COMPUTER SIMULATION OF RADIATION DAMAGE IN POTASSIUM HALIDES BY LOW AND HIGH ENERGY RECOILS

1976 ◽  
Vol 37 (C7) ◽  
pp. C7-486-C7-486
Author(s):  
K. RÖSSLER ◽  
F. W. FELIX ◽  
M. MÜLLER
Keyword(s):  
Computer Simulation ◽  
Radiation Damage ◽  
High Energy ◽  
Potassium Halides

Radiation damage of BGO crystals due to low energy γ rays, high energy protons and fast neutrons

1983 ◽  
Vol 206 (1-2) ◽  
pp. 107-117 ◽  
Author(s):  
Masaaki Kobayashi ◽  
Kenjiro Kondo ◽  
Hiromi Hirabayashi ◽  
Shin-ichi Kurokawa ◽  
Mitsuhiko Taino ◽  
...  
Keyword(s):  
Radiation Damage ◽  
High Energy ◽  
Low Energy ◽  
Fast Neutrons ◽  
Γ Rays

Radiation damage induced by channeling of high energy electrons

1972 ◽  
Vol 11 (2) ◽  
pp. K103-K104 ◽  
Author(s):  
F. Fujimoto ◽  
H. Fujita
Keyword(s):  
Radiation Damage ◽  
High Energy ◽  
High Energy Electrons

Computersimulation der Rückstreuung schneller schwerer Ionen an einkristallinen (001)-und (111̅)-Goldoberflächen / Computer Simulation of the Backscattering of High Energy Ions from (001)- and (111̅)-surfaces of Au-Single Crystals

1976 ◽  
Vol 31 (3-4) ◽  
pp. 316-326 ◽  
Author(s):  
H. Schmidt ◽  
K. Güttner
Keyword(s):  
Computer Simulation ◽  
Computer Program ◽  
Single Crystals ◽  
Grazing Incidence ◽  
High Energy ◽  
Rapid Decrease ◽  
Fcc Lattice ◽  
High Energy Ions

A computer program for following the trajectories of high energy ions in an fcc-lattice has been written to evaluate the reflection rate of high energy ions with grazing incidence to (001)- and (111̅)-Au-surfaces. The calculation yields a rapid decrease of the reflection rate for penetration directions close to low-index atomic planes. It can be shown that this result is caused by channeling of the ions between the atomic planes.

Displacement cascade evolution in tungsten with pre-existing helium and hydrogen clusters: a molecular dynamics study

2020 ◽  
Vol 111 (8) ◽  
pp. 698-705
Author(s):  
Mohammad Abu-Shams ◽  
Jeffery Moran ◽  
Ishraq Shabib
Keyword(s):  
Molecular Dynamics ◽  
Point Defect ◽  
Radiation Damage ◽  
Point Defects ◽  
High Energy ◽  
Dynamics Simulation ◽  
Power Relationship ◽  
Hydrogen Clusters ◽  
Displacement Cascades ◽  
Hydrogen Defects

Abstract The effects of radiation damage on bcc tungsten with preexisting helium and hydrogen clusters have been investigated in a high-energy environment via a comprehensive molecular dynamics simulation study. This research determines the interactions of displacement cascades with helium and hydrogen clusters integrated into a tungsten crystal generating point defect statistics. Helium or hydrogen clusters of atoms~0.1% of the total number of atoms have been randomly distributed within the simulation model and primary knock-on-atom (PKA) energies of 2.5, 5, 7.5 and 10 keV have been used to generate displacement cascades. The simulations quantify the extent of radiation damage during a simulated irradiation cycle using the Wigner-Seitz point defect identification technique. The generated point defects in crystals with and without pre-existing helium/hydrogen defects exhibit a power relationship with applied PKA energy. The point defects are classified by their atom type, defect type, and distribution within the irradiated model. The presence of pre-existing helium and hydrogen clusters significantly increases the defects (5 - 15 times versus pure tungsten models). The vacancy composition is primarily tungsten (e. g., ~70% at 2.5 keV) in models with pre-existing helium, but the interstitials are primarily He (e. g., ~89% at 10 keV). On the other hand, models with pre-existing hydrogen have a vacancy composition that is primarily tungsten (more than 90% irrespective of PKA energy), and the interstitial composition is more balanced between tungsten (average 46%) and hydrogen (average 54%) interstitials across the PKA range. The distribution of the atoms reveals that the tungsten point defects prefer to reside close to the position of cascade initiation, but helium or hydrogen defects reside close to the positions where clusters are built.

scholarly journals Damage-free vibrational spectroscopy of biological materials in the electron microscope

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Peter Rez ◽  
Toshihiro Aoki ◽  
Katia March ◽  
Dvir Gur ◽  
Ondrej L. Krivanek ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Radiation Damage ◽  
Vibrational Spectroscopy ◽  
Biological Materials ◽  
High Energy ◽  
Vibrational Modes ◽  
Native State ◽  
Organic Functional Groups ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra

Abstract Vibrational spectroscopy in the electron microscope would be transformative in the study of biological samples, provided that radiation damage could be prevented. However, electron beams typically create high-energy excitations that severely accelerate sample degradation. Here this major difficulty is overcome using an ‘aloof’ electron beam, positioned tens of nanometres away from the sample: high-energy excitations are suppressed, while vibrational modes of energies <1 eV can be ‘safely’ investigated. To demonstrate the potential of aloof spectroscopy, we record electron energy loss spectra from biogenic guanine crystals in their native state, resolving their characteristic C–H, N–H and C=O vibrational signatures with no observable radiation damage. The technique opens up the possibility of non-damaging compositional analyses of organic functional groups, including non-crystalline biological materials, at a spatial resolution of ∼10 nm, simultaneously combined with imaging in the electron microscope.

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