Andrew Mills

Graduate Student
The University of Illinois at Urbana-Champaign

Education

Research

I am actively involved in constructing the SCRIBES apparatus (Sensitive Cooled Resolved Ion BEam Spectroscopy). So far this project has involved the design of ion optics, a 90 degree quadrupole, and the power supplies to run our plasma source, the ion optics and the quadrupole.
After the ions are turned by the second quadrupole, we are building a Time of Flight (ToF) Mass Spectrometer. Because the ions are moving at a very high velocity, ToF may seem hard to do. But a technique that re-references the ion beam to ground will also slow the beam down to 30 eV instead of 10 keV. In so doing, the Time of Flight becomes a reasonable mass resolving technique.
Time of Flight depends on the fact that the velocity of ions of the same kinetic energy depends on the mass. Lighter ions travel faster. Using a fast high voltage plate pair to pulse the beam will create a packet of ions of multiple mass. After slowing the packet of ions down by rereferencing them, the ions will separate according to mass. Real time monitoring of the mass spectra will allow us to maximize the ion of interest so that better sensitivity spectroscopy can happen.

Publications