied by means of synchrotron based small angle X-ray scattering in combination with in situ annealing. Track radii vary as a function of electronic energy loss but are very similar in both minerals. Furthermore, the annealing behavior of the track radii has been investigated and preliminary results reveal a lower recovery rate of the damaged area in olivine compared with apatite.
- Published
- 2012
13. Preparation of a Pd membrane on a WO3 modified Porous Stainless Steel for hydrogen separation
- Author
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Mostafa Dehghani-Mobarake, Boshra Afra, Mostafa Zahedi, and Majid Bahmani
- Subjects
Materials science ,Hydrogen ,Metallurgy ,technology, industry, and agriculture ,chemistry.chemical_element ,Filtration and Separation ,Biochemistry ,Metal ,Membrane ,chemistry ,Chemical engineering ,Permeability (electromagnetism) ,visual_art ,visual_art.visual_art_medium ,General Materials Science ,Physical and Theoretical Chemistry ,Selectivity ,Porosity ,Palladium ,Hydrogen permeation - Abstract
A palladium membrane has been prepared by electroless plating on the surface of a Porous Stainless Steel disk. The disk surface was modified with WO3 to prevent metal penetration into palladium layer and hence a membrane with nano-sized pores could be obtained. The mean thickness of the resulting Pd membrane on the modified disk was 12 μm. The permeability and selectivity of membrane was investigated. The permeability tests at 773 K showed that the membrane prepared was highly selective towards hydrogen. Additionally aging tests showed hydrogen permeation through the membrane was independent of time.
- Published
- 2009
14. Thermal response of nanoscale cylindrical inclusions of amorphous silica embedded in α-quartz
- Author
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Patrick Kluth, Christina Trautmann, Kai Nordlund, Thomas Bierschenk, Boshra Afra, Matias Rodriguez, and Stephen T. Mudie
- Subjects
Materials science ,Ion track ,Thermal ,Nanotechnology ,Amorphous silica ,Composite material ,Elasticity (economics) ,Condensed Matter Physics ,Nanoscopic scale ,Quartz ,Electronic, Optical and Magnetic Materials - Published
- 2014
15. The influence of swift heavy ion irradiation on the recrystallization of amorphous Fe80B20
- Author
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Boshra Afra, Patrick Kluth, Christina Trautmann, Matias Rodriguez, and Nigel Kirby
- Subjects
Materials science ,Amorphous metal ,Scattering ,Annealing (metallurgy) ,Ion track ,Analytical chemistry ,Recrystallization (metallurgy) ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,Crystallography ,Swift heavy ion ,Irradiation ,Electrical and Electronic Engineering - Abstract
Ion tracks in amorphous Fe"8"0B"2"0, produced by irradiation with 11.1MeV/u Au ions, were characterized using synchrotron based small angle X-ray scattering. The tracks resemble long cylindrical structures with a radius of 8.2+/-0.1nm. Annealing experiments reveal an activation energy for track recovery E"a=0.39+/-0.10eV. Wide angle X-ray scattering measurements of irradiated and unirradiated amorphous Fe"8"0B"2"0 samples indicate enhanced recrystallization for the irradiated material.
- Published
- 2013
16. Orientation dependent annealing kinetics of ion tracks in c-SiO2
- Author
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Flyura Djurabekova, Kai Nordlund, Daniel Schauries, Christina Trautmann, Patrick Kluth, Aleksi A. Leino, Boshra Afra, Nigel Kirby, and Matias Rodriguez
- Subjects
Materials science ,Scattering ,Annealing (metallurgy) ,Ion track ,General Physics and Astronomy ,02 engineering and technology ,Activation energy ,021001 nanoscience & nanotechnology ,01 natural sciences ,Molecular physics ,Amorphous solid ,Crystallography ,Molecular dynamics ,Thermal conductivity ,0103 physical sciences ,010306 general physics ,0210 nano-technology ,Anisotropy - Abstract
The structure and thermal response of amorphous ion tracks formed along the [112¯0], [101¯0], and [0001]-directions in crystalline quartz have been investigated using small angle x-ray scattering. The radii of the ion tracks vary by about 5% (0.3 nm) for tracks along different crystallographic directions. Molecular dynamics simulations reproduce this anisotropy along the [101¯0] and [0001] directions and suggest that differences in thermal conductivity along these directions are partly responsible for this observation. Using in situ annealing, tracks along the [101¯0] and [0001] directions were shown to recrystallize during thermal annealing around 960–1020 °C with activations energies around 6 eV, while those along the [112¯0]-direction already disappeared at 640 °C with a significantly lower activation energy around 3–4 eV.
