JP3401389B2 - Loop gap resonator - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an improvement of a loop gap resonator used in an electron spin resonance device.

[0002]

2. Description of the Related Art FIG. 1 shows a loop gap resonator and a resonance frequency adjusting mechanism described in Japanese Patent Publication No. 3-79670. As shown in FIG. 1, the loop gap resonator has a structure in which a loop-shaped electrode 1 is cut by a gap 2 parallel to the axis O of the loop, and is supplied via a coupling with an external antenna circuit. A wave current flows through the electrode 1. At this time, the LC electrode is configured with the loop electrode 1 as the inductance L and the gap 2 as the capacitance C.

The resonance frequency of this loop gap resonator is basically determined by the loop length (loop diameter) and the size of the gap, that is, the shape, but it changes when the sample is placed inside the resonator. Will end up. Therefore, the resonator is provided with a resonance frequency adjusting mechanism so as to cope with such a change in the resonance frequency due to the sample.
That is, as shown in FIG. 1, by inserting the dielectric plate 3 into the gap 2, the capacitance C is changed to change the resonance frequency. It is possible to continuously change the resonance frequency by moving the dielectric in the direction of the arrow and changing the dielectric insertion amount in the gap.

[0004]

With such a configuration, when a sample having a large dielectric loss such as a biological sample is inserted into the resonator, if the height (axial length) H of the loop gap resonator is large, It is unavoidable that the Q value of the resonator is greatly reduced due to the dielectric loss of a portion other than the relatively narrow portion to be measured, and the resonance frequency is accordingly changed.

As a countermeasure against this, if the height H of the resonator is reduced, the Q value is reduced and the change in the resonance frequency is reduced, but the variable range of the resonance frequency performed by inserting the dielectric into the gap is narrowed. .

The present invention has been made in view of the above points, and the variable range of the resonance frequency is wide even if the height H of the resonator is reduced to reduce the Q value and the change of the resonance frequency. It is an object of the present invention to provide a loop gap resonator that can be manufactured.

[0007]

To achieve this object, the present invention provides a loop gap resonator including a loop portion and a gap portion, wherein the height of the gap portion is larger than the height of the loop portion in the axial direction. It is characterized by increasing.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a sectional view showing an example of the loop gap resonator according to the present invention. In FIG. 2, the loop gap resonator 11 is supported and fixed in the shield box 12 by fixing claws 13 made of, for example, fluororesin. In the loop gap resonator 11, a thin plate electrode having a predetermined width and a predetermined length is bent at a central portion in a loop shape, and both ends of the electrode at the gap 14 are gap extension electrodes 15.
It is bent so that it protrudes parallel to the outside of the loop.

The dielectric plate 16 is inserted into the gap formed between the gap extension electrodes 15. The dielectric plate 16 is fixed to the tip of the support plate 17 with screws or the like. By moving the support plate 17 forward and backward from the outside of the shield box 12 by the fine movement mechanism 18, the dielectric plate 16 is inserted into the gap. The insertion amount of is adjusted.

FIG. 3 shows a sectional view and a side view in which only the loop gap resonator 11 is extracted and drawn. As can be seen from the figure, in this resonator, the height HG of the portion of the gap extension electrode 15 is made larger than the height HL of the loop portion.

According to this structure, even if the height of the loop portion into which the sample is inserted is reduced, the electrode facing area of the gap portion is increased and the amount of the dielectric material inserted can be greatly varied, so that the frequency variable range is wide. Can be taken.

In the above embodiment, the dielectric was moved back and forth toward the center axis of the loop gap resonator.
It goes without saying that it may be moved in the direction along the central axis as shown in FIG.

FIG. 4 shows an embodiment in which the present invention is applied to a loop gap resonator having no gap extension electrode.

[0014]

As described above in detail, in the present invention, since the height of the gap portion is made larger than the height of the loop portion, the height H of the resonator is made smaller to lower the Q value and change the resonance frequency. A loop gap resonator capable of widening the variable range of the resonance frequency can be realized even if the number is reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a loop gap resonator described in Japanese Patent Publication No. 3-79670.

FIG. 2 is a sectional view showing an example of a loop gap resonator embodying the present invention.

3A and 3B are a cross-sectional view and a side view in which only the loop gap resonator 11 is extracted and drawn in the embodiment of FIG.

FIG. 4 is a diagram showing an example in which the present invention is applied to a loop gap resonator having no loop extension electrode.

[Explanation of symbols]

11 Loop gap resonator 12 shield box 13 Fixed claw 14 Gap 15 Gap extension electrode 16 Dielectric plate 17 Support plate 18 Fine movement mechanism

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 24/00-24/14 G01R 33/20-33/64 JISST file (JOIS)

Claims (4)

(57) [Claims] 1. A loop gap resonator comprising a loop portion and a gap portion, wherein the height of the gap portion is larger than the height of the loop portion in the axial direction. 2. The loop gap resonator according to claim 1, further comprising a resonance frequency adjusting mechanism for adjusting the resonance frequency by moving the dielectric while inserting a dielectric into the gap. 3. The loop gap resonator according to claim 2, wherein the dielectric is moved in the gap in the direction of the central axis of the loop gap resonator. 4. The loop gap resonator according to claim 2, wherein the dielectric is moved within the gap in a direction to reciprocate in a direction in which a distance from a central axis of the loop gap resonator changes.