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Title: Low energy light ion interactions

Abstract

Light ion reactions are of importance in many trans-disciplinary fields, particularly in cancer therapy and space radiation protection. We show here the results of an analysis of the spectra of intermediate mass fragments produced in the C+Al interaction at 13 MeV/n, both in direct and inverse kinematics, which supplies a very reasonable reproduction of a great number of data providing useful information on the leading reaction mechanisms.

Authors:
;  [1];  [2]; ; ;  [3];  [2]; ;  [4]; ; ;  [1];  [5]; ;  [6];  [7]
  1. Dipartimento di Fisica, Universita di Milano, Milan (Italy)
  2. (Italy)
  3. Dipartimento di Fisica Nucleare e Teorica, Universita di Pavia, Pavia, (Italy)
  4. INFN, Sezione di Milano, Milan (Italy)
  5. CERN, Geneva (Switzerland)
  6. iThemba LABS, Somerset West (South Africa)
  7. University of Houston, Houston, TX (United States)
Publication Date:
OSTI Identifier:
21054818
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 884; Journal Issue: 1; Conference: 6. Latin American symposium on nuclear physics and applications, Iguazu (Argentina), 3-7 Oct 2005; Other Information: DOI: 10.1063/1.2710583; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ALUMINIUM 27 TARGET; CARBON 12 REACTIONS; MEV RANGE; NUCLEAR FRAGMENTATION; NUCLEAR FRAGMENTS; NUCLEAR REACTION KINETICS; RADIATION PROTECTION

