Two and Four Quadrant Gating Circuits for Crossed Atomic Beam Experiments

Descriptions are given of two circuits which generate scaler gating pulses and beam modulating pulses as required for crossed atomic beam experiments. For the case when only one of the crossed beams is modulated, a circuit is described in which a sinusoidal‐type signal is filtered by a tuned amplifier whose gain is 2000 and Q value is 260, and then passes through a level crossing detector, a frequency doubler, and several variable delays to produce two complementary square wave pulses. When both atomic beams are modulated, a second circuit produces a scaler gating pulse from each of the quadrants of the modulating period. Several combinations of variable delays permit variable phase differences between each of the four gating pulses. Circuit stability is better than 0.01%.