JP3758983B2

JP3758983B2 - Accelerator insulation post

Info

Publication number: JP3758983B2
Application number: JP2001099410A
Authority: JP
Inventors: 英俊岡
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2001-03-30
Filing date: 2001-03-30
Publication date: 2006-03-22
Anticipated expiration: 2021-03-30
Also published as: JP2002299100A

Description

【０００１】
【発明の属する技術分野】
本発明は、電子顕微鏡等に用いられる粒子加速器の絶縁支柱であって、電子等の荷電粒子を加速して荷電粒子ビームを生成するために電圧を印加する加速電極部に用いられる加速器の絶縁支柱に関するものである。
【０００２】
【従来の技術】
従来、電子顕微鏡等においては、電子等の荷電粒子を加速するための加速器の絶縁支柱が用いられている。この加速器の絶縁支柱の断面図を図５に示し、図５のロウ付け接合部の拡大断面図を図６に示す。これらの図において、１は絶縁柱、２は電極部材、３はメタライズ層、４はＮｉ（ニッケル）メッキ層、５はロウ材であり、主にこれらで絶縁支柱は構成されている。即ち、この絶縁支柱は、一般に酸化アルミニウム（Ａｌ₂Ｏ₃）質焼結体から成る絶縁柱１と、絶縁柱１の両端面にロウ材５を介して接合されたＦｅ−Ｎｉ−Ｃｏ合金等の金属材料から成る円環状の電極部材２から構成されている。
【０００３】
そして、対向する２つの電極部材２にそれぞれ異なる電圧を印加することにより、電子等の荷電粒子が加速される。
【０００４】
電極部材２の絶縁柱１への接合は、絶縁柱１の両端面に予めモリブデン（Ｍｏ）−マンガン（Ｍｎ）等のメタライズ層３とＮｉメッキ層４を被着しておき、そのメタライズ層３とＮｉメッキ層４が被着された絶縁柱１の両端面を電極部材２にロウ材５を介して接合することによって行われる。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記のような従来の加速器においては、絶縁柱１に施されたメタライズ層３とＮｉメッキ層４とロウ材５は絶縁柱１の端面から外側に０．３〜１ｍｍ程度はみ出している。このため、電極部材２に電圧を印加し電子等の荷電粒子を加速させると、絶縁柱１に施されたメタライズ層３とＮｉメッキ層４とロウ材５のはみ出した突起部や縁部より微少放電が始まり、微少放電により生じた２次電子が絶縁柱１の表面を通り、一方の電極部材２から他方の電極部材２へと放電しやすくなるという問題点があった。
【０００６】
そこで、この問題を克服するものとして、図７に示すように、絶縁柱１の両端面にネジ切り加工を内面に施したネジ穴を形成し、そのネジ穴に金属等のボルト７を螺合して電極部材２を絶縁支柱に締め付け固定することにより、電子等の荷電粒子を生成するために電圧を印加しても放電が起こりにくい構成とするものがあった。しかしながら、この場合、外力による長時間の微振動等によってボルト７が緩み、絶縁支柱としての機能を果さなくなるといった問題点があった。
【０００７】
従って、本発明は上記従来技術における問題点に鑑みて完成されたものであり、その目的は、対向する電極部材間で発生していた放電を解消し、また電極部材を絶縁支柱に強固に接合して長時間の微振動等に対して信頼性の高いものとすることにある。そして、電子等の荷電粒子を所定の速度に確実かつ安定的に加速できるとともに、所定方向に確実かつ安定的にビームを発生できるものとすることにある。
【０００８】
【課題を解決するための手段】
本発明の加速器の絶縁支柱は、互いに対向配置されるとともにそれぞれ上下面を貫通する貫通孔が略同じ間隔で複数個形成された２つの円環状の電極部材と、上下両端面に横断面形状が略円形の凹部が形成され、該凹部が前記貫通孔と同軸状となるようにして前記両端面が前記２つの電極部材の対向する主面にそれぞれ対向配置された複数の略円柱状の絶縁柱と、前記貫通孔および前記凹部に嵌入され、前記貫通孔および前記凹部の内面にロウ付けされた略円筒形の金属接合部材とを具備したことを特徴とする。
【０００９】
本発明は、上記の構成により、荷電粒子を加速してビームを生成するために電圧を印加する電極部材間での微少放電の発生を有効に抑えられるため、安定して高電圧を印加することができる。また、運搬移動を余儀なくされる電子顕微鏡等の一般産業機器に用いられる加速器において、外力による長時間の微振動等によっても破壊されたり接合部が緩むといったことがなく、信頼性の高い加速器の絶縁支柱となるという作用効果を有する。
