Large enhancement of deuteron polarization with frequency modulated microwaves

TL;DR

This paper demonstrates a significant increase in deuteron polarization using frequency-modulated microwaves in a polarized target, enhancing the effectiveness of dynamic nuclear polarization for scattering experiments.

Contribution

It introduces a novel application of frequency modulation to substantially boost deuteron polarization in DNP, with potential implications for polarized target experiments.

Findings

Deuteron polarization increased by a factor of 1.7 to 0.6

Frequency modulation induces additional microwave absorption in spectral wings

Results suggest new avenues for understanding dynamic nuclear polarization

Abstract

We report a large enhancement of 1.7 in deuteron polarization up to values of 0.6 due to frequency modulation of the polarizing microwaves in a two liters polarized target using the method of dynamic nuclear polarization. This target was used during a deep inelastic polarized muon-deuteron scattering experiment at CERN. Measurements of the electron paramagnetic resonance absorption spectra show that frequency modulation gives rise to additional microwave absorption in the spectral wings. Although these results are not understood theoretically, they may provide a useful testing ground for the deeper understanding of dynamic nuclear polarization.