SU1019338A1 - Magnetic field square pulse amplitude measuring method - Google Patents

Abstract

A METHOD FOR MEASURING A RECTANGULAR AMPLITUDE OF MAGNETIC COGOL PULSES by acting on a magnetic system of mutually perpendicular polarizing and radio frequency magnetic fields and registering a signal of a magnetic resonance, which is different in order to improve the accuracy of measuring pulses of pulses. the magnetic system in the direction of the polarizing magnetic field; the values of the total polarizing magnetic field are set resonant; the frequency of the radio frequency is changed the field and the magnetic system are transformed into an inverted state, the frequency of the beats is recorded and the amplitude of the magnetic pulses is determined; the magnetic field is given by the formula: (L the frequency of the beats; where f is T is the gyromagnetic ratio.

Description

C0 O9 09 06

The invention relates to magnetic measurements and is intended to measure the amplitude of short pulses of a magnetic field.

Methods are known for measuring the amplitude of pulses of a magnetic field, which consists in placing an inductor in the area under study and measuring the induced emf induced by the pulse C13 under study.

However, the use of methods is difficult when measuring fields in small volumes of space.

A known method for measuring the amplitude of rectangular pulses of a magnetic field, based on the phenomenon of magnetic resonance. The method involves exposing the magnetic system to mutually perpendicular polarizing and radio frequency magnetic fields, recording the magnetic resonance signal, measuring the resonant frequency and determining the value of the polarizing magnetic field from the magnetic resonance conditions. The magnitude of the magnetic field pulse is determined; 1 as the difference between the field values measured before and during the action of the measured pulse 2.

However, the accuracy in measuring the amplitude of short pulses (shorter than c) is insufficient.

The aim of the invention is to improve the accuracy of measuring the amplitude of short pulses of a magnetic field.

This goal is achieved by agreeing on the method of measuring the amplitude of rectangular pulses of a magnetic field by acting on a magnetic system of mutually perpendicular polarizing and radio-frequency magnetic fields and registering a magnetic resoopns signal with a measured pulse acting on the magnetic system in the direction of the polarizing magnetic field , the values of the total polarizing magnetic field are set to resonant, the frequency of the radio frequency field is changed, and the magnetic system is converted into inverted of PICs, the beat frequency is recorded and determined pulse amplitude of the magnetic field by the formula

,

where f is the beat frequency;

V is the gyromagnetic ratio.

The drawing shows the dependence of the frequency of the beating from the amplitude of the pulses m, agnitnogo field.

The method is based on the fact that the frequency of a non-equilibrium radio frequency field at any time is determined by the resonant frequency of the magnetic system and is uniquely determined by the value of the polarizing magnetic field. The difference between the frequency of a non-equilibrium radio frequency field emitted by a magnetic system and the frequency of the exciting radio frequency field leading to the inversion of the magnetic system is determined by the amplitude of the magnetic field pulse.

The method is carried out as follows.

Continuous microwave radiation with a frequency of 10 GHz is supplied to a quartz sample placed in a polarizing magnetic field. The polarizing magnetic field is modulated by measured pulses. In this case, the value of the polarizing field is set such that the total magnetic field during the action of the pulses becomes resonant. The electron paramagnetic resonance signal is recorded by a broadband system. The duration of the measured pulses is, for example, 2 µs. The value of the microwave field is chosen such that during the pulse action time the magnetic system goes into an inverted state, which corresponds to a change in the sign of the absorption signal to the opposite.

The non-equilibrium radiation emitted by the inverted magnetic system and the applied microwave field affect the microwave detector. The beat frequency occurring after the end of the measured pulse is recorded. From the beat frequency, the amplitude of the magnetic field pulse is determined using the formula dH f / T (where f is the beat frequency, is the hygromagnetic ratio, for this case, it is 2, s ;.

Using this method It measures the amplitudes of short magnetic field pulses with a high accuracy characteristic of magnetic resonance-based methods.

310193384

Such a method can be especially poured the absolute value of the changes, climbed in studies of the magnetic field at the location of the resonance as it allows the determinant.

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Claims (1)

METHOD FOR MEASURING THE AMPLITUDE OF A RECTANGULAR MAGNETIC FIELD PULSES by exposing the magnetic system to mutually perpendicular polarizing and radio frequency magnetic fields, and recording a magnetic resonance signal, distinguishing it by the fact that, in order to increase the accuracy of measuring the amplitude of short pulses, measured pulse affect the magnetic system in the direction of the polarizing magnetic field, set the values of the total polarizing magnetic field resonant, change the frequency of the radio frequency For and the magnetic system is converted to an inverted state, the beat frequency is recorded, and the amplitude of the Marts pulses of the nitric field is determined by the formula: where f is the beat frequency; 1G - gyromagnetic ratio. seeeiot ’’ ns “