Glosario

H

H0: conventional symbol historically used for the constant magnetic field in an NMR system; it is physically more correct to use B0. A magnet provides a field strength, H; however, at a point in an object, the spins experience the magnetic induction, B.

H1: conventional symbol historically used for the radiofrequency magnetic field in an NMR system; it is physically more correct to use B1; → B1.

Hardware: electrical and mechanical components of a computer.

Helmholtz coil: pair of current carrying coils used to create a uniform magnetic field in the space between them.

Hertz (Hz): the standard (SI) unit of frequency; equal to the old unit "cycles per se­cond".

Homogeneity: uniformity. In NMR, the homogeneity of the static magnetic field is an important criterion of the quality of the magnet. Homogeneity requirements for magnetic resonance imaging are generally lower than the homogeneity requirements for NMR spectroscopy, but for most imaging techniques must be maintained over a larger region.

Hyperbolic secant pulse: a selective inversion pulse which is insensitive to intensity variations in the RF field.

Hz → Hertz.


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