JP2004134681A - Core apparatus and charged particle accelerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a core apparatus capable of improving an average magnetic flux density of an annular core, and a charged particle accelerator capable of emitting charged particles of high energy. <P>SOLUTION: An annular core 1 has a plurality of annular partial cores 11-16 separated, in the manner of magnetic circuit, radially from an inner peripheral part to an outer peripheral part by a magnetic insulating plate 4. Exciting coils 21-26 for individually exciting the partial cores 11-16 are wound around the partial cores and comprise annular partial core apparatuses 81-86. The annular core 1 is divided into the plurality of partial cores 11-16 to be individually excited, such that a difference of magnetic path lengths between the inner peripheral part and the outer peripheral part of each of the partial cores 11-16 is reduced in comparison with the case that the annular core 1 is not divided, and excitation approximately up to a saturated magnetic flux density is made possible for each partial core. Therefore, when using the annular core for the charged particle accelerator, an accelerating voltage by the annular core 1 is improved and charged particles of high energy are emitted. <P>COPYRIGHT: (C)2004,JPO

Description

【００１８】
この実施の形態では、ｒ０＝１、ｒ１＝１．１、ｒ２＝１．２０、ｒ３＝１．３０、ｒ４＝１．４０、ｒ５＝１．５、である。すなわち、この場合、各部分コア１１〜１６の内外径の差がほぼ一定となる。
【００１９】
以上のように構成された環状コア１、すなわち各環状部分コア装置に電圧ｖ０を印加する。各部分コア１１〜１６の内部において最内周における磁束密度Ｂｍｉを計算すると以下のようになる。
各部分コアのインダクタンスＬｍは関数ｒ（ｍ）を使って、
Ｌｍ＝Ｎ・Ｎ・μ・ｔ／（２π）・ｌｎ（ｒｍ／ｒ（ｍ−１））
＝Ｎ・Ｎ・μ・ｔ・ｒ０・ｌｎ（ｒ１／ｒ０）／（２π・ｒ（ｍ−１））
ここで、ｔは部分コアの厚み、μは部分コアのコア材の透磁率である。
【００２０】
