scholarly journals Interactions between carbon impurities and defects produced by proton irradiation in α-iron

2019 ◽  
Vol 24 ◽  
pp. 47
Author(s):  
G. Apostolopoulos ◽  
V. Lukianova ◽  
Z. Kotsina ◽  
A. Lagoyannis ◽  
K. Mergia ◽  
...  
Keyword(s):  
Point Defect ◽  
Cryogenic Temperature ◽  
Proton Irradiation ◽  
Carbon Impurities ◽  
Impurities And Defects

Resistivity recovery experiments are performed on α-Fe and an Fe - 220 at. ppm C alloy after 5 MeV proton irradiation at cryogenic temperature of 50 K. By comparing the recovery spectra of pure Fe and the Fe-C alloy we are able to resolve the effect of carbon atoms on the point defect kinetics. It is observed that carbon interacts with both interstitial and vacancy type of defects and delays their annihilation. At temperatures above 500 K the formation of carbides reduces the resistivity of the alloy.

scholarly journals Proton irradiation of a swept charge device at cryogenic temperature and the subsequent annealing

2015 ◽  
Vol 10 (01) ◽  
pp. C01037-C01037 ◽  
Author(s):  
J P D Gow ◽  
P H Smith ◽  
P Pool ◽  
D J Hall ◽  
A D Holland ◽  
...  
Keyword(s):  
Cryogenic Temperature ◽  
Proton Irradiation ◽  
Subsequent Annealing

Use of Wyckoff position splittings in the supercell model of crystals with point defects

2017 ◽  
Vol 50 (3) ◽  
pp. 893-900 ◽  
Author(s):  
R. A. Evarestov ◽  
Yu. E. Kitaev ◽  
V. V. Porsev
Keyword(s):  
Theoretical Analysis ◽  
Ab Initio ◽  
Point Defect ◽  
Point Defects ◽  
Electronic States ◽  
Host Crystal ◽  
Wyckoff Position ◽  
Supercell Model ◽  
Impurities And Defects ◽  
Group Theoretical Analysis

The atomic sublattices occupying different Wyckoff positions in a host crystal are shown to be subdivided in the supercell model owing to the splitting of the occupied Wyckoff positions. The site symmetries of the split Wyckoff positions are in general different, which significantly increases the number of possible occupation schemes for impurities and defects in the supercell model. It is demonstrated that the use of the programs and retrieval tools of the Bilbao Crystallographic Server considerably simplifies the group-theoretical analysis of Wyckoff position splittings in the supercell model of a crystal with a point defect.Ab initiocalculations of electronic states of single defects in ZnO (Zn and O neutral vacancies) within the supercell model are performed to demonstrate the influence of Wyckoff position splittings on the results.

scholarly journals Proton irradiation and resistivity recovery in stages I & II of pure and carbon-doped Fe

2020 ◽  
Vol 27 ◽  
pp. 148
Author(s):  
Andreas Theodorou ◽  
M. Syskaki ◽  
Z. Kotsina ◽  
M. Axiotis ◽  
G. Apostolopoulos
Keyword(s):  
Electrical Resistivity ◽  
Cryogenic Temperature ◽  
Proton Irradiation ◽  
Radiation Defects ◽  
Tandem Accelerator ◽  
Carbon Doped ◽  
Post Irradiation ◽  
Solute Atoms ◽  
Mev Protons

Pure and C-doped Fe specimens were irradiated with 5 MeV protons at cryogenic temperature at the NCSR-"Demokritos" TANDEM accelerator in order to investigate the interactions between carbon atoms and radiation defects. During the subsequent post-irradiation isochronal annealing up to 180 K the defects start to migrate and interact either mutually or with the C impurities. The defect evolution is observed by in-situ electrical resistivity recovery measurements. Comparison of results from pure and C-doped Fe specimens reveals the effect of C solute atoms on the defect kinetics.

Proton Irradiation Enhancement of Low-Field Negative Magnetoresistance Sensitivity of AlGaN/GaN-Based Magnetic Sensor at Cryogenic Temperature

2014 ◽  
Vol 35 (11) ◽  
pp. 1130-1132 ◽  
Author(s):  
Abdelkader Abderrahmane ◽  
Pil Ju Ko ◽  
Hiroshi Okada ◽  
Shin-Ichiro Sato ◽  
Takeshi Ohshima ◽  
...  
Keyword(s):  
Cryogenic Temperature ◽  
Proton Irradiation ◽  
Magnetic Sensor ◽  
Negative Magnetoresistance ◽  
Low Field

scholarly journals Structural and Photoluminescence Analysis on the Implantation of Carbon and Proton for the Creation of Damage-Assisted Emission in Silicon

2020 ◽  
Vol 49 (12) ◽  
pp. 2927-2936
Author(s):  
Nurul Ellena Abdul Razak ◽  
Morgan Madhuku ◽  
Ishaq Ahmad ◽  
Burhanuddin Yeop Majlis ◽  
Fu Dee Chang ◽  
...  
Keyword(s):  
Point Defect ◽  
Proton Irradiation ◽  
Defect Formation ◽  
Depth Profiling ◽  
High Energy ◽  
Carbon Ions ◽  
Active Point ◽  
Irradiation Energy ◽  
Induced Defects ◽  
Irradiation Process

