Direct high-precision mass measurements on Am 241,243, Pu 244, and Cf 249

The absolute masses of four long-lived transuranium nuclides, Am241,243, Pu244, Pu244, and Cf249, in the vicinity of the deformed N=152 neutron shell closure have been measured directly with the Penning-trap mass spectrometer TRIGA-TRAP. Our measurements confirm the AME2012 mass values of Am241,243 and Pu244 within one standard deviation, which were indirectly determined, by decay spectroscopy studies. In the case of the Cf249 mass, a discrepancy of more than three standard deviations has been observed, affecting absolute masses even in the superheavy element region. The implementation of the mass values into the AME2012 network yields a reduced mass uncertainty for 84 nuclides, particularly for Pu244 and its strongly correlated α decay chains.