Measurement of Nuclear γ Rays and μ X Rays in Muonic ²⁰⁹Bi

Abstract

The anomalous intensity ratios observed in ²⁰⁹Bi were explained by Hüfnerl by a resonance mechanism, according to which the nucleus is excited into the 15/2⁺ (2.74 MeV) and 9/2⁺ (2.56 MeV) state. In this paper we report on the observation of nuclear γ rays following this excitation. Spectra were taken with a Ge-detector at the CERN muon channel. Four γ lines were identified in the prompt (1 2 3 4 Ge) spectrum as belonging to transitions in ²⁰⁹Bi. The energies E_μ and intensities Y_exp of these lines are presented in table 1. They turn out to be shif-ted in energy by ΔE_exp (table 1) compared to energies E_e as derived from Coulomb excitation².