JP2003021670A - Noncontact type ion beam current intensity measuring device - Google Patents
Noncontact type ion beam current intensity measuring deviceInfo
- Publication number
- JP2003021670A JP2003021670A JP2001244977A JP2001244977A JP2003021670A JP 2003021670 A JP2003021670 A JP 2003021670A JP 2001244977 A JP2001244977 A JP 2001244977A JP 2001244977 A JP2001244977 A JP 2001244977A JP 2003021670 A JP2003021670 A JP 2003021670A
- Authority
- JP
- Japan
- Prior art keywords
- ion beam
- beam current
- coil
- magnetic
- current
- 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.)
- Pending
Links
- 238000010884 ion-beam technique Methods 0.000 title claims abstract description 36
- 238000001514 detection method Methods 0.000 claims abstract description 59
- 230000004907 flux Effects 0.000 claims abstract description 20
- 238000005259 measurement Methods 0.000 claims description 12
- 239000002887 superconductor Substances 0.000 claims description 5
- 239000002245 particle Substances 0.000 claims description 2
- 241000238366 Cephalopoda Species 0.000 abstract description 29
- 238000000034 method Methods 0.000 abstract description 14
- 230000002238 attenuated effect Effects 0.000 abstract description 8
- 230000008859 change Effects 0.000 abstract description 7
- 206010070834 Sensitisation Diseases 0.000 abstract 1
- 230000008313 sensitization Effects 0.000 abstract 1
- 230000001235 sensitizing effect Effects 0.000 abstract 1
- 238000004804 winding Methods 0.000 abstract 1
- 230000035945 sensitivity Effects 0.000 description 19
- 230000035699 permeability Effects 0.000 description 7
- 229910052734 helium Inorganic materials 0.000 description 6
- 239000001307 helium Substances 0.000 description 6
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 6
- 239000007788 liquid Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 230000014509 gene expression Effects 0.000 description 2
- 238000005468 ion implantation Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910052758 niobium Inorganic materials 0.000 description 2
- 239000010955 niobium Substances 0.000 description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 229910000889 permalloy Inorganic materials 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
Landscapes
- Measuring Magnetic Variables (AREA)
- Measurement Of Radiation (AREA)
Abstract
Description
【発明の属する技術分野】本発明は、イオンビーム電流
強度を非接触で測定する装置とその応用に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for non-contact measurement of ion beam current intensity and its application.
【従来の技術】半導体製造におけるイオン注入や物理学
実験に使われているμＡ〜数十ｍＡ程度のイオンビーム
電流強度の測定方法は長年研究されておりかなり確立さ
れてきている。上記電流強度を非接触で測定するには、
例えば直流電流変換器を用いればよい。しかし、現在得
られる最高感度の直流電流変換器でもμＡ以下の分解能
でイオンビーム電流を測定することはできない。また、
ファラデーカップを用いる方法もある。この方法は、イ
オンビームをカップ内に受けとめてイオンビームに接触
して電流値を測定するものである。例えば、半導体製造
におけるイオン注入では製品に注入する前に、イオンビ
ーム電流をあらかじめファラデーカップで測定してお
く。ウェハを装着した円板の受ける電流すべてをカウン
トする方法と円板の一部にスリットを設けてそのスリッ
トを通り抜けるイオンをカウントする方式がある。しか
し、この方法はイオンビームに接触して電流値を測定す
るので、イオンビーム電流値を測定している間は製品等
へのイオンビーム照射を行えなかった。以上のように、
μＡ以下の分解能でイオンビーム電流強度の測定と製品
等へのイオンビーム照射を同時に行えないという課題が
あった。この課題に対してイオンビーム電流を非接触で
精度良く測定する方法が特開平７−１３５０９９号公報
に開示されている。しかしこの方法では、イオンビーム
が流れている空間と磁場を収集する磁場収集手段と収集
した磁場に感応する超伝導素子を全て外部磁場から磁気
遮蔽する必要があった。これにより装置が大きくなると
いう課題があった。以下に詳しく説明する。例えば１μ
Ａのビーム電流によってつくられる磁場は、ビーム中心
から２０ｃｍ離れた点で１０−１２Ｔのオーダーであ
る。一方、地磁気を含む環境磁場は少なくとも１０−５
Ｔのオーダーはあるのでバックグラウンドの方が７桁程
度も大きい。外部磁場を減衰させる磁気遮蔽手段は、高
透磁率材料で囲う方法がある。しかし、一般的に用いら
れるパーマロイを用いた磁気遮蔽ではせいぜい１桁〜２
桁だけ外部磁場を減衰できる程度なので、バックグラウ
ンドを低減して１μＡのビーム電流強度を測定すること
はできない。また、大幅に磁場を減衰させる磁気遮蔽手
段は超伝導が考えられる。しかし、超伝導磁気遮蔽は完
全に遮蔽部分を超伝導体で囲う必要があるので、イオン
源やイオンを加速させる装置もイオンビームが流れてい
る空間とともに超伝導体で囲う必要があった。このため
に装置が非常に大型化するという課題がある。これらの
課題を解決する方法として、日本物理学会誌Ｖｏｌ．５
４，Ｎｏ．１，１９９９に数十ｎＡ〜数μＡのイオンビ
ーム電流を非接触でｎＡオーダーの分解能で測定する方
法が開示されている。この方法は、特開平７−１３５０
９９号公報と比較して、イオンビームが流れている空間
と磁場を収集する検知コイルの間に狭いギャップを有す
る超伝導磁気遮蔽を設けるという特徴がある。日本物理
学会誌Ｖｏｌ．５４，Ｎｏ．１，１９９９に記載された
構造の狭いギャップを有する超伝導磁気遮蔽は、外部磁
場は大幅に減衰させる一方でイオンビーム電流が発生さ
せる磁場は減衰させずに通過させる特徴がある。この特
徴により、超伝導体で囲う部分は検知コイルと超伝導素
子およびその周辺の超伝導回路だけでよいので、大幅に
装置の小型化を実現できた。ところで日本物理学会誌Ｖ
ｏｌ．５４，Ｎｏ．１，１９９９に開示の方法では超伝
導素子にＳＱＵＩＤを用いている。ここで検知コイル
は、そのインダクタンスをＳＱＵＩＤと同程度にした場
合に感度が大きくなるとされている。しかし、磁心を用
いたために検知コイルのインダクタンスはＳＱＵＩＤの
それよりもはるかに大きくなっている。そこで、検知コ
イルの巻き数を少なくした方が検知コイルのインダクタ
ンスを低減でき、巻き数が多いときより感度があがるの
で、コイルの巻き数は１ターンとされていた。しかし、
磁心上に超伝導線を１ターン巻いただけの構造では局所
的な磁束の変化の影響を受けやすいという課題が起き
る。これに対しては、薄肉のニオブ板で磁心を囲み周上
にスリットをいれた構造の磁心全周に分布した１ターン
コイルを作製して課題を解決している。2. Description of the Related Art A method for measuring the ion beam current intensity of .mu.A to several tens of mA, which is used for ion implantation and physics experiments in semiconductor manufacturing, has been studied for many years and has been well established. To measure the above current intensity without contact,
For example, a direct current converter may be used. However, even the highest-sensitivity DC / DC converter currently available cannot measure the ion beam current with a resolution of μA or less. Also,
There is also a method using a Faraday cup. In this method, an ion beam is received in a cup, and the current value is measured by contacting the ion beam. For example, in ion implantation in semiconductor manufacturing, the ion beam current is measured in advance with a Faraday cup before implanting into a product. There are a method of counting all the currents received by the disk on which the wafer is mounted, and a method of providing a slit in a part of the disk and counting the ions passing through the slit. However, since this method measures the current value by contacting the ion beam, it was impossible to irradiate the product or the like with the ion beam while measuring the ion beam current value. As mentioned above,