【００１０】
本発明において、好ましくは、前記金属接合部材の厚みが０．３〜１ｍｍであることを特徴とする。
【００１１】
本発明は、この構成により、接合部の接合力が向上し、さらに信頼性の高い加速器の絶縁支柱となる。
【００１２】
【発明の実施の形態】
本発明の加速器の絶縁支柱を以下に詳細に説明する。図１は本発明の絶縁支柱のロウ付け接合部の拡大断面図である。図１において、１は絶縁柱、２は電極部材、３はメタライズ層、４はＮｉメッキ層、５はロウ材、６は金属接合部材であり、主にこれらで絶縁支柱は構成されている。
【００１３】
そして、本発明の絶縁支柱は、互いに対向配置されるとともにそれぞれ上下面を貫通する貫通孔が略同じ間隔で複数個形成された２つの円環状の電極部材２と、両端面に横断面形状が略円形の凹部が形成され、その凹部が貫通孔と同軸状となるようにして両端面が２つの電極部材２の対向する主面にそれぞれ接合された複数の略円柱状の絶縁柱１と、貫通孔および凹部に嵌入されロウ付けされた略円筒形の金属接合部材６とを具備する。
【００１４】
本発明の絶縁柱１は、両端面に凹部が形成された略円柱状のものである。その凹部内に金属接合部材６が嵌入ロウ付けされる。この金属接合部材６によって、電極部材２と絶縁柱１とが接合される。また、絶縁柱１は、絶縁柱１両端の２つの電極部材２を絶縁する作用を有し、一般に酸化アルミニウム（Ａｌ₂Ｏ₃）質焼結体等から成る電気絶縁材料で形成される。この絶縁柱１の凹部内に予めＭｏ−Ｍｎ等のメタライズ層３とＮｉメッキ層４を被着しておき、メタライズ層３とＮｉメッキ層４と金属接合部材６とをロウ材５を介して接合させ、さらに金属接合部材６と電極部材２とをロウ材５を介して接合させる。
【００１５】
電極部材２はステンレススチール等の金属材料から成り、金属接合部材６はＦｅ−Ｎｉ−Ｃｏ合金やＣｕ−Ｗ等の金属材料から成る。
【００１６】
本発明において、金属接合部材６の直径（外径）は絶縁柱１の直径の５０〜８０％がよく、５０％未満では、金属接合部材６自体が小さくなるためその形状加工がし難くなる。８０％を超えると、絶縁柱１の凹部が大きくなるため凹部での肉厚が薄くなり、絶縁柱１は金属接合部材６との接合部において熱膨張に起因する残留応力に耐えられず、絶縁柱１の両端面部付近にクラックや割れ等が発生し易くなる。
【００１７】
また本発明において、金属接合部材６の厚みは０．３〜１ｍｍが好ましい。０．３ｍｍ未満では、外力による振動、衝撃等に対する金属接合部材６の強度が低下し、絶縁支柱としての機械的強度が低下しその機能を維持できなくなる。１mmを超えると、絶縁柱１と金属接合部材６との接合部において熱膨張に起因する応力が両部材の接合界面で残留することが多くなり、絶縁柱１の接合部にクラックや割れ等が発生し易くなる。
【００１８】
さらに本発明において、金属接合部材６の高さは電極部材２の厚みの２倍〜５倍であることが好ましい。２倍未満では、外力による振動、衝撃等に対して接合力が弱くなり、絶縁支柱全体が傾くといった変形を起こし易くなり、形状の維持が困難となり形状的に不安定な絶縁支柱となる。５倍を超えると、機械加工時の穿孔ドリルの振れが大きくなるため、円筒形の金属接合部材６の厚みを均一にして加工するのが困難になる。
【００１９】
【実施例】
本発明の実施例について以下に説明する。
（実施例１）
比較例１として、図２に示す構成のものを以下のようにして作製した。純度９９重量％の酸化アルミニウム（Ａｌ₂Ｏ₃）質焼結体から成る、直径φ１０ｍｍ、長さ４０ｍｍの円柱状の絶縁柱１を用意した。その絶縁柱１の両端面の全面にＭｏとＭｎとＳｉＯ₂をそれぞれ８９重量％、６重量％、５重量％の割合で含有する金属ペーストを、１０〜１５μｍの厚さとなるように印刷塗布し、乾燥後、加湿したフォーミングガス中で１４００℃の温度で焼成した。こうして、絶縁柱１の両端面の全面にＭｏ−Ｍｎ合金から成るメタライズ層を被着させた。その後、メタライズ層上にＮｉメッキ層を電解メッキ法により約２μｍの厚さで被着させた。
【００２０】
次に、絶縁柱１の両端面に、横５０ｍｍ、縦２５ｍｍ、厚み１ｍｍのＦｅ−Ｎｉ−Ｃｏ合金から成る平板状の電極部材９を接合した。このとき、絶縁柱１の両端面と電極部材９との間に、直径φ１０ｍｍ、厚み０．０５ｍｍの板状のＡｇ−Ｃｕ合金から成るロウ材８のプリフォームを設置し、それを８２０℃に加熱して接合させた。これにより、製作されたものをサンプルＡとした。
【００２１】
