Results are reported on the measurement of the radiations from the 2.55-min activity in ${\mathrm{P}}^{30}$, the 32.40±0.04 min activity in ${\mathrm{Cl}}^{34}$ and the 7.7-min activity in ${\mathrm{K}}^{38}$ by means of a large double-lens spectrometer and a NaI scintillation spectrometer. ${\mathrm{P}}^{30}$ has a simple positron spectrum with end point at 3.24±0.04 Mev and no gamma rays or conversion electrons. ${\mathrm{Cl}}^{34}$ has a complex positron spectrum with end points at 4.50±0.03 Mev 2.48±0.07 Mev, and 1.33±0.10 Mev. ${\mathrm{K}}^{38}$ has a simple positron spectrum with end point at 2.68±0.04 Mev and no conversion electrons. These results indicate an $\mathrm{ft}$ value for the ground ($T=1\mathrm{}$) state of ${\mathrm{Cl}}^{34}$ of 3160±120 sec, and indicate that the ground states of ${\mathrm{P}}^{30}$ and ${\mathrm{K}}^{38}$ are probably the $T=0\mathrm{}$ states.

• Received 6 September 1955

DOI:https://doi.org/10.1103/PhysRev.101.776