Development of the Digitally Controlled Quadrupole Power Supply System

The digitally controlled radio frequency (RF) output circuit for the quadrupole mass spectrometer is reported. The circuit does not include the nonlinear negative feedback circuit that reduces the accuracy for the control of RF output voltage. The mass spectra for residual gasses, Kr and Xe, those mass resolution at 10% peak height of less than 0.5 (M/z = 1 to 66) and less than 1 (M/z = 80 to 132), respectively, were obtained with this circuit. The separation of the peaks for 4He and D2, that corresponding to the mass resolution less than 0.0256, were also observed by using the second stability zone of Mathew's equation.