Observations of Irradiation-Induced Defect Formation on Si (111) Surface by a Linked Facility Between an Ion Accelerator and STM

2012 ◽  
Author(s):  
Motohiro Sato ◽  
Tairo Kikuchi ◽  
Kenta Murakami ◽  
Satoshi Miyashiro ◽  
Taira Okita
Keyword(s):  
Defect Formation ◽  
Ion Beams ◽  
Displacement Damage ◽  
Experimental Conditions ◽  
Ion Accelerator ◽  
Damage Process ◽  
Direct Collision ◽  
Cascade Damage

A linked facility between an ion accelerator and STM enabled to elucidate cascade damage process experimentally with an atomistic scale. By adjusting experimental conditions, we have successfully attained very clear images of Si (111) surface irradiated by very low-flux and stable ion beams. We can obtain the information of displacement damage produced by one injected ion. Much higher density of defects is observed than the number of injected ions throughout the area of the image, indicating that there are processes for defect formation other than direct collision with injected particles.

scholarly journals Dislocation Loop Generation Differences between Thin Films and Bulk in EFDA Pure Iron under Self-Ion Irradiation at 20 MeV

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2000
Author(s):  
Marcelo Roldán ◽  
Fernando José Sánchez ◽  
Pilar Fernández ◽  
Christophe J. Ortiz ◽  
Adrián Gómez-Herrero ◽  
...  
Keyword(s):  
Thin Films ◽  
Computational Models ◽  
Defect Formation ◽  
Ion Irradiation ◽  
Damage Zone ◽  
High Energy ◽  
Model Material ◽  
Dislocation Nucleation ◽  
Dislocation Loops ◽  
Experimental Conditions

In the present investigation, high-energy self-ion irradiation experiments (20 MeV Fe+4) were performed on two types of pure Fe samples to evaluate the formation of dislocation loops as a function of material volume. The choice of model material, namely EFDA pure Fe, was made to emulate experiments simulated with computational models that study defect evolution. The experimental conditions were an ion fluence of 4.25 and 8.5 × 1015 ions/cm2 and an irradiation temperature of 350 and 450 °C, respectively. First, the ions pass through the samples, which are thin films of less than 100 nm. With this procedure, the formation of the accumulated damage zone, which is the peak where the ions stop, and the injection of interstitials are prevented. As a result, the effect of two free surfaces on defect formation can be studied. In the second type of experiments, the same irradiations were performed on bulk samples to compare the creation of defects in the first 100 nm depth with the microstructure found in the whole thickness of the thin films. Apparent differences were found between the thin foil irradiation and the first 100 nm in bulk specimens in terms of dislocation loops, even with a similar primary knock-on atom (PKA) spectrum. In thin films, the most loops identified in all four experimental conditions were b ±a0<100>{200} type with sizes of hundreds of nm depending on the experimental conditions, similarly to bulk samples where practically no defects were detected. These important results would help validate computational simulations about the evolution of defects in alpha iron thin films irradiated with energetic ions at large doses, which would predict the dislocation nucleation and growth.

Analysis on acceleration of DT-mixed ion beams in a negative ion accelerator for a DT-mixed Neutral Beam Injector

2017 ◽  
Vol 121 ◽  
pp. 145-151
Author(s):  
A. Kojima ◽  
M. Kashiwagi ◽  
S. Matsuda ◽  
M. Hanada ◽  
T. Hayashi ◽  
...  
Keyword(s):  
Ion Beams ◽  
Negative Ion ◽  
Neutral Beam ◽  
Neutral Beam Injector ◽  
Ion Accelerator

scholarly journals Preliminary design of a ≈10 MV ion accelerator for HIF research

1987 ◽  
Vol 5 (3) ◽  
pp. 457-463 ◽  
Author(s):  
T. J. Fessenden ◽  
C. M. Celata ◽  
A. Faltens ◽  
T. Henderson ◽  
D. L. Judd ◽  
...  
Keyword(s):  
Heavy Ion ◽  
Ion Beams ◽  
Preliminary Design ◽  
Lawrence Berkeley Laboratory ◽  
Ion Accelerator ◽  
Small Spot ◽  
Heavy Ion Fusion ◽  
Accelerator Design

An experiment to study the physics of merging and of focusing ion beams is under development at the Lawrence Berkeley Laboratory. In this design, parallel beams of ions (C+, Al+, or Al++) are accelerated to several MV and merged transversely. The merged beams are then further accelerated and the growth in transverse and longitudinal emittance is determined for comparison with theory. The completed apparatus will be used to study problems associated with focusing ion beams to a small spot as required for heavy ion fusion. Details of the accelerator design and considerations of the physics of combining beams are presented.

