Pulse drive system for mass spectrometer with hyperbolic electrodes - applies two pulse trains to opposing pairs of electrodes with time delay chosen for maximum stability

摘要

The signal generator allows an increase in the difference in voltage level between the two electrodes by a factor of two and reduces the effect of dielectric film build-up on the electrodes surfaces. Two pulse trains (U1, U2) are applied to the pairs of electrodes. They consist of square-waves whose mark-space ratio and amplitudes can be adjusted. One pulse train is retarded by a variable amt. with respect to the other and the electric field in the analyzer cavity, due to the combined effect of the two signals has a d.c. component (U3) at the required level. The delay (t1) is less than the pulse repetition period (To) and is chosen so that t1/t2 = 0.55; where t2 is the mark time of signal U2 and S is the form factor of the pulse train. The form factor is given by S = 2k; where k is a positive integer greater than 2.