Efficient adiabatic fast passage for NMR population inversion in the presence of radiofrequency field inhomogeneity and frequency offsets

摘要: Abstract Adiabatic fast passage is a powerful tool for uniformly inverting magnetization in the presence of rf magnetic field inhomogeneity and frequency offsets. Long pulses or large powers are necessary this technique to be effective, however, when usual linear sweep used. A form ω(t) − ω0 = ω1tan(αω1t), on other hand, shown an order magnitude more efficient than sweep. Here frequency, Larmor w1 -γB1 (gyromagnetic ratio times strength), α constant determined by w1, total time, range This tangential can produce substantially better inversion composite same amplitude.