New neutron-deficient Pb and Bi nuclides produced in cross bombardments with heavy ions

Abstract

New $\alpha$ -emitting bismuth nuclides ranging in mass number from 189 to 197 and lead nuclides ranging from 186 to 192 have been produced in the following reactions: ${}_{}{}^{203}{}_{}{}^{}\mathrm{Tl}{({}_{}{}^3{}_{}{}^{}\mathrm{He},xn)}^{206-x}\mathrm{Bi}$, ${}_{}{}^{187}{}_{}{}^{}\mathrm{Re}{({}_{}{}^{16}{}_{}{}^{}\mathrm{O},xn)}^{205-x}\mathrm{Bi}$, ${}_{}{}^{185}{}_{}{}^{}\mathrm{Re}{({}_{}{}^{16}{}_{}{}^{}\mathrm{O},xn)}^{203-x}\mathrm{Bi}$, ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}{({}_{}{}^{20}{}_{}{}^{}\mathrm{Ne},xn)}^{201-x}\mathrm{Bi}$, ${}_{}{}^{159}{}_{}{}^{}\mathrm{Tb}{({}_{}{}^{40}{}_{}{}^{}\mathrm{Ar},xn)}^{199-x}\mathrm{Bi}$, ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}{({}_{}{}^{19}{}_{}{}^{}\mathrm{F},xn)}^{200-x}\mathrm{Pb}$, ${}_{}{}^{182}{}_{}{}^{}\mathrm{W}{({}_{}{}^{16}{}_{}{}^{}\mathrm{O},xn)}^{198-x}\mathrm{Pb}$ and ${}_{}{}^{155}{}_{}{}^{}\mathrm{Gd}{({}_{}{}^{40}{}_{}{}^{}\mathrm{Ar},xn)}^{195-x}\mathrm{Pb}$. Assignments were made on the basis of excitation function measurements and comparison with similar reactions leading to the formation of the analogous well-known Po nuclides. The following assignments were made, where for each nuclide the two listed numbers are the $\alpha$-ray energy in MeV and half-life: ${}_{}{}^{197}{}_{}{}^{}\mathrm{Bi}_{}^m{}_{}{}^{}$—5.77, 10 min; ${}_{}{}^{195}{}_{}{}^{}\mathrm{Bi}$-5.43, 170 sec; ${}_{}{}^{195}{}_{}{}^{}\mathrm{Bi}_{}^m{}_{}{}^{}$—6.11, 90 sec; ${}_{}{}^{194}{}_{}{}^{}\mathrm{Bi}$-5.61, 105 sec; ${}_{}{}^{193}{}_{}{}^{}\mathrm{Bi}$-5.90, 64 sec; ${}_{}{}^{193}{}_{}{}^{}\mathrm{Bi}_{}^m{}_{}{}^{}$—6.18; ${}_{}{}^{192}{}_{}{}^{}\mathrm{Bi}$-6.06, 42 sec; ${}_{}{}^{191}{}_{}{}^{}\mathrm{Bi}$-6.32, 13 sec; ${}_{}{}^{191}{}_{}{}^{}\mathrm{Bi}_{}^m{}_{}{}^{}$—6.63; ${}_{}{}^{191}{}_{}{}^{}\mathrm{Bi}_{}^m{}_{}{}^{}$—6.86; ${}_{}{}^{190}{}_{}{}^{}\mathrm{Bi}$-6.45, 5.4 sec; ${}_{}{}^{189}{}_{}{}^{}\mathrm{Bi}$-6.67, ${}_{}{}^{192}{}_{}{}^{}\mathrm{Pb}$-5.06, 2.3 min; ${}_{}{}^{191}{}_{}{}^{}\mathrm{Pb}$-5.29, 1.3 min; ${}_{}{}^{190}{}_{}{}^{}\mathrm{Pb}$-5.58, 1.2 min; ${}_{}{}^{189}{}_{}{}^{}\mathrm{Pb}$-5.72, 51 sec; ${}_{}{}^{188}{}_{}{}^{}\mathrm{Pb}$-5.98, 26 sec; ${}_{}{}^{187}{}_{}{}^{}\mathrm{Pb}$-6.08, 17 sec; and ${}_{}{}^{186}{}_{}{}^{}\mathrm{Pb}$-6.32, 8 sec. Estimates of $\alpha$ branching ratios are also presented.