Secondary electron emissionin protonUracil collision: preliminary results

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Secondary electron emission in proton-Uracil
collision preliminary results
P.Moretto-Capelle D.Bordenave-Montesquieu
A.Bordenave-Montesquieu(A.Rentenier) Future
members A.Lepadellec M.Richard-Viard IRSAMC,
LCAR, UMR 5589 CNRS-Univ.P.Sabatier118 rte de
Narbonne, 31062 TOULOUSE CEDEX, FRANCE
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Study of the damages created on bio molecules by
ion impact
Interaction of ions with matter possibility of
strong energy deposition in a well defined region
around the Bragg peak
?Treatment of Tumour Proton/Hadron therapy
Link between ion interaction and DNA damages?
Secondary electron emission
Radiolysis of Water H, HO
Fragmentation, ionization of bases
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Effects of secondary electrons
Boudaiffa, Science
Tracks
From GSI
Elt20eV
Huo et al Radiation2004
Ionization
Egt20eV
Dissociatif attachment
Initial electron spectrum??
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Our interestElectrons!

• H (H0) in the ?100keV energy range (Bragg peak)
• ?Spectroscopy and angular distribution (doubly
  differential cross sections) of secondary
  electrons emitted after ion-biomolecule
  interaction
• Biomolecule in gaz phaseH2O, Bases of RNA,
  DNA Uracil, Cytosine, Thymine
• ? Electron spectroscopy correlated with
  fragmentation
• Future Solvated biomolecule (coll M.and B.
  Farizon)
• Biomolecule on surface (M.Richard-Viard)

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Experimental apparatus
IonTime of flight spectrometer
Cylindrical electron analyser
High resolution electron spectrometer
Total electron detector
Oven
Ion beam 1-150keV Continuous Pulsed 5ns
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(No Transcript)
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First experimental results HUracil
Test of the Jet Fragmentation
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Electron spectroscopy H(100keV) Uracil
U
H2O
T
Denifl et al Chem.Phys.Lett 2003
C
Electron
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Collision energy dependence
Increase of ltelectron energygt with collision
energy
Corresponding intensity
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Link between electron emission and fragmentation?
Not yet investigated in ion / bio molecule
collision But in H3 C60 collision
Partial spectra
Electron spectrum depends of fragmentation
pattern Average energy of the electrons Stable
ions Evap/fission Multifragmentation ltEcgt19
eV 24 eV 28 eV
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Interpretation
Deposited energy (eV)
Intensity (arb.unit)
Electron energy (eV)
Impact parameter (ua)
Small impact parameter high energy electron AND
high energy deposited Large impact parameter low
energy electron AND low energy deposited
Key parameter impact parameter ? Biomolecules???
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Summary
?Spectroscopy of electrons emitted after H
biomolecules (DNA, RNA bases) in gas phase
?Correlation between electron spectroscopy and
fragmentation
For questions about this presentation, please
write to Patrick Moretto-Capelle pmc_at_irsamc.ups-tl
se.fr
I (PMC) would like to thank sincerely
M.Richard-Viard for the presentation of this talk
at the conference.