The pionic sodium 2p-1s transition

The width and energy of the pionic sodium 2p-1s X-ray has been measured using a Compton suppressed germanium spectrometer. The resulting reduction of the continuum Compton background has allowed a more detailed determination of the X-ray. The values obtained are: Energy = 276.45(± 0.27, ± 0.33) keV; Width = 17.1(± 1.1, ± 1.2) keV. The measured width is in better agreement with optical model predictions than previous measurements which gave anomalously narrow values.