Precision Mass Measurement: ωc
is not qB/m, does E=mc2?
Dave Pritchard
Massachusetts Institute of Technology
21 April 2004
We have developed a single ion balance that has improved atomic and molecular mass measurement accuracy to ~ 10-11. It compares the cyclotron frequency of two individual molecular or atomic ions trapped in a uniform magnetic field to find the mass ratio. Besides improving the mass of fundamental particles, this has led to a correction to the cyclotron resonance formula, a new route to determining the fine structure constant using simple physics, the best measurement of the dipole moment of any charged molecule, recalibration of the x-ray wavelength standard, a possible route to replace the artifact kilogram with an atomic mass standard, and a precise test of E=mc2.
Visit the MIT Single Ion Mass Spectroscopy or the Alkali Quantum Gases web sites.