There is a problem that the ion beam current intensity cannot be measured and the product or the like can be simultaneously irradiated with the ion beam at a resolution of μA or less. To solve this problem, a method of accurately measuring the ion beam current in a non-contact manner is disclosed in JP-A-7-135099. However, in this method, it is necessary to magnetically shield the space in which the ion beam is flowing, the magnetic field collecting means for collecting the magnetic field, and the superconducting element sensitive to the collected magnetic field from the external magnetic field. This causes a problem that the device becomes large. The details will be described below. For example, 1μ
The magnetic field created by the beam current of A is on the order of 10 −12 T at a point 20 cm away from the beam center. On the other hand, the environmental magnetic field including geomagnetism is at least 10 −5.
There is an order of T, so the background is about 7 digits larger. The magnetic shielding means for attenuating the external magnetic field may be surrounded by a high magnetic permeability material. However, magnetic shielding using permalloy, which is generally used, is at most 1 digit to 2 digits.
Since the external magnetic field can be attenuated by only a digit, the background cannot be reduced to measure the beam current intensity of 1 μA. Moreover, superconductivity can be considered as the magnetic shielding means that significantly attenuates the magnetic field. However, since the superconducting magnetic shield needs to completely enclose the shielded portion with a superconductor, the ion source and the apparatus for accelerating the ions also need to be enclosed with the space in which the ion beam is flowing. Therefore, there is a problem that the device becomes very large. As a method for solving these problems, the Physical Society of Japan, Vol. 5
4, No. 1, 1999 discloses a method of measuring an ion beam current of several tens of nA to several μA in a non-contact manner with a resolution of nA order. This method is disclosed in JP-A-7-1350.
Compared to Japanese Patent Publication No. 99, there is a feature that a superconducting magnetic shield having a narrow gap is provided between a space in which an ion beam is flowing and a detection coil for collecting a magnetic field. Journal of the Physical Society of Japan Vol. 54, No. The superconducting magnetic shield having a narrow gap of the structure described in 1, 1999 is characterized in that the external magnetic field is significantly attenuated while the magnetic field generated by the ion beam current passes through without being attenuated. Due to this feature, the portion surrounded by the superconductor only needs the detection coil, the superconducting element, and the superconducting circuit in the periphery thereof, so that the device can be greatly downsized. By the way, Journal of the Physical Society of Japan V
ol. 54, No. In the method disclosed in 1, 1999, SQUID is used for the superconducting element. Here, it is said that the sensitivity of the detection coil becomes large when the inductance thereof is set to the same level as the SQUID. However, since the magnetic core is used, the inductance of the detection coil is much larger than that of SQUID. Therefore, reducing the number of turns of the detection coil can reduce the inductance of the detection coil and improves the sensitivity when the number of turns of the detection coil is large. Therefore, the number of turns of the coil is set to one. But,
In the structure in which the superconducting wire is wound only one turn on the magnetic core, there is a problem that it is easily affected by the local change of magnetic flux. In order to solve this problem, a one-turn coil having a structure in which a magnetic core is surrounded by a thin niobium plate and slits are formed on the circumference is distributed over the entire circumference of the magnetic core to solve the problem.
【発明が解決しようとする課題】１ターンコイルでは、
検知コイルのインダクタンスをＳＱＵＩＤと同等にする
ことは困難である。検知コイルのインダクタンスは巻き
数を少なくするに従って減少する。しかし、検知コイル
のインダクタンスをＳＱＵＩＤと同等にしようとして巻
き数を減らしても、１ターン以下にはできないという課
題があった。つまり、一般に、検知コイルの磁心の透磁
率が高いほどイオンビームが発生させる磁束を多く集め
ることができる。しかし、透磁率が高いと、検知コイル
のインダクタンスをＳＱＵＩＤと同等にすることができ
なくなるという高感度を実現するのに相反する課題があ
った。また、薄肉のニオブ板を磁心全周に分布した１タ
ーンコイルは作製が難しいために、より簡単な構造で局
所的な磁束の変化の影響を受けにくくする方法も求めら
れていた。そこで、これらの課題を解決し、より感度を
向上させ、且つ、局所的な磁束の変化の影響を受けにく
い簡単な構造のイオンビーム電流強度測定装置が求めら
れていた。SUMMARY OF THE INVENTION With a one-turn coil,
It is difficult to make the inductance of the detection coil equal to that of SQUID. The inductance of the sensing coil decreases as the number of turns decreases. However, there has been a problem that even if the number of turns is reduced in order to make the inductance of the detection coil equal to that of SQUID, the number of turns cannot be 1 turn or less. That is, in general, the higher the magnetic permeability of the magnetic core of the detection coil, the more the magnetic flux generated by the ion beam can be collected. However, when the magnetic permeability is high, there is a contradictory problem to realize high sensitivity that the inductance of the detection coil cannot be made equal to that of SQUID. Further, since it is difficult to fabricate a one-turn coil in which a thin niobium plate is distributed all around the magnetic core, there has been a demand for a method having a simpler structure and less susceptible to the influence of a local change in magnetic flux. Therefore, there has been a demand for an ion beam current intensity measuring device that solves these problems, further improves the sensitivity, and has a simple structure that is not easily affected by a local change in magnetic flux.