Citation Formats

Cerutti, F., Gadioli, E., INFN, Sezione di Milano, Milan, Ballarini, F., Mairani, A., Ottolenghi, A., INFN, Sezione di Pavia, Pavia, Battistoni, G., Sala, P. R., Colleoni, P., Garzelli, M. V., Pepe, A., Ferrari, A., Foertsch, S. V., Steyn, G. F., and Pinsky, L. S.. Low energy light ion interactions. United States: N. p., 2007. Web. doi:10.1063/1.2710583.
Cerutti, F., Gadioli, E., INFN, Sezione di Milano, Milan, Ballarini, F., Mairani, A., Ottolenghi, A., INFN, Sezione di Pavia, Pavia, Battistoni, G., Sala, P. R., Colleoni, P., Garzelli, M. V., Pepe, A., Ferrari, A., Foertsch, S. V., Steyn, G. F., & Pinsky, L. S.. Low energy light ion interactions. United States. doi:10.1063/1.2710583.
Cerutti, F., Gadioli, E., INFN, Sezione di Milano, Milan, Ballarini, F., Mairani, A., Ottolenghi, A., INFN, Sezione di Pavia, Pavia, Battistoni, G., Sala, P. R., Colleoni, P., Garzelli, M. V., Pepe, A., Ferrari, A., Foertsch, S. V., Steyn, G. F., and Pinsky, L. S.. Mon . "Low energy light ion interactions". United States. doi:10.1063/1.2710583.
@article{osti_21054818,
title = {Low energy light ion interactions},
author = {Cerutti, F. and Gadioli, E. and INFN, Sezione di Milano, Milan and Ballarini, F. and Mairani, A. and Ottolenghi, A. and INFN, Sezione di Pavia, Pavia and Battistoni, G. and Sala, P. R. and Colleoni, P. and Garzelli, M. V. and Pepe, A. and Ferrari, A. and Foertsch, S. V. and Steyn, G. F. and Pinsky, L. S.},
abstractNote = {Light ion reactions are of importance in many trans-disciplinary fields, particularly in cancer therapy and space radiation protection. We show here the results of an analysis of the spectra of intermediate mass fragments produced in the C+Al interaction at 13 MeV/n, both in direct and inverse kinematics, which supplies a very reasonable reproduction of a great number of data providing useful information on the leading reaction mechanisms.},
doi = {10.1063/1.2710583},
journal = {AIP Conference Proceedings},
number = 1,
volume = 884,
place = {United States},
year = {Mon Feb 12 00:00:00 EST 2007},
month = {Mon Feb 12 00:00:00 EST 2007}
}
  • Experimental spectra of intermediate mass fragments (IMFs) produced in the interaction of two {sup 12}C ions at incident energy of 200 MeV and their reproduction by a binary fragmentation model and the Boltzmann Master Equation theory as implemented into the Monte Carlo transport and interaction code FLUKA are shown.
  • An electron transmission technique has been employed to determine the positions of the three ..pi..-negative ion states (configurations ..pi../sub 1//sup 2/..pi../sup 2//sub 2/..pi../sup 2//sub 3/..pi../sub 4//sup 1/, ..pi../sup 2//sub 1/..pi../sup 2//sub 2/..pi../sup 2//sub 3/..pi../sup 1//sub 5/, and ..pi../sup 2//sub 1/..pi../sub 2//sup 2/..pi../sup 2//sub 3/..pi../sup 1//sub 6/) of benzene and fluorobenzenes in the vapor phase. These are 1.13 (1.35), 1.13 (1.35), (4.80) eV for benzene; 0.82 (0.91), (1.40), (4.66) eV for fluorobenzene; 0.53 (0.62), (1.41), (4.51) eV for p-difluorobenzene; (0.77), (0.77), (4.48) eV for 1,3,5-trifluorobenzene; 0.34, (0.50), (1.29), (4.51) eV for 2,3,5,6-tetrafluorobenzene; <0.15 (0.36), (1.19), (4.53) eV for pentafluorobenzene; and (0.42),more » (0.42), (4.50) eV for hexafluorobenzene. The numbers in parentheses are the vertical attachment energies, and those not in parentheses are the 0..-->..0 transitions. On the basis of these data, the first ..pi..-electron affinities (E.A.) of the isolated molecules of these compounds are equal to -1.13, -0.82, -0.53, >-0.77, -0.34, > or =-0.15, >-0.42 eV for benzene, fluorobenzene, difluorobenzene, 1,3,5-trifluorobenzene, 2,3,5,6-tetrafluorobenzene, pentafluorobenzene, and hexafluorobenzene, respectively. The present results, therefore, suggest that the ..pi..-electron affinity of C/sub 6/F/sub 6/ is <0.0 eV, although C/sub 6/F/sub 6/ is known to have a positive (+1.8 eV) E.A. and although the parent ion, C/sub 6/F/sub 6//sup -/*, is known to form with a very large electron attachment cross section at approx.0.0 eV and to be long lived (approx.12 ..mu..sec). These findings are reconciled, discussed in connection with previously published data, and are theoretically treated. They extend our understanding of the negative ion states of substituted benzenes.« less
  • A simple analytical model for ion-solid interactions, suitable for low energy beam depositions, is reported. An approximation for the nuclear stopping power is used to obtain the analytic solution for the deposited energy in the solid. The ratio of the deposited energy in the bulk to the energy deposited in the surface yields a ceiling for the beam energy above which more defects are generated in the bulk resulting in defective films. The numerical evaluations agree with the existing results in the literature. {copyright} {ital 1997 American Institute of Physics.}
  • The effect of chemistry on low energy recoil events was investigated at 10 K for each type of atom in pyrochlores using molecular dynamics simulation. Contour plots of the threshold displacement energy (Ed) in Gd2Zr2O7 have been produced along more than 80 directions for each individual species. The Ed surface for each type of atom in Gd2Zr2O7 is highly anisotropic; Ed of Zr exhibits the largest degree of anisotropy, while that of O8b exhibits the smallest. The recommended values of Ed in Gd2Zr2O7 based on the observed minima are 56, 94 and 25 eV, respectively for Gd, Zr and O.more » The influence of cation radius on Ed in pyrochlores A2B2O7 (with A-site ranging from Lu3+ to La3+ and B-site ranging from Ti4+ to Ce4+) was also investigated along three directions [100], [110] and [111]. The Ed in pyrochlores strongly depended on the atom type, atom mass, knock-on direction, and lattice position. The defects produced after low energy displacement events included cation antisite defects, cation Frenkel pairs, anion Frenkel pairs, various vacancies and interstitials. Ce doping in pyrochlores may affect the radiation response, because it resulted in drastic changes in cation and anion displacement energies and formation of an unusual type of anti-site defect. This work demonstrates links between Ed and amorphization resistance.« less
  • Low energy (10--300 eV) mass-selected C/sup +/ ion beams are used to deposit thin carbon films on surfaces of Si(100), Ni(111), Ta, W, and Au in a UHV environment at room temperature. The films are characterized by Auger electron spectroscopy (AES), x-ray and UV photoelectron spectroscopy (XPS and UPS), valence level electron energy loss spectroscopy (ELS), K-shell ionization loss spectroscopy (ILS), and ellipsometry. The initial monolayer of the deposited film is in the form of a carbide layer which is chemically bonded to the substrate atoms. The film evolves gradually over the next several layers deposited, through intermediate structures, intomore » a diamond-like structure. The diamond-like structure is confirmed by comparing the results of the above spectroscopic measurements with those of pure diamond and graphite and by referring to band structure calculations. A phase diagram, prepared as C/sup +/ ion dose vs C/sup +/ kinetic energy E/sub k/, shows the regions of the different structures. The optimum C/sup +/ energy range for formation of the diamond-like structure is 30--175 eV. Below 10 eV the final diamond-like structure has not been attained and above 180 eV there is a sharp increase in the dose required to attain this final structure. The films are found to be free of impurities, inert to O/sub 2/ chemisorption, structurally stable up to 350 /sup 0/C, have a low sputtering yield, and have a sharp interface with the substrate surface. The mechanism of film deposition and growth is discussed.« less