Alpha decay of 221Rn and 217Po;: level structure of 217Po and the 213Pb ground state

Alpha recoil sources of Rn-221 were used to study the level structure of Po-217 and the ground state of Pb-213. The half-life of Po-217 was measured to be (1.6 +/- 0.2) s. When combined with unpublished data, an alpha-decay hindrance factor (HF) of 1.3 was obtained for the alpha-decay, strongly suggesting a g(9/2) --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 between Po-217 and Pb-213 ground states. Alpha-gamma coincidence studies confirm the previously observed 11/2(+) band head in Po-217. It is suggested that an unobserved 9/2(+) ground state lies below the 11/2(+) state in Po-217 and an attempt is made to observe connecting links between these two parts of the Po-217 level scheme.