JP3545502B2

JP3545502B2 - Manufacturing method of superconducting high frequency accelerating cavity

Info

Publication number: JP3545502B2
Application number: JP20568995A
Authority: JP
Inventors: 智子太田; 純市澁谷
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 1995-08-11
Filing date: 1995-08-11
Publication date: 2004-07-21
Anticipated expiration: 2015-08-11
Also published as: JPH0955300A

Description

【０００１】
【発明の属する技術分野】
本発明は、荷電粒子ビームの加速器に使用される超電導高周波加速空胴の製造方法に関する。
【０００２】
【従来の技術】
加速器は、電子、陽子、イオン等の荷電粒子を電磁力で数十億電子ボルト（数ＧｅＶ）程度の高エネルギ状態に加速するための装置であり、もともとは原子核や素粒子の研究のために開発されてきた。
【０００３】
しかし、近年では、真空中をほぼ光速で伝搬する電子が偏向磁場によりその軌道が曲げられたときにその軌道の接線方向に発生する放射光（ＳＯＲ光と呼ばれる）を利用して、超ＬＳＩ微細加工（リソグラフィ）や物質研究等、生命科学等の広範な科学技術分野まで適用範囲を広げている。
【０００４】
加速器には荷電粒子の加速や、ＳＯＲ光として失われたエネルギを補給するため、そのビームラインに高周波加速空胴が設けられている。
図１１は従来の高周波加速装置の一例を示すもので、荷電粒子を加速、蓄積する円形加速器のビームダクト１に高周波加速空胴２が介挿されている。この高周波加速空胴２には高周波発振器３で発振した高周波が導波管４を通してアンテナ５を介して供給される。
【０００５】
高周波加速空胴２内に供給された高周波は、共振によってビームダクト１の両端部１ａ間に高電界Ｅを発生させ、荷電粒子ビーム６を加速する。この場合、高電界Ｅが発生すると高周波加速空胴２の内表面に循環電流が流れ、この電流は高周波電流であるため、高周波加速空胴２の内面の材質に応じた表皮深さを流れ、ジュール損失を生じる。
【０００６】
ところで、銅やアルミニウム等で作られた常電導高周波加速空胴で荷電粒子ビーム６の加速に必要な高電界を得るには、上述したジュール損失が極めて大きくなり、このジュール損失を補うために大きな高周波電力を供給できる大出力の高周波発振器３が必要となる。
【０００７】
しかし、かかる高周波電力を賄えるだけの高周波発振器は現存していない。さらに、高周波加速空胴２の冷却上でも問題になり、常電導高周波加速空胴の適用には限界がある。
【０００８】
そこで、高周波加速空胴２の内面に電流が流れてもジュール損失が生じないように、電気抵抗がほぼ０Ωである超電導材で高周波加速空胴を形成することが考えられる。
【０００９】
超電導高周波加速空胴の使用分野は多方面にわたるが、特に荷電粒子ビーム加速器に関しては近年になって世界各地で計画、建設が進められている大型電子蓄積リング用として、限られた電力、限られた空間の範囲でできるだけ高いエネルギを持った電子を得るために超電導高周波加速空胴の実現が切望されている。
【００１０】
従来、超電導高周波加速空胴の製造方法としては、例えば特開平１−２３１３００号公報に示されるようなものが知られている。
この製造方法は、図１２に示すようにアルミニウム合金を母材とした加速空胴７を成形し、次にスパッタリングでこの加速空胴７の内側にＮｂ膜８を形成して超電導高周波加速空胴を製造するものである。
【００１１】
【発明が解決しようとする課題】
このように従来の超電導高周波加速空胴の製造方法においては、アルミニウム合金で成形した加速空胴７の内側にスパッタリングでＮｂ膜８を形成するため、Ｎｂ膜８の厚さが均一にならない、Ｎｂ膜８の純度が低い等の問題があり、超電導性を劣化させる恐れがある。
【００１２】
本発明は上述した問題点を解決するためになされたもので、超電導特性の劣化を防止し、製造が簡単でかつ製造コストの低減化に寄与できる高性能で経済的な超電導高周波加速空胴の製造方法を提供することを目的とする。
【００１３】
【課題を解決するための手段】
本発明は上記の目的を達成するため、次のような工程により超電導高周波加速空胴を製造するものである。
請求項１に対応する発明は、荷電粒子ビームにエネルギを与える高周波加速空胴であって、銅またはアルミニウムを基材とする外側空胴の前記ビームを臨む内面が超電導材からなる内側空胴で形成された超電導高周波加速空胴において、外側空胴を鍛造または機械加工によって製作する工程と、超電導材のシートで円筒を形成する工程と、前記円筒を前記外側空胴の内部に挿入し、該外側空胴の内面に円筒を膨らませて内側空胴として固着させる工程とを備える。
【００１４】
請求項２に対応する発明は、荷電粒子ビームにエネルギを与える高周波加速空胴であって、銅またはアルミニウムを基材とする外側空胴の前記ビームを臨む内面が超電導材からなる内側空胴で形成された超電導高周波加速空胴において、ビーム加速軸方向の外側空胴のほぼ中央に分割部を有するように二分割された外側半割空胴を鍛造または機械加工によって形成する工程と、前記２個の半割空胴を対向配置し、分割部を溶接して一体化して外側空胴とする工程と、超電導材のシートで円筒を成形する工程と、前記円筒を前記外側空胴の内部に挿入し、この外側空胴の内面に前記円筒を膨らませて内側空胴として固着する工程とを備える。
【００１５】
請求項３に対応する発明は、請求項１又は２に対応する発明において、良熱伝導材で成形した前記外側空胴の内面に超電導材で成形した円筒をＨＩＰ（熱間等方加圧）接合法により膨らませて固着させる。
【００１６】
請求項４に対応する発明は、請求項１又は２に対応する発明において、良熱伝導材で成形した前記外側空胴の内面に超電導材で成形した円筒を爆着接合法により膨らませて固着させる。
【００１７】
請求項５に対応する発明は、請求項１又は２に対応する発明において、良熱伝導材で成形した前記外側空胴の内面に超電導材で成形した円筒を液圧成形接合法により膨らませて密着させ、その後加熱すると共に加圧して固着させる。
【００２１】
従って、請求項１乃至請求項５に対応する発明によれば、銅やアルミニウム等の伸び率は約４０％であり、型を用いた成形や機械加工で半割空胴を容易に成形できる。また、スパッタリング等と違って電極の製作や電極を設置するための治具の製作、外側空胴の内表面の鏡面仕上げの必要がないので、製造コストの低減化に寄与できる。また、外側空胴の内面の超電導材は高純度でかつ厚さが均一であるため、超電導特性の劣化を防止することができる。
【００２３】
【発明の実施の形態】
以下本発明の実施の形態について図面を参照しながら説明する。
図１は本発明による超電導高周波加速空胴の製造方法を説明するための第１の実施の形態を示すもので、（ａ）は半割空胴の成形工程、（ｂ）は溶接一体化行程、（ｃ）は円筒挿入工程、（ｄ）は内表面への密着工程をそれぞれ示すものである。
【００２４】
最初に工程（ａ）で鍛造品からなる素材を機械加工により外側半割空胴９を成形する。この場合、外側半割空胴９の基材としては良熱伝導材でかつ加工性に優れた銅やアルミニウム等が用いられる。
【００２５】
次に工程（ｂ）で２個の外側半割空胴９を対向配置して分割部をアーク溶接、電子ビーム溶接、あるいはろう付等で接合して一体化し、外側空胴１０を形成する。その後、工程（ｃ）でＮｂやＰｂ等の超電導材からなる高純度のシートを円筒状に成形し、分割部を例えば電子ビーム溶接等で接合した円筒１１を前述した外側空胴１０の内部に挿入する。
【００２６】
そして、最後に工程（ｄ）で前記円筒１１に外力を加え、膨らませながら前記外側空胴１０の内面に内側空胴として密着させると共に接合させる。
ここで、工程（ｃ）及び工程（ｄ）を図２により具体的に説明する。
【００２７】
図２（ａ）は、円筒１１を外側空胴１０の内部に挿入し、その後円筒１１と外側空胴１０との空間１２を真空脱気し、両端部をシール溶接する。この方法は真空脱気が可能な電子ビーム溶接等で行う。図中、１３はシール溶接部を示す。
【００２８】
シール溶接後、ＨＩＰ装置１４を用いて円筒１１と外側空胴１０とを接合させる。図２（ｂ）に示すＨＩＰ装置１４内で高温高圧の等方圧、例えば８００℃、１０００ｋｇ／ｃｍ^２の雰囲気では円筒１１及び外側空胴１０には矢印１５に示す方向の等方圧が加わり、時間経過と共に円筒１１は変形して、最終的には図１（ｄ）に示すように円筒１１は内側空胴として外側空胴１０の内表面に均一に拡散接合により接合して一体化し、超電導高周波加速空胴を製造する。
【００２９】
次に上記のような第１の実施の形態の作用効果について述べる。
銅やアルミニウム等は熱伝導率が大きく、またＮｂに比較して伸び率が約４０％と高く、機械加工性も良好である。従って、外側半割空胴９を鍛造や機械加工で容易に精度良く成形加工できる。
【００３０】
