Rapid precision interferometry for the analytical ultracentrifuge. II. A laser controller based on a rate-multiplying circuit.

A laser controller that uses a fixed frequency clock and a digital rate-multiplying circuit to synchronize the triggering of a pulsed laser to the spinning of an analytical ultracentrifuge rotor has been designed. The circuit is simple, inexpensive, and virtually free of any adjustments. It tracks rotors undergoing full acceleration or deceleration. At constant rotor speed it provides triggering that is accurate and reproducible to better than 0.5 microseconds. The settings of this controller are independent of rotor speed over the full range of the ultracentrifuge.