1. 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.Sabatier 118 rte de Narbonne, 31062 TOULOUSE CEDEX, FRANCE

2. 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 Energetic ion e-e- Link between ion interaction and DNA damages? Fragmentation, ionization of bases Radiolysis of Water H, HO Secondary electron emission

3. Effects of secondary electrons… Dissociatif attachment Huo et al Radiation2004 Tracks: E<20eV E>20eV Initial electron spectrum?? Boudaiffa, Science From GSI Ionization

4. Our interest…Electrons! H + (H 0 ) 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:H 2 O, 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)

5. Experimental apparatus Cylindrical electron analyser ‘Total’ electron detector Oven IonTime of flight spectrometer Ion beam 1-150keV *Continuous *Pulsed 5ns High resolution electron spectrometer

7. First experimental results: H + +Uracil Test of the Jet: Fragmentation

8. Electron spectroscopy: H + (100keV) + Uracil e-e- H+H+ 35° Denifl et al Chem.Phys.Lett 2003 H2OH2O C T U Electron

9. Collision energy dependence Increase of with collision energy Corresponding intensity

10. Link between electron emission and fragmentation? Not yet investigated in ion / bio molecule collision… But in H 3 + + C 60 collision Partial spectra Electron spectrum depends of fragmentation pattern Average energy of the electrons: Stable ions Evap/fission Multifragmentation =19 eV 24 eV 28 eV

11. Interpretation Electron energy (eV) Impact parameter (ua) Deposited energy (eV) Intensity (arb.unit) 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???

12. Summary For questions about this presentation, please write to Patrick Moretto-Capelle pmc@irsamc.ups-tlse.fr  Spectroscopy of electrons emitted after H + + biomolecules (DNA, RNA bases) in gas phase  Correlation between electron spectroscopy and fragmentation I (PMC) would like to thank sincerely M.Richard-Viard for the presentation of this talk at the conference.