Publication

Frequency-modulated "chirp" pulses for broadband inversion recovery in magnetic resonance

Geoffrey Bodenhausen
1990
Journal Articles

Abstract

A novel approach to inversion recovery in NMR is described which combines adiabatic inversion with the observation of a spin echo refocused by a chirp pulse. This echo method allows one to generate in-phase magnetization over a broad range of frequencies. The effects are discussed of longitudinal and transverse relaxation during the pulse sequence, and the implications of scalar coupling are also investigated. [on SciFinder (R)]

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Geoffrey Bodenhausen
1990
Journal Articles

Abstract

Official source

Related concepts (32)

Spin echo

In magnetic resonance, a spin echo or Hahn echo is the refocusing of spin magnetisation by a pulse of resonant electromagnetic radiation. Modern nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) make use of this effect. The NMR signal observed following an initial excitation pulse decays with time due to both spin relaxation and any inhomogeneous effects which cause spins in the sample to precess at different rates. The first of these, relaxation, leads to an irreversible loss of magnetisation.

Nuclear magnetic resonance

Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a strong constant magnetic field are perturbed by a weak oscillating magnetic field (in the near field) and respond by producing an electromagnetic signal with a frequency characteristic of the magnetic field at the nucleus. This process occurs near resonance, when the oscillation frequency matches the intrinsic frequency of the nuclei, which depends on the strength of the static magnetic field, the chemical environment, and the magnetic properties of the isotope involved; in practical applications with static magnetic fields up to ca.

Spin–spin relaxation

In physics, the spin–spin relaxation is the mechanism by which Mxy, the transverse component of the magnetization vector, exponentially decays towards its equilibrium value in nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI). It is characterized by the spin–spin relaxation time, known as T2, a time constant characterizing the signal decay. It is named in contrast to T1, the spin–lattice relaxation time.

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Frequency-modulated "chirp" pulses for broadband inversion recovery in magnetic resonance

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