Proton states, anomalous conversion, and K-Auger spectra in 241Am from 241Cm (electron capture) and 245Bk (α) decays

γ and conversion-electron spectra of mass-separated ²⁴¹Cm (32.8 day) samples were measured at high resolution with Ge(Li) detectors and a magnetic β-ray spectrometer; 28 γ rays and 76 conversion lines were identified. The multipolarities of most of the 28 transitions in ²⁴¹Am were deduced. Two-parameter γ-γ coincidences confirmed a level scheme incorporating all transitions in six rotational bands. The observed half-life of ²⁴¹Cm via the decay of the 471.8 keV γ ray was 32.8 ± 0.2 day. The α branching deduced from the measurements of L₂ and L₃ electron lines of the 145.5 keV transition in ²³⁷Pu was (1.0 ± 0.1)%. The α singles spectrum of ²⁴⁵Bk (5 day) decay to ²⁴¹Am showed 12 α groups feeding the 3 lowest bands. On the basis of these measurements six single-particle states in ²⁴¹Am have been identified. The ground state of ²⁴¹Am is known to be 5/2-[523]. The following Nilsson band-head assignments have been made: (keV, Kπ[Nn_zΛ]: 205.9, 5/2+[642]; 3/2-[521]; 623.1,1/2+[400]; 652.1, 1/2-[530]; and 670.2, 3/2+[651]. The 266.0 keV E1 transition 3/2-[521]->5/2+[642]) was found to have the most highly anomalous conversion coefficients yet observed, with anomaly factors of 100-200, consistent with E1 penetration conversion parameter sets λ₁,λ₂ = (18.5,283) or (-19.3, -63); the exiting 205.9 keV E1 transition (5/2+[642]->5/2-[523]) shows normal E1 conversion. The 471.8 keV M1+7% E2 transition 3/2-[521]->5/2-[523] also shows anomalous (factor of 3) conversion, with an M1 penetration parameter 5.5. There is some indication of anomalously low K conversion for transitions near K threshold. Observed P₁ conversion line intensities are about twice the theoretical P₁ conversion coefficient predictions. Seven KLL- and two KLM - Auger electron lines were observed and the K-shell fluorescent yield was deduced as (96.5 ± 0.4)%.RADIOACTIVITY ²⁴¹Cm [from ²³⁹Pu(α,2n)]; measured T₁/₂, E_γ, I_γ, X_K, ω_K, Ecₑ, Icₑ, e_AKLL, anomalous E1 and M1 conversions, deduced penetration parameters and retardation, deduced α_P₁, γγ-coin, α branching, ²⁴⁵Bk [from ²⁴⁴Cm(α,p2n); measured E_α, I_α; deduced hindrance factors. ²⁴¹Am deduced levels, logft (EC), γ multipolarity, I, π, 6 single-particle states. Mass-separated ²⁴¹Cm. Toroidal β spectrometer at 0.05% FWHM.