成形加工後、外側半割空胴９を溶接等の接合方法で一体化し、外側空胴１０を製作する。別途ＮｂやＰｂ等の超電導材からなる高純度のシートを円筒状に成形し、分割部を例えば電子ビーム溶接等で接合した円筒１１を製作し、これらをＨＩＰ接合の高温高圧のガス雰囲気中で加熱、加圧することで、銅やアルミニウム等からなる外側空胴１０にＮｂとＰｂ等の原子が接合界面を介して相互拡散することで接合し、一体化する。
【００３１】
従って、銅やアルミニウム等の外側空胴１０の内表面にＮｂやＰｂ等の超電導物質からなる円筒１１が内側空胴として固着された超電導高周波加速空胴が得られる。また、この方法ではスパッタリング等と違って電極の製作や電極を設置する治具の製作、外側空胴１０の内表面の鏡面仕上げの必要がないので、製造コストの低減に寄与できる。さらに、外側空胴１０の内面のＮｂは高純度でかつ厚さが均一な内側空胴が固着されているため、超電導特性の劣化を防止することができる。
【００３２】
なお、上記実施の形態では、外側空胴１０を２個の外側半割空胴９の分割部を接合して一体化するようにしたが、これに代えて液圧成形や電鋳により外側空胴１０を一体物として製作したものでもよい。
【００３３】
また、内側空胴となる円筒１１も分割部を接合したが、これに代えて引抜きや機械加工で一体物として製作したものでもよい。また、外側空胴１０と内側空胴を拡散接合する際に、チタン等の活性金属を介在させてもよい。
【００３４】
本発明の第２の実施の形態について図３により説明する。
第２の実施の形態では、図３に示すように外側空胴１０の外側に頑強な拘束治具１６を取付け、円筒１１の内側には当板１７を配置し、その中央部には爆発接合するための火薬１８を設ける。この火薬１８を爆発させることで、円筒１１と外側空胴１０の接合面はメタルジェットを介して強固な接合が得られる。
【００３５】
なお、接合面である外側空胴１０の内表面及び円筒１１の外表面は、先ず爆発接合が可能な状態に仕上げ加工が行われている。爆発接合後、当板１７を取除き、また拘束治具１６を取外すことで、図１（ｄ）に示すような所定の形状の超電導高周波加速空胴が得られる。
【００３６】
次に上記のような第２の実施の形態の作用効果について述べる。
第１の実施の形態と同様に、外側半割空胴９を溶接等の接合方法で一体化した外側空胴１０と、別途ＮｂやＰｂ等の超電導材からなる高純度のシートを円筒状に成形して接合した円筒１１とを構成し、円筒１１内部に配置した爆薬を爆発させることで、頑強な拘束治具１６に保護された外側空胴１０を変形させずに、外側空胴１０の内面にＮｂやＰｂ等の超電導材からなる円筒１１のみが衝突する。
【００３７】
この外側空胴１０の内面と円筒１１との衝突点では双方の金属が非常に大きな変形速度と高圧によって粘性流体的な挙動を示し、衝突点から前方に金属のジェットが発生する。このジェットによって金属表面の酸化被膜やガスの吸着層が除去されるために、現れた清浄表面が高圧によって密着し、銅やアルミニウム等の外側空胴１０とＮｂやＰｂ等の超電導材からなる円筒１１は、強固に接合して一体化する。特に、本方法ではメタルジェットにより、大気中での接合にも関わらず、健全な接合が得られる。
【００３８】
本実施の形態の爆着接合では、外側空胴１０及び円筒１１を加熱することなく接合できるので、外側空胴１０及び円筒１１の軟化による材質劣化を避けることができる。従って、銅やアルミニウム等の外側空胴１０の内表面にＮｂやＰｂ等の超電導物質が構成された構造強度の高い超電導高周波加速空胴が得られる。
【００３９】
また、この方法ではスパッタリング等と違って電極の製作や電極を設置する治具の製作、外側空胴の内表面の鏡面仕上げの必要がないので、製造コストの低減に寄与できる。さらに、外側空胴の内面のＮｂは高純度でかつ厚さが均一であるため、超電導特性の劣化を防止することができる。
【００４０】
本発明の第３の実施の形態について図４により説明する。
第３の実施の形態では、外側空胴１０の内側に円筒１１を配置し、さらにそれらの中心軸の両端にシール治具１９を配置して、その内部に液体２０を挿入して加圧する。円筒１１は、円筒内部の液体圧力を高めることで徐々に変形し、最終的には外側空胴１０の内側に密着される。また、液体の温度を１００℃に保つことで、外側空胴１０と円筒１１の相互拡散による接合を行うことができる。さらに、液体の温度及び圧力の条件で接合が得られにくい場合は、図示していないが、外側空胴１０の外部に加熱ヒータを配置して予熱し、接合が可能な温度まで加熱することもある。
【００４１】
なお、接合面である外側空胴１０の内表面及び円筒１１の外表面は、先ず相互拡散による接合が可能な状態に仕上げ加工が行われている。
次に上記のような第３の実施の形態の作用効果について述べる。
【００４２】
第１及び第２の実施の形態と同様に、外側半割空胴９を溶接等の接合方法で一体化した外側空胴１０と、別途ＮｂやＰｂ等の超電導材からなる高純度のシートを円筒状に成形して接合した円筒１１とを構成し、円筒１１内部に高温高圧の液体を充填させることで、円筒１１は外側空胴１０の内表面の形状に倣いながら銅やアルミニウム等及びＮｂやＰｂ等の原子が接合界面を介して拡散接合することで接合して一体化し、超電導高周波加速空胴が得られる。
【００４３】
また、本方法では第１の実施の形態に示すような大型で高価な設備で、かつ保安上、設置条件が厳しいＨＩＰ装置を用いることなく、特に高圧ガス取締りの認可を必要とせず、法的に制約のない高温高圧の拡散接合装置を用いることができる。
【００４４】
さらには、接合装置の導入及び取扱が容易であること、さらには大型接合装置の製作も容易であることから、大型の加速空胴機器への対応も可能である。その他、第１及び第２の実施の形態と同様の効果もある。
【００４５】
本発明の第４の実施の形態について図５により説明する。
図５（ａ）は内側半割空胴の成形工程、（ｂ）は溶接一体化工程、（ｃ）は加速空胴の二重化工程、（ｄ）は外側空胴と内側空胴の固着工程である。
【００４６】
最初に工程（ａ）で内側空胴２１の素材である板材を絞り加工やスピン加工等でラッパ状に成形する。この場合、内側空胴２１の基材としては超電導材のＮｂやＰｂが用いられる。
【００４７】
次に工程（ｂ）で２個の内側半割空胴２１ａ，２１ｂを対向配置して分割部をアーク溶接、電子ビーム溶接あるいはろう付等で接合して一体化し、内側空胴２１を製作する。
【００４８】
その後、工程（ｃ）で前記内側空胴２１の外側に外側半割空胴２２ａ，２２ｂを重合わせる。この場合、外側半割空胴２２ａ，２２ｂの基材しては良熱伝導材でかつ加工性に優れた銅やアルミニウム等が用いられる。この外側半割空胴２２ａ，２２ｂの接合部を例えばアーク溶接、電子ビーム溶接あるいはろう付等で接合して一体化することにより、内側が超電導材、外側が良熱伝導材から構成される二重の超電導高周波加速空胴２３を製作する。
【００４９】
最後に工程（ｄ）で前記加速空胴において、内側の超電導材と外側の良熱伝導材を固着させる。
次に上記のような第４の実施の形態の作用効果について述べる。
【００５０】
本実施の形態の製造方法によれば、ＮｂやＰｂ等の超電導材からなる内側空胴２１の加工が前述した実施の形態のような円筒からの加工ではなく、板材を絞り加工やスピン加工等でラッパ状に成形し、その後このラッパ状の内側半割空胴２１ａ，２１ｂを突合わせて溶接することで所定の内側空胴２１が製作できる。さらに、一体化された内側空胴２１に外側半割空胴２２ａ，２２ｂを取付け、外側半割空胴２２ａ，２２ｂ同志を突合わせて溶接を行い、外側空胴２２を一体化させる。このようにして、内側空胴２１の超電導材と外側空胴２２の良熱伝導材を固着させて超電導高周波加速空胴が得られる。
【００５１】
本実施の形態ではＮｂやＰｂ等の超電導材からなる内側半割空胴２１ａ，２１ｂの加工が前述した実施の形態のような円筒からの加工ではなく、予め空胴の形状に加工した超電導材を良熱伝導材に固着させるので、アスペクト比が大きい超電導高周波加速空胴を製作することが可能である。また、加工率が小さいため、成形加工後の歪み取りの熱処理等も必要としない。
【００５２】
従って、高精度の加速空胴が製作でき、また工程が少ないために製作日数も短縮できる。その他、第１、第２及び第３の実施の形態と同様の効果を得ることができる。
【００５３】
本発明の第５の実施の形態について図６により説明する。
第５の実施の形態では、第４の実施の形態で用いられた超電導材からなる内側空胴２１の外側に良熱伝導材からなる外側半割空胴２２ａ，２２ｂを重ね、その後外側半割空胴２２ａ，２２ｂの接合面を例えば電子ビーム溶接等で接合して外側空胴２２とした二重の超電導高周波加速空胴２３を図６に示すように高温高圧の等方圧加圧装置であるＨＩＰ装置１４に入れ、内側空胴２１の超電導材と外側空胴２２の良熱伝導材を高温高圧のガス雰囲気中で拡散接合して一体化する。
【００５４】
その接合条件として良熱伝導材の融点以下、例えば銅であれば１０００℃以下、アルミニウムであれば５００℃以下の接合温度で、圧力は１００ｋｇｆ／ｍｍ^２以上、保持時間は３０分以上の条件であればＮｂあるいはＰｂ等からなる内側空胴２１の超電導材と銅やアルミニウム等からなる外側空胴２２の良熱伝導材は強固に拡散接合される。
【００５５】
なお、本実施の形態のようにＨＩＰ装置１４を用いた拡散接合では、第１の実施の形態及び図２に示した内側空胴２１の超電導材及び外側空胴２２の良熱伝導材の接合面は、先ず真空雰囲気になるように真空脱気等の処理が事前に行われている。
【００５６】
次に上記のような第５の実施の形態の作用効果について述べる。
