Method and system for measuring relative concentrations of materials in a mixture by measuring (ac) dynamic magnetic susceptibility

Patent metadata

Field	Value
Publication number	US-2025060336-A1
Application number	US-202218721952-A
Country	US
Kind code	A1
Filing date	Dec 22, 2022
Priority date	Dec 22, 2021
Publication date	Feb 20, 2025
Grant date	—

Abstract

A method for measuring relative concentrations of materials in a mixture includes providing an emission coil and at least one reception coil, providing a mixture with n materials having different magnetic susceptibilities, and introducing the mixture into the reception coil. Using a voltage generator the emission coil is supplied with at least one nonzero excitation frequency so as to generate an excitation magnetic field and the signal of the voltage induced in the reception coil is measured. Relative concentrations of the n materials are determined based on comparison between the overall susceptibility of the mixture as obtained through the voltage measurement and that of a reference mixture for which the relative concentrations of the n materials are known.

First claim

1 . A method for measuring relative concentrations of materials of a mixture, comprising:
a/ providing an emission coil and at least one reception coil; b/ providing a mixture comprising n materials with different magnetic susceptibilities; c/ introducing the mixture into the at least one reception coil; d/ using an electric voltage generator to supply the emission coil with at least one non-zero excitation frequency so as to generate an excitation magnetic field, applying a given voltage by varying the at least one excitation frequency; e/ measuring a signal of the electric voltage induced in the at least one reception coil; and f/ determining the relative concentrations of the n materials based on a comparison between an overall susceptibility of the mixture obtained by the voltage measurement according to e/ and that of a reference mixture for which relative concentrations of the n materials are known.

2 . The measurement method as claimed in claim 1 , with wherein the mixture provided according to b/ is a binary mixture of materials with two different magnetic susceptibilities (χ1, χ2).

3 . The measurement method as claimed in claim 1 , wherein the mixture provided according to b/ is a mixture comprising more than two materials, with one of the materials having a much higher susceptibility, by a factor of 100, than that of the other materials.

4 . The measurement method as claimed in claim 1 , comprising, after b/, weighing the mixture so as to obtain, in f), a relative mass concentration of the mixture.

5 . The measurement method as claimed in claim 2 , comprising, in f), based on a mass of the mixturem(mix)=m1+m2, determining the susceptibility of the mixture provided using the relationship:

χmix
=

m
⁢
1
⁢
χ1

m
⁢
1

+

m
⁢
2

+

m
⁢
2
⁢
χ2

m
⁢
1

+

m
⁢
2

 and determining respective mass concentrations of the materials using the following relationships:

m
⁢
1

=

m
⁡
(
mix
)

⁢

(

χmix
-
χ2

χ1
-
χ2

)

,

and

m
⁢
2

=

m
⁡
(
mix
)

⁢

(

χmix
-
χ1

χ2
-
χ1

)

.

6 . The measurement method as claimed in claim 1 , further comprising, in e/, an in-phase measurement of the signal of the electric voltage induced in the at least one reception coil and/or a phase quadrature measurement so as to obtain the modulus of the signal.

7 . The measurement method as claimed in claim 1 , wherein the reception coil is tuned so that its resonant frequency is substantially equal to at least one excitation frequency.

8 . The measurement method as claimed in claim 1 , wherein the mixture provided according to step b/ is in a form of a solid compound.

9 . The measurement method as claimed in claim 1 , wherein a/ comprises providing a single reception coil, and the method further comprises, before c/, carrying out d/ and e/ so as to obtain a basic signal representing an empty single reception coil.

10 . The measurement method as claimed in claim 1 , wherein a/ comprises providing two reception coils, the method comprising, before f/,
repeating c/ to e/ with each of the two reception coils, and subtracting, between the two measurements, the signals induced by the two coils.

11 . The measurement method as claimed in claim 10 , comprising electrically connecting the two reception coils in series and tuning their respective reception frequencies.

12 . The method as claimed in claim 1 , wherein e/ is carried out for each excitation frequency, with synchronous detection.

13 . The measurement method as claimed in claim 1 , wherein e/ is made up of several measurements, each at a reception frequency around a resonant frequency of the at least one reception coil.

14 . The measurement method as claimed in claim 1 , wherein d/ is carried out so as to generate an excitation magnetic field with a value of less than 50 mT.

15 . The measurement method as claimed in claim 1 , when the mixture comprises a ferromagnetic material, comprising, before c/, exposing the mixture to a constant magnetic field.

16 . A system for measuring relative concentrations of n materials of a mixture, configured to implement the method as claimed in claim 1 , comprising:
the electric voltage generator being configured to generate at least one excitation frequency, the generator being a variable-frequency low-frequency generator; the emission coil being connected to the generator; the at least one reception coil having a shape configured to receive the mixture comprising the n materials with different magnetic susceptibilities and having a reception frequency of which is tuned to the at least one excitation frequency; and voltage measurement means connected to the at least one reception coil.

17 . The system as claimed in claim 16 , comprising two reception coils electrically connected in series, the respective reception frequencies of which are tuned.

Assignees

• Commissariat Energie Atomique

Inventors

• Pannetier-Lecoeur Myriam
• Fermon Claude
• Solignac Aurélie
• Martinez Julien
• Royet Vincent

Classifications

• G01N27/023

  where the material is placed in the field of a coil · CPC title

• G01N27/72 Primary

  by investigating magnetic variables · CPC title

• G21C21/00

  Apparatus or processes specially adapted to the manufacture of reactors or parts thereof (in general section B, e.g. B23) · CPC title

• G21C3/623

  Oxide fuels · CPC title

• G01R33/16 Primary

  Measuring susceptibility {(G01R33/1238 takes precedence)} · CPC title