The relationship between interfacial bonding and radiation damage in adsorbed DNA

2014 ◽  
Vol 16 (29) ◽  
pp. 15319-15325 ◽  
Author(s):  
R. A. Rosenberg ◽  
J. M. Symonds ◽  
K. Vijayalakshmi ◽  
Debabrata Mishra ◽  
T. M. Orlando ◽  
...  
Keyword(s):  
Radiation Damage ◽  
Low Energy ◽  
Interfacial Bonding ◽  
Secondary Electrons ◽  
Damage Probability ◽  
Low Energy Electrons ◽  
The Relationship

Illustration showing that secondary electrons have a higher damage probability for thiolated DNA as opposed to unthiolated DNA, due to the former's higher density of LUMO states, which leads to more efficient capture of the low energy electrons.

scholarly journals Radiation Damage to DNA: The Indirect Effect of Low-Energy Electrons

2013 ◽  
Vol 4 (5) ◽  
pp. 820-825 ◽  
Author(s):  
Elahe Alizadeh ◽  
Ana G. Sanz ◽  
Gustavo García ◽  
Léon Sanche
Keyword(s):  
Radiation Damage ◽  
Indirect Effect ◽  
Low Energy ◽  
Low Energy Electrons

scholarly journals The role of low-energy electrons in focused electron beam induced deposition: four case studies of representative precursors

2015 ◽  
Vol 6 ◽  
pp. 1904-1926 ◽  
Author(s):  
Rachel M Thorman ◽  
Ragesh Kumar T. P. ◽  
D Howard Fairbrother ◽  
Oddur Ingólfsson
Keyword(s):  
Electron Beam ◽  
Gas Phase ◽  
Primary Electron ◽  
Low Energy ◽  
Primary Electron Beam ◽  
Secondary Electrons ◽  
Low Energy Electrons ◽  
Low Energy Electron ◽  
Precursor Molecules ◽  
Insight Into

Focused electron beam induced deposition (FEBID) is a single-step, direct-write nanofabrication technique capable of writing three-dimensional metal-containing nanoscale structures on surfaces using electron-induced reactions of organometallic precursors. Currently FEBID is, however, limited in resolution due to deposition outside the area of the primary electron beam and in metal purity due to incomplete precursor decomposition. Both limitations are likely in part caused by reactions of precursor molecules with low-energy (<100 eV) secondary electrons generated by interactions of the primary beam with the substrate. These low-energy electrons are abundant both inside and outside the area of the primary electron beam and are associated with reactions causing incomplete ligand dissociation from FEBID precursors. As it is not possible to directly study the effects of secondary electrons in situ in FEBID, other means must be used to elucidate their role. In this context, gas phase studies can obtain well-resolved information on low-energy electron-induced reactions with FEBID precursors by studying isolated molecules interacting with single electrons of well-defined energy. In contrast, ultra-high vacuum surface studies on adsorbed precursor molecules can provide information on surface speciation and identify species desorbing from a substrate during electron irradiation under conditions more representative of FEBID. Comparing gas phase and surface science studies allows for insight into the primary deposition mechanisms for individual precursors; ideally, this information can be used to design future FEBID precursors and optimize deposition conditions. In this review, we give a summary of different low-energy electron-induced fragmentation processes that can be initiated by the secondary electrons generated in FEBID, specifically, dissociative electron attachment, dissociative ionization, neutral dissociation, and dipolar dissociation, emphasizing the different nature and energy dependence of each process. We then explore the value of studying these processes through comparative gas phase and surface studies for four commonly-used FEBID precursors: MeCpPtMe3, Pt(PF3)4, Co(CO)3NO, and W(CO)6. Through these case studies, it is evident that this combination of studies can provide valuable insight into potential mechanisms governing deposit formation in FEBID. Although further experiments and new approaches are needed, these studies are an important stepping-stone toward better understanding the fundamental physics behind the deposition process and establishing design criteria for optimized FEBID precursors.

scholarly journals The Role of Low-Energy Electron Interactions in cis-Pt(CO)2Br2 Fragmentation

2021 ◽  
Vol 22 (16) ◽  
pp. 8984
Author(s):  
Maicol Cipriani ◽  
Styrmir Svavarsson ◽  
Filipe Ferreira da Silva ◽  
Hang Lu ◽  
Lisa McElwee-White ◽  
...  
Keyword(s):  
Coordination Compound ◽  
Electron Attachment ◽  
High Energy ◽  
Low Energy ◽  
Carbonyl Complexes ◽  
Secondary Electrons ◽  
High Energy Radiation ◽  
Low Energy Electrons ◽  
In Cis