本実施の形態の製造方法によれば、内側空胴２１のＮｂやＰｂ等の超電導材と銅やアルミニウム等からなる外側空胴２２の良熱伝導材は、例えば銅であれば１０００℃以下、アルミニウムであれば５００℃以下の接合温度で、圧力は１００ｋｇｆ／ｍｍ^２以上、保持時間は３０分以上の接合条件で強固に拡散接合される。特にＮｂやＰｂ等からなる内側空胴２１の超電導材の板厚が、銅やアルミニウム等からなる外側空胴２２の良熱伝導材の板厚に比較して数分の１の薄板であることから、ＨＩＰ装置を用いた拡散接合では等方加圧により、ＮｂやＰｂ等からなる内側空胴２１の超電導材は銅やアルミニウム等からなる外側空胴２２の良熱伝導材の内側の形状に倣う。
【００５７】
特に本方法では、予め超電導材からなる内側空胴２１は板材を絞り加工やスピン加工等でラッパ状に成形して溶接で所定の形状に仕上げられている。同様に外側半割空胴の内面形状も内側空胴の外面形状に倣った形状に仕上げられている。
【００５８】
従って、これらを真空シール後にＨＩＰ装置を用いて拡散接合することは、従来技術からも容易とされている。また、銅やアルミニウム等からなる外側空胴２２の良熱伝導材が比較的厚い板から構成され、かつその加工精度が所定の形状に仕上げられていることから、加速空胴として精度が要求されるＮｂやＰｂ等の超電導材からなる内側空胴２１の寸法精度は、設計通りの高精度なものが得られる。また、アスペクト比が大きい超電導高周波加速空胴を製作することが可能である。
【００５９】
本発明の第６の実施の形態について図７により説明する。
図７（ａ）は、第４の実施の形態で示した内側空胴の超電導材と外側空胴の良熱伝導材を固着させる前に、図５（ｂ）に示す２個の内側半割空胴２１ａ，２１ｂを対向配置して分割部をアーク溶接、電子ビーム溶接等で接合して一体化した内側空胴２１の外表面にペースト状のろう材２４を塗布し、その後外側半割空胴２２ａ，２２ｂを重ね、これらの接合部を例えば電子ビーム溶接等で接合して外側空胴２２とした二重の超電導高周波空胴２３を真空炉２５に入れ、真空ろう付を行い内側空胴２１と外側空胴２２を固着して一体化することにより、内側が超電導材、外側が良熱伝導材から構成される二重の超電導高周波加速空胴２３を成形する。
【００６０】
この二重の超電導高周波加速空胴２３の真空ろう付としては、良熱伝導材の融点以下、例えば銅であれば１０００℃前後、アルミニウムであれば５００℃前後の温度及びろう付できるろう材を用いて真空ろう付を行うことで、ＮｂやＰｂ等からなる内側空胴２１の超電導材と銅やアルミニウム等からなる外側空胴２２の良熱伝導材は強固に真空ろう付される。
【００６１】
本実施の形態の真空ろう付は、ペースト状のろう材を塗布した方法であるが、本実施の形態ではペースト状のろう材を塗布する方法に限定することなく、シート状のろう材を内側空胴２１の外表面に配置する、あるいは線状のろう材を内側空胴２１の外表面に設けたろう材溝に挿入して真空ろう付を行うこともできる。本実施の形態では真空ろう付で行っているが、大気中のろう付法でも同様の加速空胴は製作できる。
【００６２】
次に上記のような第６の実施の形態の作用効果について述べる。
第６の実施の形態の製造方法によれば、ＮｂやＰｂ等からなる内側空胴２１の超電導材と銅やアルミニウム等からなる外側空胴２２の良熱伝導材は、良熱伝導材の融点以下、例えば銅であれば１０００℃前後、アルミニウムであれば５００℃前後の温度及びろう付できるろう材を用いて真空ろう付を行うことで、ろう材を介して真空ろう付される。
【００６３】
特に本製造方法では、予め超電導材からなる内側空胴２１は板材を絞り加工やスピン加工などでラッパ状に成形して溶接により所定の形状に仕上げられている。同様に良熱伝導材からなる外側半割空胴２２ａ，２２ｂの内面形状も内側空胴２１の外周面形状に倣った形状に仕上げられている。この場合、これらをろう材を介して真空ろう付することは従来技術からも容易とされている。
【００６４】
従って、銅やアルミニウム等からなる外側空胴２２の良熱伝導材が比較的厚い板から構成され、かつその加工精度が所定の形状に仕上げられることから、加速空胴として精度が要求されるＮｂやＰｂ等の超電導材からなる内側空胴２１の寸法精度は、設計通りの高精度なものが得られる。また、アクペスト比が大きい超電導高周波加速空胴を製作することが可能である。
【００６５】
本発明の第７の実施の形態について図８により説明する。
図８（ａ）に示すように第４の実施の形態で示した内側空胴２１の超電導材と外側空胴２２の良熱伝導材を固着させる前に、図５（ｂ）に示す２個の内側半割空胴２１ａ，２１ｂを対向配置して分割部をアーク溶接、電子ビーム溶接等で接合して一体化した内側空胴２１の外表面にペースト状の半田２６を塗布し、その後図８（ｂ）に示すように外側半割空胴２２ａ，２２ｂを重ね、これらの接合部を例えば電子ビーム溶接等で接合して外側空胴２２とした二重の超電導高周波加速空胴２３を大気炉２７あるいはガス雰囲気炉に入れ、ペースト状の半田が溶ける温度まで加熱して半田付を行って一体化することにより、内側空胴２１が超電導材、外側空胴２２が良熱伝導材から構成される二重の超電導高周波加速空胴２３を製作する。
【００６６】
次に上記のような第７の実施の形態の作用効果について述べる。
第７の実施の形態の製造方法によれば、例えば半田付に錫−鉛半田を用い、一方そのフラックスには塩化亜鉛あるいは塩化アンモン系等を用いることで、温度約２００℃前後の比較的低い温度で接合でき、銅やアルミニウム等からなる良熱伝導材の外側空胴材料の熱による材料強度の劣化もなく、またガス雰囲気炉等を用いることで均熱加熱が可能となり、接合面全面をムラなく接合することができるので、健全な接合が得られる。
【００６７】
この場合、ＮｂやＰｂ等からなる内側空胴２１の超電導材と銅やアルミニウム等からなる外側空胴２２の良熱伝導材は強固に半田付される。特に本製造方法では、予め超電導材からなる内側空胴２１は板材を絞り加工やスピン加工等でラッパ状に成形して溶接で所定の形状に仕上げられている。また、これらを半田付することは従来技術からも容易とされている。
【００６８】
従って、銅やアルミニウム等からなる外側空胴２２の良熱伝導材が比較的厚い板から構成され、かつその加工精度が所定の形状に仕上げられることから、加速空胴として精度が要求される内側のＮｂやＰｂ等の超電導材からなる内側空胴２１の寸法精度は、設計通りの高精度なものが得られる。また、アスペクト比が大きい超電導高周波加速空胴２３を製作することが可能である。
【００６９】
本発明の第８の実施の形態について図９により説明する。
図９（ａ）に示すように第４の実施の形態で示した内側空胴２１の超電導材と外側空胴２２の良熱伝導材を密着させる前に図５に示す２個の内側半割空胴２１ａ，２１ｂを対向配置して分割部をアーク溶接、電子ビーム溶接等で接合して一体化した内側空胴２１の外表面に熱硬化性の接着剤２８を塗布し、その後図９（ｂ）に示すように外側半割空胴２２ａ，２２ｂを重ね、これらの接合部を例えば電子ビーム溶接等で接合して外側空胴とした二重の超電導高周波加速空胴２３を高温炉２９に入れて接着剤が硬化する温度まで加熱し、接着して一体化することにより、内側空胴２１が超電導材、外側空胴２２が良熱伝導材から構成される二重の超電導高周波加速空胴２３を製作する。
【００７０】
次に上記のような第８の実施の形態の作用効果について述べる。
第８の実施の形態の製造方法によれば、例えば熱硬化性の接着剤を用いれば、比較的低温で接着でき、銅やアルミニウム等からなる良熱伝導材の外側空胴の熱による材料強度の劣化もなく、接合することができる。特に本製造方法では、予め超電導材からなる内側空胴２１は板材を絞り加工やスピン加工等でラッパ状に成形して溶接により所定の形状に仕上げられている。同様に外側半割空胴２２ａ，２２ｂの内面形状も内側空胴２１の外周面形状に倣った形状に仕上げられている。この場合、これらを溶接剤を介して接合することは従来技術からも容易とされている。
【００７１】
従って、銅やアルミニウム等からなる外側空胴２２の良熱伝導材が比較的厚い板から構成され、かつその加工精度が所定の形状に仕上げられることから、加速空胴として精度が要求される内側空胴２１のＮｂやＰｂ等の超電導材の寸法精度は、設計通りの高精度なものが得られる。また、アスペクト比が大きい超電導高周波加速空胴２３を製作することが可能である。
【００７２】
本発明の第９の実施の形態について図１０により説明する。
図１０（ａ）は内側半割空胴の成形工程、（ｂ）は外側半割空胴の成形工程、（ｃ）は内側及び外側半割空胴の二重化工程、（ｄ）は内側及び外側半割空胴の合体工程である。さらに、（ｅ）は内側及び外側半割空胴を合体後に同様にして製作したもう一方の内側及び外側半割空胴とを合体する工程である。ここで、内側半割空胴の基材としては超電導材のＮｂやＰｂ等が用いられ、外側半割空胴の基材としては良熱伝導材でかつ加工性に優れた銅やアルミニウム等が用いられる。以下工程順に製作手順を説明する。
【００７３】
最初に工程（ａ）で内側半割空胴２１ａをプレス加工やスピン加工等で成形する。同様に工程（ｂ）では外側半割空胴２２ａをプレス加工やスピン加工等で成形する。
【００７４】
次に工程（ｃ）で、これらの内側半割空胴２１ａ及び外側半割空胴２２ａを重合せて接合面を脱気後、真空状態を保つためにシール溶接１３を行う。その後、工程（ｄ）でこれらをＨＩＰ装置１４を用いて拡散接合で接合して半割加速空胴３０ａを製作する。
