JPS6231889Y2 - - Google Patents
Info
- Publication number
- JPS6231889Y2 JPS6231889Y2 JP19139981U JP19139981U JPS6231889Y2 JP S6231889 Y2 JPS6231889 Y2 JP S6231889Y2 JP 19139981 U JP19139981 U JP 19139981U JP 19139981 U JP19139981 U JP 19139981U JP S6231889 Y2 JPS6231889 Y2 JP S6231889Y2
- Authority
- JP
- Japan
- Prior art keywords
- container
- coil
- cylinder
- spot
- pick
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000004907 flux Effects 0.000 claims description 10
- 241000238366 Cephalopoda Species 0.000 claims description 8
- 238000003466 welding Methods 0.000 claims description 5
- 239000004020 conductor Substances 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 229910052734 helium Inorganic materials 0.000 description 4
- 239000001307 helium Substances 0.000 description 4
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 239000012611 container material Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000005668 Josephson effect Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 210000004165 myocardium Anatomy 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
Landscapes
- Measuring Magnetic Variables (AREA)
Description
【考案の詳細な説明】
本考案は、スクイツド（SQUID）磁束計に関
するものである。更に詳しくは、本考案は、磁束
検出用のピツクアツプコイルに、ある周波数より
高い周波数の磁束が侵入しないようにしたスクイ
ツド磁束計に関するものである。[Detailed Description of the Invention] The present invention relates to a SQUID magnetometer. More specifically, the present invention relates to a squid magnetometer that prevents magnetic flux of a frequency higher than a certain frequency from entering a pickup coil for detecting magnetic flux.
スクイツド磁束計は、ジヨゼフソン効果を利用
したもので、その磁束分解能は４×10-19Wb／√
Hzにも達し、心筋の収縮による磁界変化等、微少
磁界の測定に利用されている。 The Squid magnetometer uses the Josephson effect, and its magnetic flux resolution is 4×10 -19 Wb/√
Hz, and is used to measure minute magnetic fields, such as magnetic field changes caused by contraction of the heart muscle.
ところで、このような高感度のスクイツド磁束
計において、磁束検出用のピツクアツプコイルに
高周波ノイズが侵入し、そのレベルが大きくなる
と、動作が不安定となつたり、磁束測定ができな
くなつたりする。それ故に、従来は外部からのノ
イズを消去するために、磁気シールドルームや電
波シールドルームが使用されていた。しかしなが
ら、これらは大きくて、屋外での測定には使用で
きない。 By the way, in such a highly sensitive Squid magnetometer, if high frequency noise invades the pick-up coil for magnetic flux detection and its level increases, the operation becomes unstable or magnetic flux measurement becomes impossible. Therefore, conventionally, magnetically shielded rooms and radio wave shielded rooms have been used to eliminate external noise. However, these are large and cannot be used for outdoor measurements.
ここにおいて、本考案は、簡単な構成で、ピツ
クアツプコイルに侵入する高周波ノイズを消去
し、屋外での磁界測定が安定にできスクイツド磁
束計を提供しようとするものである。 Here, the present invention aims to provide a Squid magnetometer with a simple configuration, which can eliminate high frequency noise that enters the pickup coil and can stably measure magnetic fields outdoors.
本考案に係る装置は、アルミ等の常伝導体の平
板から円筒をつくるとともに、この円筒の合せ目
をスポツト溶接し、円筒両端に蓋をかぶせて構成
した容器内に、磁束検出用のピツクアツプコイル
を収容するようにした点に構成上の特徴がある。 The device according to the present invention consists of making a cylinder from a flat plate of a normal conductor such as aluminum, spot-welding the joints of the cylinder, and placing a pick-up coil for magnetic flux detection inside a container that is constructed by covering both ends of the cylinder with a lid. A distinctive feature of the structure is that it accommodates the following.
第１図は本考案に係る装置の要部の構成図であ
る。図において、１は磁束検出用のピツクアツプ
コイル、２はピツクアツプコイル１に接続され、
これと閉回路をつくるインプツトコイル、３は一
部にジヨセフソン接合部JCをもつ超伝導リン
グ、４はコイル４１とコンデンサ４２の並列回路
で構成されたタンク回路で、超伝導リング１と誘
導的に結合している。このタンク回路４には、高
周波電源５から高周波電力が供給され、タンク回
路４に発生する高周波電圧は、増巾器６で増巾さ
れ、整流器７で整流されて出力信号となる。 FIG. 1 is a block diagram of the main parts of the device according to the present invention. In the figure, 1 is a pick-up coil for magnetic flux detection, 2 is connected to the pick-up coil 1,
Input coil 3 forms a closed circuit with this, superconducting ring 3 has Josephson junction JC in part, 4 is a tank circuit composed of a parallel circuit of coil 41 and capacitor 42, and superconducting ring 1 is inductively connected to superconducting ring 1. is combined with High frequency power is supplied to this tank circuit 4 from a high frequency power supply 5, and the high frequency voltage generated in the tank circuit 4 is amplified by an amplifier 6 and rectified by a rectifier 7 to become an output signal.
