Flux jumps in irradiated MgB$_{2}$ dense samples

This work shows magnetic flux jumps and changes in specific heat measurements studied in MgB$_{2}$ dense bulk samples irradiated: with $^{60}$Co (500 mrad), electrons (500 mrad), and protons (1x10$^{6}$ cm$^{2})$. Magnetic susceptibility measurements $\chi $(T) show that the Tc ($\sim $38.5 K) is independent of irradiation doses. M vs H data display flux jumps strongly dependent of the temperature. Specific heat measurements show an increase in the magnitude of Cp/T vs T curves just in the transition temperature for the irradiated protons, suggesting enhanced local disorder. The behavior of specific heat data at low temperature is analyzed using a two band model in order to clarify the effect of local disorder with the gap superconducting structure.