Multiple ionization effect of Ta induced by heavy ions

The M X-ray spectra of Ta induced by H+, He2+, Ar11+ and Xe20+ are measured in Heavy Ion Research Facility in Lanzhou. The intensities of M-gamma (M3N5) and M-alpha beta (M4,5N6,7), i.e. I-gamma and I-alpha beta, are also derived from the spectra. It is found that the intensity ratio of I-gamma/I-alpha beta increases with the increase of projectile atomic number. The results show that the M-3-subshell fluorescence yield omega(3) of Ta target is greatly enhanced, owing to multiple ionization effect in collision with heavy ions.