DE1670508C - Solution pairs with gyromagnetic properties for magnetic measurements with nuclear resonance and electronic resonance - Google Patents

Description

The invention relates to pairs of solutions with gyromagnetic properties for magnetic Measurements with nuclear and electronic resonance, especially in magnetometers, are usable. A magnetometer of this type is described in German Auslegeschrift 1,516,924.

In the aforementioned patent, two pairs of solutions with gyromagnetic properties are given, which are used in the magnetometer described, namely

a) a first pair formed by a first solution of ditertiobutyl nitroxide (hereinafter abbreviated DTBN called), which is dissolved in a solvent that (in terms of volume) half through Water and half formed by acetone, and a second solution of triacetonamine nitroxide (hereinafter referred to as TANO for short), which is dissolved in a solvent that is divided by seven parts of water and three parts Ethylene glycol is formed with the common electronic resonance line being 68.5 MHz;

b) a second pair that is replaced by a first solution of TANO and a second solution of TANOXIM or tetramethyl-2,2,6,6-azo-1-cyclohexynonoxime-4-oxide-1 is formed.

These two pairs of solutions, which contain two different paramagnetic substances, give good results, however, they have a number of disadvantages, namely the following:

The TANOXIM has a low polarization factor, so that the amplitude of the line of the TANOXIM is much weaker than that of the corresponding line of TANO, so that when using the second mentioned solution pair no good compensation of the energy emission and absorption is possible.

The DTBN is only stable in a very pure state, but can only be produced with great difficulty in this state (in practice, the DTBN solution, which has changed, often had to be replaced); In addition, the solutions of the first pair above were strongly aqueous solutions, the freezing point of which was only a little below ⁰ ° C., so that there was a risk of them freezing during storage.

It has now been discovered that the TANO, which does not have the disadvantages of the TANOXIM and the DTBN (Especially because it can be produced in its pure state and in this a very good one Stability), which allows the production of two solutions which are the same for the same high frequency Have a resonance line with opposite effects in the two solutions, d. i.e., those at their saturation

3 4

an energy absorption at the core frequency of a magnetic field with strength H by the formula

Solvent in one of the solutions and a / = γΗβπ is given, and on the other hand by a

Energy emission at the core frequency of the paramagnetic solution dissolved in this solvent

using in the other solution.!. Substance is formed, which in its molecule an un-

Surprisingly, it was also found that 5 has paired electron that interacts

for a TANO solution that represents the unpaired electron with an atomic nucleus of this substance, the one

of the TANO corresponding electronic resonance - electronically saturable resonance line with one of

frequency to a non-negligible extent in radio zero different frequency in a magnetic field

tion of the solvent used is changed. of size zero.

This property allows the co- io The magnetometer also contains devices

Adjust the subsidence of the two halves of the sample to saturate this electronic resonance.

that when applying a maximum frequency field with the by a maximum frequency oscillator 7 with the

Frequency 62.65 MHz the two opposite frequencies of this line and a coil 8 ε ^ε ^ ^{ιΐ £ ΐε1}

Lines of electronic resonance become saturated. that is fed by this generator and

According to the invention, such magnetic 15 is immersed in the liquid sample 12 in the container 6

Measurements with nuclear magnetic resonance and electronic (to clarify FIG. 1, coils 2 and 8 are

Resonance, in particular by means of a magnetometer, shown separately from the container 6),

a pair of solutions provided by triacetone, an electromagnetic screen, not shown

Nitroxide is formed in two different solutions between the one immersed in the container 6 the two triacetonamine solutions, the coil 8 on the one hand and the container 6 surrounding it

have the same electronic resonance line and the coils 1 and 2 are provided on the other hand, in the

Saturation of this common electronic nuclear magnetic resonance frequency permeable and_ in the case of the elec-

sonanzlinie in one of the solutions an energy ab- tronic resonance frequency is impermeable.

sorption and in the other solution a stimulated Furthermore, there is a condensation energy emission at the terminals of the coil 1 Arranged at the common nuclear resonance generator 9, which forms a resonance circuit with this

generated frequency of the two solutions. forms, which is based on the nuclear magnetic resonance frequency j a D-

In a further embodiment of the invention, the first is tuned and a low quality or Uoer-

Solvent pure dimethoxyethane (abbreviated to stress coefficient Q (of the order of magnitude)

DME) and the second solvent pure methanol. 30 5) has to take the frequency (pulUng) too

According to the further invention, it can also reduce 30 that would occur if Q was very large

the following concentrations are used: would. .

