K-ALPHA X-RAY YIELD FROM ALPHA-PARTICLE BOMBARDMENT OF THICK TARGETS

Numerical and experimental investigations have been conducted on the generation of intense sources of monochromatic X-rays via bombardment of thick targets of pure elemental composition by alpha particle beams with energy of tens of MeV. The present results extend a previous study made with protons. The thick target K(alpha) yield bas been calculated for 62 elements, for energies of the incident ions ranging from 1 MeV to 100 MeV and polynomial approximations for the yield functions have been deduced. Experimental measurements on Mo, Cd and Ta for bombarding energies between 15 and 36 MeV have been compared with the numerical predictions. Satellite X-ray lines have been observed in Cd and Ta spectra, which are particularly intense in the case of the latter clement. Measurements on Ta and Pb made with protons of the same energy have shown that the phenomenon is much weaker than in alpha induced reactions. It is concluded that alpha particles are advantageous over protons in producing very intense monochromatic sources with targets of low-medium atomic number.