The Effect of Simultaneous Electron and Kr+ Irradiation on Amorphization of CuTi

1988 ◽  
Vol 128 ◽  
Author(s):  
J. Koike ◽  
P. R. Okamoto ◽  
L. E. Rehn ◽  
M. Meshii
Keyword(s):  
Dose Rate ◽  
Point Defects ◽  
Electron Irradiation ◽  
Irradiation Temperature ◽  
Additive Effect ◽  
Retardation Effect ◽  
Displacement Cascades ◽  
Simultaneous Irradiation ◽  
Relative Electron

ABSTRACTCuTi was irradiated with 1-MeV electrons and Kr+ ions simultaneously at temperatures from 10 to 423 K. Retardation of Kr+-induced amorphization was observed with simultaneous electron irradiation at 295 and 423 K. The retardation effect increased with increasing irradiation temperature and relative electron-to-Kr dose rate. In contrast, simultaneous irradiation below 100 K showed an additive effect of electron- and Kr+-induced amorphization. The results can be explained by the mobility point defects introduced by electron irradiation interacting with Kr+-induced displacement cascades.

Dose-rate dependence in the production of point defects in quartz

1993 ◽  
Vol 44 (1-2) ◽  
pp. IN11-277 ◽  
Author(s):  
L.E. Halliburton ◽  
A. Hofstaetter ◽  
A. Scharmann ◽  
M.P. Scripsick ◽  
G.J. Edwards
Keyword(s):  
Dose Rate ◽  
Point Defects ◽  
Rate Dependence

Crystalline-To-Amorphous Transformation of Intermetallic Compounds in the Zr-Fe-M System Induced by Irradiation

1994 ◽  
Vol 373 ◽  
Author(s):  
Arthur T. Motta ◽  
Lawrence M. Howe ◽  
Paul R. Okamoto
Keyword(s):  
Critical Temperature ◽  
Low Temperature ◽  
Dose Rate ◽  
Intermetallic Compounds ◽  
Electron Energy ◽  
Energy Dependence ◽  
Electron Irradiation ◽  
Critical Temperatures ◽  
Lower Critical Temperature ◽  
Ternary Intermetallic Compounds

AbstractThe binary and ternary intermetallic compounds Zr3Fe, Zr2 Fe, (Zr0.5,Nb0.5)3Fe, Zr3(Fe0.9,Ni0.1) and Zr3(Fe0.5,Ni0.5) were subjected to 900 keV electron irradiation until amorphous to study the change in the dose-to-amorphization with temperature. The critical temperatures were observed to vary with dose rate, and with the type of compound. Hexagonal (Zr0.5,Nb0.5)3Fe had an appreciably lower critical temperature and higher dose to amorphization at low temperature than orthorombic Zr3Fe, whereas other orthorombic Zr3(Fex,NiI-x) compounds were essentially identical in behavior to Zr3Fe. The electron energy dependence of the dose-to-amorphization was studied in Zr3Fe between 250 and 900 keV. The analysis of the results gives displacement energies of EZrd = 26 eV, EFed = 18 eV in the Zr3Fe compound.

scholarly journals Irradiation temperature effects on the induced point defects in Ge-doped optical fibers.

2017 ◽  
Vol 169 ◽  
pp. 012008
Author(s):  
A. Alessi ◽  
I. Reghioua ◽  
S. Girard ◽  
S. Agnello ◽  
D. Di Francesca ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Point Defects ◽  
Temperature Effects ◽  
Irradiation Temperature

Migration energies of point defects during electron irradiation of hydrogenated Si crystals

2002 ◽  
Vol 66 (15) ◽  
Author(s):  
M. Suezawa ◽  
Y. Takada ◽  
T. Tamano ◽  
R. Taniguchi ◽  
F. Hori ◽  
...  
Keyword(s):  
Point Defects ◽  
Electron Irradiation

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.

Negative-U Properties for Point Defects in Silicon

1980 ◽  
Vol 2 ◽  
Author(s):  
G. D. Watkins
Keyword(s):  
Experimental Evidence ◽  
Point Defects ◽  
Electron Irradiation ◽  
Correlation Energy ◽  
Energy Levels ◽  
Unusual Property ◽  
Simple Point ◽  
Normal Order ◽  
Defect Energy ◽  
Lattice Vacancy

ABSTRACTA defect has negative-U properties if it can trap two electrons (or holes) with the second bound more strongly than the first. It is as if there were a net attraction between the two carriers (negative Hubbard correlation energy U) at the defect, and the defect energy levels in the gap are therefore inverted from their normal order. Experimental evidence is presented that interstitial boron and the lattice vacancy, both common simple point defects produced by electron irradiation of silicon, have this unusual property. These defects represent the first and only concrete examples of negative-U centers in any material and serve as models for an understanding of the phenomenon.

Coupled irradiation-temperature effects on induced point defects in germanosilicate optical fibers

2017 ◽  
Vol 52 (18) ◽  
pp. 10697-10708 ◽  
Author(s):  
A. Alessi ◽  
S. Agnello ◽  
S. Girard ◽  
D. Di Francesca ◽  
I. Reghioua ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Point Defects ◽  
Temperature Effects ◽  
Irradiation Temperature

The Effect of Temperature on Defect Production by Displacement Cascades in alpha;-IRON

1996 ◽  
Vol 439 ◽  
Author(s):  
F. Gao ◽  
D. J. Bacon ◽  
P. E. J. Flewitt ◽  
T. A. Lewis
Keyword(s):  
Molecular Dynamics ◽  
Md Simulations ◽  
Irradiation Temperature ◽  
Effect Of Temperature ◽  
Cascade Process ◽  
Thermal Spike ◽  
Defect Production ◽  
Alpha Iron ◽  
Displacement Cascades ◽  
The Continuum

AbstractMolecular dynamics (MD) simulations have been used to study the number and arrangement of defects produced by displacement cascades as functions of irradiation temperature, Tirr, in α-iron. The continuum treatment of heat conduction was used to adjust the temperature of the MD boundary atoms throughout the cascade process. This new hybrid model has been applied to cascades of either 2 or 5 keV at 100K, 400K, 600K and 900K. The number of Frenkel pairs decreases by about 20–30% as Tir increases from 100K to 900K, due to the increase in the lifetime of the thermal-spike phase. The same effect also brings about an increase in the proportion of selfinterstitial atoms that form clusters.

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