【課題を解決するための手段】検知コイルとＳＱＵＩＤ
を磁気的に結合させるトランスを設ける。トランスの入
力側と出力側の巻き数を調整することで磁心が集めた磁
束を最適にＳＱＵＩＤに伝達する。また検知コイルの巻
き数を複数ターンとして磁心に全周にわたって対称に巻
いた構造とする。Means for Solving the Problems Detecting coil and SQUID
A transformer for magnetically coupling is provided. The magnetic flux collected by the magnetic core is optimally transmitted to the SQUID by adjusting the number of turns on the input side and the output side of the transformer. In addition, the number of turns of the detection coil is set to a plurality of turns and the magnetic core is symmetrically wound around the entire circumference.
【作用】磁心とＳＱＵＩＤの性能で規定される本来の電
流感度を得ることが可能となった。このために、従来は
磁心の巻き数を１ターン以下にできないことで制限され
ていた電流感度は、この制限をうけない。さらに検知コ
イルの巻き数を複数ターンにできることで簡単に局所的
な磁束の変化の影響を受けにくい構造が得られる。この
場合も、トランスの入力側と出力側の巻き数を調整する
ことで上記と同様の電流感度を得ることができる。[Function] The original current sensitivity defined by the performance of the magnetic core and SQUID can be obtained. Therefore, the current sensitivity, which was conventionally limited by the number of turns of the magnetic core not being less than 1 turn, is not subject to this limitation. Furthermore, since the number of turns of the detection coil can be set to a plurality of turns, it is possible to easily obtain a structure that is not easily affected by a local change in magnetic flux. Also in this case, the same current sensitivity as described above can be obtained by adjusting the number of turns on the input side and the output side of the transformer.
【発明の実施の形態】本発明による装置の構成を以下で
説明する。ただし、これは実施例の一つである。ビーム
電流４に対応した磁場を検知する検知部は、磁心に超伝
導線を１ターンまたは複数ターン巻いた構成の検知コイ
ル１とした。磁心はＳＱＵＩＤ８の動作温度でできるだ
け大きな透磁率をもつものの方が、装置の感度を良くで
きるので望ましい。検知された磁場に対応した磁束に感
応する超伝導素子を有する測定部は、超伝導素子にＤＣ
ＳＱＵＩＤ８を用いた超伝導回路とした。これについ
ては後で詳しく述べる。検知部と測定部を磁気的に結合
させるトランスを設けた。検知部と測定部を超伝導磁気
遮蔽２により囲んだ。ただし、この超伝導磁気遮蔽２は
閉じた構造ではなく、ギャップ１７を設けた。イオンビ
ームが流れる空間とターゲット１２、および他の装置は
超伝導磁気遮蔽２の外部にある構成とした。またＳＱＵ
ＩＤ８の動作温度に冷却するためにクライオスタット３
に液体ヘリウムを入れて冷却した。
［測定原理］ビーム電流４の測定原理を図１に示す。イ
オンビームは荷電粒子の流れなので、その周りにはアン
ペールの法則に従って電流強度に応じた磁場が発生す
る。この磁場はビーム電流４に比例するのでこの磁場を
測定することでビームに非接触で電流強度を測定でき
る。ビーム電流４により発生した磁場は超伝導磁気遮蔽
２で減衰されることなく通過し、検知コイル１で収集さ
れる。つまり、検知コイル１は、検知コィル１が作る閉
ループを貫く電流に比例した磁場を減衰させることなく
収集できる。例えば、１０ｎＡのビーム電流４によって
つくられる磁場はビーム中心から２０ｃｍ離れた点で１
０−１４Ｔのオーダーであり、これは磁気遮蔽によって
減衰されることなく検知コイル１で収集される。一方、
環境磁場を含む外部磁場は少なくとも１０−５Ｔのオー
ダーはある。このことから、バックグラウンドの方がは
るかに大きいことになる。しかし、本装置では外部磁場
は、超伝導体のマイスナー効果を利用した超伝導磁気遮
蔽２で約１０−８〜１０−１０倍のオーダーで大幅に減
衰される。このことを実現するために超伝導磁気遮蔽２
の形状が工夫されている。超伝導磁気遮蔽２は狭いギャ
ップ１７を備えており、必要な減衰率に応じてギャップ
１７の長さや内径および外径を決めることができる。検
知コイル１で収集された磁場により、検知コイル１とト
ランス入力コイル１１で構成される超伝導閉ループに超
伝導電流が誘起される。次に、トランス入力コイル１１
はトランスの巻き数に応じた超伝導電流をトランス出力
コイル１０に誘起させる。トランス出力コイル１０に誘
起された超伝導電流はＳＱＵＩＤ入力コイル９に流れ、
ＳＱＵＩＤ８を貫くように磁束を発生させようとする。
しかし、ＳＱＵＩＤ８にはＳＱＵＩＤ８を貫く磁束量を
一定に保つようにフィードバックコイル５が配置されて
おり、ＳＱＵＩＤ８を貫く磁束量の変化を打ち消すよう
にフィードバックコイル５にフィードバック電流が流れ
る。このフィードバック電流はビーム電流４に比例する
ので、フィードバック電流がフィードバック抵抗７の両
端に発生させる電位差を測定することでビーム電流４の
測定が可能となる。
［超伝導磁気回路］さらに詳しくＳＱＵＩＤ８と駆動回