電圧ｖ０を各部分コアの励磁コイルに印加したときの電流ｊｍは、
ｊｍ＝−ｖ０／Ｌｍ
＝（−２π・ｒ（ｍ−１））／（ω・Ｎ・Ｎ・μ・ｔ・ｒ０・ｌｎ（ｒ１／ｒ０））｜Ｖ｜（ｓｉｎ（ω・ｔ））／ｎ
最内周部の厚さδの部分について考えると、インダクタンスＬｍｉは
Ｌｍｉ＝Ｎ・Ｎ・μ・ｔ／（２π）・ｌｎ（ｒｍ／ｒ（ｍ−１））
＝Ｎ・Ｎ・ｔ・μ・（１／２π）・（δ／ｒ（ｍ−１））
各部分コアの厚みδの最内周部における磁束密度ｂｍｉは、
ｂｍｉ＝ｊｍ・Ｌｍｉ／（ｔ・δ）
＝−Ｖ・（ｓｉｎ（ω・ｔ））／（ｎ・ω・ｔ・ｒ０・ｌｎ（ｒ１／ｒ０））
【００２１】
振幅で考えると、
Ｂｍｉ＝｜ｂｍｉ｜＝Ｖ／（ω・ｎ・ｔ・ｒ０・ｌｎ（ｒ１／ｒ０））
すなわち、全ての部分コアの最内周部においては一定振幅の磁束密度Ｂｍｉが得られる。
加速電圧の最大振幅Ｖｍａｘは、コア材の飽和磁束密度をＢｍａｘとしたとき｜Ｂｍｉ｜＝Ｂｍａｘのときに得られる。
Ｖｍａｘ（ｎ）＝（ω・ｎ・ｔ・ｒ０・ｌｎ（ｒ１／ｒ０））・Ｂｍａｘ
十分大きい分割数ｎでは、部分コアは等分割でよいと考えられるので、ｒ１→ｒ０＋（ｒｎ−ｒ０）／ｎと置くと、
Ｖｍａｘ（∞）＝（ｒｎ−ｒ０）・ｔ・ω・Ｂｍａｘ
となる。
【００２２】
上記実施の形態においては、環状コア１の分割数ｎを６としているが、各部分コアの内部でも最内周において先に飽和磁束密度Ｂｍａｘに達し、外周部が飽和磁束密度Ｂｍａｘ以下で使用され、部分コアの特性をさらに利用する余地が残っている。従って、理論的には無限に分割すればコアの特性を完全に利用できることになるが、現実的でない。実際は、コスト面等を考慮して適当な分割数を設定する。
【００２３】
そこで、横軸に分割数をとり、縦軸に環状コア１による加速電圧Ｖｍａｘ（ｎ）／Ｖｍａｘ（ｎ→∞）をプロットした結果を、図２に示す。但し、環状コア１の外周長／内周長比は１．５とした。図２に示すように、分割無しの場合のＶｍａｘ（ｎ＝１）／Ｖｍａｘ（ｎ一∞）＝０．８１に対して、５分割程度とすればＶｍａｘ（ｎ＝５）／Ｖｍａｘ（ｎ→∞）＝０．９６となり、従来よりおよそ１８％の加速電圧Ｖの増大が可能になる。
【００２４】
以上のように、この実施の形態によれば、環状コアを、複数に分割された形の部分コアにより構成し、各部分コアにそれぞれ励磁コイルを設けて複数の環状部分コア装置とし、各部分コアを独立に励磁している。従って、各部分コアの内周部と外周部の磁路長の差が、環状コアを分割しない場合に比し小さくなり、各部分コアごとに飽和磁束密度近くまで励磁可能となる。荷電粒子加速装置に用いた場合、複数の部分コアによる加速電圧を向上させることができ、高エネルギーの荷電粒子を出射できる。また、各部分コアに設けた励磁コイルに同じ電圧を印加すると各部分コアの磁束密度がほぼ同じになり、単一の電源で複数の部分コアを並列に励磁できるので、一つの電源で足りコスト低減できるという効果がある。
【００２５】
実施の形態２．
図３及び図４は、この発明の他の実施の形態を示すものであり、図３は矩形状の環状コアを備えたコア装置の構成図、図４は環状コアの分割数と環状コアによる加速電圧との関係を示す特性図である。上記実施の形態１では環状コアの形状は円環状としていたが、図３に示すような角部が円弧状に形成された矩形状や四角形状である環状コア１であってもよい。
【００２６】
この場合、部分コア１１〜１５の形成方法や使用する材料は、実施の形態１と同様である。また、各部分コア１１〜１５に励磁コイル２１〜２５を設けて、環状部分コア装置８１〜８６を形成するのも同様である。なお、図示の都合上、環状部分コア装置は５個として図示している。
環状コアを各部分コアに分割して構成する場合、各部分コアの分割割合は、次の方程式を解いて求められる。なお、矩形状の環状コア１の各直線部の寸法をａ，ｂ、円弧部の内半径をｒ０とする。
ｒ（ｎ）＝ｒｎ
但し、関数ｒ（ｍ）は再帰的関数として次の数式２のように定義される。
