K -Electron Capture in Radioactive Argon A 37
1944; American Institute of Physics; Volume: 66; Issue: 7-8 Linguagem: Inglês
10.1103/physrev.66.209
ISSN1536-6065
AutoresP.K. Weimer, J. D. Kurbatov, M. L. Pool,
Tópico(s)Quantum, superfluid, helium dynamics
ResumoA radioactive gas possessing a half-life of 34.1\ifmmode\pm\else\textpm\fi{}0.3 days has been produced by bombarding solid samples containing potassium, chlorine, calcium, or sulfur. The observed data require that this activity be assigned to ${\mathrm{A}}^{37}$ in accord with the following reactions: ${{\mathrm{K}}^{39}+{\mathrm{H}}^{2},\ensuremath{\rightarrow}{\mathrm{A}}^{37}+{\mathrm{He}}^{4}}{{\mathrm{Cl}}^{37}+{\mathrm{H}}^{2},\ensuremath{\rightarrow}{\mathrm{A}}^{37}+2n}{{\mathrm{Cl}}^{37}+{\mathrm{H}}^{1},\ensuremath{\rightarrow}{\mathrm{A}}^{37}+n}{{\mathrm{S}}^{34}+{\mathrm{He}}^{4},\ensuremath{\rightarrow}{\mathrm{A}}^{37}+n}{{\mathrm{Ca}}^{40}+n,\ensuremath{\rightarrow}{\mathrm{A}}^{37}+{\mathrm{He}}^{4}.}$ Alpha-bombardment of chlorine has failed to produce a measurable quantity of this activity by an ($\ensuremath{\alpha},d$) reaction. The detection of 4.72A Cl $K\ensuremath{\alpha}$ x-rays by means of critical absorption measurements in gaseous compounds of chlorine and sulfur reveals that ${\mathrm{A}}^{37}$ decays by $K$-electron capture. Cloud-chamber observations and aluminum absorption measurements indicate that $K$-electron capture accounts for more than 99.9 percent of the total number of disintegrations. The probability of the x-ray quantum being internally converted has been calculated to be 0.96\ifmmode\pm\else\textpm\fi{}0.03. No gamma-rays were observed.
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