路を図２に示す。ビーム電流４がフィードバック電流に
変換される超伝導磁気回路の磁気結合を以下で説明す
る。検知コイル１で収集された磁束は式１〜３の磁気結
合によってＳＱＵＩＤ８に伝達される。
（Ｌｐ＋Ｌｔ１）ΔＩｐ＋Ｍｔ・ΔＩｔ＝Ｎｐ・ΔΦＢ （式１）
（Ｌｔ２＋２Ｉｉ＋２ｌｗ）ΔＩｔ＋２ｍｆｉ・ΔＩｆ＋Ｍｔ・ΔＩｐ＝０
（式２）
Ｍｉｓ・ΔＩｔ−ｍｆｓ・ΔＩｆ＝０ （式３）
ここで、検知コイル１の自己インダクタンスをＬｐ、ト
ランス入力コイル１１の自己インダクタンスをＬｔ１、
検知コイル１とトランス入力コイル１１かつくる超伝導
閉ループに流れる電流をＩｐ、トランス入力コイル１１
とトランス出力コイル１０間の相互インダクタンスをＭ
ｔ、トランス出力コイル１０とワッシャーコイル１３と
ＳＱＵＩＤ入力コイル９がつくる超伝導閉ループに流れ
る電流をＩｔ、検知コイル１の巻き数をＮｐ、検知コイ
ル１断面を貫く磁束量をΦＢ、トランス出力コイル１０
の自己インダクタンスをＬｔ２、各ＳＱＵＩＤ入力コイ
ル９の自己インダクタンスをｌｉ、各ワッシャーコイル
１３の自己インダクタンスをｌｗ、各フィードバックコ
イル５とワッシャーコイル１３間の相互インダクタンス
をｍｆｉ、フィードバックコイル５に流れる電流を
Ｉｒ、各ＳＱＵＩＤ入力コイル９とＳＱＵＩＤ８間の相
互インダクタンスをＭｉｓ、各フィードバックコイル５
とＳＱＵＩＤ８間の相互インダクタンスをｍｆｓとす
る。式１〜３からΔＩｐとΔＩｔを消去して、さらにΔ
ΦＢ＝ｌｐ・ΔＩｂの関係を用いてΦＢを消去すると式
４を得る。
ΔＩｆ／ΔＩｂ＝｛（Ｍｉｓ／ｍｆｓ）Ｍｔ・ｌｐ・Ｎｐ｝／［｛２ｌｉ＋２ｌｗ
＋（２ｍｆｉ・Ｍｉｓ／ｍｆｓ）＋（Ｌｐ・Ｌｔ２／（Ｌｐ＋Ｌｔ１））｝・
（Ｌｐ＋Ｌｔ１）］ （式４）
ここで、１ターン巻いた検知コイル１の自己インダクタ
ンスをｌｐ、ビーム電流強度をＩｂとする。さらに、１
ターン巻いたトランスの自己インダクタンスをｌｏ、ト
ランス入力コイル１１の巻き数をＮ１、トランス出力コ
イル１０の巻き数をＮ２とすると、トランス入力コイル
１１の自己インダクタンスＬｔ１＝ｌｏ・Ｎ１ ２、トラ
ンス出力コイル１０の自己インダクタンスＬｔ２＝ｌｏ
・Ｎ２ ２である。また、検知コイル１の自己インダクタ
ンスＬｐ＝ｌｐ・Ｎｐ ２である。これらを式４に代入し
て式５を得る。
ΔＩｆ／ΔＩｂ＝｛（Ｍｉｓ／ｍｆｓ）ｌｏ・Ｎ１・Ｎ２・Ｎｐ・ｌｐ｝／［｛
２ｌｉ＋２ｌｗ＋（２ｍｆｉ・Ｍｉｓ／ｍｆｓ）＋（ｌｐ・Ｎｐ ２・ｌｏ・Ｎ２ ２
／（ｌｐ・Ｎｐ ２＋ｌｏ・Ｎｌ ２））｝・（ｌｐ・Ｎｐ ２＋ｌｏ・Ｎｌ ２）］
（式５）
式５で可変な変数をＮｐ、Ｎ１、Ｎ２とし、これらは互
いに独立とすると、式５の右辺を最大にする条件は式６
となる。
Ｎ２＝［（ｌｐ・Ｎｐ ２＋ｌｏ・Ｎｌ ２）・｛２ｌｉ＋２ｌｗ＋（２ｍｆｉ・Ｍ
ｉｓ／ｍｆｓ）｝／ｌｏ・ｌｐ・Ｎｐ ２］１／２且つ、Ｎ１は無限大
（式６）
式６の条件は検知コイル１の自己インダクタンスＬｐを
用いて書き直すことができる。すなわち式６を二乗する
と式７を得る。
Ｌｐ・（Ｎ２／Ｎ１）２＝｛（ｌｐ・Ｎｐ ２／ｌｏ・Ｎ１ ２）＋１｝｛２ｌｉ＋
２ｌｗ＋（２ｍｆｉ・Ｍｉｓ／ｍｆｓ）｝ （式７）
ここでＮ１を無限大にとると、右辺の（ｌｐ・Ｎｐ ２／
Ｉｏ・Ｎ１ ２）は１に対して無視できるので式８を得
る。
Ｌｐ・（Ｎ２／Ｎ１）２＝２ｌｉ＋２ｌｗ＋（２ｍｆｉ・Ｍｉｓ／ｍｆｓ）
（式８）
このときに与えられる式５右辺の最大値は式９となる。
（ΔＩｆ／ΔＩｂ）ＭＡＸ＝｛（Ｍｉｓ／ｍｆｓ）・ｌｐ １／２｝／［２｛２ｌ
ｉ＋２ｌｗ＋（２ｍｆｉ・Ｍｉｓ／ｍｆｓ）｝１／２］）（式９）
以上まとめると、ビーム電流４がフィードバック電流に
変換される最適な条件は、式８に加えて、（ｌｐ・Ｎｐ
２／ｌｏ・Ｎ１ ２）を１に対して無視できるだけＮ１を
大きくとるというものにまとめることができる。そし
て、そのときにビーム電流４がフィードバック電流に変
換される割合は式９によって与えられる。
［電流感度と分解能］ＳＱＵＩＤ８の冷却には液体ヘリ
ウムを用いた。液体ヘリウム温度では磁心の比透磁率は
室温より低下する。本実施例では液ヘリウム温度での比
透磁率が２．５×１０４の磁心を用いて実験を行った。
磁心の寸法は内径φ１５０ｍｍ、外径φ２６０ｍｍ、高
さ３０ｍｍである。よって、１ターン巻いた検知コイル
１の液体ヘリウム温度での自己インダクタンスｌｐは８
３μＨである。液体ヘリウム温度でのその他の各種パラ
メータは、各ＳＱＵＩＤ８の自己インダクタンスは２５
０ｐＨ、各ＳＱＵＩＤ入力コイル９の自己インダクタン
スは１００ｎＨ、各フィードバックコイル５の自己イン
ダクタンスは７５ｎＨ、各ＳＱＵＩＤ入力コイル９とＳ
ＱＵＩＤ８間の相互インダクタンスは５ｎＨ、各フィー
ドバックコイル５とワッシャーコイル１３間の相互イン
ダクタンスは３ｎＨ、各ワッシャーコイル１３の自己イ
ンダクタンスは１２５ｐＨ、各フィードバックコイル５
とＳＱＵＩＤ８間の相互インダクタンスは２．２ｐＨの
ものを用いた。図３は検知コイル１の巻き数を変えたと
きの１０ｎＡのビーム電流４に対する出力１４である。
比較例はトランスを付けずに測定した結果である。すな
わち検知コイル１とＳＱＵＩＤ入力コイル９を超伝導線
で接続して閉ループをつくった磁気回路で実験を行った
ときの測定結果である。この場合は、検知コイル１の巻
き数を少なくした方が電流感度は上がった。巻き数を１
ターンにしたときに電流感度は最大となり９０ｍＶ／１
０ｎＡであった。このときの雑音レベルは１０ｍＶであ
り、分解能は１．１ｎＡであった。実施例はトランスを
付けたときの測定結果である。従来例と同様に検知コイ
ル１の巻き数を変えて測定を行った。ただし、トランス
の巻き数を各検知コイル１に合わせて最適な巻き数に変
えて出力１４を測定した。例えば、検知コイル１の巻き
数を４ターンとしたときは、トランス入力コイル１１の
巻き数を９８ターン、トランス出力コイル１０の巻き数
を１０ターンとした。実施例では、検知コイル１の巻き
数に関係なく電流感度は１２７ｍＶ／１０ｎＡであっ
た。これは比較例の最大値より４０％以上高い値であ
る。このときの雑音レベルは１０ｍＶであり、分解能は
０．７９ｎＡであった。以上のことから、実施例のよう
に検知コイル１とＳＱＵＩＤ入力コイル９の間にトラン
スを付けることで、従来の比較例と比べて電流感度と分
解能を向上できることが了解できる。さらに実施例の検
知コイル１は、磁心に超伝導線を等角度間隔で複数ター
ン巻いただけの簡単な構造で、且つ、磁束の局所的な変
動に対して影響を受けにくい構造を実現している。
