V. V. Davydov

Fiber-optical communication line for the NMR signals transmission in the control systems of the ships atomic power plants work

For the new surface ships with atomic power plant models, where the cooling system and nuclear-magnetic measuring instruments are situated close to the reactor, the fiber-optic communication line was developed. This communication line is used for the information about the cooling liquid medium consumption and the registered NMR signal transmission from measuring instruments to the central and reactor compartment computers.

Improvement Frequency Stability of Caesium Atomic Clock for Satellite Communication System

One of the directions of modernization of the caesium atomic clocks is considered. A new implementation of a digital frequency converter for atomic clocks is presented. The new design of frequency converter is based on method of direct digital synthesis. The theoretical calculations and experimental research showed decrease step frequency tuning by several orders and improvement the spectral characteristics of the output signal of frequency converter. A range of generated output frequencies is expanded, and the possibility of detuning the frequency of the neighboring resonance of spectral line that makes it possible to adjust the C-field in quantum frequency standard is implemented. Experimental research of the metrological characteristics of the quantum frequency standard on the atoms of caesium - 133 with a new functional unit showed an improvement in the daily frequency stability.

Fiber-Optic Super-High-Frequency Signal Transmission System for Sea-Based Radar Station

A fiber-optic system for transmission of super-high-frequency signals in the 8-12 GHz range from a multi-component active phased antenna array of a sea-based radar station to an information processing system located in a ship compartment is suggested and investigated. Power loss and total attenuation of optical signals are calculated. The power loss margin and signal transmission time of the system are analyzed. Dependences of the characteristics of the fiberoptic data transmission system on the input signal frequency and temperature are experimentally measured. The fiber-optic data transmission system we have developed can prove an efficient tool for improving interaction between the wireless radar and wired signal transmission systems.

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.

Fiber-optic imitator of accident situation for verification of work of control systems of atomic energy plants on ships

The article is dedicated to the developed fiber-optic imitator of accident situation for verification of work of control systems and cooling sets, made on the base of nuclear-magnetic meters. The work of fiber-optic imitator and its dynamic characteristics were investigated. The further ways of improvement of the work of control systems, based on nuclear-magnetic meters and made with use of optical fibers and systems were also defined.

A two-channel nutation nuclear-magnetic magnetometer for remote control of the magnetic-field induction

A two-channel nutation magnetometer on the basis of the nuclear-magnetic resonance (NMR) is described. It allows measurements of the magnetic-field induction within a range of 0.06–8.29 mT with an inhomogeneity of ≥10–2 cm–1 in different compartments of a sea ship. The distance from the location of a device that records NMR signals to the point at which the magnetic induction is determined ranges from 1 to 69 m. The measurement error is 0.3% and the sensitivity is 10–11 Т/Hz1/2.

Fiber-Optics System for the Radar Station Work Control

The purpose of this paper was to develop fiber-optics system for the multifunctional radar stations control in the frequency range of 0.1-12 GHz. Power losses and total attenuation of the optical signal was calculated for developed fiber-optics systems. Different methods for fiber-optics system characterization were developed, and the results of input signal frequency, temperature and vibration influence was experimentally investigated. Methods for fiber-optics system improvement were identified.

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.