A microscale quadrupole mass spectrometer for ion species analysis
Investigators have identified a quadrupole structure that uses non-traditional geometry with rectangular cantilevered electrodes and that is amenable to semiconductor fabrication. Despite the revolutiotiary electrode geometry, the proposed microscale quadrupole mass filter displays a sizeable internal volume within which the field is equivalent to that of a conventional quadrupole mass filter with circular electrodes. Numerical analyses predict that the mass resolution and transmission efficiency are nearly identical with those of an equivalent cylindrical device. Batch processing techniques could be employed to produce massively parallel arrays of microscale quadrupole filters in a cost-effective manner. Prototype filters were fabricated using conventional semi-conductor manipulation protocols in conjunction with molecular beam epitaxy on GaAs/AlGaAs. The preliminary electric characterization of the prototype indicates broad mass range up to 1,500 amu with minimal power requirements. Such a micro device would be invaluable for light species analysis in numerous applications including plasma diagnostics, residual gas analysis, detection of chemical and products of biological agents, and integrated sensing of gas quality in medical and pharmaceutical applications. © 2004 by Lyon B. King.
