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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
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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
Energetic ion e- 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
Effects of secondary electrons… Boudaiffa, Science Tracks: From GSI E<20eV Ionization Huo et al Radiation2004 E>20eV Dissociatif attachment Initial electron spectrum??
Our interest…Electrons! 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 phase:H2O, 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)
Experimental apparatus IonTime of flight spectrometer Cylindrical electron analyser High resolution electron spectrometer ‘Total’ electron detector Oven Ion beam 1-150keV *Continuous *Pulsed 5ns
First experimental results: H++Uracil Test of the Jet: Fragmentation
H+ e- 35° Electron spectroscopy: H+(100keV) + Uracil U T H2O Denifl et al Chem.Phys.Lett 2003 C Electron
Collision energy dependence Increase of <electron energy> with collision energy Corresponding intensity
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 <Ec>=19 eV 24 eV 28 eV
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???
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@irsamc.ups-tlse.fr I (PMC) would like to thank sincerely M.Richard-Viard for the presentation of this talk at the conference.