比較例２として、比較例１と同じ絶縁柱１の両端面の中心部にネジ穴加工（ＪＩＳ−Ｂ０２０５によるＭ８）を施し、比較例１と同じ電極部材９の中心部に、上側より直径φ１２ｍｍの穴を途中まで形成し、それに続いて同心状に直径φ８．５ｍｍ穴を形成して成る、内部の途中に段差を有する貫通孔を形成した。その段差付き貫通孔を有する電極部材１１を、絶縁柱１の両端面のそれぞれに、頭部上面に六角穴を有するＭ８（Ｍ８：ネジの呼び径）ボルト１０を上記貫通孔およびネジ穴に挿通螺合することによって固定したものをサンプルＢ（図３）とした。
【００２２】
本発明の実施例１として、比較例１と同寸法の絶縁柱１の両端面の中心部に直径φ８．０５ｍｍ、深さ４ｍｍの穴（凹部）加工を施し、この穴の内面にＭｏとＭｎとＳｉＯ2をそれぞれ８９重量％、６重量％、５重量％の割合で含有する金属ペーストを、１０〜１５μｍの厚さとなるように印刷塗布し、乾燥後、加湿したフォーミングガス中で１４００℃の温度で焼成した。こうして、絶縁柱１の両端面の凹部の内面全面にＭｏ−Ｍｎ合金から成るメタライズ層３を被着させた。その後、メタライズ層３上にＮｉメッキ層を電解メッキ法により約２μｍの厚さで被着した。
【００２３】
次に、横５０ｍｍ、縦２５ｍｍ、厚み１ｍｍから成る平板状の電極部材２の中心部に直径φ８．０５ｍｍの穴（貫通孔）加工を施した貫通孔つき電極部材２を用意し、絶縁柱１と電極部材２とを、上記凹部と貫通孔を同心状に配置しそれらに金属接合部材６を嵌入して接合した。この金属接合部材６は、外径φ８ｍｍ、内径φ７．４ｍｍ、高さ４ｍｍのＦｅ−Ｎｉ−Ｃｏ合金から成るものであった。また、絶縁柱１の凹部内面と金属接合部材６との隙間には、直径φ０．１ｍｍの線状とされたＡｇ−Ｃｕ合金から成るロウ材５のプレフォームを設置し、それを８２０℃に加熱して接合し、これにより製作されたものをサンプルＣ（図４）とした。
【００２４】
サンプルＡ〜Ｃのそれぞれについて、大気雰囲気中、常温で衝撃試験{ＭＩＬ−ＳＴＤ(Military Standard：アメリカ軍用規格)−２０２ＦＭＥＴＨＯＤ２１３Ａ}を行い、１１ｍｓ（ミリ秒）の間に正弦半波の波形で５０Ｇ（Ｇ：重力加速度）程度の衝撃を1回加え、各接合部について光学機器を用い異常がないかを検査した。その結果、サンプルＡは接合部には異常は見られなかった。サンプルＢは、絶縁柱１の両端面の外周部に長さ０．３〜０．５程度ｍｍのクラックが確認できた。サンプルＣは接合部に異常は見られなかった。
【００２５】
また、上記と同様に作製した別のサンプルＡ〜Ｃそれぞれを用意し、大気雰囲気中、常温で振動試験{ＭＩＬ−ＳＴＤ−２０２ＦＭＥＴＨＯＤ２０１Ａ}を行い、周波数１０〜５５Ｈｚ（ヘルツ）、最大振れ幅１．５２ｍｍの振動を、Ｘ，Ｙ，Ｚの３方向に順次各２時間づつ加え、各接合部において異常がないかを光学機器を用いて検査した。その結果、サンプルＡは接合部に異常は見られなかった。サンプルＢは、試験中にボルト１０が緩んだので、試験を途中で中断し絶縁柱１を検査したところ、絶縁柱１の両端面の外周部に長さ０．１〜０．３ｍｍ程度のクラックが確認できた。サンプルＣは接合部に異常は見られなかった。
【００２６】
さらに、上記と同様に作製した別のサンプルＡ〜Ｃそれぞれを用意し、大気雰囲気中、常温で耐電圧試験{ＭＩＬ−ＳＴＤ−２０２ＦＭＥＴＨＯＤ３０１}を基準操作とし、絶縁柱１の両端にある電極部材間に電圧２０ｋＶを印加して各接合部において異常がないかを試験した。サンプルＡは接合部より放電が生じ、接合部付近に黒く炭化されたような跡が確認された。サンプルＢについて放電発生は見られなかった。サンプルＣについて放電発生は見られなかった。
【００２７】
これらのサンプルＡ〜Ｃについて、衝撃、振動等の外力が加わる状態では、ボルト１０により固定されたサンプルＢより、ロウ付けにより接合されたサンプルＡ，Ｃの方が接合強度は大きいという結果が得られた。また、耐電圧試験については、サンプルＡでは絶縁柱１の両端面の外側にメタライズ層３等の金属膜のはみ出しがあるために放電が発生し、サンプルＢでは放電を起こさないといった結果が得られた。サンプルＣについては放電が発生しないという優れた効果が得られた。これらの結果を総合すると、サンプルＣが衝撃、振動等に対して強く、かつ耐電圧性に優れているということが判った。
【００２８】
（実施例２）
本実施例２では、金属接合部材６の寸法を種々に変更して、実施例１と同様の衝撃試験、振動試験、耐電圧試験を行なった。先ず、実施例１と同様にして、絶縁柱１に表１の金属接合部材６の各種寸法に合わせて加工を施し、電極部材１２とロウ付け接合し絶縁支柱を作製した。得られたサンプル（ＮＯ．１〜１２）について試験を行った。その結果を表１に示す。
【００２９】
【表１】

【００３０】
