JP2002357649A - Sheet cavity resonator for electron spin resonance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet cavity resonator for electron spin resonance enhanced in transmittance of high frequency modulation magnetic field so as to be suitable for external modulation method. SOLUTION: This cavity resonator of X-band rectangular parallelepiped TE102 mode is blocked at one end with a copper plate 12 and has, at the other end, a flange part 20 for connecting a guide plate 16 having a connecting hole 14 to a waveguide 18, wherein the cavity length L is set equal to the intra-tube wavelength of microwave. Groove parts 24 and 26 are provided on the cavity wall (E-face) on both side surfaces of the cavity resonator 10, and insert holes 22 and 22 for inserting a measuring sample tube are provided on the H-face of the cavity resonator 10. The cavity wall thickness t1 of the groove parts 24 and 26 is set to about the thickness of the surface skin effect of modulation frequency. Magnetic field modulation coils not shown are buried in the groove parts 24 and 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cavity resonator used in an electron spin resonance apparatus, and more particularly to a thin cavity resonator for electron spin resonance which can measure an electron spin resonance signal with high sensitivity.

[0002]

2. Description of the Related Art Conventionally, in an electron spin resonance apparatus,
How superimposing the modulated magnetic field of frequency omega _m polarization static magnetic field B to improve the detection sensitivity, for amplification and detection of only a signal component of the frequency omega _m appearing at resonance is widely. On this occasion,
In order to avoid low frequency noise that is widely distributed in a signal amplifier including a microwave detector, the modulation frequency ω _m is desirably as high as possible within the response range of the microwave cavity resonator. about 100kHz as a frequency ω _m has been widely adopted. This modulation magnetic field is generated by passing a high-frequency current through a modulation coil disposed inside or outside the cavity resonator. The former is called (1) an internal modulation system, and the latter is called (2) an external modulation system. Are distinguished.

[0003]

However, the following problems are involved in the above-mentioned 100 kHz modulation (1) internal modulation system. That is, the Q of the resonant cavity is reduced due to the modulation coil provided inside the cavity resonator, and the internal coil is put into practical use with the efficient number of turns and shapes restricted to minimize the decrease in Q. Since the number of turns is only one or two turns, an excessively large modulation current must be supplied.Because the coil penetrates the inner wall of the resonant cavity, microwave leakage occurs, requiring careful operation, In addition, there is a problem that the through portion is often loosened due to an increase in coil temperature due to an excessive modulation current, and the like.

(2) In the case of the external modulation method, since the modulation magnetic field penetrates the side wall of the cavity resonator, an eddy current is generated on the side wall in a direction obstructing the modulation magnetic field.

There is a problem that the transmission of the modulation magnetic field into the cavity is significantly reduced. For example, if the side wall thickness is about 1.2 mm in the TE ₁₀₂ rectangular hexahedral cavity, the 100 kHz modulated magnetic field generated outside the cavity is attenuated to 10 ⁻⁴ or less inside the cavity. I will. For this reason, the required modulation intensity can hardly be obtained, which limits the improvement of the detection sensitivity. Accordingly, there is also a problem that an excessively large modulation magnetic field must be generated outside the cavity resonator.

[0006] A problem that noise is generated due to the vibration of the cavity. This is because an eddy current is generated on the side wall when a high-frequency magnetic field for modulating the magnetic field penetrates the side wall of the cavity, and this eddy current interferes with the applied static magnetic field and causes vibration in the cavity. is there. Since this vibration frequency is equal to the magnetic field modulation frequency, it has a great influence on the sensitivity.

[0007] The problem of sensitivity reduction caused by lowering the modulation frequency. In the above external modulation method, the modulation frequency is almost reduced to about 10 to 300 Hz and the thickness of the skin effect is made substantially equal to the side wall of the cavity. Avoids decay. However, in this case, there has been a problem that a decrease in sensitivity due to low-frequency noise of the signal amplifier cannot be avoided.

Therefore, an object of the present invention is to adopt an external modulation method which is more advantageous than the internal modulation method in that an excessive modulation current is not required, and to reduce the transmission attenuation of the modulation magnetic field into the cavity. It is an object of the present invention to provide a thin-plate cavity for electron spin resonance suitable for an external modulation system, which can perform highly sensitive measurement of electron spin resonance without causing unnecessary vibration of the cavity.

