In summary, it appears that a DNP transfer ratio ESSE of 2 obtained with the ASE and SSE is, thus far, the more efficient pulsed technique. This transfer ratio compares to a value of 0.686 for the ISE [20] which is derived from Eq. ( ), and 1.3 for NOVEL [10]. TOP-, XiX-, and TPPM-DNP can have a similar theoretical maximum transfer ratio as NOVEL per pulse train. However, TOP-DNP and XiX-DNP 24 require longer irradiation periods, which yields additional decoherence of the spins, and therefore an efficiency lower than NOVEL. The high DNP transfer ratio of chirped pulses is attributable to the adiabatic level crossing that is intrinsically more efficient than other transition pumping pulsed techniques. This is also the case for ramped-amplitude NOVEL and BEAM-DNP . These estimates are discussed in more detail in the Supporting Information. Finally, chirped DNP allows utilization of all the electron spins by integrating the EPR frequencies, which is an advantage over single frequency pulsed techniques. Similar improvements have been demonstrated for other frequency modulation DNP schemes .