［装置の小型化］本発明のように検知コイル１とＳＱＵ
ＩＤ入力コイル９の間にトランスを付けることで、装置
を小型化することもできる。前述の比較例では９０ｍＶ
／１０ｎＡの電流感度を得るためには、磁心の寸法は内
径φ１５０ｍｍ、外径φ２６０ｍｍ、高さ３０ｍｍが必
要であった。これは検知コイル１の巻き数を１ターン以
下にすることはできないので、これ以上はインダクタン
スを低減できないからである。このためにＳＱＵＩＤ８
のインダクタンスとの関係から、検知コイル１で収集し
た磁束を有効に出力１４に変換できないのである。一
方、本発明では検知コイル１とＳＱＵＩＤ入力コイル９
の間にトランスを付けることにより、検知コイル１で収
集した磁束をほぼ完全に出力１４に変換することができ
た。このために、検知コイル１の寸法を小さくしても比
較例と同等の電流感度を得ることができた。図４は外径
が小さい検知コイル１を作製して出力１４を測定した結
果である。検知コイル１の内径と高さは同じ寸法で作製
した。ただし、トランスの巻き数は各検知コイル１に合
わせて最適な巻き数に変えて出力１４を測定した。図４
から、従来例と同等の９０ｍＶ／１０ｎＡの電流感度を
得るためには、本発明では検知コイル１の外径は約φ２
０５ｍｍで十分であることが了解できる。これは検知コ
イル１の外径で約２１％、体積で約５７％小型化できた
ことに相当する。外径を小さくできることは本装置を設
置する空間による制限を低減するし、体積の小型化は重
量による制限を低減するので、本発明は工業的な応用面
で大変有効である。DETAILED DESCRIPTION OF THE INVENTION The construction of the device according to the invention is described below. However, this is one of the embodiments. The detection unit for detecting the magnetic field corresponding to the beam current 4 is the detection coil 1 having a structure in which the superconducting wire is wound around the magnetic core for one turn or for a plurality of turns. It is desirable that the magnetic core has a magnetic permeability as large as possible at the operating temperature of SQUID8 because the sensitivity of the device can be improved. The measuring unit having a superconducting element sensitive to the magnetic flux corresponding to the detected magnetic field is
A superconducting circuit using SQUID8 was used. This will be described in detail later. A transformer that magnetically couples the detection unit and the measurement unit is provided. The detection part and the measurement part were surrounded by the superconducting magnetic shield 2. However, the superconducting magnetic shield 2 is not a closed structure, but has a gap 17. The space in which the ion beam flows, the target 12, and other devices are arranged outside the superconducting magnetic shield 2. Also SQU
Cryostat 3 to cool to ID8 operating temperature
Liquid helium was put in the flask and cooled. [Measurement Principle] FIG. 1 shows the measurement principle of the beam current 4. Since the ion beam is a flow of charged particles, a magnetic field corresponding to the current intensity is generated around the ion beam according to Ampere's law. Since this magnetic field is proportional to the beam current 4, the current intensity can be measured without contacting the beam by measuring this magnetic field. The magnetic field generated by the beam current 4 passes through the superconducting magnetic shield 2 without being attenuated and is collected by the detection coil 1. That is, the detection coil 1 can collect the magnetic field proportional to the current passing through the closed loop formed by the detection coil 1 without attenuating. For example, the magnetic field created by a beam current 4 of 10 nA is 1 at a point 20 cm away from the beam center.
