Breakdown of the isobaric multiplet mass equation at A=33, T=3/2 -: art. no. 142501

Mass measurements on Ar-33,Ar-34,Ar-42,Ar-43 were performed using the Penning trap mass spectrometer ISOLTRAP and a newly constructed linear Paul trap. This arrangement allowed us, for the first time, to extend Penning trap mass measurements to nuclides with half-lives below one second ((33) Ar: T-1/2 = 174 ms). A mass accuracy of about 10(-7) (deltam approximate to 4 keV) was achieved for all investigated nuclides. The isobaric multiplet mass equation was checked for the A = 33, T = 3/2 quartet and found to be inconsistent with the generally accepted quadratic form.