text: Magic angle spinning Dynamic Nuclear Polarization (MAS-DNP) is a technique that increases the sensitivity of NMR experiments by several orders of magnitude. It involves the transfer of the very high electron polarisation from unpaired electrons to nearby nuclei. This is achieved at cryogenic temperatures by the means of a continuous microwave irradiation coming from a klystron or a Gyrotron, with a frequency close to the corresponding electron paramagnetic resonance (EPR) frequency.
  The development in the MAS-DNP instrumentation, as well as the improvement of polarising agents (TOTAPOL, AMUPOL, TEKPOL, etc.) to achieve a more efficient transfer of polarisation has dramatically reduced experiments times which enabled the observation of surfaces, insensitive isotopes, and multidimensional experiments on low natural abundance nuclei, and diluted species.