An Ion Balance for Ultra-High-Precision Atomic Mass Measurements
Simon Rainville,*
James K. Thompson,
David E. Pritchard
We have developed the analog of a double-pan balance for determining
the masses of single molecular ions from the ratio of their
two cyclotron frequencies. By confining two different ions on
the same magnetron orbit in a Penning trap, we balance out many
sources of noise and error (such as fluctuations of the magnetic
field). To minimize the systematic error associated with the
Coulomb interaction between the two ions, they are kept about
1 millimeter apart from each other, resulting in fractional
uncertainty below 1
x 10
–11. Such precision opens the
door to numerous applications of mass spectrometry, including
metrology, fundamental physics, and weighing chemical bonds.
Present address: Harvard University, 100 Edwin H. Land Boulevard, Cambridge, MA 02142, USA.
* To whom correspondence should be addressed. E-mail: rainville{at}alum.mit.edu.
