Spectra of secondary electrons generated in water by energetic ions

Scifoni, E.; Surdutovich, Eugene; Solov’yov, Andrey V.

doi:10.1103/physreve.81.021903

Cited by 53 publications

(66 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since the major part of the energy deposited by ionizing radiation in condensed matter is channeled into the production of abundant low-energy secondary electrons, spectroscopic data and absolute cross-section values for electron impact on biomacromolecules (DNA, proteins) and its constituents are needed in order to improve our understanding of the chain * vraz@ipb.ac.rs of reactions leading to radiation damage. It should be noted that high-energy particles, such as energetic ions that are of high interest in cancer therapy [7,8], may induce quite a broad energy spectrum of secondary electrons tailing to hundreds of eVs [9]. With this respect, our previous work includes measurements of absolute differential cross sections for electron scattering from several different molecules representing backbone sugar and nucleobasis subunits of DNA [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Absolute cross sections for elastic electron scattering from methylformamide

et al. 2012

View full text Add to dashboard Cite

Elastic electron scattering from gaseous methylformamide (N -methylformamide, C 2 H 5 NO) has been investigated. Absolute elastic differential cross sections (DCSs) were determined both experimentally and theoretically for the incident energies from 50 to 300 eV. The measurements were performed using a cross-beam technique, for scattering angles from 20 • to 110 • . Relative elastic DCSs were measured as a function of both the angle and the incident energy and the absolute DCSs were determined using the relative flow method. The calculations of electron interaction cross sections are based on a corrected form of the independent-atom method, known as the SCAR (screen corrected additivity rule) procedure and using an improved quasifree absorption model. Calculated integral cross sections have been presented, as well, both for methylformamide and formamide, in the energy range 10-1000 eV, and discussed. The results are compared with and discussed regarding existing data for other small molecules representing building blocks of large biomolecules.

show abstract

Section: Introductionmentioning

confidence: 99%

Absolute cross sections for elastic electron scattering from methylformamide

et al. 2012

View full text Add to dashboard Cite

show abstract

“…The aim of this Letter is to present a simple theoretical method that provides the above mentioned required ionization data with the use of little input information, based on the dielectric formalism [6] and some physically motivated approximations. Results are here presented for proton impact, although the methodology can be immediately extended to heavier ions, electrons, and other charged particles.Although several simple theoretical and semiempirical methods already exist nowadays to calculate the energy spectra of secondary electrons [7] (and are currently in use [8][9][10]), such as the Rudd formula [11] or the semiclassical binary encounter approximation (BEA) [12], they are limited to some particular targets (atomic ones or small molecules), and its extension to complex biological systems is far from being trivial. Moreover, they can suffer problems resulting from neglecting many-body interactions and target physical state effects.…”

mentioning

confidence: 99%

“…Although several simple theoretical and semiempirical methods already exist nowadays to calculate the energy spectra of secondary electrons [7] (and are currently in use [8][9][10]), such as the Rudd formula [11] or the semiclassical binary encounter approximation (BEA) [12], they are limited to some particular targets (atomic ones or small molecules), and its extension to complex biological systems is far from being trivial. Moreover, they can suffer problems resulting from neglecting many-body interactions and target physical state effects.…”

