A New Mass Spectrograph and the Isotopic Constitution of Nickel

A new double focusing mass spectrograph which has a 90° electric field and a 60° magnetic field has been constructed and used to determine the isotopic constitution of nickel. The instrument and the null method of measurement are described. The isotopic constitution of nickel is found to be ${\mathrm{Ni}}^{58}$-62.8 percent ${\mathrm{Ni}}^{60}$-29.5 percent, ${\mathrm{Ni}}^{61}$-1.7 percent, ${\mathrm{Ni}}^{62}$-4.7 percent, ${\mathrm{Ni}}^{64}$-1.3 percent.