V. I. Dudkin

A nuclear magnetic relaxometer for express testing of the condensed medium conditions

The design of a compact nuclear magnetic relaxometer is described. This relaxometer is capable of measuring longitudinal T1 and transverse T2 relaxation times of condensed media in a weak magnetic field with B0 = 62 mT. The Giulotto method in a weak magnetic field is used in the relaxometer design to measure T1. The NMR signal accumulation circuit has been developed for measuring relaxation times of small-volume samples (1.0–1.5 mL) at a signal-to-noise ratio of 1.2.

Equations of motion of the magnetization vector in the nutation coil of a nuclear magnetic flowmeter

The dependence of the nutation line shape in a nuclear magnetic flowmeter on the magnetic-field inhomogeneity in the zone of nutation-coil arrangement and the time of occurrence of the magnetized liquid under the action of a radio-frequency field in the coil has been studied by experimental and theoretical methods. The obtained experimental and theoretical data are compared, and directions of investigations to come are outlined.

On the sensitivity of running-fluid NMR magnetometers

A new procedure for determining the sensitivity of running-fluid NMR magnetometers is considered. The procedure is based on mathematical processing of experimental data that are related to measuring the gradient of a nutation-line slope at the point at which an inverted NMR signal crosses zero. The procedure allows one to determine the sensitivity of running-fluid NMR magnetometers for resonance frequencies of magnetic-field measurements within a range of 0.5 Hz to 840 MHz.

Formation of the nutation line in NMR measuring systems with flowing samples

In this Letter, we present the results of investigations of the influence of the magnetic field intensity and inhomogeneity in the zone of the nutation coil location on the nutation line shape for different relaxation constants and temperatures of the flowing liquid. It is shown experimentally that the nutation line shape in NMR measuring systems is independent of changes in transverse relaxation time T2 of the flowing liquid.

Fiber-optic system for simulating accidents in the cooling circuits of a nuclear power plant

This article describes a fiber-optic accident simulator that has been developed for checking the operation of monitoring systems, based on nuclear magnetic meters for the cooling facilities of a nuclear power plant. The operation of the fiber-optic simulator has been checked and its dynamic characteristics investigated. Further approaches are determined for improving the operation of monitoring systems based on nuclear magnetic meters that use optical fibers and systems.

Equations of motion of the nuclear magnetization vector of a flowing liquid in a modulated magnetic field of a nutation coil

We describe a new approach to description of the formation of the nutation line in an NMR flow-meter under conditions of modulation of a constant magnetic field by a variable (RF) magnetic field. The dependence of the nutation line shape (number of peaks, their amplitudes, and line width) on the parameters of the modulation field and the magnetic field inhomogeneity in the zone of nutation coil arrangement has been studied.

NMR study of domain wall pinning in a magnetically ordered material

The use of nuclear magnetic resonance in the form of spin echo in combination with magnetic field pulses applied to a magnetically ordered material sample offers a convenient tool for studying characteristics of the centers of domain-wall pinning. Possibilities of this method have been demonstrated in experiments with lithium–zinc ferrite.