SU661451A1 - Nutation meter for determining constant conductive measures of magnetic induction - Google Patents

Description

The invention relates to the field of measuring permanent magnetic fields by nutation of the total magnetization vector in a flowing fluid, in particular, it can be used for metrological certification of Magyit induction conductors, measurement created by conductive coils of a weak magnetic field under conditions of interference from external sources of constant magnetic fields. and slowly varying magnetic fields, to study the effect of ferromagnetic shields on the parameters of conductor coils.

A wide-band proton teslameter is known for measuring the magnetic field, containing a polarizing volume, placed in a measuring dande, measuring to: nutation attenuator, connecting tube with flowing liquid, high frequency generators, nuclear magnetic resonance signal analyzer (NMR) I.

The main disadvantage of this test meter is the low accuracy of the measurements. Go for low magnetic field strengths due to the use of polarization measures of the liquid measured by the magnetic helmet.

The closest technical solution to this invention is the installation for a jeere {B1-DI-CI magnetic field nut-box; with a polarizing volume, polarizer magnet,

nutation measuring coil, connecting tube with the current liquid, high-frequency generator, NMR signal analyzer 2.

In this setup, the chi chickpea Qi measuring coil also acts as a parasitic magnetic field caused by scattering polarizer, analyzer, the Earth’s magnetic field and other technical objects, which dramatically increases the T10 value of the magnetic induction generated by the conductor measure, which in absolute value can reach values equal to the magnitude of the parasitic magnetic field in the working space measures. Eliminate the influence of the parasitic magnetic field on the result of the determination of the constant conductors

The measures are not represented as possible because the installation uses a single-frequency oscillator, the current one, which is created by the high-frequency circuit:

Claims (2)

The aim of the invention is to improve the accuracy of determining the constant conductive measures of magnetic induction. This goal is achieved by the fact that in a device containing a polarizing volume associated with a source of a polarizing magnetic field and through a connecting tube with a flowing liquid, with a nuclear magnetic resonance signal analyzer, a high frequency generator, and a measuring wheel of nutation located around the connecting tube with the current fluid, a series-connected low-frequency generator, a low-pass filter and a high-frequency tee, the output of which is connected to the nutation measuring coil, are introduced, as well as a high-pass filter whose input is connected to the output of the high-frequency generator, and the output to the second input of the high-frequency tee. The functional diagram of the nutation gauge is shown in the drawing. The meter contains a polarizing volume 1, a source of polarizing magnetic field 2, a nutation measuring coil 3, a connecting tube with a current liquid 4, a nuclear magnetic resonance signal analyzer 5, a high-purity generator 6, a high-frequency filter 7, a high-frequency tee 8, a low-frequency generator frequency 9, low pass filter 10. The nutation meter works as follows. The pre-polarized liquid in the polarizing volume 1 by the source of the polarizing magnetic field 2 through the connecting tube 4 enters through the nutation measuring coil 3 into the NMR analyzer 5. The polarized magnetic field at the location of the measuring coil of nutation 3 simultaneously acts on the parasitic magnetic field; field; created by a conductive magnetic induction measure (not shown), a two-frequency oscillating magnetic field created by a low-frequency generator 9, and a high-frequency generator 6. To disconnect the frequencies of these THAT generators, they were connected to the high-frequency tee 8, the output of which is connected to the nutation measuring coil through a low pass filter 10 and a high pass filter 7. If the resonance conditions are met, when ω. Ur B (co is the frequency of the EMF of the generator at a low frequency, T5p is the hygromagnetic ratio of the proton, B is the modulus of the total magnetic induction vector at the location of the measuring coil of nutation), and the total nuclear vector magnetization vector is mutated. It is observed by a change in the amplitude of the NMR signal at the output of the analyzer 5. Since the nutation meter responds to the modulus of the total magnetic induction vector acting on the measuring coil of nutation, when measuring the magnetic field induced by the measure, there is an additional measurement error due to the parasitic magnetic field . To eliminate this error, the nutation meter has two simultaneously operating oscillating magnetic fields created by low and high frequency generators. When determining the true value of the magnetic induction produced by the measure, the frequency of the low frequency generator 9 is set equal to the center of the resonance line of the nutation signal from the parasitic magnetic field. Then, the supply current of the conductive measure of the magnetic field is turned on and its required value is set to 1. The frequency of the high-frequency generator 6 is measured, and the modules of the total values of the magnetic induction vectors B and B T acting on the measuring coil of nutation are measured, respectively, in the plus and minus direction of the power supply current. measures. Monitoring and determination of the parasitic magnetic field induction of the power supply unit is performed in the process of measuring the components B and V by means of a low-frequency generator, briefly turning on the current for the measure. The true value of the magnetic field induced by the conductor measure of the magnetic field is determined from the expression (c) (& -) - g & n In this case, the value of the constant conductive measure, the magnetic induction is equal to В / /. The use of a dual-frequency oscillating field minimizes the measurement time of the components of expression (1), eliminates the effect of the induction of a parasitic magnetic field and its instability, and reduces the error in determining the magnetic induction produced by the measure to its minimum value determined by the capabilities of the nutation measurement method. The accuracy of the determination of permanent conductor measures is reduced by several orders of magnitude. This is ensured by the introduction into the nutation gauge of appropriately included new elements: a low frequency generator, low and high frequency filters and a high frequency tee. The absolute value of the measurement error created by conductive measures of fields with induction (10-500) T known nutation teslameters depending on the measurement conditions and the parameters of the source of the polarizing magnetic field is in the range of (0.2-3) 10T. When using the proposed meter, the error of determining the induction of a magnetic field created by a conductor measure does not depend on the magnitude of the magnetic induction of the parasitic field, has a minimum value determined by the instrumental error of the device and in the worst case does not exceed 0.1 % The error in determining permanent conductor measures is reduced by an order of magnitude. NUTTING METHOD A nutation meter for determining constant conductive magnetic induction measures containing a polarizing volume associated with a source of a polarizing magnetic field and through a connecting tube with a flowing fluid, a high frequency magnetic resonance signal analyzer, and a measuring a nutation coil located around the cushioning tube with a flowing fluid, characterized in that, in order to increase the accuracy of the determination of permanent conductor measures by magnetic induction, injected in series, a low-frequency generator, a low-pass filter and a high-frequency tee, the output of which is connected to the measuring coil of nutation, as well as a high-frequency filter, the input of which is connected to the output of the high-frequency generator, and the output to the second input of the high-frequency tee . Sources of information taken into account in the examination 1. “Measuring equipment, 1975, No. 10, p. 76. 2. “Measuring equipment, 1973, No. 11, p. 81.