[en] This paper aims to a better understanding of the effect of ionizing radiation on carbon nanotubes. High purity Single Wall Carbon Nanotubes (SWNTs) from Carbon Nanotechnology Incorporated (CNI) were irradiated with accelerated proton, helium and neon ions, at room temperature. The energy of the incoming beam was calculated to fully stop the impinging particles in the SWNT film. The nature of radiation - induced modifications has been investigated by Electron Spin Resonance (ESR) spectroscopy, utilizing a Bruker EMX spectrometer operating in X band (∼9.5 GHz). The temperature dependence of the ESR line parameters (such as g value, resonance linewidth, line amplitude, and double integral of the resonance line) of pristine and irradiated SWNTs in the temperature range 25 K to 300 K is reported. The ESR data are correlated with additional data obtained by Raman spectroscopy and thermal analysis on the same samples. All these results indicated an increase of SWNTs degradation as the atomic mass of the impinging particle is increased from 1 (proton) to 20 (neon). The observed correlation between ESR data and Raman spectroscopy results will be analyzed in detail