β-Rays from Radioactive Isotopes, Ni⁶³, Zn⁶³, Zn⁶⁵, Zn⁶⁹, Zn⁶⁹, Ga⁶⁸, Ga⁷⁰, Ga⁷², Ge⁷¹, Ge⁷⁵ and Ge⁷⁷

抄録

The β-ray spectra of Ni⁶³, Zn⁶³, Zn⁶⁵, Zn⁶⁹ (57 m), Zn⁶⁹ (13.8 h), Ga⁶⁸, Ga⁷⁰, Ga⁷², Ge⁷¹, Ge⁷⁵ and Ge⁷⁷ have been investigated, by measuring the curvature of the tracks in a cloud chamber situated in a known magnetic field. The upper limit derived from K-U plots are summarised as follows.
Ni⁶³ 2.5h e^- 1.65 × 10⁶ eV 0.67 × 10⁶ eV
Zn⁶³ 35m e⁺ 1.92 × 10⁶ eV
Zn⁶⁵ 210d e⁺ 0.37 × 10⁶ eV 0.19 × 10⁶ eV
Zn⁶⁹ 57m e^- 0.99 × 10⁶ eV
Zn⁶⁹ 13.8h e^- 0.99 × 10⁶ eV
Ga⁶⁸ 66m e⁺ 1.37 × 10⁶ eV
Ga⁷⁰ 20m e^- 1.68 × 10⁶ eV
Ga⁷² 14h e^- 1.71 × 10⁶ eV
Ge⁷¹ 26h e⁺ 1.15 × 10⁶ eV
Ge⁷⁵ 81m e^- 1.10 × 10⁶ eV
Ge⁷⁷ 8h e^- 1.92 × 10⁶ eV

From the consideration of energy balance, the minimum neutron energies to produce neutron loss processes-, for Cu⁶², Zn⁶³ and Ga⁶⁸ are estimated roughly to be 12.7, 9.8 and 9.0 MeV respectively, which are in good agreement with the values reported by one of the authors except the last case.