【００７５】
さらに、前記工程（ｄ）で接合した二重の半割加速空胴３０ａと、同様に製作した二重の半割加速空胴３０ｂを対向配置してその分割部を突合わせ、工程（ｅ）でＨＩＰ装置１４を用いて拡散接合で接合して合体し、内側空胴が超電導材、外側空胴が良熱伝導材から構成される二重の超電導高周波加速空胴３１を製作する。
【００７６】
例えば、ＨＩＰ装置１４を用いた拡散接合では接合面を真空雰囲気にする必要がある。そこで、その具体的な方法としては、接合面の表面の凹凸をなくし、かつ洗浄した後に内面をＹＡＧレーザ等でシール溶接し、その後外周部の接合面を電子ビーム溶接等で真空シール溶接する。真空シールする目的は、ＨＩＰ装置１４を用いた拡散接合時の高温高圧のガスが接合面に侵入しないようにするためである。
【００７７】
この場合、その溶接の溶け込みは数ミリ程度の深さで良い。また、内面のシール溶接にＹＡＧレーザを用いることは、半割加速空胴３０ａ，３０ｂ同士を対向配置しても、数箇所あるポートからＹＡＧレーザのビームを導くファイバが挿入可能であることも大きな要因である。さらに、接合条件は内側空胴が超導電材、外側空胴が良熱伝導材から構成される二重の超電導高周波加速空胴３１であるが、特に融点が低い外側空胴２２の良熱伝導材の融点以下の温度範囲で、また圧力を前後させることにより、その接合の適正範囲を選択することは可能である。
【００７８】
なお、上記第９の実施の形態では、ＨＩＰ装置１４を用いた拡散接合であるが、内側半割空胴２１ａ，２１ｂ及び外側半割空胴２２ａ，２２ｂの接合方法としてはＨＩＰ装置１４を用いた拡散接合に限定されるものではなく、ＨＩＰ装置１４を用いないホットプレスによる拡散接合やろう付、半田付けあるいは接着等による接合方法でも同様の内側空胴が超電導材で外側空胴が良熱伝導材から構成される二重の超電導高周波加速空胴３１を製造することができる。
【００７９】
次に上記のような第９の実施の形態の作用効果について述べる。
第９の実施の形態の製造方法によれば、ＮｂやＰｂ等からなる超電導材の内側空胴２１と銅やアルミニウム等からなる良熱伝導材の外側空胴２２はそれぞれ半割空胴の状態で接合するために、接合前の加工精度及び寸法精度が高く、また組立ての容易さなどからもＨＩＰ装置１４を用いた拡散接合やホットプレスによる拡散接合、ろう付、半田付あるいは接着等による接合方法において、内側半割空胴及び外側半割空胴の接合体である半割加速空胴３０ａ，３０ｂが得られる。この高精度に接合された半割加速空胴同士をさらに同様の接合方法で接合して合体することで、所定の形状のＮｂやＰｂ等の超電導材からなる内側空胴２１と銅とアルミニウム等からなる良熱伝導材の外側空胴２２からなる二重の超電導高周波加速空胴３１が得られる。
【００８０】
従って、銅やアルミニウム等からなる外側空胴２２の良熱伝導材が比較的厚い板及びＮｂやＰｂ等からなる内側空胴２１の超電導材が比較的薄い板から構成された二重の超電導高周波加速空胴は、特に加速空胴として精度が要求されるＮｂやＰｂ等の超電導材からなる内側空胴２１の寸法精度が設計通りの高精度なものが得られる。また、アスペクト比が大きい超電導高周波加速空胴を製作することが可能である。
【００８１】
【発明の効果】
以上説明したように本発明によれば、外側空胴が銅またはアルミニウムで成形されているので、伸び率が高く機械加工が良好であり、鍛造または機械加工によって容易に精度良く成形加工を行うことができ、また外側空胴の内面に超電導物質からなる内側空胴で形成されているので、超電導特性の劣化を防止でき、且つ内表面の鏡面仕上げの必要がないことから、製造を容易にして製造コストの低減化を図ることができる超電導高周波加速空胴の製造方法を提供することができる。
【図面の簡単な説明】
【図１】（ａ），（ｂ），（ｃ），（ｄ）は本発明による超電導高周波加速空胴の製造方法の第１の実施の形態を示す説明図。
【図２】（ａ），（ｂ）は同実施の形態を具体的に示す説明図。
【図３】本発明による超電導高周波加速空胴の製造方法の第２の実施の形態を示す説明図。
【図４】本発明による超電導高周波加速空胴の製造方法の第３の実施の形態を示す説明図。
【図５】（ａ），（ｂ），（ｃ），（ｄ）は本発明による超電導高周波加速空胴の製造方法の第４の実施の形態を示す説明図。
【図６】本発明による超電導高周波加速空胴の製造方法の第５の実施の形態を示す説明図。
【図７】（ａ），（ｂ）は本発明による超電導高周波加速空胴の製造方法の第６の実施の形態を示す説明図。
【図８】（ａ），（ｂ）は本発明による超電導高周波加速空胴の製造方法の第７の実施の形態を示す説明図。
【図９】（ａ），（ｂ）は本発明による超電導高周波加速空胴の製造方法の第８の実施の形態を示す説明図。
【図１０】（ａ），（ｂ），（ｃ），（ｄ），（ｅ）は本発明による超電導高周波加速空胴の製造方法の第９の実施の形態を示す説明図。
【図１１】従来の高周波加速装置の構成例を示す説明図。
【図１２】（ａ），（ｂ）は従来の超電導高周波加速空胴の製造方法の一例を示す説明図。
【符号の説明】
１……ビームダクト、２……高周波加速空胴、３……高周波発振器、４……導波管、５……アンテナ、６……荷電粒子ビーム、７……アルミ合金製加速空胴、８……Ｎｂ膜、９，２２ａ，２２ｂ……外側半割空胴、１０，２２……外側空胴、１１……円筒、１２……空間、１３……シール溶接部、１４……ＨＩＰ装置、１５……等方圧、１６……拘束治具、１７……当板、１８……火薬、１９……シール治具、２０……液体、２１……内側空胴、２１ａ，２１ｂ……内側半割空胴、２３……超電導高周波加速空胴、２４……ろう材、２５……真空炉、２６……半田、２７……大気炉、２８……接着剤、２９……高温炉、３０ａ……半割加速空胴、３０ｂ……半割加速空胴、３１……超電導高周波加速空胴、３２……シール溶接、３３……ＨＩＰ装置、３４……半割加速空胴、３５……加速空胴。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a superconducting high-frequency accelerating cavity used for a charged particle beam accelerator.
[0002]
[Prior art]
An accelerator is a device for accelerating charged particles such as electrons, protons, and ions to a high energy state of about several billion electron volts (several GeV) by electromagnetic force, and was originally used to study atomic nuclei and elementary particles. Has been developed.
[0003]
However, in recent years, when an electron propagating in a vacuum at almost the speed of light has its trajectory bent by a deflecting magnetic field, the irradiating light (referred to as SOR light) generated in the tangential direction of the trajectory is used to reduce the size of the super LSI. The application range is extended to a wide range of science and technology fields such as life science such as processing (lithography) and material research.
[0004]
The accelerator is provided with a high-frequency accelerating cavity in its beam line in order to accelerate charged particles and supply energy lost as SOR light.
FIG. 11 shows an example of a conventional high-frequency accelerator, in which a high-frequency accelerating cavity 2 is inserted in a beam duct 1 of a circular accelerator for accelerating and accumulating charged particles. A high frequency oscillated by a high frequency oscillator 3 is supplied to the high frequency accelerating cavity 2 through an antenna 5 through a waveguide 4.