Platinum coordination complexes have found wide applications as chemotherapeutic anticancer drugs in synchronous combination with radiation (chemoradiation) as well as precursors in focused electron beam induced deposition (FEBID) for nano-scale fabrication. In both applications, low-energy electrons (LEE) play an important role with regard to the fragmentation pathways. In the former case, the high-energy radiation applied creates an abundance of reactive photo- and secondary electrons that determine the reaction paths of the respective radiation sensitizers. In the latter case, low-energy secondary electrons determine the deposition chemistry. In this contribution, we present a combined experimental and theoretical study on the role of LEE interactions in the fragmentation of the Pt(II) coordination compound cis-PtBr2(CO)2. We discuss our results in conjunction with the widely used cancer therapeutic Pt(II) coordination compound cis-Pt(NH3)2Cl2 (cisplatin) and the carbonyl analog Pt(CO)2Cl2, and we show that efficient CO loss through dissociative electron attachment dominates the reactivity of these carbonyl complexes with low-energy electrons, while halogen loss through DEA dominates the reactivity of cis-Pt(NH3)2Cl2.

scholarly journals Study Stopping Power Collision in one of Nuclear Element

2018 ◽  
Vol 28 (2) ◽  
pp. 202
Author(s):  
Sanar G. Hassan
Keyword(s):  
Nuclear Medicine ◽  
Nuclear Physics ◽  
Physical Phenomenon ◽  
Charged Particles ◽  
Low Energy ◽  
Stopping Power ◽  
Beta Particles ◽  
Low Energy Electrons ◽  
The Relationship

The retarding force of the charged particles when interacts with matter causing loss of particle energy, this physical phenomenon in nuclear physics called stopping power. it has a lot of important applications such as in nuclear medicine and privation effects of radiations. The charge particles are alpha and beta particles. in this paper we studies the stopping power, collision and the stopping power of radioactivity of nuclear elements and to find the relationship between stopping power collision and stopping power of radioactivity, with arrange of CSDA range for the low energy electrons data of element F. the CSDA range he CSDA range it is an average distant length of the moving charge particles when it is path slows to stop. By using approximation of CSDA range we can calculate the rate of the loss in the energy at any point along the path of the travel by assuming these energies loss at points of the track are equal to whole stopping power loss. The CSDA range can be found by reciprocal integration of the total stopping power. from the Figures (3),(4),(5) and(6)we can get good results

Information, Localization, and Damage in the Stim

1976 ◽  
Vol 34 ◽  
pp. 502-503
Author(s):  
Wm. H. Escovitz ◽  
T. R. Fox ◽  
R. Levi-Setti
Keyword(s):  
High Resolution ◽  
Radiation Damage ◽  
Cross Sections ◽  
Energy Region ◽  
Figure Of Merit ◽  
Low Energy ◽  
Empirical Estimate ◽  
Scanning Transmission ◽  
The Relationship

We present an estimation and evaluation of cross sections relevant to the performance of the scanning transmission ion microscope (STIM). Figure 1 shows the relationship between the total elastic and inelastic cress sections (σe, σi) for protons and electrons at energies important to microscopy. Assuming equal collection efficiencies, the ratio σe/σi is a figure-of-merit for evaluating high resolution information obtainable for a given amount of radiation damage for different microscopes. The ratio σe/σjis calculated for carbon. Since there is no reliable calculation of σifor protons in the low energy region, we obtained an empirical estimate of σiby the following procedure. First, it was assumed that the ratio Ri of dE/dx for protons (experimental2) and dE/dx for electrons (theoretical3) is the same as the ratio of the respective σi:

Transfer optics for high spatial resolution electron spectroscopy

1988 ◽  
Vol 46 ◽  
pp. 666-667
Author(s):  
G. G. Hembree ◽  
Luo Chuan Hong ◽  
P.A. Bennett ◽  
J.A. Venables
Keyword(s):  
Magnetic Field ◽  
Scanning Transmission Electron Microscope ◽  
Low Energy ◽  
Objective Lens ◽  
State University ◽  
Arizona State University ◽  
Initial Field ◽  
Resolution Electron ◽  
Scanning Transmission ◽  
Low Energy Electrons

A new field emission scanning transmission electron microscope has been constructed for the NSF HREM facility at Arizona State University. The microscope is to be used for studies of surfaces, and incorporates several surface-related features, including provision for analysis of secondary and Auger electrons; these electrons are collected through the objective lens from either side of the sample, using the parallelizing action of the magnetic field. This collimates all the low energy electrons, which spiral in the high magnetic field. Given an initial field Bi∼1T, and a final (parallelizing) field Bf∼0.01T, all electrons emerge into a cone of semi-angle θf≤6°. The main practical problem in the way of using this well collimated beam of low energy (0-2keV) electrons is that it is travelling along the path of the (100keV) probing electron beam. To collect and analyze them, they must be deflected off the beam path with minimal effect on the probe position.

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