Decay ofP35

Abstract

The $\ensuremath{\beta}$ decay of $^{35}\mathrm{P}$ to levels of $^{35}\mathrm{S}$ has been studied with a large-volume Ge(Li) detector and a gas-flow proportional counter. The $^{35}\mathrm{P}$ was produced via the $^{37}\mathrm{Cl}(t,\ensuremath{\alpha}p)^{35}\mathrm{P}$ reaction by bombardment of NaCl and LiCl targets with 16-MeV tritons, and was chemically separated by conversion to phosphate ion and adsorption on a selective polyvalent anion exchanger. The half-life was measured to be 47.4 \ifmmode\pm\else\textpm\fi{} 0.8 sec. Only one $\ensuremath{\gamma}$ transition was observed, at 1572.2 \ifmmode\pm\else\textpm\fi{} 0.4 keV. The $^{35}\mathrm{P}$ decays ${99}_{\ensuremath{-}7}^{+10}$% ($logft=4.1\ifmmode\pm\else\textpm\fi{}0.1$) to the 1572-keV ${\frac{1}{2}}^{+}$ first excited level of $^{35}\mathrm{S}$ and 9% ($log\mathrm{ft}6.1$) to the ${\frac{3}{2}}^{+}$ ground state, whence its spin-parity is deduced to be ${\frac{1}{2}}^{+}$. Less than 0.45% of the $\ensuremath{\beta}$ transitions proceed to any of the other known $^{35}\mathrm{S}$ levels. The results are compared with the predictions of a recent shell-model treatment.