It is of the order of 0-14 T, which is collected in the sensing coil 1 without being attenuated by the magnetic shield. on the other hand,
External magnetic fields, including ambient magnetic fields, are on the order of at least 10 −5 T. From this, the background is much larger. However, in this apparatus, the external magnetic field is significantly attenuated by the order of about 10 −8 to 10 −10 times by the superconducting magnetic shield 2 utilizing the Meissner effect of the superconductor. To achieve this, superconducting magnetic shield 2
The shape of is devised. The superconducting magnetic shield 2 has a narrow gap 17, and the length, inner diameter and outer diameter of the gap 17 can be determined according to the required attenuation rate. The magnetic field collected by the sensing coil 1 induces a superconducting current in the superconducting closed loop composed of the sensing coil 1 and the transformer input coil 11. Next, the transformer input coil 11
Induces a superconducting current in the transformer output coil 10 according to the number of turns of the transformer. The superconducting current induced in the transformer output coil 10 flows in the SQUID input coil 9,
An attempt is made to generate a magnetic flux so as to penetrate SQUID8.
However, the feedback coil 5 is arranged in the SQUID 8 so as to keep the amount of magnetic flux passing through the SQUID 8 constant, and the feedback current flows through the feedback coil 5 so as to cancel the change in the amount of magnetic flux passing through the SQUID 8. Since this feedback current is proportional to the beam current 4, the beam current 4 can be measured by measuring the potential difference generated by the feedback current across the feedback resistor 7. [Superconducting Magnetic Circuit] FIG. 2 shows the SQUID 8 and the driving circuit in more detail. The magnetic coupling of the superconducting magnetic circuit in which the beam current 4 is converted into the feedback current will be described below. The magnetic flux collected by the detection coil 1 is transmitted to the SQUID 8 by the magnetic coupling of Expressions 1 to 3. (L p + L t1 ) ΔI p + M t · ΔI t = N p · ΔΦ B (Formula 1) (L t2 + 2Ii + 2l w ) ΔI t + 2m fi · ΔI f + M t · ΔI p = 0 (Formula 2) Mis · ΔI t −m fs · ΔI f = 0 (Equation 3) Here, the self-inductance of the detection coil 1 is L p , the self-inductance of the transformer input coil 11 is L t1 ,
The detection coil 1 and the transformer input coil 11 carry a current I p flowing in a closed superconducting closed loop, and the transformer input coil 11
And the mutual inductance between the transformer output coil 10 and M
t , the current flowing in the superconducting closed loop formed by the transformer output coil 10, the washer coil 13, and the SQUID input coil 9 is I t , the number of turns of the detection coil 1 is N p , the amount of magnetic flux penetrating the cross section of the detection coil 1 is Φ B , and the transformer is Output coil 10
, L t2 , the self-inductance of each SQUID input coil 9 is li, the self-inductance of each washer coil 13 is l w , the mutual inductance between each feedback coil 5 and the washer coil 13 is m fi , and flows into the feedback coil 5. The current is I r , the mutual inductance between each SQUID input coil 9 and SQUID 8 is Mis, and each feedback coil 5
When the mutual inductance between the SQUID8 and m fs. Eliminating ΔI p and ΔI t from Equations 1 to 3,
Equation 4 is obtained by eliminating Φ B using the relationship of Φ B = l p · ΔI b . ΔI f / ΔI b = {(Mis / m fs ) M t · l p · N p } / [{2li + 2l w + (2 m fi · Mis / m fs ) + (L p · L t2 / (L p + L t1 ))} · (L p + L t1 )] (Equation 4) Here, the self-inductance of the detection coil 1 wound one turn is l p , and the beam current intensity is I b . Furthermore, 1
If the self-inductance of the wound transformer is lo, the number of turns of the transformer input coil 11 is N 1 , and the number of turns of the transformer output coil 10 is N 2 , the self-inductance of the transformer input coil 11 is L t1 = lo · N 1 2 , Self-inductance of transformer output coil 10 L t2 = lo
A · N 2 2. Further, the self-inductance of the detection coil 1 is L p = l p · N p 2 . Substituting these into equation 4 yields equation 5. ΔI f / ΔI b = {(Mis / m fs ) lo · N 1 · N 2 · N p · l p } / [{2li + 2l w + (2m fi · Mis / m fs ) + (l p · N p 2). · lo · N 2 2 / ( l p · N p 2 + lo · N l 2))} · (l p · N p 2 + lo · N l 2)] ( a variable variable in formula 5) 5 N p , N 1 , N 2 and these are independent of each other, the condition for maximizing the right side of Expression 5 is as follows:
Becomes N 2 = [(l p · N p 2 + lo · N l 2 ) · {2li + 2l w + (2m fi · Mis / m fs )} / lo · l p · N p 2 ] 1/2 and N 1 Is infinite (Equation 6) The condition of Equation 6 can be rewritten using the self-inductance L p of the detection coil 1. That is, if Equation 6 is squared, Equation 7 is obtained. L p · (N 2 / N 1) 2 = {(l p · N p 2 / lo · N 1 2) +1} {2li + 2l w + (2m fi · Mis / m fs)} ( Equation 7) where If N 1 is set to infinity, (l p · N p 2 /
Since Io · N 1 2 ) can be ignored with respect to 1, Equation 8 is obtained. L p · (N 2 / N 1 ) 2 = 2li + 2l w + (2m fi · Mis / m fs ) (Equation 8) The maximum value on the right side of Equation 5 given at this time is Equation 9. (ΔI f / ΔI b ) MAX = {(Mis / m fs ) · l p 1/2 } / [2 {2l i + 2l w + (2m fi · Mis / m fs )} 1/2 ]) (Equation 9) In summary, the optimum conditions for converting the beam current 4 into the feedback current include (l p · N p
2 / lo · N 1 2 ) can be summarized as one in which N 1 is set to be as large as possible with respect to 1. The rate at which the beam current 4 is converted into the feedback current at that time is given by Equation 9. [Current Sensitivity and Resolution] Liquid helium was used for cooling SQUID8. At liquid helium temperature, the relative permeability of the magnetic core is lower than room temperature. In this example, an experiment was conducted using a magnetic core having a relative magnetic permeability of 2.5 × 10 4 at the liquid helium temperature.
