221Rn decay

The α-, β- - and γ-spectra of the decay of 221Rn in equilibrium with 221Fr are investigated. For measuring the α-spectrum a magnetic α-spectrograph is used; for the γ-spectrum - a Ge(Li) detector; for the spectrum of the conversion electrons - a Si(Li) detector. The α-groups are determined by the half-life. 221Fr and 217Po transitions arising in the β- - and α-decays of 221Rn are first investigated. A table of the energies, intensivities and multipolarities observed in the decay is given. The distribution of the 2221Fr and 217Po transition is also shown. The scheme and quantum characteristics of the 221Fr levels are discussed. An analysis of the results shows that the share of α-decay of 221Rn comprises 22+-1% and the share of β- - decay of 217Po comprises no more than 5% (theoretical estimate - no more than 2%). The chain of the 221Rn decay is discussed