表１のＮＯ．１より、金属接合部材６の肉厚が０．２mmでは、衝撃試験後に試験前の状態と比べて電極部材１２に０．３ｍｍ程度のズレが確認でき、また金属接合部材６には衝撃による変形が見られた。ＮＯ．２、ＮＯ．３より、金属接合部材６の肉厚が０．３ｍｍと１．０ｍｍでは、異常は確認されなかった。ＮＯ．４より、金属接合部材６の肉厚が１．１ｍｍでは、絶縁柱１と金属接合部材６をロウ付けする工程において絶縁柱１の両端面部付近に長さ０．５ｍｍ程度のマイクロクラックの発生が確認できた。
【００３１】
ＮＯ．５より、絶縁柱１の外径に対する金属接合部材６の外径が４０％では、金属接合部材６自身が小さすぎて機械加工がし難く、加工歩留まりが低下し高コストになるといった問題が生じた。ＮＯ．６、ＮＯ．７より、絶縁柱１の外径に対する金属接合部材６の外径が５０％と８０％では、異常は確認されなかった。ＮＯ．８より、絶縁柱１の外径に対する金属接合部材６の外径が９０％では、絶縁柱１と金属接合部材６をロウ付けする工程において絶縁柱１の両端面部付近に長さ０．５ｍｍ程度のマイクロクラックの発生が確認された。
【００３２】
ＮＯ．９より、金属接合部材６の高さが電極部材１２の厚みに対して１倍の場合、当然のことながら絶縁柱１と電極部材２とを結合するのが不能な金属接合部材６となり、ロウ付け接合できなかった。ＮＯ．１０、ＮＯ．１１より、電極部材１２の厚みに対する金属接合部材６の高さが２倍と５倍の場合、異常は確認されなかった。ＮＯ．１２より、電極部材１２の厚みに対する金属接合部材６の高さが６倍の場合、円筒形の金属接合部材６を作製するために貫通孔の加工をするうえで、０．３ｍｍの肉厚を確保しながらの加工が困難となり、加工歩留まりが低下し高コストになるといった問題が生じた。
【００３３】
なお、本発明は上記実施の形態および実施例に限定されるものではなく、本発明の要旨を逸脱しない範囲内において種々の変更を施すことは何等差し支えない。
【００３４】
【発明の効果】
本発明は、互いに対向配置されるとともにそれぞれ上下面を貫通する貫通孔が略同じ間隔で複数個形成された２つの円環状の電極部材と、上下両端面に横断面形状が略円形の凹部が形成され、その凹部が貫通孔と同軸状となるようにして両端面が２つの電極部材の対向する主面にそれぞれ対向配置された複数の略円柱状の絶縁柱と、貫通孔および凹部に嵌入され、貫通孔および凹部の内面にロウ付けされた略円筒形の金属接合部材とを具備したことにより、荷電粒子を加速してビームを生成するために電圧を印加する電極部材間での微少放電の発生を有効に抑えられるため、安定して高電圧を印加することができる。また、運搬移動を余儀なくされる電子顕微鏡等の一般産業機器に用いられる加速器において、外力による長時間の微振動等によっても破壊されたり接合部が緩むといったことがなく、信頼性の高い加速器の絶縁支柱となる。
【００３５】
本発明において、好ましくは、金属接合部材の厚みが０．３〜１ｍｍであることにより、接合部の接合力が向上し、さらに信頼性の高い加速器の絶縁支柱となる。即ち、絶縁柱と金属接合部材との熱膨張係数の相違に起因する絶縁柱のロウ付部分からのクラックや割れ等の発生を有効に抑えられ、強固に接合された高信頼性の加速器の絶縁支柱とすることができた。
【図面の簡単な説明】
【図１】本発明の加速器の絶縁支柱におけるロウ付け部の拡大断面図である。
【図２】従来のロウ付けによる接合構造を有する絶縁支柱の斜視図である。
【図３】従来のネジ止めによる接合構造を有する絶縁支柱の斜視図である。
【図４】本発明のロウ付け構造を有する絶縁支柱の斜視図である。
【図５】従来の加速器の絶縁支柱を示す断面図である。
【図６】図２の絶縁支柱のロウ付け部の拡大断面図である。
【図７】従来の絶縁支柱のボルト止め部を示す拡大断面図である。
【符号の説明】
１：絶縁柱
２：電極部材
３：メタライズ層
４：Ｎｉメッキ層
５：ロウ材
６：金属接合部材
７：金属のボルト[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an insulating support column of a particle accelerator used in an electron microscope or the like, and is used for an acceleration electrode unit that applies a voltage to accelerate charged particles such as electrons to generate a charged particle beam. It is about.
