K-shell ionization cross sections of the elements Pr, Nd, Sm, Tm, Ta, and W for 1-3 MeV protons

The author attempted to measure with an improved degree of accuracy the values of the K-Shell ionization cross section, σKI, for selected elements in the region, 59 ≤ Z ≤ 74, using 1.0-3.0 MeV H+ as the projectiles. This is a region of the Periodic Table where due to the strong permanent deformations, βo, of the nuclear ground state, the values of the nuclear Coulomb excitation cross sections, σCE, become comparable in magnitude to the values of σKI for the direct atomic collision process. Not only are the two inelastic channels comparable in overall magnitude, but because the same nuclear states that are easily populated by CE tend to decay primarily by K-Shell internal conversion. This nuclear deexcitation process results in the emission of K x-rays which are identical to the K x-rays produced by the direct atomic ionization, DAI. This means that the yields of K x-rays produced in these types of collisions must be corrected for by either calculating the values of σCE or by measuring the yields of CE γ-rays. The portion of K x-rays arising from the CE channel can then be subtracted from the total yield of K x-rays. He has tried the strategy of using where possible isotopes which have smaller values of βo, and therefore smaller values of σCE, as a means of practically eliminating the CE contribution to the yield of K x-rays. Where no spherical isotopes exist, we have attempted to both calculate and to measure the yield of CE γ-rays to a high level of accuracy and then use the appropriate internal conversion coefficients, ICC. This was done to arrive at the true amount of K x-rays coming from CE