JPS59214746A - Spin-echo measuring device - Google Patents

Abstract

PURPOSE:To measure an echo signal with a good S/N ratio and sensitivity, by providing a microwave detecting means, which is connected to an output port provided at a position having about 90 degrees with an input port with respect to the central axis of a circular cylinder of a cavity resonator. CONSTITUTION:Microwave pulses generated in a pulse generator 1 are supplied to a circular cylinder type cavity resonator 6 through an attenuator 5. The cavity resonator 6 has an input port 7 and an output port 8. The two ports are provided so that an angle of 90 degrees is formed with respect to a central axis O of the circular cylinder. The microwave extracted through a waveguide 10 is guided to a microwave detector 4 through a limiter 11 and detected. The isolation between the input side and the output side is -20dB or more. In comparison with a conventional device, the leakage of the microwave due to ringing becomes 1/100 or less. The foot due to the ringing is quickly attenuated. Since the effect of the ringing is quickly attenuated, T can be shortened. The echo signal can be detected under the state the signal strength is large by the amount corresponding to this shortened amount with a good S/N ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron spin resonance apparatus, and particularly to an electron spin resonance apparatus suitable for spin echo measurements.

Figure 1 shows a conventional groove configuration used when performing spin echo measurements with an electron spin resonance apparatus. In the figure, 1 is a microwave pulse generator, 2 is a magic 1 circuit, and 3 is a magic 1 circuit 2. The connected cavity resonator 4 is a microwave detector for receiving the reflected wave from the cavity resonator 3 taken out from the Magic 1 circuit 2. In actual measurement, the interval −[J is
A pulse train consisting of a π/2 pulse (a microwave pulse with a time width and intensity that rotates the electron spin by 90') and a microwave pulse with a time width and intensity that rotates the electron spin by <180' is the same as the π pulse. The echo signal (3[E) that appears after the period T is detected.Then, by plotting the change in when -1- is avoided, the phase 72 relationship between the nucleus and the electron can be determined. For example, the Nieko signal is directly converted and the C spectrum signals are converted to C spectrum signals.

However, in the conventional device C shown in FIG. 1, even if the pulse generator correctly generates the pulse train shown in FIG. Due to ringing, etc. that occurs at the falling edge of the wave pulse, the microphone wave reflected from the resonator 3 is shown in Figure 2 (
As shown in b), J: The signal had a very large tail, and the echo signal, which had an intensity of 1/106 or less of the input pulse, was hidden in the tail and was not easy to detect.

It is also possible to detect the echo signal after the intensity of the tail becomes smaller by lengthening V, but since the intensity of the echo signal becomes smaller as T becomes longer, detection becomes difficult in this case as well.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a spin 1-coe measurement device that can easily detect echo signals.

The present invention comprises a means for creating a microwave pulse or a pulse train, a cylindrical cavity resonator in which the microwave and microwaves from the pulse creating means are installed on a surface and supplied to the inside from an input hole 1c, and the cavity. It is characterized by comprising a microwave detection means connected to an output hole numbered at a position making an angle of approximately 90 degrees with the input hole with respect to the cylindrical center axis of the body resonator. Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 3 shows the configuration of an embodiment of the present invention, and the same components as in the embodiment of FIG. 1 are given the same numbers. Third
In the figure, a microwave pulse generated from a pulse generator 1 is transmitted through an attenuator 5 inside a cylinder and has a high-frequency magnetic field symmetrical to a certain plane passing through the center of the cylinder, for example 1'.
It is supplied to the E11n mode cylindrical cavity resonator 6. The cavity resonator 6 is shown in FIG.
), it has an input hole 7 and an output hole 8, and the two holes are opened so as to form an angle of 90 degrees with respect to the central axis of the cylinder. In Fig. 4, 9 is an input waveguide, and 10 is an output waveguide.
The microwave extracted through the microwave is guided to the microwave detector 4 via the limiter 11 and detected. The obtained detection signal 13 is sent to a computer 14 and a recorder 15 via an amplifier 12 and an A-D converter 13. 16
is a magnet that applies a DC magnetic field to the resonator.