[0005]
The high frequency supplied into the high frequency acceleration cavity 2 generates a high electric field E between both ends 1 a of the beam duct 1 by resonance, and accelerates the charged particle beam 6. In this case, when the high electric field E is generated, a circulating current flows on the inner surface of the high-frequency accelerating cavity 2, and since this current is a high-frequency current, it flows through the skin depth according to the material of the inner surface of the high-frequency accelerating cavity 2, This causes Joule loss.
[0006]
By the way, in order to obtain a high electric field required for accelerating the charged particle beam 6 in a normal-conducting high-frequency accelerating cavity made of copper, aluminum, or the like, the above-described Joule loss becomes extremely large. A high-frequency high-frequency oscillator 3 that can supply high-frequency power is required.
[0007]
However, there is no high-frequency oscillator that can supply such high-frequency power. Further, there is a problem in cooling the high-frequency accelerating cavity 2, and there is a limit in applying the normal-conducting high-frequency accelerating cavity.
[0008]
Therefore, it is conceivable to form the high-frequency accelerating cavity with a superconducting material having an electric resistance of approximately 0Ω so that no Joule loss occurs even when a current flows through the inner surface of the high-frequency accelerating cavity 2.
[0009]
The field of use of superconducting high-frequency accelerating cavities is wide-ranging, but especially for charged particle beam accelerators, limited power and limited power are used for large electron storage rings that are being planned and constructed around the world in recent years. In order to obtain electrons having as high an energy as possible in a limited space, the realization of a superconducting high-frequency accelerating cavity has been desired.
[0010]
Conventionally, as a method of manufacturing a superconducting high-frequency accelerating cavity, for example, a method disclosed in Japanese Patent Application Laid-Open No. 1-231300 is known.
In this manufacturing method, as shown in FIG. 12, an acceleration cavity 7 made of an aluminum alloy as a base material is formed, and then an Nb film 8 is formed inside the acceleration cavity 7 by sputtering to form a superconducting high-frequency acceleration cavity. Is to manufacture.
[0011]
[Problems to be solved by the invention]
As described above, in the conventional method for manufacturing a superconducting high-frequency accelerating cavity, since the Nb film 8 is formed by sputtering inside the accelerating cavity 7 formed of an aluminum alloy, the thickness of the Nb film 8 is not uniform. There is a problem that the purity of the film 8 is low, and the superconductivity may be deteriorated.
[0012]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a high-performance and economical superconducting high-frequency accelerating cavity capable of preventing deterioration of superconducting characteristics, being simple to manufacture and contributing to a reduction in manufacturing cost. It is intended to provide a manufacturing method.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is to manufacture a superconducting high-frequency accelerating cavity by the following steps.
The invention corresponding to claim 1 is a high-frequency accelerating cavity for applying energy to a charged particle beam, Copper or aluminum In the superconducting high-frequency accelerating cavity in which the inner surface facing the beam of the outer cavity having the base material is formed by the inner cavity made of superconducting material, the outer cavity is By forging or machining Manufacturing, forming a cylinder with a sheet of superconducting material, and inserting the cylinder into the outer cavity, inflating the cylinder on the inner surface of the outer cavity, and fixing the inner cavity. Prepare.
[0014]
The invention corresponding to claim 2 is a high-frequency accelerating cavity for applying energy to a charged particle beam, Copper or aluminum In the superconducting high-frequency accelerating cavity in which the inner surface of the outer cavity facing the beam of the outer cavity having the base material is formed by the inner cavity made of a superconducting material, the outer cavity has a divided portion substantially at the center in the beam acceleration axis direction. The outer half cavity divided into two By forging or machining Forming, arranging the two half-cavities to face each other, welding the divided portions to form an outer cavity, and forming a cylinder with a sheet of superconducting material; Inserting the cylinder into the interior of the outer cavity and inflating the cylinder on the inner surface of the outer cavity to secure the cylinder as an inner cavity.
[0015]
The invention corresponding to claim 3 is the invention according to claim 1 or 2, wherein a cylinder formed of a superconducting material is formed on the inner surface of the outer cavity formed of a good heat conductive material by HIP (hot isostatic pressing). It is expanded and fixed by a joining method.
[0016]
According to a fourth aspect of the present invention, in the first or second aspect, a cylinder formed of a superconducting material is expanded and fixed to the inner surface of the outer cavity formed of a good heat conductive material by an explosion bonding method. .
[0017]
The invention corresponding to claim 5 is the invention corresponding to claim 1 or 2, wherein a cylinder formed of a superconducting material is inflated and adhered to the inner surface of the outer cavity formed of a good heat conductive material by a hydraulic forming joining method. Then, it is heated and pressurized to be fixed.
[0021]
Therefore, according to the first to fifth aspects of the present invention, the elongation percentage of copper, aluminum or the like is about 40%, and the half cavity can be easily formed by molding using a mold or machining. Further, unlike sputtering or the like, there is no need to manufacture an electrode, manufacture a jig for installing the electrode, or mirror-finish the inner surface of the outer cavity, thereby contributing to a reduction in manufacturing cost. In addition, since the superconducting material on the inner surface of the outer cavity has a high purity and a uniform thickness, deterioration of superconducting characteristics can be prevented.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1A and 1B show a first embodiment for explaining a method of manufacturing a superconducting high-frequency accelerating cavity according to the present invention, wherein FIG. 1A shows a half cavity forming step, and FIG. , (C) shows the step of inserting the cylinder, and (d) shows the step of close contact with the inner surface.
[0024]
First, in step (a), the outer half cavity 9 is formed by machining a material made of a forged product. In this case, as the base material of the outer half cavity 9, copper, aluminum, or the like, which is a good heat conductive material and has excellent workability, is used.
[0025]
Next, in step (b), the two outer half cavities 9 are arranged to face each other, and the divided portions are joined and integrated by arc welding, electron beam welding, brazing, or the like to form the outer cavity 10. Then, in step (c), a high-purity sheet made of a superconducting material such as Nb or Pb is formed into a cylindrical shape, and the divided portion is joined to the outer cavity 10 by, for example, electron beam welding. insert.
[0026]
Finally, in step (d), an external force is applied to the cylinder 11 so that the cylinder 11 is brought into close contact with the inner surface of the outer cavity 10 as an inner cavity while being inflated and joined.
Here, the steps (c) and (d) will be specifically described with reference to FIG.
[0027]
In FIG. 2A, the cylinder 11 is inserted into the outer cavity 10, and then the space 12 between the cylinder 11 and the outer cavity 10 is evacuated to vacuum and both ends are sealed and welded. This method is performed by electron beam welding or the like that can perform vacuum degassing. In the drawing, reference numeral 13 denotes a seal welding portion.
[0028]
After the seal welding, the cylinder 11 and the outer cavity 10 are joined using the HIP device 14. In the HIP device 14 shown in FIG. 2B, isotropic pressure of high temperature and high pressure, for example, 800 ° C., 1000 kg / cm ² Is applied to the cylinder 11 and the outer cavity 10 in the direction shown by the arrow 15, the cylinder 11 is deformed with the passage of time, and finally, as shown in FIG. The inner cavity is uniformly joined to the inner surface of the outer cavity 10 by diffusion bonding and integrated to manufacture a superconducting high-frequency accelerating cavity.
[0029]
Next, the operation and effect of the above-described first embodiment will be described.
Copper, aluminum, and the like have high thermal conductivity, a high elongation of about 40% as compared with Nb, and good machinability. Therefore, the outer half cavity 9 can be easily and accurately formed by forging or machining.
[0030]
After the forming process, the outer half cavity 9 is integrated by a joining method such as welding to manufacture the outer cavity 10. Separately, a high-purity sheet made of a superconducting material such as Nb or Pb is formed into a cylindrical shape, and a cylinder 11 having divided portions joined by, for example, electron beam welding or the like is manufactured. By heating and pressurizing, atoms such as Nb and Pb diffuse into the outer cavity 10 made of copper, aluminum, or the like via the bonding interface to bond and integrate.
[0031]
Accordingly, a superconducting high-frequency accelerating cavity in which the cylinder 11 made of a superconducting material such as Nb or Pb is fixed as the inner cavity to the inner surface of the outer cavity 10 such as copper or aluminum is obtained. In addition, unlike this method, it is not necessary to manufacture an electrode, manufacture a jig for installing the electrode, or mirror-finish the inner surface of the outer cavity 10. This method can contribute to a reduction in manufacturing cost. Furthermore, since Nb on the inner surface of the outer cavity 10 is fixed to the inner cavity having a high purity and a uniform thickness, it is possible to prevent deterioration of superconducting characteristics.
[0032]
In the above-described embodiment, the outer cavity 10 is integrated by joining the divided portions of the two outer half cavities 9. Instead, the outer cavity 10 is formed by hydraulic forming or electroforming. The body 10 may be manufactured as an integral body.
[0033]
In addition, although the cylinder 11 serving as the inner cavity is also joined at the divided portion, it may be made as an integral body by drawing or machining instead. Further, when the outer cavity 10 and the inner cavity are diffusion-bonded, an active metal such as titanium may be interposed.
[0034]
A second embodiment of the present invention will be described with reference to FIG.