[0009]

According to the present invention, there is provided a thin plate resonator for electron spin resonance, wherein one end is closed by a conductor, and the other end has a hexahedral cavity having a flange for connection with a waveguide. The body resonator is characterized in that all of the metal parts of the pair of side walls arranged so as to be orthogonal to the magnetic field are formed to be as thin as the skin effect of the high-frequency modulation magnetic field.

[0010] The thin-plate resonator for electron spin resonance according to the present invention is a straight hexahedral resonator having one end closed by a conductor and a flange at the other end for connection to a waveguide. A pair of side walls arranged perpendicular to the magnetic field, a plywood in which a metal foil in which the thickness of the skin effect of the high-frequency modulated magnetic field is sufficiently thinner and an insulating material plate for reinforcing the metal foil are laminated. Can also.

In this case, the thickness of the entire metal portion on the side wall surface is preferably 30 to 100 μm, and the thickness of the latter metal foil is preferably 3 to 30 μm.

[0012]

According to the thin cavity resonator for electron spin resonance according to the present invention, the side wall surface arranged so as to be orthogonal to the magnetic field of the cavity resonator is thinned to a thickness of about the thickness of the skin effect of the modulation frequency. By using a metal plate or a plywood in which a metal foil and a reinforcing insulating material plate that are sufficiently thinner than the thickness of the skin effect are used, a high-frequency modulation magnetic field is hardly generated even in the external modulation method. It can be applied to the sample in the cavity without attenuation.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of a thin-plate cavity for electron spin resonance according to the present invention.

[0014] Figure 1 is an external perspective view of an electronic spin resonance thin cavity resonator showing an embodiment of the present invention, an example of X-band rectangular parallelepiped TE ₁₀₂ mode. In FIG. 1, reference numeral 10 denotes a cavity resonator, the cavity length L of the cavity resonator 10 is selected to be equal to the guide wavelength of the microwave, and one end of the cavity resonator 10 is soldered with a copper plate 12. Or it is closed by brazing. The other end of the cavity resonator 10 has a flange portion 20 for connecting the conductive plate 16 having the coupling hole 14 and the waveguide 18 connected to a microwave circuit (not shown). Connection hole 14 provided in conductive plate 16
Is selected to have a reflection coefficient suitable for the measurement conditions. Further, similarly to other electron spin resonance apparatuses, the cavity 10 is provided with insertion holes 22 for inserting a measurement sample tube through the H-plane of the cavity 10.

The feature of this embodiment is that grooves 24 and 26 are provided on the cavity side walls (surface E) on both side surfaces of the cavity resonator 10. A magnetic field modulation coil (not shown) is embedded in the grooves 24 and 26. At this time, the coil width W is selected to be substantially equal to the H-plane width so as not to impair the uniformity of the modulation magnetic field applied to the measurement sample in the cavity resonator 10.

The thickness t _{1 of the} cavity side walls of the grooves 24 and 26 is
The modulation frequency is engraved about the thickness of the skin effect or somewhat thinner leaving the side walls. The thickness of the skin effect depends on the material of the cavity resonator 10, the thickness _{t 1} of the cavity side wall of the groove 24, 26, for example, in the case of copper, it is sufficient even 30 to 100 [mu] m. It should be noted that this level of processing is currently at a processing level that can be sufficiently achieved by mechanical processing or electrolytic polishing. The grooves 24 and 26 of this size, which are cut in the waveguide frame, do not hinder the practical use, and the strength of the processing coil unit (not shown) is fixed in the grooves 24 and 26. There is no problem because it is reinforced.

[0017] For example, a copper material having the structure
_{When the} cavity resonator 10 having the grooves 24 and 26 having a thickness of 30 to 100 μm is used, the transmittance of the modulation magnetic field transmitted through the side wall even in the external modulation method is 53 to 28%, which is a practically acceptable level. The attenuation of the modulation magnetic field is suppressed.

In the above embodiment for the X band, thin grooves 24 and 26 are provided in a part of the E surface of the cavity resonator 10 in order to maintain the mechanical strength. As described above, when the cavity resonator itself becomes small, it goes without saying that the entire side wall (E surface) of the cavity resonator 10 can be made a thin plate.