FIG. 5 shows the distribution of the microwave magnetic field within the cylindrical cavity resonator 6, taking the 1' E 1.12 mode as an example. As can be seen from the figure, two closed-loop magnetic fields are generated inside the resonator, and the sample tube S containing the sample is inserted into the boundary between the two magnetic fields. The magnetic field in this portion is generated in the direction (y direction) connecting the central axis O and the input hole 7, as shown by the broken line in FIG.

In the above-mentioned configuration, at the position of the output hole 8, the magnetic field is directed in the direction of the arrow C as shown in FIG. Leakage f1 leaks to the outside only when the direction of the magnetic field deviates from arrow C, and the leakage is maximum when the direction of the magnetic field points toward the output hole 10.

The above-mentioned component when ringing occurs is actually - due to the fact that the cylindrical surface is not a perfect circle, in the x direction as shown by C'.
It has a b component. (FIG. 4(b)) The component in the direction from O toward the output hole 8 caused by the shift is as small as d. In this regard, in the conventional example shown in Fig. 1 in which the manual hole and the output hole are the same, the y-direction component from 0 to the output hole becomes extremely large as e, and the microwave leaks to the outside by that much, as shown in Fig. 2 ( As shown in b), this caused the hem to be drawn significantly.

According to actual measurements by the inventor, in the present invention, the power ratio of isolation between the input side and the output side is more than 1206B, and therefore, compared to the conventional device in which isolation between the input side and the output side was impossible, microwaves due to belling Leakage is 1/10
This means that the value becomes less than 0, and the tail caused by ringing quickly attenuates as shown in FIG. 2(C). In this way, the effect of ringing quickly subsides, so that ■ can be shortened, and the intensity is correspondingly large] L = 1 - signal S
It becomes possible to detect with a good N ratio.

On the other hand, when considering the detected resonance signal intensity, the signal intensity induced immediately after applying an excitation pulse is Mx
(t) (signal intensity taken out from hole 7), My(
t) (signal strength taken out from hole 8), MX
(t) and MY(t) are each expressed as follows.

Mx (t) = MOCO3ωt −exD (
-X/T2) My (t) = Mo sin c
c>t-exp (-X/1-2>In the above equation, Mo is the magnetization base level in equilibrium, ω is the Larmor frequency, and T2 is the transverse relaxation time.

Mx(t) corresponds to the conventional example shown in FIG. 1 in which detection is performed from the input hole, and My(t) corresponds to the case of the present invention.

As you can see by comparing the above equations, MX(t) and MY(1)
Although there is a phase difference of 90°, the signal strength is the same. Therefore, in the present invention, even if the influence of ringing is suppressed, the resonance signal is not suppressed, and the resonance signal can be detected at the same level as the conventional example shown in FIG.

As described in detail above, according to the present invention, an apparatus capable of measuring echo signals with a high signal-to-noise ratio and high sensitivity is realized.

Note that the input hole and the output hole only need to form an angle of 90' with respect to the axis O, and it goes without saying that the output hole 8 may be provided at a position where the input hole 7 is rotated 90 degrees around the axis O, for example. stomach.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the conventional configuration, Fig. 2 is a waveform diagram to explain the conventional problems and a waveform diagram based on the present invention, and Fig. 3 is a diagram showing the conventional configuration.
The figure does not show the configuration of an embodiment of the present invention, and FIG.
-A and B-8 sectional views, and FIG. 5 are diagrams for showing modes within the resonator. 1: Microwave pulse generator, 4: Microphone [1 wave detector, 6: Cylindrical cavity resonator, 7:
Input hole, 8: Output hole, 9, 10: Hydraulic wave tube, 16: Magnet. Patent application population Hondenshi Co., Ltd. Representative Imai-husband Figure 4 (a) Figure 4 (b)

Claims (1)

[Claims] A means for creating a microwave pulse or a pulse train; a cylindrical cavity resonator into which the microwave from the pulse creating means is supplied through an input hole provided on the periphery; A spin echo characterized by comprising microwave detection means connected to an output hole located at a position at an angle of approximately 90' with respect to the central axis of the air conditioning resonator with respect to the input horn hole. measuring device.