Molecular Dynamics Simulations to Evaluate the Effect of Applied Strain on Interstitial Cluster Formation and Orientation Under Collision Cascade Damage

2012 ◽  
Author(s):  
Satoshi Miyashiro ◽  
Satoshi Fujita ◽  
Mitsuhiro Itakura ◽  
Taira Okita
Keyword(s):  
Molecular Dynamics ◽  
Defect Formation ◽  
Cluster Formation ◽  
Md Simulations ◽  
Defect Cluster ◽  
Applied Strain ◽  
Collision Cascade ◽  
Defect Clusters ◽  
Dynamics Simulations ◽  
Cascade Damage

We conducted molecular dynamics (MD) simulations to analyze the strain influence on defect formation and orientation. Collision cascade damage was initiated under uniaxial applied strain with a PKA energy of 10 keV. The number of residual defects increased with applied strain because of the enhanced formation of larger defect cluster. We also applied uniaxial strain to the simulation cell which included an interstitial cluster and detected the change in its direction. The probability of a change in the defect cluster direction was significantly higher under strain. Results further showed that the probability of the change in direction is higher with smaller defect clusters, and that it is extremely low with clusters larger than a certain size.

Range and Damage Distribution in Cluster Ion Implantation

1996 ◽  
Vol 438 ◽  
Author(s):  
I. Yamada ◽  
J. Matsuo ◽  
E. C. Jones ◽  
D. Takeuchi ◽  
T. Aoki ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Defect Formation ◽  
Incident Beam ◽  
High Energy ◽  
Ion Beams ◽  
Cluster Ions ◽  
Attractive Alternative ◽  
Cluster Ion Beams ◽  
Cluster Ion ◽  
Dopant Redistribution

AbstractCluster ion implantation is an attractive alternative to conventional ion implantation, particularly for shallow junction formation. It is easy to obtain high-current ion beams with low equivalent energy using cluster ion beams. The implanted boron distribution in 5keV B10H14 implanted Si is markedly shallower than that in 5keV BF2 ion implanted Si. The implanted depth is less than 0.04 μm, indicating that cluster ion implantation is capable of forming shallow junctions. The sheet resistance of 3keV B10H14 implanted samples falls below 500 Ω/sq after annealing at 1000°C for 10s. Shallow implantation can be realized by a high energy cluster beam without space-charge problems in the incident beam. Defect formation, resulting from local energy deposition and multiple collisions, is unique for cluster ions. The thickness of the damaged layer formed by cluster ion bombardment increases with the size of the cluster, if implant energy and ion dose remain constant. This is one of the nonlinear “cluster effects,” which may allow some control over the implant damage distributions that accompany implanted ions, and which have been shown to have a great effect on dopant redistribution during annealing

scholarly journals Simulation of neutron displacement damage in bipolar junction transistors using high-energy heavy ion beams.

2006 ◽  
Author(s):  
Barney Lee Doyle ◽  
Daniel L. Buller ◽  
Harold Paul Hjalmarson ◽  
Robert M Fleming ◽  
Edward Salvador Bielejec ◽  
...  
Keyword(s):  
Heavy Ion ◽  
High Energy ◽  
Ion Beams ◽  
Bipolar Junction Transistors ◽  
Displacement Damage

Defect formation and modulation during patterning supported graphene sheets using focused ion beams

2018 ◽  
Vol 17 ◽  
pp. 60-68 ◽  
Author(s):  
Cheng-Lun Wu ◽  
Hsiang-Ting Lin ◽  
Hsuan-An Chen ◽  
Shih-Yen Lin ◽  
Min-Hsiung Shih ◽  
...  
Keyword(s):  
Defect Formation ◽  
Ion Beams ◽  
Focused Ion Beams ◽  
Graphene Sheets

HVEM Radiation Damage Studies: Past, Present and Future

1980 ◽  
Vol 38 ◽  
pp. 22-25
Author(s):  
T.E. Mitchell ◽  
L.W. Hobbs
Keyword(s):  
Radiation Damage ◽  
Scientific Method ◽  
Defect Formation ◽  
Technological Problem ◽  
Extreme Caution ◽  
Secondary Defect ◽  
Damage Process ◽  
Fast Breeder Reactors ◽  
Breeder Reactors ◽  
Damage Processes

First let it be said that this article is not intended to be a comprehensive review of HVEM radiation damage studies. The reader will do much better to peruse the writings of Urban, Kiritani, Cosslett and others, or to scan the various HVEM symposium reports. Nor is this article intended to justify the use of HVEM to develop suitable materials for fast-breeder reactors, fusion reactors, ion implantation devices, nuclear waste disposal or any other technological problem where radiation damage is important. Rather, this article seeks to assess the role that HVEM has, can, and will display in understanding the fundamental aspects of radiation damage processes. The point to be made is that HVEM provides an excellent scientific method of investigating the primary displacement process, and, especially, secondary defect formation. However, although the electron damage process is much simpler than neutron or ion damage, HVEM damage observations still must be evaluated with extreme caution.

Sign in / Sign up

Export Citation Format

Share Document