【００２７】
【数２】

【００２８】
この実施の形態では、ａ＝１、ｂ＝１．５、ｒ０＝１、ｒｎ＝２．５、ｎ＝５、として計算すると、
ｒ０＝１、ｒ１＝１．３１、ｒ２＝１．６１、ｒ３＝１．９１、ｒ４＝２．２０、ｒ５＝２．５と、分割割合が求められる。すなわち、各部分コアの内外周の寸法差をほぼ一定とすればよい。
上記実施例と同様にして加速電圧の最大振幅Ｖｍａｘを求めると、
Ｖｍａｘ（ｎ）＝（ω・ｎ・ｔ・（ａ＋ｂ＋ｒ０）・ｌｎ（（ａ＋ｂ＋ｒ１）／（ａ＋ｂ＋ｒ０）））・Ｂｍａｘ
Ｖｍａｘ（ｎ→∞）＝（ｒｎ−ｒ０）・ｔ・ω・Ｂｍａｘ
となる。
【００２９】
横軸に分割数ｎ、縦軸に加速電圧Ｖｍａｘ（ｎ）／Ｖｍａｘ〈ｎ＝∞）をプロットした計算結果を図４に示す。図４に示すように、分割無しの場合のＶｍａｘ（ｎ＝１）／Ｖｍａｘ（ｎ＝∞）＝０．８３に対して、５分割とすればＶｍａｘ（ｎ＝５）／Ｖｍａｘ（ｎ＝∞）＝０．９８となり、ほぼ１００％近く、従来より約１８％加速電圧Ｖの増大が可能になる。
【００３０】
この実施の形態によれば、矩形状や四角形状の環状コアであっても、実施の形態１と同様の効果を奏する。
【００３１】
実施の形態３．
図５及び図６は、さらにこの発明の他の実施の形態を示すものであり、図５は円環状の環状コアを備えたコア装置の構成図、図６は励磁コイルの接続図である。上記各実施の形態では、電源電圧は従来の分割されていない環状コアを励磁するときの電圧ｖに対して、環状コアの分割数ｎ等分した電源電圧ｖ０＝ｖ／ｎを使用している。従って、電源電流はｎ倍となっている。通常、加速器としてのベータトロンでは、電圧ｖは数ｋＶと高いので、電源電圧を下げる方向である上記各実施の形態は、望ましい方向である。
【００３２】
しかし、電源の電流容量に制限があるので、電圧を高くして投入電力を大きくしたい場合には、励磁コイルを所定個数、直並列接続にして電源に接続する。すなわち、この実施の形態では、図５及び図６に示すように、２ターンの励磁用の励磁コイル２１〜２６を、励磁コイル２１と励磁コイル２６とを並列接続し、励磁コイル２２と励磁コイル２５とを並列接続し、励磁コイル２３と励磁コイル２４とを並列接続し、これら並列接続された３組の励磁コイルを３個直列に接続にして、電源３に接続している。このような構成を採れば、電源３の電圧は従来と同じ電圧ｖで駆動することが可能である。
【００３３】
この実施の形態によれば、各部分コアに設けた各励磁コイルに電圧を印加するにあたって適宜、並列接続と直列接続とを組み合わせたので、励磁コイルに流す電流を任意に選ぶことができるようになり、電源の製作の自由度が高くなるのでコスト低減が可能となるという効果がある。
【００３４】
実施の形態４．
図７は、さらにこの発明の他の実施の形態である円環状の環状コアを備えた電磁石装置の構成図である。以上の各実施の形態では、１台の電源装置により環状コアを励磁するために各部分コアに同じ電圧を印加した場合に、環状コアの特性を最大限に利用できるように環状コアを分割する方法を採っている。これに対し、この実施の形態においては、図７に示すように部分コア１１〜１６の分割寸法を任意として、励磁コイル２１〜２６をおのおの設けて環状部分コア装置８１〜８６を構成し、各部分コア１１〜１６に対して、それぞれ最適な電圧を印加できるように各励磁コイル２１〜２６に対応して電源３１〜３６を設けている。
【００３５】
各部分コアにおけるインダクタンスＬｍは、近似的に次のように表される。
Ｌｍ＝Ｎ・Ｎ・ｔ・（μｍ）・（１／２π）・ｌｎ（ｒｍ／ｒ（ｍ−１））
≒Ｎ・Ｎ・ｔ・（μｍ）・（１／２π）・（ｒｍ／ｒ（ｍ−１）−１）
各部分コアに印加する電圧をｖｍ＝Ｖｍ・ｃｏｓ（ω・ｔ）とすると励磁コイルに流れる電流ｊｍは
ｊｍ＝ｖｍ／Ｌｍ
となる。
【００３６】
部分コアにおける最内周部のインダクタンスＬｍｉは、最内周部の厚さδの部分について考えると、次式で表される。