mentioning

confidence: 99%

Semiempirical Model for the Ion Impact Ionization of Complex Biological Media

et al. 2013

Self Cite

View full text Add to dashboard Cite

We present a semiempirical model for calculating the electron emission from any organic compound after ion impact. With only the input of the density and composition of the target we are able to evaluate its ionization cross sections using plausible approximations. Results for protons impacting in the most representative biological targets (such as water or DNA components) show a very good comparison with experimental data. Because of its simplicity and great predictive effectiveness, the method can be immediately extended to any combination of biological target and charged particle of interest in ion beam cancer therapy. DOI: 10.1103/PhysRevLett.110.148104 PACS numbers: 87.53.Àj, 79.20.Àm, 87.14.gk, 87.56.Àv Secondary electron emission is a key step in the mechanism of radiation damage to biomolecular systems induced by ion impact. As a matter of fact, ion beam cancer therapy exploits the particular properties of ion tracks, in which the ionization yield reaches a maximum near the end of their trajectories (the Bragg peak), allowing a precise and narrow energy deposition in deep-seated tumors, minimizing the radiation effects in healthy surrounding tissues [1]. These ejected electrons can produce further ionizations, initiating an avalanche effect, leading to the energy transfer to sensitive biomolecular targets, such as DNA or proteins. But not only is the number of emitted electrons relevant, but also their energy spectrum, since, although high energy electrons are those capable of producing further ionizations, it has been shown that low energy electrons (below ionization threshold) can also produce damage to biomolecules by dissociative electron attachment [2,3].In order to reach a deeper understanding of ion beam cancer therapy from a fundamental point of view, a great amount of data is needed regarding several and very diverse processes, since the whole mechanism implies steps in very different energy, space, and time scales. Therefore, the problem must be studied within a multiscale approach [4], a fact that motivates an interdisciplinary effort within the European COST Action Nano-IBCT (Nanoscale insights into ion beam cancer therapy) to build a comprehensive database [5]. In this context, ionization data for a wide variety of projectile and organic target combinations, covering a broad range of incident and ejected energies, is needed in order to get insight into micro-and nanometric aspects of radiation damage to biomolecular systems. The aim of this Letter is to present a simple theoretical method that provides the above mentioned required ionization data with the use of little input information, based on the dielectric formalism [6] and some physically motivated approximations. Results are here presented for proton impact, although the methodology can be immediately extended to heavier ions, electrons, and other charged particles.Although several simple theoretical and semiempirical methods already exist nowadays to calculate the energy spectra of secondary electrons [7] (and are currently in us...

show abstract

“…Although it is usually considered that the dominant part of the secondary electrons are formed with rather low energies (below about 30 eV), the tail of their distributions can have a significant fraction of electrons with energies of the order of 10 2 eV. 3 Note also that an insight and accurate estimation of radiation damage produced by a specific type of high-energy particles represents an important part of research connected with cancer therapy. 4,5 For a better understanding a) E-mail: vraz@ipb.ac.rs.…”

Section: Introductionmentioning

confidence: 99%

Absolute cross sections for electron scattering from furan

Maljković

Blanco

Čurík

et al. 2012

The Journal of Chemical Physics

View full text Add to dashboard Cite

We report results of measurements and calculations of absolute cross sections for electron scattering from furan molecules (C 4 H 4 O). The experimental absolute differential cross sections (DCSs) for elastic electron scattering were obtained for the incident energies from 50 eV to 300 eV and for scattering angles from 20 o to 110 o , by using a crossed electron-target beam setup and the relative flow technique for calibration to the absolute scale. The calculations of the electron interaction cross sections are based on a corrected form of the independent-atom method, known as the screening corrected additivity rule (SCAR) procedure and using an improved quasifree absorption model. The latter calculations also account for rotational excitations in the approximation of a free electric dipole and were used to obtain elastic DCSs as well as total and integral elastic cross sections which are tabulated in the energy range from 10 to 10 000 eV. All SCAR calculated cross sections agree very well with both the present and previously published experimental results. Additionally, calculations based on the first Born approximation were performed to calculate both elastic and vibrationally inelastic DCSs for all the modes of furane, in the energy range from 50 eV to 300 eV. The ratios of the summed vibrational to elastic DCSs are presented and discussed. Finally, the present results for furan are compared with previously published elastic DCSs for the tetrahydrofuran molecule and discussed.

show abstract

Spectra of secondary electrons generated in water by energetic ions

Cited by 53 publications

References 34 publications

Absolute cross sections for elastic electron scattering from methylformamide

Absolute cross sections for elastic electron scattering from methylformamide

Semiempirical Model for the Ion Impact Ionization of Complex Biological Media

Absolute cross sections for electron scattering from furan

Contact Info

Product

Resources

About