Design and implementation of an FPGA-based timing pulse programmer for pulsed-electron paramagnetic resonance...

Area of Science:

• Physical Chemistry
• Spectroscopy
• Instrumentation

Background:

• Pulsed electron paramagnetic resonance (EPR) experiments require precise control over pulse sequences.
• Existing pulse programmers, based on commercial digital delay generators, logic pattern generators, and ASICs, have limitations in flexibility and cost.
• There is a need for advanced, adaptable, and cost-effective pulse programming solutions in magnetic resonance spectroscopy.

Purpose of the Study:

• To design, construct, and implement a novel FPGA-based pulse programmer for pulsed EPR experiments.
• To offer a more flexible and cost-effective alternative to existing pulse programmers.
• To demonstrate the utility of the FPGA pulse programmer in advanced EPR experiments.

Main Methods:

• Utilized a Spartan-6 FPGA (Xilinx) for implementing a novel transition-based algorithm and command protocol.
• Designed an auxiliary board for FPGA-instrument interfacing, buffering outputs for power and capacitive load requirements.
• Developed hardware and software for facile reconfiguration to meet diverse experimental needs.

Main Results:

• Achieved nanosecond pulse formation (≤3 ns rise/fall times) and low jitter (≤150 ps).
• Implemented a system with 16 channels (expandable to 48) and no limit on pulse duration.
• Successfully demonstrated operation through 1-D Electron Spin Echo Envelope Modulation (ESEEM) and 2-D Hyperfine Sublevel Correlation (HYSCORE) experiments.

Conclusions:

• The FPGA-based pulse programmer provides a flexible, cost-effective, and high-performance solution for pulsed EPR.
• The developed transition-based algorithm and command protocol are optimized for pulsed magnetic resonance timing.
• The FPGA approach is transferable to other magnetic resonance techniques (NMR, MRI) and broader spectroscopic applications.