Artificial Radioactivity of Ti 45
1941; American Institute of Physics; Volume: 60; Issue: 6 Linguagem: Inglês
10.1103/physrev.60.425
ISSN1536-6065
AutoresJ. S. Allen, M. L. Pool, J. D. Kurbatov, L. L. Quill,
Tópico(s)Chemical Reactions and Isotopes
ResumoA radioactive isotope possessing a half-life of 3.08\ifmmode\pm\else\textpm\fi{}0.06 hours has been produced by four different types of bombardment. Evidence is presented which indicates that the activity should be assigned to ${\mathrm{Ti}}^{45}$. The four nuclear reactions are: ${{\mathrm{Ca}}^{42}+{\mathrm{He}}^{4},\ensuremath{\rightarrow}{\mathrm{Ti}}^{45}+{n}^{1} {\mathrm{Sc}}^{45}+{\mathrm{H}}^{2}\ensuremath{\rightarrow}{\mathrm{Ti}}^{45}+2{n}^{1}}{{\mathrm{Sc}}^{45}+{\mathrm{H}}^{1},\ensuremath{\rightarrow}{\mathrm{Ti}}^{45}+{n}^{1} {\mathrm{Ti}}^{46}+{n}^{1}\ensuremath{\rightarrow}{\mathrm{Ti}}^{45}+2{n}^{1}.}$ Nuclear spin considerations indicate that a fifth reaction, ${\mathrm{Ti}}^{46}(\ensuremath{\gamma},n){\mathrm{Ti}}^{45}$, is improbable, as was verified experimentally. Analysis of cloud-chamber pictures reveals the maximum positron energy to be 1.2 Mev. On a Sargent diagram, the reaction ${\mathrm{Ti}}^{45}\ensuremath{\rightarrow}{\mathrm{Sc}}^{45}+{e}^{+}$, is a permitted one. The half-life of 3.08\ifmmode\pm\else\textpm\fi{}.06 hours for ${\mathrm{Ti}}^{45}$ is the weighted average of 3.17, 3.10, and 3.02 hours from $\mathrm{Sc}(p,n)$; 3.04 hours from $\mathrm{Sc}(d,2n)$; 3.17 hours from $\mathrm{Ca}(\ensuremath{\alpha},n)$; 3.0 hours from $\mathrm{Ti}(n,2n)$.
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