Evaluation of DNA damage induced by Auger electrons from Cs

Watanabe, Ritsuko; Hattori, Yuya; Kai, Takeshi

International Journal of Radiation Biology, 92(11), p.660 - 664, 2016/11

https://doi.org/10.3109/09553002.2015.1136853

To understand the effect of internal exposure of Cs, we focus on estimation of microscopic energy deposition pattern and DNA damage induced by directly emitted electrons (beta-rays, internal conversion electrons, Auger electrons) from Cs. Monte Carlo track simulation method was used to calculate the microscopic energy deposition pattern. To simulate the energy deposition by directly emitted electrons, we considered the multiple ejections of electrons after internal conversion. Induction process of DNA strand breaks and base lesions was modeled and simulated using Monte Carlo methods for cell mimetic condition. The yield and spatial distribution of simple and complex DNA damage were calculated for the cases of -rays and electrons from Cs. The simulation showed that significant difference of DNA damage spectrum was not caused by the difference between secondary electron spectrum by -rays and directly ejected electron spectrum. The result support that the existing evaluation that internal exposure and external exposure are almost equivalent.

Yields of strand breaks and base lesions induced by soft X-rays in plasmid DNA

Yokoya, Akinari; Fujii, Kentaro; Ushigome, Takeshi; Shikazono, Naoya; Urushibara, Ayumi; Watanabe, Ritsuko

Radiation Protection Dosimetry, 122(1-4), p.86 - 88, 2006/12

https://doi.org/10.1093/rpd/ncl408

We have studied yields of DNA damages induced by soft X-rays obtained from a conventional soft X-ray machine in a LET region between -rays and ultrasoft X-rays. Practically soft X-rays with a broad energy spectrum emitted from a target of heavy metal, such as tungsten, have been widely used not only for radiobiological experiments but also for medical application such as mammography. Radiation weighting factors for these soft X-rays have been assigned to be 1 by ICRP. However, the fraction of a large number of low energy photons in the spectrum (below several tens keV) provided by bremsstrahlung is expected to be more effective for DNA damage induction than -rays since low energy photo- and Auger electrons predominantly ejected in consequence of a photoelectric effect can produce dense clusters of ionization/excitation on DNA molecules. We have examined the yield of DNA strand breaks induced by white soft X-rays (150 kVp, tungsten target). Yields of base lesions revealed by base excision repair enzymes will be also presented.

X-ray-induced ion desorption from solid surfaces

Baba, Yuji

Trends in Vacuum Science & Technology, Vol.5, p.45 - 74, 2002/10

This article reviews recent works on the ion desorption from solid surfaces induced by the irradiation of soft X-rays ranging from 100 eV to 3 keV. The data presented here are focused on the positive ion desorption from adsorbed, condensed, and solid molecules following the core-level excitations. The element-specific and site-specific fragment-ion desorptions are clearly realized, when we tune the photon energy at the core-to-valence resonance regions. The specificity of the ion desorption more clearly shows up following the deep-core excitations, i.e., 1s4p resonant excitations in third-row elements, rather than the shallow-core excitations. Since the main decay channels after the core-level excitation are the Auger transitions, the Auger decay spectra excited by the photons around the core-level thresholds are also presented for some of the adsorbed systems. The mechanism of the observed highly specific ion desorption is discussed on the basis of the photon-energy dependencies of the electron and ion yields and the analysis of the Auger decay spectra.

Polarization dependence of carbon K-edge NEXAFS spectra of formate on Si(100)

Sekiguchi, Hiromi*; Sekiguchi, Tetsuhiro

Photon Factory Activity Report 1998, Part B, P. 220, 1998/11

http://ccdb5fs.kek.jp/cgi-bin/img/tiff2gif?199823003+00238

no abstracts in English

Resonant Auger electron spectroscopy for analysis of the chemical state of phosphorus segregated at SiO/Si Interfaces

Oshima, Masaharu*; *; Ono, Kanta*; Fujioka, Hiroshi*; *; Baba, Yuji; Yoshii, Kenji; Sasaki, Teikichi

Journal of Electron Spectroscopy and Related Phenomena, 88-91, p.603 - 607, 1998/00

https://doi.org/10.1016/S0368-2048(97)00169-2

no abstracts in English

Surface photochemical reaction in adsorbed molecules induced by synchrotron soft X-ray

Baba, Yuji; Yoshii, Kenji; Yamamoto, Hiroyuki; Sasaki, Teikichi; W.Wurth*

Material Chemistry 96: Proc. of Int. Symp. on Material Chemistry in Nuclear Environment, 0, p.391 - 399, 1996/00

no abstracts in English

Measurement of secondary electron emission coefficient of wall materials using auger electron spectromter

Hiroki, S.; ; ; Murakami, Yoshio

Shinku, 30(1), p.14 - 21, 1987/01

https://doi.org/10.3131/jvsj.30.14

no abstracts in English

Measurement of Secondary Electron Emission Coefficient of Wall Materials Using Auger Electron Spectroscopy

Hiroki, S.; ; *; ; Murakami, Yoshio

JAERI-M 85-123, 23 Pages, 1985/08

JAERI-M-85-123.pdf:0.71MB

no abstracts in English

Transmission sputtering of titanium by 114MeV fluorine ions

; ; ; Aruga, T.

Journal of Nuclear Materials, 132, p.95 - 97, 1985/00

https://doi.org/10.1016/0022-3115(85)90401-5

no abstracts in English

X-Ray Photoelectron and X-Ray-Induced Auger Electron Spectroscopic Data, I; 3d Transition-Metals(Sc,Ti,V,Ni)and Related Oxides

;

JAERI-M 84-005, 37 Pages, 1984/02

JAERI-M-84-005.pdf:0.57MB

no abstracts in English