Rapid precision interferometry for the analytical ultracentrifuge. I. A laser controller based on a phase-lock-loop...

Area of Science:

• Biophysical techniques
• Analytical chemistry
• Optical instrumentation

Background:

• The Beckman Model E analytical ultracentrifuge is a powerful tool for studying macromolecular properties.
• Efficient data acquisition and reduction are crucial for maximizing the utility of analytical ultracentrifugation.
• Existing methods for data collection can be time-consuming and may introduce artifacts.

Purpose of the Study:

• To develop and present a novel pulsed laser controller for the Beckman Model E analytical ultracentrifuge.
• To enable rapid reduction of data acquired from the Rayleigh interference optical system.
• To improve the precision and efficiency of interferometric data collection.

Main Methods:

• A phase-lock-loop circuit was designed to generate precisely timed light pulses.
• The controller operates across a rotor speed range of 3000 to 60,000 rpm.
• The system resolves rotor motion into 4096 discrete angular positions per revolution, independent of speed fluctuations.

Main Results:

• The pulsed laser controller ensures selectable, speed-independent laser burst timing.
• This independence is maintained even during rapid rotor acceleration or deceleration.
• The controller has been successfully utilized for 7 years in both photographic and real-time data acquisition.

Conclusions:

• The developed pulsed laser controller significantly enhances data acquisition capabilities for analytical ultracentrifugation.
• This method facilitates rapid data reduction and improves the quality of interferometric measurements.
• The controller represents a valuable advancement for researchers using the Beckman Model E ultracentrifuge.