８はアルミの平板から円筒をつくるとともにこ
の円筒の合せ目の数ケ所（ここでは８１，８２，
８３，８４の４ケ所）をスポツト溶接し、円筒両
端に例えばアルミの蓋８５，８６をかぶせて構成
した容器で、この容器８内にピツクアツプコイル
１が収容されている。容器８、ピツクアツプコイ
ル１、インプツトコイル２、超伝導リング３及び
タンク回路４は、例えばクライオスタツト内に置
かれ、いずれもヘリウム温度に保たれる。なお、
この実施例では、容器材料としてアルミ板を用い
たが、他の常伝導体の金属材料であれば、他の材
料を用いてもよい。 8 makes a cylinder from a flat plate of aluminum, and connects the cylinder at several joints (here 81, 82,
The pickup coil 1 is housed in the container 8, which is constructed by spot-welding the coils 83 and 84 at four locations and covering both ends of the cylinder with aluminum lids 85 and 86, for example. The container 8, the pick-up coil 1, the input coil 2, the superconducting ring 3, and the tank circuit 4 are placed, for example, in a cryostat, and all are maintained at helium temperature. In addition,
In this embodiment, an aluminum plate was used as the container material, but other normal conductor metal materials may be used.
このように構成された装置は、容器８が、その
形状で定まるインダクタンスＬと、容器材料のシ
ート抵抗及び円筒の合せ目の抵抗のヘリウム温度
における合成抵抗Ｒとで決まる(1)式で示すような
カツトオフ時定数γを有する。 In the device thus constructed, the container 8 has a cut-off time constant γ as shown in equation (1), which is determined by the inductance L determined by its shape, and the combined resistance R at helium temperature of the sheet resistance of the container material and the resistance of the cylinder seam.
γ＝Ｌ／Ｒ＝μ０・σ・π・ｒ２・ｔ／２πｒ＝μ０・
σ・ｒ・ｔ／２…(1)
ただし、ｒ：容器８の半径
ｔ：厚さ
μ０：透磁率
σ：導電率
ここで、容器８の外部磁界をHex（ω）とする
と、容器８の内部の磁界Ｈは(2)式で示す通りとな
る。γ=L/R=μ 0・σ・π・r 2・t/2πr=μ 0・
σ・r・t/2...(1) where r: radius t of container 8: thickness μ 0 : magnetic permeability σ: electrical conductivity Here, if the external magnetic field of the container 8 is Hex (ω), then the container 8 The internal magnetic field H is as shown in equation (2).
Ｈ＝Hex（ω）・１／１＋ｊωγ …(2)
したがつて、容器８は、外部磁界Hex（ω）に
対してローパスフイルタとして機能し、その周波
数特性は、容器８のカツトオフ時定数γで定まる
こととなる。ここで、容器８のカツトオフ時定数
γは、(1)式から明らかなように、容器８の形状、
材質、合せ目の抵抗等で決まるものであるが、本
考案においては、特に、円筒の合せ目のスポツト
溶接の数を変えることによつて（スポツト溶接を
何個所行なうかによつて）、周波数特性を所望の
特性になるように調整している。このように、ス
ポツト溶接の数を変えることによつて、ローパス
フイルタの周波数特性を調整する手法は、容易で
あつて、容器８の形状や材質を一定にできるうえ
に、容器８をヘリウム温度と常温との間でくり返
して使用しても、周波数特性が変らないという特
長を有する。 H=Hex(ω)・1/1+jωγ (2) Therefore, the container 8 functions as a low-pass filter for the external magnetic field Hex(ω), and its frequency characteristic is determined by the cutoff time constant γ of the container 8. It will be decided. Here, as is clear from equation (1), the cutoff time constant γ of the container 8 is determined by the shape of the container 8,
It is determined by the material, the resistance of the joint, etc., but in this invention, the frequency can be adjusted by changing the number of spot welds at the joint of the cylinder (depending on how many spot welds are performed). The characteristics are adjusted to the desired characteristics. In this way, the method of adjusting the frequency characteristics of the low-pass filter by changing the number of spot welds is easy, allows the shape and material of the container 8 to be constant, and also allows the container 8 to be adjusted to the helium temperature. It has the feature that the frequency characteristics do not change even if it is repeatedly used at room temperature.