- Published
- 2015
17. SAXS study on the morphology of etched and un-etched ion tracks in apatite
- Author
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P. Mota-Santiago, Allina Nadzri, Daniel Schauries, Patrick Kluth, Boshra Afra, Adrian Hawley, Matias Rodriguez, and S. Muradoglu
- Subjects
Materials science ,Fission ,Small-angle X-ray scattering ,Scattering ,Physics ,QC1-999 ,Ion track ,Analytical chemistry ,Isotropic etching ,Apatite ,Synchrotron ,law.invention ,Crystallography ,Etching (microfabrication) ,law ,visual_art ,visual_art.visual_art_medium - Abstract
Natural apatite samples were irradiated with 185 MeV Au and 2.3 GeV Bi ions to simulate fission tracks. The resulting track morphology was investigated using synchrotron small angle x-ray scattering (SAXS) measurements before and after chemical etching. We present preliminary results from the SAXS measurement showing the etching process is highly anisotropic yielding faceted etch pits with a 6-fold symmetry. The measurements are a first step in gaining new insights into the correlation between etched and unetched fission tracks and the use of SAXS as a tool for studying etched tracks.
- Published
- 2015
18. Nano-porosity in GaSb induced by swift heavy ion irradiation
- Author
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Ryan Weed, Wen Lei, Patrick Kluth, Rodney C. Ewing, Boshra Afra, Weixing Li, Leandro Araujo, Mark C Ridgway, Raquel Giulian, Thomas Bierschenk, Matias Rodriguez, James Sullivan, and Claudia Schnohr
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,Bombardeamento de ions ,Microscopia eletrônica de transmissão ,Crystallographic defect ,Ion ,Condensed Matter::Materials Science ,Swift heavy ion ,Transmission electron microscopy ,Chemical physics ,Vacancy defect ,Materiais porosos ,Crystallite ,Irradiation ,Atomic physics ,Porous medium - Abstract
Nano-porous structures form in GaSb after ion irradiation with 185 MeV Au ions. The porous layer formation is governed by the dominant electronic energy loss at this energy regime. The porous layer morphology differs significantly from that previously reported for low-energy, ion-irradiated GaSb. Prior to the onset of porosity, positron annihilation lifetime spectroscopy indicates the formation of small vacancy clusters in single ion impacts, while transmission electron microscopy reveals fragmentation of the GaSb into nanocrystallites embedded in an amorphous matrix. Following this fragmentation process, macroscopic porosity forms, presumably within the amorphous phase.
