Building a 263 GHz Pulsed DNP Microwave Bridge, Waveguides, Probe, and MAS Drive Caps
Résumé
I will discuss some important considerations in designing a 263 GHz pulsed microwave bridge equipped with an arbitrary waveform generator (AWG), which allows us to generate arbitrarily shaped microwave pulses for DNP. Corrugated waveguides are preferred low-loss microwave transmission from the bridge to the DNP sample in the probe. We demonstrate the possibility of fabricating corrugated waveguides using 3D printing and electroless plating technology. The unique homebuilt low-temperature 1.4 K DNP instrumentation at 9.4 T is well-suited for studying low-gamma nuclei (e.g., 63/65Cu) that have ultrawide NMR linewidths. At last, we show that 1.3 - 4 mm MAS drive caps compatible with commercial probes can be affordably fabricated in the lab using a desktop 3D printer.