In the second embodiment, as shown in FIG. 3, a robust restraining jig 16 is attached to the outside of the outer cavity 10, a contact plate 17 is arranged inside the cylinder 11, and an explosive joint is provided at the center thereof. Is provided. By exploding the explosive 18, a strong joint can be obtained between the cylinder 11 and the outer cavity 10 via the metal jet.
[0035]
The inner surface of the outer cavity 10 and the outer surface of the cylinder 11, which are the joining surfaces, are first finished so that explosive joining is possible. After the explosion bonding, the superconducting high-frequency accelerating cavity having a predetermined shape as shown in FIG. 1D is obtained by removing the contact plate 17 and the restraining jig 16.
[0036]
Next, the operation and effect of the above-described second embodiment will be described.
As in the first embodiment, an outer cavity 10 in which outer half cavities 9 are integrated by a joining method such as welding, and a high-purity sheet separately made of a superconducting material such as Nb or Pb are formed into a cylindrical shape. By constructing a cylinder 11 formed and joined, and exploding the explosive disposed inside the cylinder 11, the outer cavity 10 protected by the robust restraining jig 16 is not deformed, and the outer cavity 10 is not deformed. Only the cylinder 11 made of a superconducting material such as Nb or Pb collides with the inner surface.
[0037]
At the collision point between the inner surface of the outer cavity 10 and the cylinder 11, both metals exhibit viscous fluid behavior due to a very high deformation speed and high pressure, and a metal jet is generated forward from the collision point. The jet removes an oxide film and a gas adsorption layer on the metal surface, so that the clean surface that has appeared adheres by high pressure, and the outer cavity 10 such as copper or aluminum and a cylinder made of a superconducting material such as Nb or Pb. 11 is firmly joined and integrated. In particular, in this method, a sound bond can be obtained by the metal jet despite the bonding in the atmosphere.
[0038]
In the explosion bonding according to the present embodiment, since the outer cavity 10 and the cylinder 11 can be joined without heating, material deterioration due to softening of the outer cavity 10 and the cylinder 11 can be avoided. Therefore, a superconducting high-frequency accelerating cavity having high structural strength in which a superconducting material such as Nb or Pb is formed on the inner surface of the outer cavity 10 such as copper or aluminum can be obtained.
[0039]
In addition, this method does not require the production of an electrode, the production of a jig for installing the electrode, and the mirror finishing of the inner surface of the outer cavity unlike sputtering or the like, and thus can contribute to a reduction in manufacturing cost. Furthermore, since Nb on the inner surface of the outer cavity has a high purity and a uniform thickness, it is possible to prevent deterioration of superconducting characteristics.
[0040]
A third embodiment of the present invention will be described with reference to FIG.
In the third embodiment, the cylinders 11 are arranged inside the outer cavity 10, and the sealing jigs 19 are arranged at both ends of the central axis, and the liquid 20 is inserted into the inside and pressurized. The cylinder 11 is gradually deformed by increasing the liquid pressure inside the cylinder, and is finally brought into close contact with the inside of the outer cavity 10. Also, by maintaining the temperature of the liquid at 100 ° C., the outer cavity 10 and the cylinder 11 can be joined by mutual diffusion. Further, in the case where it is difficult to obtain a bond under the conditions of the temperature and the pressure of the liquid, although not shown, a heater may be arranged outside the outer cavity 10 to preheat and heat to a temperature at which the bonding is possible. is there.
[0041]
The inner surface of the outer cavity 10 and the outer surface of the cylinder 11, which are bonding surfaces, are first finished so that bonding by mutual diffusion is possible.
Next, the operation and effect of the third embodiment as described above will be described.
[0042]
Similarly to the first and second embodiments, an outer cavity 10 in which outer half cavities 9 are integrated by a joining method such as welding, and a high-purity sheet made of a superconducting material such as Nb or Pb are separately provided. The cylinder 11 is formed by molding into a cylindrical shape and joined, and the inside of the cylinder 11 is filled with a high-temperature and high-pressure liquid, so that the cylinder 11 follows the shape of the inner surface of the outer cavity 10 such as copper, aluminum, and Nb. Atoms such as Pb and Pb are bonded and integrated by diffusion bonding via the bonding interface to obtain a superconducting high-frequency accelerating cavity.
[0043]
In addition, the present method does not require the use of a large and expensive facility as shown in the first embodiment, a HIP device whose installation conditions are strict for security, does not require a special approval for high-pressure gas control, and is legally applicable. It is possible to use a high-temperature and high-pressure diffusion bonding apparatus having no restriction on the temperature.
[0044]
Further, since the joining apparatus can be easily introduced and handled, and the large-sized joining apparatus can be easily manufactured, it can be applied to a large-sized acceleration cavity device. In addition, there are effects similar to those of the first and second embodiments.
[0045]
A fourth embodiment of the present invention will be described with reference to FIG.
5 (a) is a forming process of the inner half cavity, (b) is a welding integration process, (c) is a double process of the accelerating cavity, and (d) is a fixing process of the outer cavity and the inner cavity. is there.
[0046]
First, in step (a), a plate material as a material of the inner cavity 21 is formed into a trumpet shape by drawing or spinning. In this case, as a base material of the inner cavity 21, Nb or Pb of a superconducting material is used.
[0047]
Next, in step (b), the two inner half cavities 21a and 21b are arranged to face each other, and the divided portions are joined by arc welding, electron beam welding, brazing, or the like to be integrated to produce the inner cavity 21. .
[0048]
Then, in step (c), the outer half cavities 22a and 22b overlap the outer side of the inner cavity 21. In this case, as the base material of the outer half cavities 22a and 22b, copper, aluminum, or the like, which is a good heat conductive material and has excellent workability, is used. By joining the joints of the outer half cavities 22a and 22b together by, for example, arc welding, electron beam welding, brazing, or the like, the inside is made of a superconducting material and the outside is made of a good heat conductive material. A heavy superconducting high-frequency accelerating cavity 23 is manufactured.
[0049]
Finally, in the step (d), the inner superconducting material and the outer good heat conducting material are fixed in the acceleration cavity.
Next, the operation and effect of the above-described fourth embodiment will be described.
[0050]
According to the manufacturing method of the present embodiment, processing of the inner cavity 21 made of a superconducting material such as Nb or Pb is not processing from a cylinder as in the above-described embodiment, but drawing or spinning a plate material. Then, the predetermined inner cavity 21 can be manufactured by butt welding the inner half cavities 21a and 21b of the trumpet shape. Further, the outer half cavities 22a and 22b are attached to the integrated inner cavity 21, and the outer half cavities 22a and 22b are joined to each other and welded to integrate the outer cavities 22. In this manner, the superconducting material of the inner cavity 21 and the good heat conducting material of the outer cavity 22 are fixed to obtain a superconducting high-frequency accelerating cavity.
[0051]
In this embodiment, the processing of the inner half cavities 21a and 21b made of a superconducting material such as Nb or Pb is not performed from a cylinder as in the above-described embodiment, but a superconducting material previously processed into a cavity shape. Is fixed to a good heat conducting material, so that a superconducting high-frequency accelerating cavity having a large aspect ratio can be manufactured. Further, since the processing rate is small, heat treatment for removing distortion after forming is not required.
[0052]
Accordingly, a highly accurate accelerating cavity can be manufactured, and the number of manufacturing days can be reduced due to the small number of processes. In addition, the same effects as those of the first, second, and third embodiments can be obtained.
[0053]
A fifth embodiment of the present invention will be described with reference to FIG.
In the fifth embodiment, outer half cavities 22a and 22b made of a good heat conductive material are superimposed on the outside of the inner cavity 21 made of the superconducting material used in the fourth embodiment, and then the outer half halves are formed. As shown in FIG. 6, a double superconducting high-frequency accelerating cavity 23 in which the joining surfaces of the cavities 22a and 22b are joined by, for example, electron beam welding or the like to form the outer cavity 22, is subjected to a high-temperature and high-pressure isotropic pressure pressing device. In a certain HIP device 14, the superconducting material of the inner cavity 21 and the good heat conducting material of the outer cavity 22 are integrated by diffusion bonding in a high-temperature and high-pressure gas atmosphere.
[0054]
The bonding conditions are below the melting point of the good thermal conductive material, for example, at 1000 ° C. or less for copper and 500 ° C. or less for aluminum at a pressure of 100 kgf / mm. ² As described above, if the holding time is 30 minutes or more, the superconducting material of the inner cavity 21 made of Nb or Pb and the good heat conductive material of the outer cavity 22 made of copper, aluminum, or the like are firmly diffusion bonded.
[0055]
In the diffusion bonding using the HIP device 14 as in this embodiment, the superconducting material of the inner cavity 21 and the good heat conductive material of the outer cavity 22 shown in the first embodiment and FIG. The surface is first subjected to a process such as vacuum degassing in advance so as to have a vacuum atmosphere.
[0056]
Next, the operation and effect of the fifth embodiment as described above will be described.