- Published
- 2014
19. SAXS investigations of the morphology of swift heavy ion tracks in α-quartz
- Author
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Raquel Giulian, Matias Rodriguez, Mark C Ridgway, Patrick Kluth, Flyura Djurabekova, Kai Nordlund, Boshra Afra, Olli H. Pakarinen, Christina Trautmann, Marcel Toulemonde, Nigel Kirby, Thomas Bierschenk, and Giancarlo Rizza
- Subjects
Astrophysics::High Energy Astrophysical Phenomena ,Molecular Dynamics Simulation ,Ion ,Swift heavy ion ,Microscopy, Electron, Transmission ,Oscillometry ,Scattering, Small Angle ,Scattering, Radiation ,Heavy Ions ,General Materials Science ,Irradiation ,Ions ,Small-angle X-ray scattering ,Chemistry ,Scattering ,Physics ,X-Rays ,Quartz ,Condensed Matter Physics ,Rutherford backscattering spectrometry ,Crystallographic defect ,Spectrophotometry ,Anisotropy ,Electronics ,Atomic physics ,Small-angle scattering ,Monte Carlo Method - Abstract
The morphology of swift heavy ion tracks in crystalline α-quartz was investigated using small angle x-ray scattering (SAXS), molecular dynamics (MD) simulations and transmission electron microscopy. Tracks were generated by irradiation with heavy ions with energies between 27 MeV and 2.2 GeV. The analysis of the SAXS data indicates a density change of the tracks of ~2 ± 1% compared to the surrounding quartz matrix for all irradiation conditions. The track radii only show a weak dependence on the electronic energy loss at values above 17 keV nm(-1), in contrast to values previously reported from Rutherford backscattering spectrometry measurements and expectations from the inelastic thermal spike model. The MD simulations are in good agreement at low energy losses, yet predict larger radii than SAXS at high ion energies. The observed discrepancies are discussed with respect to the formation of a defective halo around an amorphous track core, the existence of high stresses and/or the possible presence of a boiling phase in quartz predicted by the inelastic thermal spike model.
- Published
- 2012
20. Morphology and annealing kinetics of ion tracks in minerals
- Author
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Maik Lang, Boshra Afra, Patrick Kluth, Matias Rodriguez, Christina Trautmann, and Rodney C. Ewing
- Subjects
Materials science ,Small-angle X-ray scattering ,Annealing (metallurgy) ,Physics ,QC1-999 ,Ion track ,Synchrotron ,Apatite ,Amorphous solid ,law.invention ,Ion ,Crystallography ,Chemical physics ,law ,visual_art ,visual_art.visual_art_medium ,Nanometre - Abstract
We have studied the morphology and annealing kinetics of ion tracks in Durango apatite using synchrotron small angle X-ray scattering. The non-destructive, artefact-free technique enables us to determine the track radii with a resolution of fractions of a nanometre. The tracks were generated using different heavy ions with energies between 185 MeV and 2.6 GeV. The track morphology is consistent with the formation of long cylindrical amorphous tracks. The annealing kinetics, measured by SAXS in combination with ex situ and in situ annealing experiments, suggests structural relaxation followed by recrystallisation of the damaged material. The measurement methodology shown here provides a new means for in-depth studies of ion-track formation in minerals under a wide variety of geological conditions.
- Published
- 2012
21. Modification of Fe-B based metallic glasses using swift heavy ions
- Author
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Marcel Toulemonde, Thomas Bierschenk, Boshra Afra, Matias Rodriguez, Christina Trautmann, N Kirby, Raquel Giulian, and Patrick Kluth
- Subjects
Amorphous metal ,Materials science ,Small-angle X-ray scattering ,Scattering ,Physics ,QC1-999 ,Ion track ,Irradiation ,Radius ,Atomic physics ,Amorphous solid ,Ion - Abstract
We report on small-angle x-ray scattering (SAXS) measurements of amorphous Fe80B20, Fe85B15, Fe81B13.5Si3.5C2, and Fe40Ni40B20 metallic alloys irradiated with 11.1 MeV/u 132Xe, 152Sm, 197Au, and 8.2 MeV/u 238U ions. SAXS experiments are nondestructive and give evidence for ion track formation including quantitative information about the size of the track radius. The measurements also indicate a cylindrical track structure with a sharp transition to the undamaged surrounding matrix material. Results are compared with calculations using an inelastic thermal spike model to deduce the critical energy loss for the track formation threshold. The damage recovery of ion tracks produced in Fe80B20 by 11.1 MeV/u 197Au ions was studied by means of isochronal annealing yielding an activation energy of 0.4 ± 0.1 eV
- Published
- 2012
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