Table 2.

Basic calibrations of NMR and DNP.

Step	Operation	Duration	Results and comments
1	Calibration of NMR frequency using 63Cu Tune and match the NMR coil to estimated ν63Cu Record 63Cu NMR signal and refine ν63Cu Calculate B0, ν13C, ν15N, νe−	2 min	ν63Cu = 75.259 MHz 63Cu signal originates from the coil itself, no sample needed
2	Fine calibration of NMR frequency ν13C or ν15N or other νX Insert DNP sample Tune and match NMR coil to the desired nucleus Perform microwave frequency sweep Use hyperpolarized NMR signal to adjust RF transmitter		ν13C = 71.492 MHz for pyruvate-radical concentrate ν15N = 28.8225 MHz for urea-radical concentrate
3	Optimize µW frequency νµW and power $p_w^{\mathit{MW}}$ Insert DNP sample (or leave it after step 2 inside) Tune and match NMR coil to desired nucleus Perform µW frequency and power sweep	ca. 60 min
4	Optimize sample position xs inside VTI Insert DNP sample (or leave it after step 2 inside) Acquire NMR signal for different sample positions	ca. 30 min	Optimal position xs found at 10 mm above bottom; closer to bottom assures colder sample temperature
5	Calibration of the NMR flip angle α Insert DNP sample and adjust coil Perform DNP until sufficient signal is obtained Apply train of low flip angle pulses Fit signals to obtain α for the given $p_d^{\mathit{RF}}$,$p_a^{\mathit{RF}}$		Several iterations may be needed to fulfill low flip angle condition. Depending on the sample position in the coil and VTI (Step 4)

Note that the results of some steps are dependable on another and may need to be repeated (e.g. No. 3–5).