The Wisconsin Oscillator: A Low-Cost Circuit for Powering Ion Guides, Funnels, and Traps

In this work, we
present the Wisconsin Oscillator, a small, inexpensive,
low-power circuit for powering ion-guiding devices such as multipole
ion guides, ion funnels, active ion-mobility devices, and non-mass-selective
ion traps. The circuit can be constructed for under $30 and produces
two antiphase RF waveforms of up to 250 Vp–p in
the high kilohertz to low megahertz range while drawing less than
1 W of power. The output amplitude is determined by a 0–6.5
VDC drive voltage, and voltage amplification is achieved using a resonant
LC circuit, negating the need for a large RF transformer. The Wisconsin
Oscillator automatically oscillates with maximum amplitude at the
resonant frequency defined by the onboard capacitors, inductors, and
the capacitive load of the ion-guiding device. We show that our circuit
can replace larger and more expensive RF power supplies without degradation
of the ion signal and expect this circuit to be of use in miniature
and portable mass spectrometers as well as in home-built systems utilizing
ion-guiding devices.