According to the manufacturing method of the present embodiment, the superconducting material such as Nb or Pb of the inner cavity 21 and the good heat conductive material of the outer cavity 22 made of copper, aluminum, or the like are, for example, 1000 ° C. or less for copper. For aluminum, at a joining temperature of 500 ° C or less, the pressure is 100 kgf / mm. ² As described above, the diffusion bonding is firmly performed under the bonding condition of a holding time of 30 minutes or more. In particular, the thickness of the superconducting material of the inner cavity 21 made of Nb, Pb, or the like is a fraction of the thickness of the good heat conducting material of the outer cavity 22 made of copper, aluminum, or the like. Therefore, in the diffusion bonding using the HIP device, the superconducting material of the inner cavity 21 made of Nb, Pb, or the like is changed into a shape inside the good heat conducting material of the outer cavity 22 made of copper, aluminum, or the like by isotropic pressing. follow.
[0057]
In particular, in this method, the inner cavity 21 made of a superconducting material is previously formed into a trumpet shape by drawing or spinning a plate material and finished to a predetermined shape by welding. Similarly, the inner surface shape of the outer half cavity is finished in a shape following the outer surface shape of the inner cavity.
[0058]
Therefore, diffusion bonding using a HIP device after vacuum-sealing them is also easy from the prior art. In addition, since the high thermal conductive material of the outer cavity 22 made of copper, aluminum, or the like is formed of a relatively thick plate and the processing accuracy is finished to a predetermined shape, high accuracy is required as an acceleration cavity. The dimensional accuracy of the inner cavity 21 made of a superconducting material such as Nb or Pb can be as high as designed. Further, it is possible to manufacture a superconducting high-frequency accelerating cavity having a large aspect ratio.
[0059]
A sixth embodiment of the present invention will be described with reference to FIG.
FIG. 7A shows two inner halves shown in FIG. 5B before the superconducting material of the inner cavity and the good heat conducting material of the outer cavity shown in the fourth embodiment are fixed. A paste brazing material 24 is applied to the outer surface of the integrated inner cavity 21 by arranging the cavities 21a and 21b to face each other and joining the divided portions by arc welding, electron beam welding, or the like, and then outer half cavities. The two superconducting high-frequency cavities 23, which are formed by superposing the bodies 22a and 22b and joining these joints by, for example, electron beam welding or the like, to form the outer cavity 22, are put into a vacuum furnace 25, and are subjected to vacuum brazing to perform inner brazing. A double superconducting high-frequency accelerating cavity 23 composed of a superconducting material on the inside and a good heat conducting material on the outside is formed by fixing and integrating the 21 and the outer cavity 22.
[0060]
The vacuum brazing of the double superconducting high-frequency accelerating cavity 23 is performed at a temperature lower than the melting point of the good heat conducting material, for example, at a temperature of about 1000 ° C. for copper and about 500 ° C. for aluminum and a brazing material that can be brazed. By performing vacuum brazing using such a material, the superconducting material of the inner cavity 21 made of Nb, Pb, or the like and the good heat conducting material of the outer cavity 22 made of copper, aluminum, or the like are firmly vacuum brazed.
[0061]
The vacuum brazing according to the present embodiment is a method in which a paste-like brazing material is applied, but the present embodiment is not limited to a method in which a paste-like brazing material is applied, and a sheet-like brazing material is applied inside. Vacuum brazing can be performed by disposing the brazing material on the outer surface of the cavity 21 or by inserting a linear brazing material into a brazing material groove provided on the outer surface of the inner cavity 21. In this embodiment, vacuum brazing is performed, but a similar accelerating cavity can be manufactured by brazing in the atmosphere.
[0062]
Next, the operation and effect of the sixth embodiment as described above will be described.
According to the manufacturing method of the sixth embodiment, the superconducting material of the inner cavity 21 made of Nb, Pb, or the like and the good heat conducting material of the outer cavity 22 made of copper, aluminum, or the like have a melting point of the good heat conducting material. Hereinafter, vacuum brazing is performed using a brazing material that can be brazed at a temperature of about 1000 ° C. for copper and about 500 ° C. for aluminum.
[0063]
In particular, in the present manufacturing method, the inner cavity 21 made of a superconducting material is previously formed into a trumpet shape by drawing or spinning a plate material, and is finished to a predetermined shape by welding. Similarly, the inner surfaces of the outer half cavities 22a and 22b made of a good heat conductive material are finished in a shape following the outer peripheral shape of the inner cavity 21. In this case, vacuum brazing them via a brazing material is also easy from the prior art.
[0064]
Therefore, since the high-heat-conductivity material of the outer cavity 22 made of copper, aluminum, or the like is formed of a relatively thick plate and the processing accuracy is finished to a predetermined shape, Nb required to have high accuracy as an acceleration cavity The dimensional accuracy of the inner cavity 21 made of a superconducting material such as Pb or Pb can be as high as designed. Further, it is possible to manufacture a superconducting high-frequency accelerating cavity having a large apest ratio.
[0065]
A seventh embodiment of the present invention will be described with reference to FIG.
Before fixing the superconducting material of the inner cavity 21 and the good heat conducting material of the outer cavity 22 shown in the fourth embodiment as shown in FIG. 8A, the two pieces shown in FIG. The inner half cavities 21a and 21b are arranged to face each other, and the divided portions are joined by arc welding, electron beam welding or the like, and paste-like solder 26 is applied to the outer surface of the integrated inner cavity 21. As shown in FIG. 8 (b), the outer half cavities 22a and 22b are overlapped, and these joints are joined to each other by, for example, electron beam welding or the like to form a double superconducting high-frequency accelerating cavity 23 as the outer cavity 22. The inner cavity 21 is made of a superconducting material, and the outer cavity 22 is made of a good heat conductive material by putting it in a furnace 27 or a gas atmosphere furnace, heating it to a temperature at which the paste-like solder can be melted, soldering and integrating. The superconducting high-frequency accelerating cavity 23 is manufactured.
[0066]
Next, the operation and effect of the seventh embodiment as described above will be described.
According to the manufacturing method of the seventh embodiment, for example, tin-lead solder is used for soldering, while zinc flux or ammonium chloride is used for the flux, so that the temperature is relatively low at about 200 ° C. It can be joined at a temperature, there is no deterioration of the material strength due to the heat of the outer cavity material of the good thermal conductive material made of copper, aluminum, etc.Also, it is possible to perform uniform heating by using a gas atmosphere furnace etc. Since bonding can be performed without unevenness, sound bonding can be obtained.
[0067]
In this case, the superconducting material of the inner cavity 21 made of Nb, Pb or the like and the good heat conducting material of the outer cavity 22 made of copper, aluminum, or the like are firmly soldered. In particular, in this manufacturing method, the inner cavity 21 made of a superconducting material is previously formed into a trumpet shape by drawing or spinning a plate material, and is finished in a predetermined shape by welding. Further, it is easy to solder them from the prior art.
[0068]
Therefore, since the good thermal conductive material of the outer cavity 22 made of copper, aluminum, or the like is formed of a relatively thick plate, and the processing accuracy is finished to a predetermined shape, the inner cavity, which is required to have high accuracy as an acceleration cavity, is formed. The dimensional accuracy of the inner cavity 21 made of a superconducting material such as Nb or Pb can be as high as designed. Further, it is possible to manufacture the superconducting high-frequency accelerating cavity 23 having a large aspect ratio.
[0069]
An eighth embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 9A, before the superconducting material of the inner cavity 21 and the good heat conducting material of the outer cavity 22 shown in the fourth embodiment are brought into close contact, the two inner halves shown in FIG. The cavities 21a and 21b are arranged to face each other, and the divided portions are joined by arc welding, electron beam welding or the like, and a thermosetting adhesive 28 is applied to the outer surface of the integrated inner cavity 21, and then FIG. As shown in b), the outer half cavities 22a and 22b are overlapped, and these joints are joined by, for example, electron beam welding or the like to form a double superconducting high-frequency accelerating cavity 23 as an outer cavity in the high-temperature furnace 29. A double superconducting high-frequency accelerating cavity in which the inner cavity 21 is made of a superconducting material and the outer cavity 22 is made of a good heat conducting material by being heated to a temperature at which the adhesive is hardened and bonded and integrated. 23 is manufactured.
[0070]
Next, the operation and effect of the eighth embodiment as described above will be described.
According to the manufacturing method of the eighth embodiment, for example, if a thermosetting adhesive is used, the bonding can be performed at a relatively low temperature, and the material strength due to the heat of the outer cavity of a good heat conductive material made of copper, aluminum, or the like. Can be joined without deterioration. In particular, in this manufacturing method, the inner cavity 21 made of a superconducting material is previously formed into a trumpet shape by drawing or spinning a plate material and finished to a predetermined shape by welding. Similarly, the inner surface shapes of the outer half cavities 22a and 22b are finished in a shape following the outer peripheral shape of the inner cavity 21. In this case, it is easy from the prior art to join them via a welding agent.
[0071]
Therefore, since the good thermal conductive material of the outer cavity 22 made of copper, aluminum, or the like is formed of a relatively thick plate, and the processing accuracy is finished to a predetermined shape, the inner cavity, which is required to have high accuracy as an acceleration cavity, is formed. The dimensional accuracy of the superconducting material such as Nb and Pb of the cavity 21 can be as high as designed. Further, it is possible to manufacture the superconducting high-frequency accelerating cavity 23 having a large aspect ratio.
[0072]
A ninth embodiment of the present invention will be described with reference to FIG.