The magnetic core has an inner diameter of 150 mm, an outer diameter of 260 mm and a height of 30 mm. Therefore, the self-inductance l p of the detection coil 1 wound one turn at the liquid helium temperature is 8
It is 3 μH. As for various other parameters at liquid helium temperature, the self-inductance of each SQUID8 is 25
0 pH, the self-inductance of each SQUID input coil 9 is 100 nH, the self-inductance of each feedback coil 5 is 75 nH, each SQUID input coil 9 and S
Mutual inductance between QUIDs 8 is 5 nH, mutual inductance between each feedback coil 5 and washer coil 13 is 3 nH, self-inductance of each washer coil 13 is 125 pH, each feedback coil 5 is
The mutual inductance between SQUID8 and SQUID8 was 2.2 pH. FIG. 3 shows the output 14 for a beam current 4 of 10 nA when the number of turns of the detection coil 1 is changed.
The comparative example is the result measured without a transformer. That is, it is a measurement result when an experiment was conducted in a magnetic circuit in which the detection coil 1 and the SQUID input coil 9 were connected by a superconducting wire to form a closed loop. In this case, the current sensitivity was improved by reducing the number of turns of the detection coil 1. Number of turns 1
When turned, the current sensitivity becomes maximum and 90 mV / 1
It was 0 nA. At this time, the noise level was 10 mV and the resolution was 1.1 nA. The example is a measurement result when a transformer is attached. As in the conventional example, the number of turns of the detection coil 1 was changed and the measurement was performed. However, the output 14 was measured while changing the number of turns of the transformer to an optimum number of turns according to each detection coil 1. For example, when the number of turns of the detection coil 1 is 4 turns, the number of turns of the transformer input coil 11 is 98 turns and the number of turns of the transformer output coil 10 is 10 turns. In the example, the current sensitivity was 127 mV / 10 nA regardless of the number of turns of the detection coil 1. This is 40% or more higher than the maximum value of the comparative example. At this time, the noise level was 10 mV and the resolution was 0.79 nA. From the above, it can be understood that by attaching a transformer between the detection coil 1 and the SQUID input coil 9 as in the embodiment, the current sensitivity and resolution can be improved as compared with the conventional comparative example. Furthermore, the detection coil 1 of the embodiment has a simple structure in which the superconducting wire is wound around the magnetic core at a plurality of turns at equal angular intervals, and realizes a structure that is not easily affected by the local fluctuation of the magnetic flux. . [Miniaturization of device] Like the present invention, the detection coil 1 and SQU
By installing a transformer between the ID input coils 9, the device can be downsized. 90 mV in the above comparative example
In order to obtain a current sensitivity of / 10 nA, it was necessary for the magnetic core to have an inner diameter of 150 mm, an outer diameter of 260 mm and a height of 30 mm. This is because the number of turns of the detection coil 1 cannot be set to 1 turn or less, and the inductance cannot be reduced any more. For this purpose SQUID8
The magnetic flux collected by the detection coil 1 cannot be effectively converted into the output 14 due to the relationship with the inductance of the. On the other hand, in the present invention, the detection coil 1 and the SQUID input coil 9
It was possible to almost completely convert the magnetic flux collected by the detection coil 1 into the output 14 by attaching a transformer between the two. Therefore, even if the size of the detection coil 1 is reduced, the same current sensitivity as that of the comparative example can be obtained. FIG. 4 is a result of measuring the output 14 by producing the detection coil 1 having a small outer diameter. The inner diameter and height of the detection coil 1 were made the same. However, the number of turns of the transformer was changed to an optimum number of turns according to each detection coil 1, and the output 14 was measured. Figure 4
Therefore, in order to obtain the same current sensitivity of 90 mV / 10 nA as in the conventional example, the outer diameter of the detection coil 1 is about φ2 in the present invention.
It can be seen that 05 mm is sufficient. This corresponds to downsizing of the detection coil 1 by about 21% and volume by about 57%. The fact that the outer diameter can be made smaller reduces the limitation due to the space where the apparatus is installed, and the reduction in volume reduces the limitation due to weight, so the present invention is very effective in industrial applications.
【発明の効果】以上のように、本発明による非接触型イ
オンビーム電流強度測定装置を用いれば、検知コイルの
自己インダクタンスに関係なく、検知コイルの磁心とＳ
ＱＵＩＤ８の性能で規定される本来の電流感度を得るこ
とができる。これにより、磁心の透磁率や内径と外径の
比、および高さを大きくしてビーム電流４が発生させる
磁束を検知コイルで多く収集すればするほど出力１４を
大きくできるようになった。さらに、検知コイルの巻き
数を複数ターンとすることで局所的な磁束の変化の影響
を受けにくい構造が簡単に得られた。この場合も、トラ
ンスの入力側と出力側の巻き数を調整することで上記と
同様の電流感度を得ることができた。また、従来と同等
の電流感度であれば、装置を小型化できる。As described above, by using the non-contact type ion beam current intensity measuring device according to the present invention, the magnetic core of the detection coil and the S
The original current sensitivity defined by the performance of QUID8 can be obtained. As a result, the output 14 can be increased as the magnetic permeability, the ratio of the inner diameter to the outer diameter, and the height of the magnetic core are increased to collect more magnetic flux generated by the beam current 4 by the detection coil. Furthermore, by making the number of turns of the detection coil a plurality of turns, a structure that is not easily affected by the local change in magnetic flux was easily obtained. Also in this case, the same current sensitivity as described above could be obtained by adjusting the number of turns on the input side and the output side of the transformer. Further, if the current sensitivity is equivalent to that of the conventional one, the device can be downsized.
【図１】非接触イオンビーム電流測定の原理を示す要部
断面図FIG. 1 is a sectional view of an essential part showing the principle of non-contact ion beam current measurement.
【図２】ＳＱＵＩＤと駆動回路の模式図FIG. 2 is a schematic diagram of a SQUID and a drive circuit.
【図３】検知コイル１の巻き数を変えたときの１０ｎＡ
のビーム電流４に対する出力１４を示す図FIG. 3 is 10 nA when the number of turns of the detection coil 1 is changed.
Of output 14 for beam current 4 of
【図４】検知コイル１の外径と１０ｎＡのビーム電流４
に対する出力１４の関係を示す図FIG. 4 is an outer diameter of the detection coil 1 and a beam current 4 of 10 nA.