[0002]
[Prior art]
Conventionally, in an electron microscope or the like, an insulating support column of an accelerator for accelerating charged particles such as electrons is used. FIG. 5 shows a cross-sectional view of the insulating support post of this accelerator, and FIG. 6 shows an enlarged cross-sectional view of the brazed joint of FIG. In these drawings, 1 is an insulating column, 2 is an electrode member, 3 is a metallized layer, 4 is a Ni (nickel) plating layer, and 5 is a brazing material, and these mainly constitute insulating posts. That is, this insulating support is generally composed of an insulating column 1 made of an aluminum oxide (Al ₂ O ₃ ) -based sintered body, an Fe—Ni—Co alloy joined to both end faces of the insulating column 1 via a brazing material 5, and the like. It is comprised from the annular electrode member 2 which consists of these metal materials.
[0003]
Then, by applying different voltages to the two opposing electrode members 2, charged particles such as electrons are accelerated.
[0004]
For joining the electrode member 2 to the insulating column 1, a metallized layer 3 such as molybdenum (Mo) -manganese (Mn) and a Ni plating layer 4 are deposited in advance on both end surfaces of the insulating column 1, and the metallized layer 3 The both ends of the insulating pillar 1 to which the Ni plating layer 4 is applied are joined to the electrode member 2 via the brazing material 5.
[0005]
[Problems to be solved by the invention]
However, in the conventional accelerator as described above, the metallized layer 3, the Ni plating layer 4, and the brazing material 5 applied to the insulating column 1 protrude from the end surface of the insulating column 1 by about 0.3 to 1 mm. For this reason, when a voltage is applied to the electrode member 2 to accelerate charged particles such as electrons, the metallized layer 3, the Ni plating layer 4, and the brazing material 5 applied to the insulating pillar 1 are slightly smaller than the protruding portions and edges. There is a problem in that discharge starts and secondary electrons generated by the minute discharge easily pass through the surface of the insulating column 1 and discharge from one electrode member 2 to the other electrode member 2.
[0006]
In order to overcome this problem, as shown in FIG. 7, screw holes are formed on both ends of the insulating pillar 1 by threading, and bolts 7 such as metal are screwed into the screw holes. Then, by fixing the electrode member 2 to the insulating support column, there is a configuration in which discharge is not easily caused even when a voltage is applied in order to generate charged particles such as electrons. However, in this case, there is a problem in that the bolt 7 is loosened due to a long-time slight vibration or the like due to an external force, and the function as an insulating support is not performed.
[0007]
Accordingly, the present invention has been completed in view of the above-mentioned problems in the prior art, and its purpose is to eliminate the discharge generated between the opposing electrode members, and to firmly bond the electrode members to the insulating columns. Therefore, it is to be highly reliable against long-time micro vibrations. In addition, charged particles such as electrons can be reliably and stably accelerated to a predetermined speed, and a beam can be generated reliably and stably in a predetermined direction.
[0008]
[Means for Solving the Problems]
The insulating support column of the accelerator according to the present invention has two annular electrode members each having a plurality of through-holes that are arranged to face each other and penetrate the upper and lower surfaces at substantially the same interval, and have a cross-sectional shape on both upper and lower end surfaces. A plurality of substantially cylindrical insulating pillars each having a substantially circular recess formed so that the recess is coaxial with the through-hole and whose both end faces are opposed to the opposing main surfaces of the two electrode members, respectively. And a substantially cylindrical metal joining member fitted into the through hole and the recess and brazed to the inner surface of the through hole and the recess.
[0009]
According to the present invention, since the generation of the micro discharge between the electrode members to which the voltage is applied in order to generate the beam by accelerating the charged particles can be effectively suppressed by the above configuration, the high voltage can be stably applied. Can do. In addition, in accelerators used in general industrial equipment such as electron microscopes that must be transported and moved, they are not broken or loosened due to long-term microvibrations caused by external forces, and highly reliable accelerator insulation. It has the effect of becoming a support.
[0010]
In this invention, Preferably, the thickness of the said metal joining member is 0.3-1 mm.
[0011]
With this configuration, the present invention improves the bonding force of the bonding portion, and further provides a highly reliable insulating column of the accelerator.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The insulator post of the accelerator of the present invention will be described in detail below. FIG. 1 is an enlarged cross-sectional view of a brazed joint portion of an insulating support according to the present invention. In FIG. 1, 1 is an insulating column, 2 is an electrode member, 3 is a metallized layer, 4 is a Ni plating layer, 5 is a brazing material, and 6 is a metal joining member, and these mainly constitute insulating posts.
