A computationally efficient discrete pseudomodulation algorithm for real-time magnetic resonance measurements.

Rapid-scan electron paramagnetic resonance (RSEPR) results in a significant improvement in signal-to-noise over magnetic field modulated continuous wave EPR (CWEPR). However, the RSEPR raw absorption spectra can make the real-time comparison of CWEPR spectra difficult, especially in systems where the total number of paramagnetic spins is low. In this paper, we illustrate a method of applying pseudomodulation within RSEPR data collection software in real-time. Pseudomodulation is generally carried out in post-processing to increase signal-to-noise and simulate the effects of modulation on the spectra observed in traditional magnetic field modulated CWEPR. By applying the pseudomodulation method on a discrete computational basis, the technique can be utilized in parallel with data collection due to the significantly reduced computational power of the discretized pseudomodulation calculation. This allows for the live alteration of modulation parameters, such as the modulation amplitude and modulation harmonic. This real-time simulation allows for the comparison of the accumulated non-adiabatic rapid-sweep EPR spectra with the known CWEPR spectra available in the literature and has the ability to view smaller and less sensitive resonance features for various harmonics during high-frequency experiments while retaining all signal-to-noise improvements.

An improved adaptive signal averaging technique for noise reduction and tracking enhancements in continuous wave magnetic resonance.

We have significantly refined an adaptive signal averaging approach developed primarily for continuous wave electron paramagnetic resonance and electrically detected magnetic resonance measurements. This refinement overcomes several limitations and greatly simplifies the earlier approach. The new technique provides a large improvement in tracking and numerical stability and also features fewer adjustable parameters making this approach more user intuitive.

Apparatus for electrically detected electron nuclear double resonance in solid state electronic devices.

We have developed a sensitive electron nuclear double resonance spectrometer in which the detection takes place through electrically detected magnetic resonance. We demonstrate that the spectrometer can provide reasonably high signal to noise spectra of 14N interactions with deep level centers in a fully processed bipolar junction transistor at room temperature.