Showing the relationship of output 14 with respect to
１ ：検知コイル ２ ：超伝導磁気遮蔽 ３ ：クライオスタット ４ ：ビーム電流 ５ ：フィードバックコイル ６ ：電子制御 ７ ：フィードバック抵抗 ８ ：ＳＱＵＩＤ ９ ：ＳＱＵＩＤ入力コイル １０ ：トランス出力コイル １１ ：トランス入力コイル １２ ：ターゲット １３ ：ワッシャーコイル １４ ：出力 １５ ：プリアンプ １６ ：積分器 １７ ：ギャップ 1: Detection coil 2: Superconducting magnetic shield 3: Cryostat 4: Beam current 5: Feedback coil 6: Electronic control 7: Feedback resistance 8: SQUID 9: SQUID input coil 10: Transformer output coil 11: Transformer input coil 12: Target 13: Washer coil 14: Output 15: Preamplifier 16: integrator 17: Gap
Claims (6)
る検知部と、検知された磁場に対応した磁束に感応する
超伝導素子を有する測定部と、検知部と測定部を磁気的
に結合させるトランスと、前記検知部と測定部をイオン
ビームが流れる空間を含む外部空間から磁気遮蔽する超
伝導体からなるギャップを有する磁気遮蔽部を少なくと
も有することを特徴とするイオンビーム電流強度測定装
置。1. A detection unit for detecting a magnetic field corresponding to an ion beam current, a measurement unit having a superconducting element sensitive to a magnetic flux corresponding to the detected magnetic field, and the detection unit and the measurement unit are magnetically coupled. An ion beam current intensity measuring device comprising at least a transformer and a magnetic shield part having a gap made of a superconductor for magnetically shielding the detection part and the measurement part from an external space including a space in which an ion beam flows.
以下であることを特徴とする請求項１記載のイオンビー
ム電流強度測定装置。2. The current intensity of the ion beam current is 100 μA.
The ion beam current intensity measuring device according to claim 1, wherein:
た構成であることを特徴とする請求項１記載のイオンビ
ーム電流強度測定装置。3. The ion beam current intensity measuring device according to claim 1, wherein the detector has a structure in which a superconducting wire is wound around a magnetic core in plural turns.
ように配置した超伝導体からなるギャップを有する超伝
導磁気遮蔽であることを特徴とする請求項１記載のイオ
ンビーム電流強度測定装置。4. The ion beam current intensity measuring device according to claim 1, wherein the magnetic shield portion is a superconducting magnetic shield having a gap made of a superconductor arranged so as to surround the ion beam current.
装置を備えたイオン注入装置。5. An ion implanter equipped with the ion beam current intensity measuring device according to claim 1.
装置を備えた粒子線照射装置。6. A particle beam irradiation apparatus equipped with the ion beam current intensity measuring apparatus according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001244977A JP2003021670A (en) | 2001-07-08 | 2001-07-08 | Noncontact type ion beam current intensity measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001244977A JP2003021670A (en) | 2001-07-08 | 2001-07-08 | Noncontact type ion beam current intensity measuring device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2003021670A true JP2003021670A (en) | 2003-01-24 |
Family
ID=19074818
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001244977A Pending JP2003021670A (en) | 2001-07-08 | 2001-07-08 | Noncontact type ion beam current intensity measuring device |
Country Status (1)
| Country | Link |
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| JP (1) | JP2003021670A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004081966A1 (en) * | 2003-03-14 | 2004-09-23 | Matsushita Electric Industrial Co., Ltd. | Beam current measuring instrument and beam current measuring method using same |
| WO2004107463A1 (en) * | 2003-05-30 | 2004-12-09 | Riken | Beam current meter |
| EP1715362A1 (en) * | 2004-02-10 | 2006-10-25 | Matsushita Electric Industrial Co., Ltd. | Beam measuring equipment and beam measuring method using the same |
| CN111025203A (en) * | 2019-11-27 | 2020-04-17 | 中国船舶重工集团有限公司第七一0研究所 | SQUID device induction coil |
| EP3496167A4 (en) * | 2016-08-03 | 2020-09-16 | Riken | Charged particle beam current measurement apparatus |
| CN111796319A (en) * | 2020-07-14 | 2020-10-20 | 中国科学院近代物理研究所 | Broadband imaginary part beam coupling impedance measurement system and method |
-
2001
- 2001-07-08 JP JP2001244977A patent/JP2003021670A/en active Pending
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7619223B2 (en) | 2003-03-14 | 2009-11-17 | Panasonic Corporation | Beam current measuring instrument and beam current measuring method using same |
| JPWO2004081966A1 (en) * | 2003-03-14 | 2006-06-15 | 松下電器産業株式会社 | Beam current measuring apparatus and beam current measuring method using the same |
| WO2004081966A1 (en) * | 2003-03-14 | 2004-09-23 | Matsushita Electric Industrial Co., Ltd. | Beam current measuring instrument and beam current measuring method using same |
| WO2004107463A1 (en) * | 2003-05-30 | 2004-12-09 | Riken | Beam current meter |
| JP2004356573A (en) * | 2003-05-30 | 2004-12-16 | Institute Of Physical & Chemical Research | Beam current meter |
| US7435970B2 (en) | 2003-05-30 | 2008-10-14 | Riken | Beam current meter |
| JP4550375B2 (en) * | 2003-05-30 | 2010-09-22 | 独立行政法人理化学研究所 | Beam ammeter |
| EP1715362A1 (en) * | 2004-02-10 | 2006-10-25 | Matsushita Electric Industrial Co., Ltd. | Beam measuring equipment and beam measuring method using the same |
| EP1715362A4 (en) * | 2004-02-10 | 2013-09-04 | Panasonic Corp | Beam measuring equipment and beam measuring method using the same |
| EP3496167A4 (en) * | 2016-08-03 | 2020-09-16 | Riken | Charged particle beam current measurement apparatus |
| CN111025203A (en) * | 2019-11-27 | 2020-04-17 | 中国船舶重工集团有限公司第七一0研究所 | SQUID device induction coil |
| CN111796319A (en) * | 2020-07-14 | 2020-10-20 | 中国科学院近代物理研究所 | Broadband imaginary part beam coupling impedance measurement system and method |
| CN111796319B (en) * | 2020-07-14 | 2022-05-31 | 中国科学院近代物理研究所 | Broadband imaginary part beam coupling impedance measurement system and method |
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