The cross sections of the ${\mathrm{Zr}}^{90}(p, 3p6n){\mathrm{Sr}}^{83}$ and ${\mathrm{Zr}}^{90}(p, 2p6n){\mathrm{Y}}^{83}$ reactions have been determined for proton energies of 60-240 Mev. The cross section for even-odd ${\mathrm{Sr}}^{83}$ production in the energy range 100-240 Mev is 1330-2140 times as large as that of odd-even ${\mathrm{Y}}^{83}$, as contrasted with much smaller values for the production of odd-odd and even-even isobars in similar reactions.

• Received 31 August 1959

DOI:https://doi.org/10.1103/PhysRev.122.1875