title: Radical distributions in ammonium tartrate single crystals exposed to photon and neutron beams.
abstract: The radiation therapy carried out by means of heavy charged particles (such as carbon ions) and neutrons is rapidly becoming widespread worldwide. The success of these radiation therapies relies on the high density of energy released by these particles or by secondary particles produced after primary interaction with matter. The biological damages produced by ionising radiations in tissues and cells depend more properly on the energy released per unit pathlength, which is the linear energy transfer and which determines the radiation quality. To improve the therapy effectiveness, it is necessary to grasp the mechanisms of free radical production and distribution after irradiation with these particles when compared with the photon beams. In this work some preliminary results on the analysis of the spatial distributions of the free radicals produced after exposure of ammonium tartrate crystals to various radiation beams ((60)Co gamma photons and thermal neutrons) were reported. Electron spin resonance analyses were performed by the electron spin echo technique, which allows the determination of local spin concentrations and by double electron-electron resonance technique, which is able to measure the spatial distance distribution (range 1.5-8 nm) among pairs of radicals in solids. The results of these analyses are discussed on the basis of the different distributions of free radicals produced by the two different radiation beams used.
authors.affiliation: Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Ed.18, I-90128 Palermo, Italy Gruppo V, INFN, Sezione di Catania, Catania, Italy maurizio.marrale@unipa.it.
authors.forename: M
authors.initials: M
authors.lastname: Marrale
authors.affiliation: Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Ed.18, I-90128 Palermo, Italy Gruppo V, INFN, Sezione di Catania, Catania, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Longo
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Padova, Via F. Marzolo 1, 35131 Padova, Italy Sezione di Padova Istituto Nazionale di Fisica Nucleare, Via Marzolo 8, 35131 Padova, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Barbon
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Padova, Via F. Marzolo 1, 35131 Padova, Italy Sezione di Padova Istituto Nazionale di Fisica Nucleare, Via Marzolo 8, 35131 Padova, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Brustolon
authors.affiliation: Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Ed.18, I-90128 Palermo, Italy Gruppo V, INFN, Sezione di Catania, Catania, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Brai
mesh_terms: D002244:Carbon / Q000627:therapeutic use; D003037:Cobalt Radioisotopes / Q000737:chemistry; D003460:Crystallization; D004578:Electron Spin Resonance Spectroscopy; D004583:Electrons; D005609:Free Radicals; D005720:Gamma Rays; D020450:Heavy Ions; D008280:Magnetics; D009502:Neutrons; D017785:Photons; D011839:Radiation, Ionizing; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods*; D013644:Tartrates / Q000737:chemistry*
chemical_list: D003037:Cobalt Radioisotopes; D005609:Free Radicals; D013644:Tartrates; D002244:Carbon; C029768:tartaric acid