[0013]
The insulating column of the present invention includes two annular electrode members 2 that are arranged to face each other and each have a plurality of through-holes that penetrate the upper and lower surfaces at substantially the same interval, and have a cross-sectional shape on both end surfaces. A plurality of substantially cylindrical insulating columns 1 each having a substantially circular recess formed therein and having both end surfaces bonded to the opposing main surfaces of the two electrode members 2 so that the recess is coaxial with the through hole; And a substantially cylindrical metal joining member 6 fitted into the through hole and the concave portion and brazed.
[0014]
The insulating column 1 of the present invention is a substantially columnar shape having recesses formed on both end faces. The metal joining member 6 is fitted and brazed in the recess. The electrode member 2 and the insulating column 1 are joined by the metal joining member 6. The insulating pillar 1 has an action of insulating the two electrode members 2 at both ends of the insulating pillar 1 and is generally formed of an electrically insulating material made of an aluminum oxide (Al ₂ O ₃ ) sintered body or the like. A metallized layer 3 such as Mo-Mn and a Ni plated layer 4 are deposited in advance in the recesses of the insulating pillar 1, and the metallized layer 3, the Ni plated layer 4, and the metal joining member 6 are interposed via the brazing material 5. Further, the metal bonding member 6 and the electrode member 2 are bonded via the brazing material 5.
[0015]
The electrode member 2 is made of a metal material such as stainless steel, and the metal joining member 6 is made of a metal material such as Fe—Ni—Co alloy or Cu—W.
[0016]
In the present invention, the diameter (outer diameter) of the metal joining member 6 is preferably 50 to 80% of the diameter of the insulating pillar 1, and if it is less than 50%, the metal joining member 6 itself becomes small and it is difficult to process the shape. If it exceeds 80%, the concave portion of the insulating pillar 1 becomes large and the thickness of the concave portion becomes thin, and the insulating pillar 1 cannot withstand the residual stress caused by thermal expansion at the joint portion with the metal joint member 6, so Cracks and cracks are likely to occur near both end portions of the column 1.
[0017]
In the present invention, the thickness of the metal bonding member 6 is preferably 0.3 to 1 mm. If the thickness is less than 0.3 mm, the strength of the metal joining member 6 against vibration, impact, etc. due to external force is lowered, the mechanical strength as an insulating support is lowered, and the function cannot be maintained. If it exceeds 1 mm, stress due to thermal expansion often remains at the joint interface between the two members at the joint between the insulating pillar 1 and the metal joint member 6, and cracks, cracks, etc. are present at the joint of the insulating pillar 1. It tends to occur.
[0018]
Furthermore, in the present invention, the height of the metal bonding member 6 is preferably 2 to 5 times the thickness of the electrode member 2. If it is less than 2 times, the bonding force is weak against vibrations, impacts, etc. due to external forces, and the entire insulating column is liable to be deformed, making it difficult to maintain its shape and resulting in an unstable column. If it exceeds five times, the deflection of the drill drill during machining increases, and it becomes difficult to process the cylindrical metal joining member 6 with a uniform thickness.
[0019]
【Example】
Examples of the present invention will be described below.
Example 1
As Comparative Example 1, a structure shown in FIG. 2 was produced as follows. A cylindrical insulating column 1 having a diameter of 10 mm and a length of 40 mm made of an aluminum oxide (Al ₂ O ₃ ) sintered body having a purity of 99% by weight was prepared. A metal paste containing 89% by weight, 6% by weight, and 5% by weight of Mo, Mn, and SiO ₂ , respectively, is printed and applied to the entire end surfaces of the insulating pillar 1 to a thickness of 10 to 15 μm. After drying, firing was performed at 1400 ° C. in a humidified forming gas. Thus, a metallized layer made of a Mo—Mn alloy was deposited on the entire surface of both end faces of the insulating pillar 1. Thereafter, a Ni plating layer was deposited on the metallized layer to a thickness of about 2 μm by electrolytic plating.
[0020]
Next, flat electrode members 9 made of an Fe—Ni—Co alloy having a width of 50 mm, a length of 25 mm, and a thickness of 1 mm were joined to both end faces of the insulating pillar 1. At this time, a preform of a brazing material 8 made of a plate-like Ag—Cu alloy having a diameter of 10 mm and a thickness of 0.05 mm is placed between both end faces of the insulating pillar 1 and the electrode member 9, and the preform is set to 820 ° C. It was heated and joined. The manufactured product was designated as Sample A.
[0021]
As Comparative Example 2, threaded hole machining (M8 according to JIS-B0205) is applied to the center of both end faces of the same insulating column 1 as in Comparative Example 1, and the diameter φ12 mm from above is applied to the central part of the same electrode member 9 as in Comparative Example 1. A through hole having a step in the middle of the inside was formed, in which a hole having a diameter of 8.5 mm was formed concentrically. The electrode member 11 having the stepped through hole is inserted into each of both end faces of the insulating pillar 1 and an M8 (M8: nominal diameter of screw) bolt 10 having a hexagonal hole on the top surface of the head is inserted into the through hole and the screw hole. Sample B (FIG. 3) was fixed by screwing.