•, _m . _c . ·.,, Finally, a frequency meter 10 is at the output

a) as the first solvent DME in the pure state amplifier 5 arranged to measure the core and as the second solvent a mixture of * n _{ananzfreauenz} or Larmor frequency /, about 73 volume percent DME and about 27 volume ^^ Ά ^^^ immediately in magnetic percent water, _{tjschen field strengths can be calibrated} , since H

b) as the first solvent a mixture of about _ infly

73 percent by volume DME and about 27 vol- ume, _{m bet} ' _r j _e b produces the saturation of the electronic

percent water and, as a second solvent, a reversal of the occupation of the resonance line

a mixture of about 88 percent by volume methanol ₄₀ nuclear spins i _n the sample of the container 6, which the

and about 12 percent by volume water. stimulated energy emission in nuclear magnetic resonance

In a further embodiment of the invention, the frequency is due to the back to the lower level.

preferred concentration of triacetonamine-nitro-sweeping nuclear spins result. This stimui.erie

Oxide in every solution near the millimolecular emission expresses itself in a moment aas sicn π

Concentration. 45 of the nuclear magnetic resonance frequency (about 2100 Hz ur das

The invention is described below with reference to the proton in the earth's magnetic field

explained on the drawing by way of example. considerable coupling m between the ( ^nor ™ ^ler ™

F i g. 1 schematically shows the circuit structure of decoupled coils 1 and 2, but with this

a simple magnetometer with an oscillator frequency. As a result «« m ™ with spin coupling · 50 coupled oscillator in which the nuclear magnetic resonance curve.

F i g. 2 schematically shows the circuit structure of one which is relatively pointed (since the resonance

Magnetometer, in which a pair of solutions are narrow according to the lines), plays the same role as

Frfindune uses the resonance curve of an oscillating circuit η a uDiicnen

^E tÄSS3, ™. «F F ί g. 1 is initially an oscillator that is fed back to it, where g ™ ^ * <. »

reminds that an oscillator with spin coupling in the 55 is the entrainment and thus for the factual work

essentially contains two Bloch coils 1 and 2, is that the Vf ^^ jX

which at the input 3 or the output 4 of a certain threshold value surpasses g- ^we ^

linear amplifier 5 are connected. De coils for each oscillator with Spinkopp "" S ^{calculate 1} ^

1 and 2 are electromagnetic as far as possible (wöbe, also to be considered. '£ that em Te 1 de

decoupled, the directions A-, Y of their axes 60 energy of the oscillator at II for transmission aut

stand vertically on top of each other. ^{Frequency meter} "> ^en i nomme" ^ ¹ ™ ^ _{and the}

The coils 1 and 2 are on a container 6 according to this explanation of the structure and each

wound, which contains a liquid sample 12, the one- working method of magnetometers with Spnkg

sdts by a solvent with atomic nuclei (ins- with a single solution with J ^^ f ^

special protons) with a different from zero 6 ₅ properties should now be accepted

magnetic and kinetic moment, d. H. a magnetometer with spin coupling

exactly determined gyromagnetic ratio ,,, which a ^ gemaBe. ^

where the resonance frequency / these atomic nuclei are used in with gyromagnetic properties.

The magnetometer of FIG. 2 initially contains a first and a second container 6a, 6b, which reveal the inventive pair of solutions 12a, 126 with gyromagnetic properties.

In a first embodiment, the container 6a contains a solution 12a, which is formed by a millimolecular solution of TANO in pure DME, while the second container 6b contains a second solution Mb , which is formed by a millimolecular solution.

forming a capacitor 9, with the coils Xa and 1 b a resonant circuit for NMR frequency.

The operation of the magnetometer with a solution pair according to the invention with a gyromagnetic η Features is the following:

The oscillator 7 feeds the two coils 8g and 86 at a maximum frequency, which feed into the solutions 12a

molecular solution Tano in a mixture of io and 126 of the container 6a and 66 appear being 73 volume percent DME and 27 volume percent water is i.ehildet electronic resonance line of TANO in each ^{of these Losu} saturate "Sen.

