Fig. 6.
Enhancements on the membrane protein, bacteriorhodopsin, with the tunable gyrotron. Changing the cathode potential by 1.2 kV shifts the output frequency 460 MHz, which is sufficient to lead to a positive enhancement of +54 (top) and negative enhancement of −42 (bottom). The gyrotron and NMR magnets were held constant at 9.12 T, 8.93 T (1H resonant frequency of 380.378 MHz), respectively. The spinning frequency was 4 kHz and the sample temperature 81 K.