JPH0324487A - Nuclear magnetic resonance probe - Google Patents

Abstract

PURPOSE:To prevent a lowering of resolutions by heating a sample part concentratedly above a part facing coils wound in the perimeter of a test tube to suppress convection within the test tube. CONSTITUTION:Air kept at an optional temperature by a temperature adjusting means 10 is introduced to an air reservoir 7 to keep a temperature of a part above saddle-type coils 3a and 3b wound on a test tube 1 with nozzles 6a and 6c. This heating temperature is set at a value slightly higher than a rising temperature by an induction heating from a transmitting circuit 5. Thus, the temperature of a sample 2 above the coils 3a and 3b becomes higher than the temperature thereof 2 at a position facing the coils 3a and 3b to eliminate convection within the tube 1 thereby enabling prevention of a drop in resolutions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a probe used in a nuclear magnetic resonance apparatus (NMR), and particularly provides a probe capable of improving resolution.

[Prior Art] Recently, in NMR, the frequency of high-frequency waves that irradiate a sample has become extremely high, reaching several hundred MHz.

[Problems to be Solved by the Invention] As the frequency with which the sample is irradiated increases as described above, the temperature of the sample increases due to dielectric heating. adversely affects resolution. Furthermore, the high-frequency power supplied to the probe coil is increasing, and the sample temperature is also rising due to the heat generated by the coil. This temperature increase is particularly significant when decoupling is performed.

The present inventor has confirmed that the decrease in resolution as the temperature rises is mainly due to the generation of convection inside the sample tube due to the rise in temperature.

Therefore, the present invention has been made in view of the above points, and
The object of the present invention is to provide a probe that can prevent a decrease in resolution by suppressing convection inside a sample tube.

[Means for Solving the Problems] In order to achieve the above object, the probe of the present invention includes a sample tube containing a sample, and a coil placed on the outer periphery of the sample tube for irradiating a high-frequency magnetic field to the sample liquid. The probe is characterized in that it is provided with means for intensively heating a portion of the sample above the portion facing the coil wound around the sample tube.

Hereinafter, one embodiment of the present invention will be explained in detail based on the drawings.

[Example] Fig. 1 is a schematic diagram showing an example of a probe according to the present invention, and Fig. 2 is an enlarged sectional view showing the main part of the present invention.

In FIG. 1, 1 is a sample tube, and a sample 2 is housed inside. 3a and 3b are saddle-shaped coils arranged so as to sandwich the sample 2 therebetween, and are used to irradiate the sample 2 with a high-frequency magnetic field. Reference numeral 4 denotes a bobbin for holding these coils, which is arranged around the outer periphery of the sample tube with an arbitrary gap maintained therebetween.

5 is an observation transmitting circuit for applying high frequency power to the coils 3a and 3b.

6a to 6d are nozzles provided above the coils 3a and 3b of the bobbin 4, and each nozzle is a second nozzle.
As shown in the figure, they are arranged at approximately equal intervals, and their inner tips are arranged close to the sample tube 1. Further, the outer end of each nozzle communicates with a ring-shaped air reservoir 7 fixed to the outer periphery of the bobbin 4. 8 is a compressor for supplying air into the air reservoir 7 via the vibrator 9; 10 is a temperature control means provided in the middle of the pipe 9; and 11 is a human power for setting the temperature of this temperature control means. It is a means.

By doing this, the air from the compressor 8 maintained at an arbitrary temperature by the temperature control means 10 is introduced into the air reservoir 7 and is ejected from each nozzle 6a to 6d, so that the air in the upper part of the sample 2 than the coils 3a and 3b is The temperature can be maintained at any desired temperature. Further, when desired high frequency power is supplied to the coils 3a and 3b from the transmitting circuit 5, the temperature of the portion of the sample 2 facing the coil increases to a certain temperature by dielectric heating or the like. Therefore, if the heating temperature of the air by the temperature adjustment means 10 is set to a temperature slightly higher than the temperature at which the sample rises due to dielectric heating, etc., the sample temperature above the coil will be higher than the sample temperature at the position facing the coil. Therefore, convection of the sample can be prevented. Therefore, it is sufficient to measure the temperature rise of the sample in advance according to the supplied power, and then change the set temperature of the temperature adjustment means 10 in accordance with the supplied power. Here, a memory is built into the input means 11, and the above-mentioned temperature rise of the sample according to the supplied power is stored in this memory as a table, and the supplied power to be observed from the transmitting circuit 5 is calculated as shown by the dotted line in FIG. If the configuration is such that the output signal shown in FIG.
The temperature of the air blown into the sample tube 1 can be automatically set in conjunction with the power supply operation to the sample tube 1.

It should be noted that the above description is an example of the present invention, and many modifications can be made in implementing the present invention. For example, in the above embodiment, the nozzle is passed through the bobbin, but the thin hole may be formed directly in the bobbin without using a nozzle.

Further, in the above embodiment, four nozzles were used to spray air onto the sample tube, but the number is not limited to this and any number may be used.

Furthermore, as another embodiment, a plurality of nozzle groups arranged as in the above embodiment may be installed along the axial direction of the sample tube. By doing so, the sample can be efficiently heated according to the amount of sample contained in the sample tube.

Furthermore, in the above embodiment, it has been described that the temperature of the sample is measured in advance according to the supplied power, but it is also possible to provide means for measuring the temperature of the sample at the portion facing the coil, and to control the temperature adjustment means using the output signal thereof. It may be configured as follows.

Furthermore, although the above embodiment shows a case where heated air is blown, nitrogen gas or an inert gas may also be used.

Further, in the above embodiment, heated air is blown onto the sample tube as the sample heating means, but the method is not limited to this, and infrared rays, microwaves, lasers, etc. may also be used.

Further, in the above embodiment, a saddle type coil is used, but a solenoid type coil may also be used.

[Effect] As detailed above, according to the present invention, as the temperature of the part of the sample facing the coil increases, the temperature of the part of the sample above the coil can also be increased at the same time. Convection is no longer generated inside the tube, and resolution degradation can be prevented.

[Brief explanation of drawings]

FIG. 1 is a schematic view showing an example of a probe according to the present invention, and FIG. 2 is an enlarged sectional view showing essential parts of the present invention. 1: Sample tube 2: Samples 3a, 3b: Saddle-shaped coil 4: Bobbin 5: Transmission circuit

Claims (1)

[Claims] In a probe equipped with a sample tube containing a sample and a coil placed on the outer periphery of the sample tube for irradiating a high-frequency magnetic field to the sample liquid, from the part facing the coil wound around the sample tube. A nuclear magnetic resonance probe characterized in that it is provided with means for intensively heating an upper sample portion.