[0022]
As Example 1 of the present invention, a hole (concave portion) having a diameter of 8.05 mm and a depth of 4 mm is formed at the center of both end faces of the insulating pillar 1 having the same dimensions as those of Comparative Example 1, and Mo and Mn are formed on the inner surface of the hole. A metal paste containing 89%, 6% and 5% by weight of SiO2 and SiO2, respectively, is printed and applied to a thickness of 10 to 15 μm, dried, and then heated to 1400 ° C. in a humidified forming gas. Baked with. In this way, the metallized layer 3 made of a Mo—Mn alloy was deposited on the entire inner surface of the recesses on both end surfaces of the insulating pillar 1. Thereafter, a Ni plating layer was applied on the metallized layer 3 to a thickness of about 2 μm by electrolytic plating.
[0023]
Next, an electrode member 2 with a through hole in which a hole (through hole) with a diameter of 8.05 mm is formed at the center of a flat plate electrode member 2 having a width of 50 mm, a length of 25 mm, and a thickness of 1 mm is prepared. And the electrode member 2 were concentrically arranged with the concave portion and the through hole, and the metal joining member 6 was fitted and joined thereto. This metal joining member 6 was made of an Fe—Ni—Co alloy having an outer diameter of φ8 mm, an inner diameter of φ7.4 mm, and a height of 4 mm. Further, a preform of a brazing material 5 made of an Ag—Cu alloy having a diameter of 0.1 mm is installed in the gap between the inner surface of the concave portion of the insulating pillar 1 and the metal joining member 6, and the preform is set at 820 ° C. A sample C (FIG. 4) was prepared by heating and bonding.
[0024]
For each of the samples A to C, an impact test {MIL-STD (Military Standard) -202F METHOD213A} is performed at normal temperature in an air atmosphere, and a 50G sine half-wave waveform is generated in 11 ms (milliseconds). An impact of about (G: gravitational acceleration) was applied once, and each joint was examined for abnormalities using an optical device. As a result, sample A showed no abnormality at the joint. In sample B, cracks having a length of about 0.3 to 0.5 mm were confirmed on the outer peripheral portions of both end faces of the insulating pillar 1. Sample C showed no abnormalities at the joint.
[0025]
In addition, each of the other samples A to C prepared in the same manner as described above is prepared, and a vibration test {MIL-STD-202F METHOD201A} is performed at room temperature in an air atmosphere. The frequency is 10 to 55 Hz (Hertz) and the maximum swing width is 1. .52 mm vibration was sequentially applied in the three directions of X, Y, and Z for 2 hours each, and each junction was inspected for any abnormality using an optical device. As a result, Sample A showed no abnormality at the joint. In sample B, because the bolt 10 was loosened during the test, when the test was interrupted and the insulating pillars 1 were inspected, cracks with a length of about 0.1 to 0.3 mm were formed on the outer peripheral portions of both end faces of the insulating pillar 1. Was confirmed. Sample C showed no abnormalities at the joint.
[0026]
Further, each of the other samples A to C prepared in the same manner as described above is prepared, and the electrode members at both ends of the insulating column 1 are prepared by using the withstand voltage test {MIL-STD-202F METHOD301} in the air atmosphere at room temperature. A voltage of 20 kV was applied between them to test whether there was any abnormality at each junction. In Sample A, a discharge was generated from the joint, and a trace of carbonization in the vicinity of the joint was confirmed. No discharge was observed for Sample B. No discharge was observed for Sample C.
[0027]
Regarding these samples A to C, in the state where an external force such as impact or vibration is applied, the result is that the bonding strength of the samples A and C joined by brazing is higher than that of the sample B fixed by the bolt 10. It was. Further, with regard to the withstand voltage test, in Sample A, discharge occurred because the metal film such as the metallized layer 3 protruded outside the both end faces of the insulating pillar 1, and in Sample B, no discharge occurred. It was. With respect to Sample C, an excellent effect that no discharge occurs was obtained. When these results were combined, it was found that Sample C was strong against impact, vibration, etc. and excellent in voltage resistance.
[0028]
(Example 2)
In Example 2, the dimensions of the metal joining member 6 were variously changed, and the same impact test, vibration test, and withstand voltage test as in Example 1 were performed. First, in the same manner as in Example 1, the insulating pillar 1 was processed in accordance with various dimensions of the metal joining member 6 shown in Table 1 and brazed to the electrode member 12 to produce insulating posts. The obtained samples (NO. 1 to 12) were tested. The results are shown in Table 1.
