Alpha decay of221Rn and217Po; level structure of217Po and the213Pb ground state

Alpha recoil sources of²²¹Rn were used to study the level structure of²¹⁷Po and the ground state of²¹³Pb. The half-life of²¹⁷Po was measured to be (1.6±0.2) s. When combined with unpublished data, an alpha-decay hindrance factor (HF) of 1.3 was obtained for the alpha-decay, strongly suggesting a g_9/2 → g_9/2 transition between²¹⁷Po and²¹³Pb ground states. Alpha-gamma coincidence studies confirm the previously observed 11/2⁺ band head in²¹⁷Po. It is suggested that an unobserved 9/2⁺ ground state lies below the 11/2⁺ state in²¹⁷Po and an attempt is made to observe connecting links between these two parts of the²¹⁷Po level scheme.