10 (a) is a forming process of the inner half cavity, (b) is a forming process of the outer half cavity, (c) is a duplexing process of the inner and outer half cavity, and (d) is an inner and outer half. This is the process of combining the half cavities. Further, (e) is a step of combining the inner and outer half cavities after the inner and outer half cavities have been combined in the same manner. Here, as the base material of the inner half cavity, Nb or Pb of superconducting material is used, and as the base material of the outer half cavity, copper or aluminum which is a good heat conductive material and has excellent workability is used. Used. The manufacturing procedure will be described below in the order of steps.
[0073]
First, in step (a), the inner half cavity 21a is formed by press working, spin working, or the like. Similarly, in the step (b), the outer half cavity 22a is formed by press working, spin working, or the like.
[0074]
Next, in step (c), the inner half cavity 21a and the outer half cavity 22a are superimposed to deaerate the joint surface, and then seal welding 13 is performed to maintain a vacuum state. Thereafter, in a step (d), these are joined by diffusion joining using the HIP device 14 to manufacture the half acceleration cavity 30a.
[0075]
Further, the double half acceleration cavity 30a joined in the step (d) and the double half acceleration cavity 30b manufactured in the same manner are arranged to face each other, and their divided portions are joined to each other. Then, a double superconducting high-frequency accelerating cavity 31 in which the inner cavity is made of a superconducting material and the outer cavity is made of a good heat conducting material is manufactured by diffusion bonding using the HIP device 14.
[0076]
For example, in the diffusion bonding using the HIP device 14, the bonding surface needs to be in a vacuum atmosphere. Therefore, as a specific method, the inner surface is sealed and welded with a YAG laser or the like after removing the unevenness of the surface of the joint surface, and then the outer peripheral joint surface is vacuum-sealed by electron beam welding or the like. The purpose of vacuum sealing is to prevent high-temperature and high-pressure gas from entering the bonding surface during diffusion bonding using the HIP device 14.
[0077]
In this case, the depth of the welding may be about several millimeters. In addition, using a YAG laser for seal welding of the inner surface greatly increases the possibility of inserting a fiber for guiding the beam of the YAG laser from several ports even when the half acceleration cavities 30a and 30b are arranged to face each other. Is a factor. Further, the joining condition is a double superconducting high-frequency accelerating cavity 31 in which the inner cavity is made of a superconductive material and the outer cavity is made of a good heat conductive material. It is possible to select an appropriate range for the joining by changing the pressure in a temperature range equal to or lower than the melting point of the material and by changing the pressure.
[0078]
In the ninth embodiment, the diffusion bonding using the HIP device 14 is performed. However, the HIP device 14 is used as a bonding method of the inner half cavities 21a and 21b and the outer half cavities 22a and 22b. The method is not limited to the conventional diffusion bonding, but the same inner cavity is made of a superconducting material and the outer cavity is made of a good heat by a bonding method using a hot press without using the HIP device 14, a brazing method, a soldering method, a bonding method, or the like. A double superconducting high-frequency accelerating cavity 31 composed of a conductive material can be manufactured.
[0079]
Next, the operation and effect of the ninth embodiment as described above will be described.
According to the manufacturing method of the ninth embodiment, the inner cavity 21 made of a superconducting material made of Nb or Pb and the outer cavity 22 made of a good heat conducting material made of copper, aluminum or the like are each in a half cavity state. Because of the high processing accuracy and dimensional accuracy before joining, and the ease of assembly, diffusion joining using the HIP device 14, diffusion joining by hot pressing, brazing, soldering, bonding or the like are also used. In the method, the half acceleration cavities 30a and 30b, which are the joint of the inner half cavity and the outer half cavity, are obtained. The half-acceleration cavities joined with high precision are further joined by the same joining method and united to form an inner cavity 21 of a predetermined shape made of a superconducting material such as Nb or Pb, and copper and aluminum. A double superconducting high-frequency accelerating cavity 31 composed of an outer cavity 22 made of a good heat conductive material is obtained.
[0080]
Therefore, a double superconducting high-frequency wave in which the outer conductor 22 made of copper, aluminum or the like is made of a relatively thick plate with a good heat conducting material and the inner cavity 21 made of Nb, Pb or the like is made of a relatively thin plate. As the acceleration cavity, a dimensional accuracy of the inner cavity 21 made of a superconducting material such as Nb or Pb, which is required to have high precision as the acceleration cavity, is obtained as high as designed. Further, it is possible to manufacture a superconducting high-frequency accelerating cavity having a large aspect ratio.
[0081]
【The invention's effect】
According to the present invention as described above, Since the outer cavity is formed of copper or aluminum, it has high elongation and good machining, and can be easily and accurately formed by forging or machining. Since it is formed of an inner cavity made of a material, deterioration of superconducting characteristics can be prevented, and there is no need to mirror-finish the inner surface, facilitating manufacture and reducing manufacturing costs. And a method for manufacturing a superconducting high-frequency acceleration cavity.
[Brief description of the drawings]
1 (a), 1 (b), 1 (c) and 1 (d) are explanatory views showing a first embodiment of a method for manufacturing a superconducting high-frequency accelerating cavity according to the present invention.
FIGS. 2A and 2B are explanatory diagrams specifically showing the embodiment.
FIG. 3 is an explanatory view showing a second embodiment of the method for manufacturing a superconducting high-frequency accelerating cavity according to the present invention.
FIG. 4 is an explanatory view showing a third embodiment of the method for manufacturing a superconducting high-frequency accelerating cavity according to the present invention.
FIGS. 5 (a), (b), (c) and (d) are explanatory views showing a fourth embodiment of the method for manufacturing a superconducting high-frequency accelerating cavity according to the present invention.
FIG. 6 is an explanatory view showing a fifth embodiment of the method for manufacturing a superconducting high-frequency accelerating cavity according to the present invention.
FIGS. 7A and 7B are explanatory views showing a sixth embodiment of the method for manufacturing a superconducting high-frequency accelerating cavity according to the present invention.
FIGS. 8A and 8B are explanatory views showing a seventh embodiment of a method for manufacturing a superconducting high-frequency accelerating cavity according to the present invention.
FIGS. 9A and 9B are explanatory views showing an eighth embodiment of the method for manufacturing a superconducting high-frequency accelerating cavity according to the present invention.
FIGS. 10 (a), (b), (c), (d), and (e) are explanatory views showing a ninth embodiment of a method for manufacturing a superconducting high-frequency accelerating cavity according to the present invention.
FIG. 11 is an explanatory view showing a configuration example of a conventional high-frequency accelerator.
12A and 12B are explanatory views showing an example of a conventional method for manufacturing a superconducting high-frequency accelerating cavity.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Beam duct, 2 ... High frequency accelerating cavity, 3 ... High frequency oscillator, 4 ... Waveguide, 5 ... Antenna, 6 ... Charged particle beam, 7 ... Aluminum alloy accelerating cavity, 8 ... Nb film, 9, 22a, 22b ... outer half cavity, 10, 22 ... outer cavity, 11 ... cylinder, 12 ... space, 13 ... seal welded part, 14 ... HIP device, 15 ... isotropic pressure, 16 ... restraining jig, 17 ... this plate, 18 ... explosive, 19 ... seal jig, 20 ... liquid, 21 ... inner cavity, 21a, 21b ... inner Half cavity, 23 superconducting high-frequency accelerating cavity, 24 brazing material, 25 vacuum furnace, 26 solder, 27 atmospheric furnace, 28 adhesive, 29 high temperature furnace, 30a ... half acceleration cavity, 30b half acceleration cavity, 31 ... superconducting high frequency acceleration cavity, 32 ... seal welding, 33 ... HI Apparatus, 34 ...... half accelerating cavity, 35 ...... accelerating cavity.

Claims

A high-frequency accelerating cavity for applying energy to a charged particle beam, wherein the inner surface of the outer cavity based on copper or aluminum facing the beam is formed by an inner cavity made of a superconducting material. Manufacturing the outer cavity by forging or machining , forming a cylinder from a sheet of superconducting material, inserting the cylinder into the outer cavity and inflating the cylinder on the inner surface of the outer cavity. And a step of fixing the superconducting high-frequency acceleration cavity as an inner cavity.

A high-frequency accelerating cavity for applying energy to a charged particle beam, wherein the inner surface of the outer cavity based on copper or aluminum facing the beam is formed by an inner cavity made of a superconducting material. Forming, by forging or machining, an outer half cavity that is divided into two parts so as to have a divided portion substantially at the center of the outer cavity in the beam acceleration axis direction, and opposingly disposing the two half cavities. Welding the divided portions to form an outer cavity by integrating them; a step of forming a cylinder with a sheet of superconducting material; inserting the cylinder into the outer cavity; and an inner surface of the outer cavity. Further comprising a step of expanding the cylinder and fixing the cylinder as an inner cavity.

The cylinder formed of a superconducting material is expanded and fixed to the inner surface of the outer cavity formed of a good heat conductive material by a hot isostatic pressing (HIP) bonding method. Of manufacturing superconducting high-frequency accelerating cavities.

The superconducting high-frequency accelerating cavity according to claim 1 or 2, wherein a cylinder formed of a superconducting material is expanded and fixed to an inner surface of the outer cavity formed of a good heat conductive material by an explosion bonding method. Production method.

The cylinder formed of a superconducting material is inflated and adhered to the inner surface of the outer cavity formed of a good heat conducting material by a hydraulic molding bonding method, and then heated and pressed to be fixed. A method for manufacturing a superconducting high-frequency accelerating cavity according to claim 2.