the microwave system was tuned again. the minimum resonance deep of the reflected microwave is 60mV at cw mode. when it is pulse mode, during the triggered microwave, the reflected wave is still large (8.4V), and we can see a clear charge and discharge signal. we also correct the microwave trigger.

the NMR coil is 60 turns now, compare to the old one is 10 turns. thus it is more sensitive. we cannot find a polarized signal. the NMR signal either has large noise or large reflected wave. may be the impedance is not matching or the resonance deep is not enough.


  1. minimize the NMR noise
  2. reduce the reflected NMR pulse.
  3. polarize target
  4. optimization
  5. laser polarization measurement
  6. spin echo
  7. polarization transfer.