[0029]
[Table 1]

[0030]
The NO. 1 shows that when the thickness of the metal joining member 6 is 0.2 mm, the electrode member 12 can be confirmed to be displaced by about 0.3 mm after the impact test as compared to the state before the test, and the metal joining member 6 is deformed by impact. It was observed. NO. 2, NO. 3, no abnormality was confirmed when the thickness of the metal joining member 6 was 0.3 mm and 1.0 mm. NO. 4, when the thickness of the metal joining member 6 is 1.1 mm, microcracks having a length of about 0.5 mm are generated near both end surfaces of the insulating pillar 1 in the step of brazing the insulating pillar 1 and the metal joining member 6. It could be confirmed.
[0031]
NO. 5 indicates that when the outer diameter of the metal joining member 6 is 40% with respect to the outer diameter of the insulating pillar 1, the metal joining member 6 itself is too small to be machined, the machining yield is reduced, and the cost is increased. It was. NO. 6, NO. 7 shows that no abnormality was confirmed when the outer diameter of the metal bonding member 6 with respect to the outer diameter of the insulating pillar 1 was 50% and 80%. NO. 8, when the outer diameter of the metal joining member 6 is 90% with respect to the outer diameter of the insulating pillar 1, a length of about 0.5 mm is provided near both end surfaces of the insulating pillar 1 in the step of brazing the insulating pillar 1 and the metal joining member 6. The occurrence of microcracks was confirmed.
[0032]
NO. 9, when the height of the metal joining member 6 is 1 times the thickness of the electrode member 12, it is natural that the insulating pillar 1 and the electrode member 2 cannot be joined together, and the It was not possible to attach. NO. 10, NO. 11 shows that when the height of the metal bonding member 6 with respect to the thickness of the electrode member 12 is 2 times and 5 times, no abnormality was confirmed. NO. 12, when the height of the metal joining member 6 is 6 times the thickness of the electrode member 12, the thickness of 0.3 mm is required for processing the through-hole in order to produce the cylindrical metal joining member 6. Processing while securing it becomes difficult, resulting in a problem that the processing yield decreases and the cost increases.
[0033]
In addition, this invention is not limited to the said embodiment and Example, A various change may be performed in the range which does not deviate from the summary of this invention.
[0034]
【The invention's effect】
The present invention includes two annular electrode members that are arranged to face each other and each have a plurality of through-holes that penetrate the upper and lower surfaces at substantially the same interval, and concave portions that are substantially circular in cross section on the upper and lower end surfaces. A plurality of substantially cylindrical insulating pillars, both end faces of which are arranged opposite to the opposing main surfaces of the two electrode members, with the concave portion being coaxial with the through hole, and fitted into the through hole and the concave portion. And having a substantially cylindrical metal joining member brazed to the inner surface of the through hole and the recess, a minute discharge between the electrode members for applying a voltage to accelerate charged particles and generate a beam Since generation | occurrence | production of can be suppressed effectively, a high voltage can be applied stably. In addition, in accelerators used in general industrial equipment such as electron microscopes that must be transported and moved, they are not broken or loosened due to long-term microvibrations caused by external forces, and highly reliable accelerator insulation. It becomes a support.
[0035]
In the present invention, preferably, the thickness of the metal bonding member is 0.3 to 1 mm, so that the bonding force of the bonded portion is improved, and the insulating support column of the accelerator is further reliable. That is, it is possible to effectively suppress the occurrence of cracks and cracks from the brazed portion of the insulating column due to the difference in thermal expansion coefficient between the insulating column and the metal bonding member, and to insulate the highly reliable accelerator that is firmly bonded. It was possible to use it as a support.
[Brief description of the drawings]
FIG. 1 is an enlarged cross-sectional view of a brazing portion in an insulating post of an accelerator according to the present invention.
FIG. 2 is a perspective view of an insulating support having a joining structure by conventional brazing.
FIG. 3 is a perspective view of an insulating support having a conventional screw-bonding structure.
FIG. 4 is a perspective view of an insulating post having a brazing structure according to the present invention.
FIG. 5 is a cross-sectional view showing an insulating post of a conventional accelerator.
6 is an enlarged cross-sectional view of a brazed portion of the insulating support in FIG. 2;
FIG. 7 is an enlarged cross-sectional view showing a bolting portion of a conventional insulating post.
[Explanation of symbols]
1: Insulating pillar 2: Electrode member 3: Metallized layer 4: Ni plating layer 5: Brazing material 6: Metal joint member 7: Metal bolt

Claims

Two annular electrode members that are arranged to face each other and each have a plurality of through-holes penetrating the upper and lower surfaces at substantially the same interval, and concave portions having a substantially circular cross section are formed on both upper and lower end surfaces, A plurality of substantially cylindrical insulating columns each having a concave portion coaxial with the through-hole and opposite end surfaces of the two electrode members opposed to each other, and the through-hole and the concave portion fitted to the through-hole and the accelerator of the insulating struts, characterized by comprising a metal bonding member brazed substantially circular cylindrical on the inner surface of the recess.

The insulating post of an accelerator according to claim 1, wherein the thickness of the metal joining member is 0.3 to 1 mm.