FIG. 2 is an external perspective view showing another embodiment of a thin-plate cavity for electron spin resonance according to the present invention.
It is an example of a band hexahedral _{TE 102} mode. The cavity lower plate 32 is not shown for convenience of explanation. The material of the cavity 30 is a ceramic substrate for a printed circuit board or a microwave integrated circuit, which is frequently used recently, and the thin conductive foil 34 formed on the ceramic substrate is used as the inner wall of the cavity 30. It is configured. Cavity lower side plate 3
As shown in FIG. 2, on a ceramic substrate having a thickness T, a thickness t ₂
Is formed. The cavity lower plate 32 and the opposing cavity upper plate 36 are provided with insertion holes 38, 38 for inserting sample tubes at opposing positions, respectively.
Is chosen equal to the microwave guide wavelength,
One end of the cavity resonator 30 is closed by a ceramic substrate 40 on which a copper plate or a conductive foil 34 is formed. The other end of the cavity 30 is provided with a flange portion 42 for connecting a conductive plate 46 having a coupling hole 44 and the waveguide 18 connected to a microwave circuit (not shown). Again,
The coupling hole 44 provided in the conductive plate 46 is selected so as to have a reflection coefficient suitable for the measurement conditions as in the above embodiment. The end face 48 of the lower cavity plate 32 is plated with gold, and the inner wall of the cavity 30 is also plated with gold in order to increase the electrical conductivity and prevent the Q from being lowered by rusting. .

[0020] Thus configured electron spin resonance for thin cavity resonator 30, for example, a ceramic substrate for printed circuit board thickness T is 1.2 mm, 30 [mu] m copper as the thickness _{t 2} of the conductive foil 34 modulated magnetic field in the case of forming the foil 68% transmittance is obtained, cavity resonance without thickness t ₂ of the conductive foil 34 with a ceramic substrate for microwave modulated magnetic field in the case of 3~20μm is that most attenuated It can be applied to the sample in the vessel 30. It is easy to form the rectangular hexahedral cavity 30 by using these ceramic substrates, and a low-cost, high-performance thin cavity resonator for electron spin resonance can be manufactured using commercially available materials.

[0021]

As is clear from the above-described embodiment, according to the thin cavity resonator for electron spin resonance according to the present invention,
Even in the external modulation method, effective magnetic field modulation can be applied to the measurement sample by an appropriate high-frequency current output. Therefore, highly sensitive measurement of electron spin resonance can be performed without using an excessive output amplifier and without inducing unnecessary vibration in the cavity resonator.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various design changes can be made without departing from the spirit of the present invention. It is.

[Brief description of the drawings]

[1] is an external perspective view showing an embodiment of an electronic spin resonance thin cavity resonator according to the present invention, an example of X-band rectangular parallelepiped TE ₁₀₂ mode.

Figure 2 is an external perspective view showing another embodiment of an electronic spin resonance thin cavity resonator according to the present invention, an example of X-band rectangular parallelepiped TE ₁₀₂ mode.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 cavity resonator 12 copper plate 14 coupling hole 16 conductive plate 18 waveguide 20 flange portion 22 insertion hole 24 groove portion 26 groove portion 30 cavity resonator 32 lower cavity plate 34 conductor foil 36 cavity upper plate 38 insertion hole 40 ceramic Substrate 42 Flange 44 Connection hole 46 Lead plate 48 End face

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] May 22, 2002 (2002.5.2)
2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

[0009]

To achieve the above object, a thin-plate cavity for electron spin resonance according to the present invention is provided.
In a rectangular hexahedral cavity resonator having one end closed by a conductor plate and the other end having a flange for connection with a waveguide, a pair of sides in a waveguide framework arranged orthogonal to a magnetic field. The entire metal part of the wall surface is thinly cut to the thickness of the skin effect of the high-frequency modulation magnetic field, and one end of the waveguide frame and the end conductor plate are soldered or brazed.
It is adapted to be closed.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

Further, the thin-plate cavity for electron spin resonance according to the present invention has one end closed by a conductor plate ,
In a rectangular hexahedral cavity having a flange at the other end for connection with a waveguide, a pair of side walls arranged so as to be orthogonal to the magnetic field are made sufficiently thinner than the skin effect of the high frequency modulation magnetic field. Without using a fastening means by a plywood in which a metal foil and an insulating material plate for reinforcing the metal foil are overlapped
It can also be configured .

