Baseline resolution of 1,2H and 3,4He isotope mixtures with a Paul ion trap mass spectrometer

Abstract

A Paul ion trap mass spectrometer with fractional resolution of m/Δm=1565 was constructed and tested. The major improvement in this new trap over that previously reported with m/Δm=324 [Rev. Sci. Instrum. 73, 2157 (2002)] was due to tighter machining tolerances of the hyperboloidal surfaces, with minor improvement due to better stability of the amplitude of the radio frequency trapping voltage. The present resolution is shown to be sufficient to separate clearly (to baseline) the following masses: 4He+ and D2+ (0.0256 u separation), 3He+ and H3+ (0.0074 u), 3He+ and HD+ (0.0059 u), and 4He2+ and H2+ (0.0143 u separation). Resolution of 4He+ and HT+ (0.0043 u separation) should also be possible, but was not carried out. Resolution of H3+ and HD+ (0.0015 u separation) is possible with peaks of comparable intensity, or with deconvolution.