第２図は、厚さが0.3mmのアルミ板で、直径50
mm、高さ150mmの容器を構成し、ヘリウム温度に
おける周波数特性を実験で求めた線図である。 Figure 2 shows an aluminum plate with a thickness of 0.3 mm and a diameter of 50 mm.
This is a diagram showing the frequency characteristics at helium temperature determined through experiments in a container with a height of 150 mm and a height of 150 mm.
第２図において、イはアルミ板を円筒にし、合
せ目を全く溶接しない場合、ロは合せ目を４ケ所
スポツト溶接した場合、ハは合せ目を８ケ所スポ
ツト溶接した場合である。この実験結果からも明
らかなように、スポツト溶接の数を増大させる
と、カツトオフ周波数が矢印ａ方向に示すように
低下することが認められる。 In Fig. 2, A shows the case where the aluminum plate is made into a cylinder and no seams are welded, B shows the case where the seams are spot welded at 4 places, and C shows the case where the seams are spot welded at 8 places. As is clear from this experimental result, it is recognized that as the number of spot welds increases, the cutoff frequency decreases as shown in the direction of arrow a.
したがつて、円筒の合せ目に行うスポツト溶接
の数を特定な数に選定することによつて、所望の
カツトオフ周波数をもつたローパスフイルタが実
現できる。 Therefore, by selecting a specific number of spot welds to be performed at the joints of the cylinders, a low-pass filter with a desired cutoff frequency can be realized.
なお、この実施例では、容器８内に収容するピ
ツクアツプコイル１は、１個のものを示したが、
複数個でもよい。 In this embodiment, one pick-up coil 1 is housed in the container 8, but
There may be more than one.
以上説明したように、本考案は、常伝導体の平
板から円筒をつくるとともに、この円筒の合せ目
をスポツト溶接し、両端に蓋をかぶせて容器を構
成するとともに、この容器内にピツクアツプコイ
ルを収容したもので、容器はローパスフイルタと
して機能する。したがつて、ピツクアツプコイル
は、高周波ノイズに影響されないで、低周波の磁
束だけを検出し、屋外での磁束測定が安定に行え
るスクイツド磁束計が実現できる。 As explained above, the present invention involves making a cylinder from a flat plate of a normal conductor, spot-welding the seams of this cylinder, and covering both ends with a lid to form a container, and placing a pick-up coil inside this container. The container functions as a low-pass filter. Therefore, the pick-up coil detects only low-frequency magnetic flux without being affected by high-frequency noise, making it possible to realize a squid magnetometer that can stably measure magnetic flux outdoors.
第１図は本考案に係る装置の要部の構成図、第
２図は容器の周波数特性を示す線図である。
１……ピツクアツプコイル、２……インプツト
コイル、３……超伝導リング、４……タンク回
路、８……容器、８１〜８４……スポツト溶接
部。
FIG. 1 is a block diagram of the main parts of the device according to the present invention, and FIG. 2 is a diagram showing the frequency characteristics of the container. 1... Pick-up coil, 2... Input coil, 3... Superconducting ring, 4... Tank circuit, 8... Container, 81 to 84... Spot welding section.
Claims (1)
この円筒の合せ目をスポツト溶接し、円筒両端
に蓋をかぶせて構成した容器内に、磁束検出用
のピツクアツプコイルを収容するようにしたス
クイツド磁束計。 (2) スポツト溶接の数を特定な値に選定すること
によつて容器の周波数特性を変えるようにした
実用新案登録請求の範囲第１項記載のスクイツ
ド磁束計。[Scope of claims for utility model registration] (1) Making a cylinder from a flat plate of a normal conductor,
This squid magnetometer has a pick-up coil for detecting magnetic flux housed in a container made by spot-welding the joints of the cylinders and covering both ends of the cylinders with lids. (2) The Squid magnetometer according to claim 1, wherein the frequency characteristics of the container are changed by selecting a specific number of spot welds.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19139981U JPS5896278U (en) | 1981-12-22 | 1981-12-22 | squid magnetometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19139981U JPS5896278U (en) | 1981-12-22 | 1981-12-22 | squid magnetometer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5896278U JPS5896278U (en) | 1983-06-30 |
| JPS6231889Y2 true JPS6231889Y2 (en) | 1987-08-15 |
Family
ID=30104864
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19139981U Granted JPS5896278U (en) | 1981-12-22 | 1981-12-22 | squid magnetometer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5896278U (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2556378B2 (en) * | 1989-04-28 | 1996-11-20 | 大同ほくさん株式会社 | Noise removal method in buried object detection method using SQUID magnetometer |
-
1981
- 1981-12-22 JP JP19139981U patent/JPS5896278U/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5896278U (en) | 1983-06-30 |
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