In a second embodiment, the solution is the saturation of the electronic resonance lines

12a produces a millimolecular solution of TANO in one of the solutions (due to the coupling mixture of 73 volume percent DME and 27 volume percent water between the electronic spins and the nuclear spin percent water while the second solution 126 of this solution) increases the energy absorption Lrrh an Millimolecular solution of TANO in at the nuclear resonance frequency of this solution, while a mixture of 88 volume percent methanol and the saturation of the electronic resonance line of 1 ■> volume percent water is formed. second solution (due to the coupling between the

~ In a third embodiment, which by the way * <> electronic spins and the nuclear spins of this second is the preferred solution 12e is a milli solution) a stimulated energy emission with the molecular solution of TANO in pure DME and nuclear resonance frequency of this second solution generates the second solution 126 a millimolecular solution which, by the way, is the same as the core frequency of TANO in pure methanol. first solution is, namely the resonance frequency of the

The common electronic resonance line for the 25 hydrogen nuclei or protons of the solvent in both samples of these pairs is of the order of magnitude (DME, methanol or water) in the magnetic field. MalJie 62 65 MHz during the nuclear magnetic resonance in which the containers 6a and 6b are located, frequency in the magnetic earth field that of the water between the coils la and la of the first pair

Substance is, namely about 2100 Hz. And the coils 16 and 26 of the second pair

In combination with these two containers, 30 contains a coupling via the nuclear spins that are in the below

the magnetometer of FIG. 2 following parts:

an oscillator 7 which generates an electromotive force at the highest frequency of the electronic

Referring to FIG. 1 acts as explained. Since the axes of the receiving coils Io and 16 are parallel but are arranged in opposite directions, the electromotive forces are compensated

Resonance liquid of the two solutions 12a and 12 35 separated, which in these coils through the outer

supplies, that is, with the frequency of 62.65 MHz in the above embodiments, two coils Sa and 86 (with e.g. two windings), which are fed in parallel by the oscillator 7 and immerse in the solutions 12a and 126, respectively, in order to saturate the electronic resonance line with 62.65 MHz in each of these,

electromagnetic field and the movements of the magnetometer are induced. The excitation coils 1 a, 1 b are connected in series, their axes having the same direction as the axes of the coils 1 a, 16. Since the two coils 2a and la of the one part 26 and 16 on the other hand not decoupled and in a natural way, it directs it so that the coupling coefficient of mutual induction m _a between the coils 2a and la and mj between

a linear amplifier 5

_{two pairs of coils 45} parallel to one another, the coils 26 and 6 are opposed to one another:

1α-2σ and 16-26, where the first pair 1α-2α with dh m _b -m _a . The lifting of the induced

the first solution 12a and the second pair 16-26 is coupled to the second solution 126 , the first coil la of the first pair in series with the first coil 1 6 of the second pair to the

Input terminals 3 of the linear amplifier 5

is connected, while the second coil la of the first pair and the second coil Ib of the second pair in parallel to output 4 of the

electromotive forces at the input terminals 3 of the amplifier 5 are completed by means of the potentiometer 13.

So that those originating from the nuclei, in the two receiving coils 1 a, 16 induced electromotive forces at the input terminals 3 of the amplifier add 5, it is necessary (and sufficient) that the macroscopic resultant

Amplifier are connected. In particular 55 of the magnetic moments of the entirety of the

Atomic nuclei of the two samples are in phase opposition, since the coils Xa and 16 are wound in opposite directions and the couplings between the two coils la, la on the one hand and 16, Ib on the other hand are specified in accordance with the construction amplifier 60.

The opposite phase of the two macroscopic

the arrangement formed by the two parallel coils la and 26 between an output terminal of the amplifier and the body is geschähet via a compensation potentiometer 13, while the other output terminal has the body shortage,

a frequency meter 10, which at 11 is connected to the components through the use of an output terminal of the amplifier solution pair lla and 126 with the above characteristic, which has no body contact around the shaft, the saturation of the common frequency of the output voltage of the amplifier 6s to measure the electronic resonance line of the two solutions in, which is proportional to the magnetic field of the two solutions, mutually macroscopic. in which the two containers 6a and 66 components are produced, arranged side by side, and so one finally obtains at the path of the linear

Amplifier 5 erne voltage with a frequency which is exactly proportional to the strength of the magnetic field which prevails in the zone in which the two containers 6a and 66 are located. This frequency is measured by a frequency meter 10 of known design, in particular a frequency meter which is suitable for measuring a frequency in the order of magnitude of 2100 Hz if it is a question of measuring the strength of the earth's magnetic field.

