wizyta

od 2020-09-20

Title: NMR strong off-resonance irradiation without sample overheating

Source: Solid State Nuclear Magnetic Resonance

Year : 2004

Abstract:

A prototype NMR probe for long RF pulse has been constructed. Its main elements are two coils mounted in the concentric position. The first bigger coil is wound around a glass dewar tube and the second smaller coil is placed inside the dewar. These two coils are thermally isolated by the dewar. A long and strong RF pulse is applied to the bigger coil. The smaller detection coil inside the dewar contains a sample and to this coil a short RF pulse is applied. The two coils are independently tuned and electrically isolated. During the operation of the strong RF pulse the smaller coil has a high resistance to ground (very low Q factor) and does not absorb energy from the bigger coil. During the operation of the short on-resonance RF pulse the bigger coil is detuned to a higher frequency, but the resonance circuit with the small coil is in the electrical resonance. The NMR probe may be used in off-resonance experiments in which long and strong RF pulses are applied to the bigger coil and thereby the problem of the sample overheating is avoided.
(C) 2003 Elsevier Inc. All rights reserved.

DOI: 10.1016/j.ssnmr.2003.05.001   (Pobrane:  2020-10-21)