We study the induced defects in the depth profiling of the silicon structure after being implanted with carbon and followed by high energy proton irradiation. It has been reported before that the formation of the optically active point-defect, specifically the G-centre is due to the implantation and irradiation of carbon and proton, respectively. It is crucial to quantify the diffusional broadening of the implanted ion profile especially for proton irradiation process so that the radiation damage evolution can be maximized at the point-defect formation region. Profiling analysis was carried out using computational Stopping and Range of Ions in Matter (SRIM) and Surrey University Sputter Profile Resolution from Energy Deposition (SUSPRE) simulation. The energies of carbon ions adopted for this investigation are 10, 20, 30, and 50 keV, while proton irradiation energy was kept at 2 MeV. Photoluminescence measurements on silicon implanted with carbon at different energies were carried out to study the interrelation between the numbers of vacancies produced during the damage event and the peak emission intensities.

scholarly journals Use of the point defect model to interpret the iron oxidation kinetics under proton irradiation

2007 ◽  
Vol 101 (6) ◽  
pp. 064905 ◽  
Author(s):  
S. Lapuerta ◽  
N. Moncoffre ◽  
H. Jaffrézic ◽  
N. Millard-Pinard ◽  
N. Bérerd ◽  
...  
Keyword(s):  
Point Defect ◽  
Oxidation Kinetics ◽  
Proton Irradiation ◽  
Iron Oxidation ◽  
Defect Model ◽  
Point Defect Model

Phase Transformation In Ti-6al-4v Alloys

1972 ◽  
Vol 30 ◽  
pp. 584-585
Author(s):  
Shiro Fujishiro
Keyword(s):  
Phase Transformation ◽  
Grain Boundary ◽  
Cryogenic Temperature ◽  
Β Phase ◽  
Heat Treated ◽  
Mixed Microstructure ◽  
Ductile Behavior

The Ti-6 wt.% Al-4 wt.% V commercial alloys have exhibited an improved formability at cryogenic temperature when the alloys were heat-treated prior to the tests. The author was interested in further investigating this unusual ductile behavior which may be associated with the strain-induced transformation or twinning of the a phase, enhanced at lower temperatures. The starting materials, supplied by RMI Co., Niles, Ohio were rolled mill products in the form of 40 mil sheets. The microstructure of the as-received materials contained mainly ellipsoidal α grains measuring between 1 and 5μ. The β phase formed an undefined grain boundary around the a grains. The specimens were homogenized at 1050°C for one hour, followed by aging at 500°C for two hours, and then quenched in water to produce the α/β mixed microstructure.

Detection of a point defect in a silicon single crystal by high-resolution TEM

1995 ◽  
Vol 53 ◽  
pp. 466-467
Author(s):  
M. Awaji
Keyword(s):  
High Resolution ◽  
Single Crystal ◽  
Point Defect ◽  
Point Defects ◽  
Noise Level ◽  
Dark Field ◽  
Silicon Single Crystal ◽  
High Resolution Image ◽  
Dark Field Imaging ◽  
Field Imaging

It is necessary to improve the resolution, brightness and signal-to-noise ratio(s/n) for the detection and identification of point defects in crystals. In order to observe point defects, multi-beam dark-field imaging is one of the useful methods. Though this method can improve resolution and brightness compared with dark-field imaging by diffuse scattering, the problem of s/n still exists. In order to improve the exposure time due to the low intensity of the dark-field image and the low resolution, we discuss in this paper the bright-field high-resolution image and the corresponding subtracted image with reference to a changing noise level, and examine the possibility for in-situ observation, identification and detection of the movement of a point defect produced in the early stage of damage process by high energy electron bombardment.The high-resolution image contrast of a silicon single crystal in the [10] orientation containing a triple divacancy cluster is calculated using the Cowley-Moodie dynamical theory and for a changing gaussian noise level. This divacancy model was deduced from experimental results obtained by electron spin resonance. The calculation condition was for the lMeV Berkeley ARM operated at 800KeV.

Point Defect Absorption and Dislocation Loop Formation at Grain Boundaries in Hvem-Irradiated Zr and Its Alloys:1. Influence of Solute Addition

1985 ◽  
Vol 43 ◽  
pp. 350-351
Author(s):  
R.A. Herring ◽  
M. Griffiths ◽  
M.H Loretto ◽  
R.E. Smallman
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Point Defect ◽  
Reactor Core ◽  
Solute Concentration ◽  
Nuclear Industry ◽  
Dislocation Loops ◽  
Loop Formation ◽  
Component Material ◽  
Impurity Interaction

Because Zr is used in the nuclear industry to sheath fuel and as structural component material within the reactor core, it is important to understand Zr's point defect properties. In the present work point defect-impurity interaction has been assessed by measuring the influence of grain boundaries on the width of the zone denuded of dislocation loops in a series of irradiated Zr alloys. Electropolished Zr and its alloys have been irradiated using an AEI EM7 HVEM at 1 MeV, ∼675 K and ∼10-6 torr vacuum pressure. During some HVEM irradiations it has been seen that there is a difference in the loop nucleation and growth behaviour adjacent to the grain boundary as compared with the mid-grain region. The width of the region influenced by the presence of the grain boundary should be a function of the irradiation temperature, dose rate, solute concentration and crystallographic orientation.

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