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

The feature of this embodiment is that grooves 24 and 26 are provided on the cavity side walls (surface E) on both side surfaces of the cavity resonator 10. A magnetic field modulation coil (not shown) is embedded in the grooves 24 and 26. At this time, coil width W barrel selection cormorants'm not impair the uniformity of the modulation magnetic field applied to the sample of the cavity resonator 10. ────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] May 22, 2002 (2002.5.2)
2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

6. The thin-plate cavity for electron spin resonance according to claim 4 , wherein the thickness of the metal foil is 3 to 30 μm.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

[0009]

To achieve the above object, a thin-plate cavity for electron spin resonance according to the present invention is provided.
In a rectangular hexahedral cavity resonator having one end closed by a conductor plate and the other end having a flange for connection with a waveguide, a pair of sides in a waveguide framework arranged orthogonal to a magnetic field. The entire metal portion of the wall surface is thinly cut to the thickness of the skin effect of the high frequency modulation magnetic field, and one end of the waveguide frame and the end conductor plate are closed by soldering or brazing. Further, the cavity resonator body may have a seamless structure of the drawing waveguide.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

Further, the thin-plate cavity for electron spin resonance according to the present invention has one end closed by a conductor plate,
In a rectangular hexahedral cavity having a flange at the other end for connection with a waveguide, a pair of side walls arranged so as to be orthogonal to the magnetic field are made sufficiently thinner than the skin effect of the high frequency modulation magnetic field. the plywood with constituting a metal foil, a plywood obtained by superimposing an insulating material plate to reinforce the metal foil
And the end conductor plate are soldered or
It can also be a seamless connection by attaching . Further, the thin-plate resonator for electron spin resonance according to the present invention is characterized in that, in a rectangular hexahedral resonator having one end closed by a conductor plate and the other end having a flange for connection to a waveguide, Using a fastening means by a plywood in which a pair of side walls arranged perpendicular to the metal foil whose thickness is sufficiently thinner than the skin effect of the high-frequency modulation magnetic field and an insulating material plate for reinforcing the metal foil are laminated. It can also be configured without .

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

[0014] Figure 1 is an external perspective view of an electronic spin resonance thin cavity resonator showing an embodiment of the present invention, an example of X-band rectangular parallelepiped TE ₁₀₂ mode. In FIG. 1, reference numeral 10 denotes a cavity, and the cavity of the cavity
As shown in the figure, the commercial waveguide is
It is used after being cut into a length L equal to the wavelength. Commercially available
Currently, waveguides based on Japanese Industrial Standards are used as waveguides.
It is frequently used in black-wave circuits. X band waveguide is JIS
C 6606 `` Rectangular waveguide and flange for 10000MHz band ''
"The pipe is manufactured seamlessly by the cold drawing method"
Have been. This means that the microwave propagating in the tube
As a characteristic, the tube wall current crosses the ridge line from wall to wall.
This treatment takes into account the flowing phenomenon. That is, each surface connection
Can be constructed seamlessly by microwave current interruption
Prevents interruption of tube wall current or disturbance of current distribution and transmits
Basically important process to prevent loss. The situation is cavity resonance
In vessels, it becomes even more important. That is, micro
The Q of a wave cavity resonator is extremely high, from several thousand to ten thousands.
Is common. This means that even with a small loss, the high Q
Of the tube wall current.
In other words, the disturbance of the current distribution must be avoided. others
Therefore, the seamless structure of the drawing waveguide is necessary for the high Q cavity resonator
Structure. The situation is the same for the end plate. did
Accordingly , one end of the cavity resonator 10 is connected to the copper plate 12 by soldering or brazing to form a seamless connection.
Prevent interruption or disturbance of distribution of tube wall current
are doing. The same applies to the other end of the cavity resonator 10 . What
This portion is provided with a flange portion 20 for connecting the thin plate 16 having the coupling hole 14 and the waveguide 18 connected to a microwave circuit (not shown). The coupling hole 14 provided in the thin plate 16 is selected so as to have a reflection coefficient suitable for measurement conditions. Further, similarly to other electron spin resonance apparatuses, the cavity 10 is provided with insertion holes 22 for inserting a measurement sample tube through the H-plane of the cavity 10.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

