Wavelength measurements of 1s2s³S-1s2p³P transitions in helium-like²⁸Si¹²⁺,³²S¹⁴⁺and³⁵Cl¹⁵⁺

Abstract

The authors have measured the wavelengths of the 1s2s 3S-1s2p 3P transitions in two-electron Si XIII, S XV, and Cl XVI, produced by foil excitation of 50-90 MeV silicon, sulphur, and chlorine ions. Our wavelength precision provides sensitivity to Lamb shift contributions to the transition energies to +or-3%. The results for S XV represent the first measurements of the 3S-3P transitions for this ion.