Rapid scan EPR: Automated digital resonator control for low-latency data acquisition

Area of Science:

• Scientific instrumentation
• Automation in research
• Digital control systems

Background:

• Modern scientific instruments generate large volumes of complex dynamic data.
• Automation is crucial for real-time data acquisition and instrument parameter adjustment.
• Human operators cannot match the speed and precision of automated systems, leading to potential errors and reduced reproducibility.

Purpose of the Study:

• To develop an automatic digital control (ADiC) system for scientific instruments.
• To enable reliable critical coupling of a resonator under time-varying loading conditions.
• To improve the speed, accuracy, and reproducibility of experimental data acquisition.

Main Methods:

• Developed an ADiC system utilizing a microcontroller for direct communication with instrument components, independent of a PC.
• Designed a printed circuit board resonator for digital control.
• Evaluated the ADiC system's performance by varying resonator loading with aqueous sodium chloride solutions.
• Integrated the ADiC into a rapid scan (RS) electron paramagnetic resonance (EPR) imaging instrument.

Main Results:

• The ADiC system reliably sustained critical coupling of the resonator within approximately 5 ms.
• The upgraded EPR instrument successfully acquired RS spectra and an in vivo image of oxygen in a mouse tumor model.
• The ADiC demonstrated robust performance across a wide range of resonator loading conditions.
• The system proved effective in maintaining resonator coupling during demanding measurements.

Conclusions:

• The developed ADiC system significantly enhances the performance and reliability of scientific instruments.
• Automation via ADiC improves experimental reproducibility and data quality in complex dynamic measurements.
• The ADiC design is adaptable for use in various EPR techniques, including slow-scan and pulsed EPR.