Submitted on October 7, 2003
Accepted on November 18, 2003
An Ion Balance for Ultra-High-Precision Atomic Mass Measurements
Simon Rainville 1*,
James K. Thompson 2,
David E. Pritchard 2
1 Research Laboratory of Electronics, MIT-Harvard Center for Ultracold Atoms, and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Present address: Harvard University, 100 Edwin H. Land Boulevard, Cambridge, MA 02142, USA.
2 Research Laboratory of Electronics, MIT-Harvard Center for Ultracold Atoms, and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
* To whom correspondence should be addressed. E-mail: rainville{at}alum.mit.edu.
We have developed the analogue 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 (e.g. fluctuations of the magnetic field). To minimize the systematic error associated with the Coulomb interaction between the two ions, they are kept about 1 mm 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.