The feature of this embodiment is that grooves 24 and 26 are provided on the cavity side walls (surface E) on both side surfaces of the cavity resonator 10. A magnetic field modulation coil (not shown) is embedded in the grooves 24 and 26. At this time, the coil width W is selected so as not to impair the uniformity of the modulation magnetic field applied to the measurement sample in the cavity resonator 10.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction contents]

FIG. 2 is an external perspective view showing another embodiment of a thin-plate cavity for electron spin resonance according to the present invention.
It is an example of a band hexahedral _{TE 102} mode. The cavity lower plate 32 is not shown for convenience of explanation. The material of the cavity 30 is a ceramic substrate for a printed circuit board or a microwave integrated circuit, which is frequently used recently, and the thin conductive foil 34 formed on the ceramic substrate is used as the inner wall of the cavity 30. It is configured. Cavity lower side plate 3
As shown in FIG. 2, on a ceramic substrate having a thickness T, a thickness t ₂
Is formed. The cavity lower plate 32 and the opposing cavity upper plate 36 are provided with insertion holes 38, 38 for inserting sample tubes at opposing positions, respectively.
Is chosen equal to the microwave guide wavelength,
One end of the cavity resonator 30 is closed by a ceramic substrate 40 on which a copper plate or a conductive foil 34 is formed. The other end of the cavity 30 is provided with a flange portion 42 for connecting a conductive plate 46 having a coupling hole 44 and the waveguide 18 connected to a microwave circuit (not shown). Again,
The coupling hole 44 provided in the conductive plate 46 is selected so as to have a reflection coefficient suitable for the measurement conditions as in the above embodiment. The end face 48 of the lower cavity plate 32 is plated with gold, and the inner wall of the cavity 30 is also plated with gold in order to increase the electrical conductivity and prevent the Q from being lowered by rusting. .
As shown in FIG. 2, each side of the cavity is formed.
The connection between the substrates with the thin conductor foil formed on
Soldering without fastening or banding
Seamless structure by brazing or brazing
Means a cavity resonator using the drawn waveguide described in detail above.
Same as in the case.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Furuse 2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka Prefecture Sumitomo Special Metals Co., Ltd. Yamazaki Works (72) Inventor Kazuo Nakagawa 3-43 Ebisu, Shibuya-ku, Tokyo No. 2 Nikkiso Co., Ltd. (72) Inventor Makoto Tsuneta 3-43-2 Ebisu, Shibuya-ku, Tokyo Nikkiso Co., Ltd. (72) Atsushi Nukanobu 3-43 Ebisu, Shibuya-ku, Tokyo No.2 Nikkiso Co., Ltd. F-term (reference) 5J006 HC01 HC12 LA02 NA06 NA09

Claims (4)

[Claims] In a rectangular hexahedral cavity resonator having one end closed by a conductor and a flange at the other end for connection with a waveguide, a pair of side wall surfaces arranged perpendicular to a magnetic field are provided. A thin cavity resonator for electron spin resonance, characterized in that all of the parts are configured to be as thin as the thickness of the skin effect of a high-frequency modulation magnetic field. 2. The total thickness of the metal portion on the side wall surface is 30 to
2. The thin-plate cavity for electron spin resonance according to claim 1, which has a thickness of 100 [mu] m. 3. A rectangular hexahedral cavity resonator having one end closed by a conductor and a flange at the other end for connection to a waveguide, wherein a pair of side walls arranged so as to be orthogonal to a magnetic field have a high frequency. A thin-plate cavity for electron spin resonance, comprising a plywood in which a metal foil sufficiently thinner than a skin effect of a modulated magnetic field and an insulating material plate for reinforcing the metal foil are laminated. 4. The thin cavity resonator for electron spin resonance according to claim 3, wherein the thickness of the metal foil is 3 to 30 μm.