2007 Fiscal Year Final Research Report Summary
Study of damaging processes induced by direct core-excitations of DNA using electron spectroscopy
| Project/Area Number |
18540326
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics I
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| Research Institution | High Energy Accelerator Research Organization |
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Principal Investigator |
KAZUHIKO Mase High Energy Accelerator Research Organization, Institute of Materials Structure Science, Associate Professor (40241244)
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| Co-Investigator(Kenkyū-buntansha) |
KOBAYASHI Eiichi High Energy Accelerator Research Organization (KEK), Kyushu Synchrotron Light Research Center, Researcher (80319376)
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| Project Period (FY) |
2006 – 2007
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| Keywords | Photoemission spectroscopy / DNA / Auger electron spectroscopy / Synchrotron radiation / Auver-photoelectron coincidence suectroscopy / electron-ion coincidence spectroscopy |
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| Research Abstract |
Study of radiation-induced damaging processes of DNA is an important topic in radiation biology. The elucidation of the processes in atomic levels using electron spectroscopy, however, is a frontier field. The damaging processes are -roughly classified into two categories; one is the direct damaging processes induced by the electronic transitions of DNA itself; and the other is indirect processes induced by radicals formed by electric transitions of molecules surrounding DNA such as water. For the direct processes, the following three-step process, i. e., core-excitations, Auger processes, and ion desorption (Auger-stimulated ion desorption) is thought to play an important role. The aim of the present study is to investigate core-excitations, Auger processes, and ion desorption of DNA using X-ray photoelectron spectroscopy, ion kinetic energy measurements, and coincidence spectroscopy, and to clarify the processes of chemical bond breaking induced by direct core-excitations of DNA.
We measured photoelectron photoion coincidence spectra and Auger-photoelectron coincidence spectra of DNA thiol self-assembled on gold surfaces. However most of the coincidence signals were smeared out by the accidental coincidence signals except for C-KVV-Auger-C-1s-photoelectron coincidence spectra. Since the signal/accidental ratio of the present coincidence spectrometer was found to be not sufficient enough, we have developed an improved apparatus for coincidence spectroscopy. We have improved an apparatus for the photoelectron spectroscopy at PF713L11D.
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