Improved magnetization alignment schemes for spin-lock relaxation experiments.
A pair of pulse schemes that spin-lock magnetization efficiently are presented. The design of the sequences benefited from a particularly simple relation that is derived describing to first order the evolution of any magnetization component due to the application of an off-resonance 90 degrees pulse. The sequences are shown theoretically and experimentally to significantly outperform the 90 degrees -delay-90 degrees element that is often used in current applications. It is shown that alignment of magnetization to within 1 degrees of the effective field can be obtained over a bandwidth extending between [-omega(SL), omega(SL)], where omega(SL) is the strength of the spin-lock field using a simple scheme that is an order of magnitude shorter than an adiabatic pulse that might also be used for a similar purpose.
Hansen
D Flemming
DF
Department of Medical Genetics, The University of Toronto, 1 King's College Circle, Toronto, ON, Canada, M5S 1A8.
Kay
Lewis E
LE
D016477:Artifacts; D002247:Carbon Isotopes / Q000032:analysis; D008280:Magnetics; D008962:Models, Theoretical; D009587:Nitrogen Isotopes / Q000032:analysis; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011506:Proteins / Q000737:chemistry
D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D011506:Proteins