Mass spectrometry at 0.1 part per billion for fundamental metrology

The single ion Penning trap mass spectrometer at M.I.T. now compares masses with an accuracy of 0.1 part per billion. We have created a table of fundamental atomic masses and made measurements useful for calibrating the X-ray wavelength standard, and determining Avogadro's number, the molar Planck constant, and the fine structure constant.<
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