title: Discrimination of radiation quality through second harmonic out-of-phase cw-ESR detection.
abstract: The ability to discriminate the quality of ionizing radiation is important because the biological effects produced in tissue strongly depends on both absorbed dose and linear energy transfer (LET) of ionizing particles. Here we present an experimental electron spin resonance (ESR) analysis aimed at discriminating the effective LETs of various radiation beams (e.g., 19.3 MeV protons, (60)Co photons and thermal neutrons). The measurement of the intensities of the continuous wave spectrometer signal channel first harmonic in-phase and the second harmonic out-of-phase components are used to distinguish the radiation quality. A computational analysis, was carried out to evaluate the dependence of the first harmonic in-phase and second harmonic out-of-phase components on microwave power, modulation amplitude and relaxation times, and highlights that these components could be used to point out differences in the relaxation times. On the basis of this numerical analysis the experimental results are discussed. The methodology described in this study has the potential to provide information on radiation quality.
authors: a Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo, Italy and Gruppo V INFN Sezione di Catania, Via Santa Sofia, 64, Catania, 95123, Italy.
authors: Maurizio
authors: M
authors: Marrale
authors: Anna
authors: A
authors: Longo
authors: Maria
authors: M
authors: Brai
authors: Antonio
authors: A
authors: Barbon
authors: Marina
authors: M
authors: Brustolon
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D018499:Linear Energy Transfer; D008872:Microwaves; D011786:Quality Control; D011839:Radiation, Ionizing; D013997:Time Factors