Nuclear Structure ofZr90

Beta- and gamma-ray spectroscopy, utilizing both single and coincident NaI(Tl) crystals and a magnetic spectrometer, has been used to study the radiations from ${\mathrm{Nb}}^{90}$. The positron spectrum was resolved into components of 1.505 and 0.655 Mev; the internal-conversion electron spectrum was obtained, from which gamma-ray transitions of 0.132, 0.141, 0.372, 1.13, and 2.34 Mev were determined. The internal-conversion electron spectrum characteristic of the 1.76-Mev monopole transition in ${\mathrm{Zr}}^{90}$ was also seen. The scintillation gamma-ray spectrum was resolved into components of 2.32, 2.19, 2.0, 1.85, 1.60, 1.48, 1.27, 1.13, 1.1, 0.89, 0.372, (0.43), 0.142, 0.133 Mev.