4月14日（周日）下午4点理化大楼6楼6017室
Interactions of charged particles and laser pulses with solids and surfaces
K. Tőkési
Institute of Nuclear Research, Hungarian Academy of Sciences (Atomki),
H-4001 Debrecen, P.O. Box 51, Hungary, EU
The key point of material science is the fundamental understanding of charged particles and electric magnetic field interactions with solids and surfaces. During the talk I will give a short overview of my recent investigations performed during the last few years. The presentation will cover the following topics: a) proton microbeam transmission through insulator single capillary, b) study of mouse bones and related compounds by electron Rutherford backscattering technique c) Time-resolved photoelectron emission from surfaces.
a) Charged particles, keeping their initial charge states, can be transmitted through an insulating capillary even if the capillary axis is tilted with respect to the incident beam axis larger than the geometrical limit. This phenomenon is called charged particle guiding. As a unique feature, we used the combination of single charged projectiles and single capillaries. The time dependent behavior of a 1 MeV proton microbeam passing through a Teflon single microcapillary was investigated. We identified three completely different regions in the transmission as a function of time. At first, at the beginning of the creation of the charge patch on the inner wall of the capillary, the energy spectra of the transmitted protons contained only inelastic contributions. This is due to Coulomb scattering on the inner wall atoms. Later the elastic peak also appears and becomes more and more significant. Finally, in the third region, after the amount of deposited charge on the wall reached a dynamical equilibrium, stable guided transmission was obtained.
b) Electron Rutherford backscattering (ERBS) is a new technique that could be developed into a tool of materials analysis. We establish a methodology for the use of ERBS for materials analysis of more complex samples using bone minerals. For this purpose we studied also several reference samples containing Ca: calcium carbonate, hydroxyapatite as well as mouse bone powder itself. A very good understanding of the spectra of calcium carbonate and hydroxyapatite was obtained. ERBS can become a useful tool to study bone mineralization. More in general this case study has shown that ERBS provides an interesting new favor of microanalysis, a technique that, we think, could have interesting applications, especially if it would be integrated in some kind of electron microscopy.
c) The attosecond streaking technique provides a unique tool to study the motion of particles with unprecedented accuracy. While originally developed for investigations of atomic systems streaking is now also applied to condensed-matter systems. As a last part of the talk we have concentrated on emission time delay due to transport effects for core and conduction band levels of metallic systems with electron energies of about 100 eV. We model the target as amorphous with bulk values for the atomic and electron densities together with quantum mechanically calculated cross sections providing information about scattering events (i.e. the mean free path) under the combined influences of crystal atoms, other target electrons, and the external pump and streaking fields. Good agreement between this semiclassical model and experimental results was reached.
Curriculum vitae
Károly Tőkési
Personal Data:
Date of Birth: February 9, 1962
Birthplace:
Citizenship: Hungarian
Marital Status: Married
Name of Wife: Mária Dudás (financial director, economic and financial expert,
computer mathematician)
Children: son Gergely, born in 1987, daughter, Alexandra born in 1989,
daughter, Nikoletta born in 1990.
Permanent home address: H-4032 Debrecen, Kürtgyarmat u. 56,
Permanent office address:
of the
(ATOMKI),
H-4001
Education:
Habilitation, Institute of Nuclear Research of the
Ph.D. equivalent in Physics,
Dr.Univ. in Physics,
M.Sc. in Physics,
Permanent Position:
Scientific adviser,
Research Experience:
Electronoptics
Electron spectroscopy
Electron-atom, ion-atom collision studies
Classical Trajectory Monte Carlo calculations
Electron energy loss spectroscopy
XPS and Auger spectroscopy
Simulation of electron spectra using
Experiences in developing programs using FORTRAN programming languages
Teaching Experience:
I was a supervisor for 11 graduate students working on their M.Sc. degree and 6 PhD students.
Awards:
1992 � Award for young Scentists from the Hungarian Acedemy of Science
1997 - Award for young Scentists from the Hungarian Acedemy of Science
2005 - the grant "Bolyai" from the Hungarian Academy Sciences -prominent qualification
2006 - Bolyai- plaquette - Hungarian Acedemy of Science
2008 �Szalay Sándor award - Roland Eötvös Physical Society
2010 - the grant "Bolyai" from the Hungarian Academy Sciences -prominent qualification
Referee works for international journals:
Physical Review Letters
Physical Review A
Physical Review B
Journal of Electronspectroscopy and Related Phenomena
Surface Science
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
Physica Scripta
Role in scientific community
2007 - board member of the Roland Eötvös Physical Society
2008 - 2012 Management Committee member of Cost Action CM0702, Chemistry with Ultrashort Pulses and Free-Electron Lasers: Looking for Control Strategies Through ”Exact” Computations
2009 - Member of the International Advisory Board of the International Conference on, the Physics of Electronic and Atomic Collisions (ICPEAC)
2009- Member of the International Advisory Board of the International Conference on the Physics of Highly Charged Ions (HCI)
2012- Management Committee member of Cost Action CM1204, XUV/X-ray light and fast ions for ultrafast chemistry (XLIC)
Present Research:
Studies of the interactions of highly charged ions with surfaces.
Investigation of the energy loss of ions in grazing interaction with the capillary walls.
Investigation of laser-atom, laser-molecule collisions.
Programming in languages:
FORTRAN,
Knowledge of languages:
English (state examination)
Publications:
517 in referred journals or volumes
3 book chapter
835 fully independent citations
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