The solution pairs according to the invention have compared to the two in the aforementioned German The pairs described in the patent, whose disadvantages were mentioned at the beginning (weak polarization of the TANOXIM, instability of the DTBN and risk of freezing of the aqueous solutions), the following advantages: The DME can be produced in a very pure state. In this state it is very stable and grips do not turn on the TANO, especially if it is anhydrous. So it is more convenient to have DME in its pure state to use as a solvent of the TANO.

The methanol is also a stable compound and does not attack the TANO. The risk of freezing is very low, especially when pure methanol and DME are used as solvents because the freezing temperature of DME is about -58 ° C and of methanol about -95 ° C.

The pair of solutions according to the invention is thus by TANO in pure DME to form the first solution and TANO in pure methanol to form the second solution formed.

With this preferred pair, magnetometers with magnetic resonance can be made, S who work for many months and even many years, especially in an airplane without having to change the solutions with gyromagnetic properties. A Such a magnetometer has the advantages of the ίο magnetometer according to FIG. 3 of said patent specification, namely:

very accurate measurement of weak magnetic fields, e.g. B. the earth's magnetic field;

the measurement is insensitive to any movement and to external electromagnetic fields;

there is only one forbidden axis (if the magnetic field runs along this axis, it cannot be measured), namely the common direction of the four axes of the coils Ia-Ib, ao Ia-Ib. In an airplane, this direction is chosen so that it coincides with the axis of the airplane or is parallel to it.

The pairs of solutions according to the invention can be used in different types of magnetometers »5 den, also in those of the in the named Patent specification differ, in particular in a magnetometer in the German interpretation 1 591 867 described Art.

1 sheet of drawings

Claims (5)

Patent claims: 1. Pair of solutions with gyromagnetic properties for magnetic measurements with Nuclear magnetic resonance and electronic resonance, especially for a magnetometer with a first and a second container, which are arranged side by side and each have a solution of a solution pair containing gyromagnetic properties, each of which is represented by a paramagnetic Substance is formed which at least one electronic saturable by a high frequency radiation Has resonance line and is dissolved in a solvent which has a nuclear magnetic resonance frequency possesses, the pair of solutions being such that the same high frequency two opposite electronic lines excited, d. that is, the saturation of the resonance line of the paramagnetic Substance of the first solution (due to the coupling between the electronic spins and the nuclear spins in this solution) an increase in energy absorption at the nuclear resonance frequency this solution causes while the saturation of the electronic resonance line second solution (as a result of the coupling between the electronic spins and the nuclear spins of these second solution) a stimulated energy emission at the nuclear magnetic resonance frequency of this second Solution, which by the way is the same as the nuclear magnetic resonance frequency of the first solution, as well as with devices for saturating the common electronic resonance line of the two Solutions in the two containers, a linear amplifier, two pairs of mutually parallel Coils, a first pair being coupled to the first solution and the second pair being coupled to the second solution the first coil of the first pair and the first coil of the second pair being connected to the input of the linear amplifier are connected, while the second coil of the first pair and the second Srkile of the second pair to the output of the amplifier, and one connected to the output of the amplifier Frequency meter for measuring the output frequency of the amplifier, which is related to the strength of the Magnetic field in which the two containers are located, characterized in that that the solution pair is formed by triacetonamine nitroxide in two different solutions, the two triacetonamine solutions possess the same electronic resonance line and the saturation of this common electronic resonance line in one of the solutions an energy absorption and in the other solution a stimulated energy emission at the common nuclear magnetic resonance frequency of the two solutions generated. 2. Solution pair according to claim 1, characterized in that the first solvent is pure Dimethoxyethane and the second solvent is pure methanol. 3. Solution pair according to claim 1, characterized in that one of the solvents is dimethoxyethane in the pure state and the other a mixture of about 73 percent by volume dimethoxyethane and 27 percent by volume is water. 4. solution pair according to claim 1, characterized in "that one of the solvents Mixture of 73 percent by volume dimethoxyethane and 27 percent by volume water and the second Solvent is a mixture of 88 percent by volume methanol and 12 percent by volume water 5. pair of solutions according to one of claims 1 to 4, characterized in that the concentration of Triazutonamine Nitroxide in every solution in the Close to the millimolecular concentration.