Ｌｍｉ＝Ｎ・Ｎ・ｔ・（μｍ）・（１／２π）・ｌｎ（ｒｍ／ｒ（ｍ−１））
＝Ｎ・Ｎ・ｔ・（μｍ）・（１／２π）・（δ／ｒ（ｍ−１））
部分コアの最内周部における磁束密度ｂｍｉは、次のようになる。
ｂｍｉ＝−ｊｍ・Ｌｍｉ／（ｔ・δ）＝−Ｖｍ／｛ｔ・（ｒｍ−ｒ（ｍ−１））｝
【００３７】
従って、磁束密度が各部分コアにかかわらず同じになるようにする条件は、
Ｖｍ∝ｒｍ−ｒ（ｍ−１）
となり、任意のコア分割半径ｒｍに対して上の式で規定されるＶｍが最適であることが分かる。
【００３８】
この実施の形態によれば、各励磁コイルをそれぞれ個別に励磁できる励磁電源を設け、独立に励磁電圧を設定するようにしたので、各部分コアを任意に分割せざるを得ない場合にも、飽和磁束密度近くまでの励磁が可能となり、加速電圧が向上するという効果がある。なお、実施の形態１や実施の形態２と同様に、部分コアへの分割数を増加させるほど、加速電圧を向上できる。
【００３９】
実施の形態５．
上記実施の形態４においては、環状コアが円環状である場合について示した。この実施の形態５においては、環状コアの形状が矩形状である場合について説明する。なお、矩形状の環状コアの内外周の寸法は、図３に示したものと同じであるが、部分コア１１〜１６の分割の寸法を任意としたものである。
【００４０】
矩形状の環状コアの各部分コアにおけるインダクタンスＬｍは近似的に、次の式で表される。
Ｌｍ＝Ｎ・Ｎ・ｔ・（μｍ）・（１／２π）・ｌｎ（（ａ＋ｂ＋π・ｒｍ）／（ａ＋ｂ＋π・ｒ（ｍ−１））
≒Ｎ・Ｎ・ｔ・（μｍ）・（１／２）・（ｒｍ−ｒ（ｍ−１））／（（ａ＋ｂ＋π・ｒ（ｍ−１））
各部分コアに印加する電圧をｖｍ＝Ｖｍ・ｃｏｓ（ω・ｔ）とすると、励磁コイルに流れる電流はｊｍは
ｊｍ＝ｖｍ／Ｌｍ
となる。
【００４１】
部分コアにおける最内周部のインダクタンスＬｍｉは、最内周部の厚さδの部分について考えると、次式で表される。
Ｌｍｉ＝Ｎ・Ｎ・ｔ・（μｍ）・（１／２π）・ｌｎ（（ａ＋ｂ＋π・ｒｍ）／（ａ＋ｂ＋π・ｒ（ｍ−１））
＝Ｎ・Ｎ・ｔ・（μｍ）・（１／２）・（δ／（ａ＋ｂ＋π・ｒ（ｍ−１））
【００４２】
部分コアの最内周部における磁束密度ｂｍｉは、次のようになる。
ｂｍｉ＝−ｊｍ・Ｌｍｉ／（ｔ・δ）
＝−Ｖｍ／｛ｔ・（ｒｍ−ｒ（ｍ−１））｝
従って、磁束密度が各部分コアにかかわらず同じになるようにする条件は、
Ｖｍ∝ｒｍ−ｒ（ｍ−１）
となり、任意のコア分割半径ｒｍに対して上の式で規定される電圧Ｖｍが最適であることが分かる。
【００４３】
この実施の形態によれば、矩形状や四角形状の環状コアであっても、実施の形態５と同様の効果を奏する。
【００４４】
実施の形態６．
図８は、さらにこの発明の他の実施の形態である円環状の環状コアを備えたコア装置の構成図である。以上の各実施の形態では、部分コアに用いるコア材料は同じで、その透磁率μは一定としていた。この実施の形態では、図８に示すように、任意の半径ｒｍで部分コア１１〜１６に分割し、各部分コア１１〜１６ごとに異なる透磁率μｍのコア材を、特に環状コアの内周部に位置する部分コアほど透磁率の大きな材料を使用する。すなわち、部分コア１１のコア材料の透磁率μ１が一番大きく、部分コア１６のコア材料の透磁率μ６は部分コアの中では一番小さいものを選ぶ。そして、励磁コイル２１〜２６を設けて、環状部分コア装置８１〜８６を製作する。
【００４５】
各部分コアにおける透磁率をμｍとするとき、各部分コアのインダクタンスＬｍは、近似的に次の式で表される。
Ｌｍ＝Ｎ・Ｎ・ｔ・μｍ・（１／２π）・ｌｎ（ｒｍ／ｒ（ｍ−１））
部分コアにおける最内周部のインダクタンスＬｍｉは、最内周部の厚さδの部分について考えると、次式で表される。
Ｌｍｉ＝Ｎ・Ｎ・ｔ・（μｍ）・（１／２π）・ｌｎ（ｒｍ／ｒ（ｍ−１））
＝Ｎ・Ｎ・ｔ・（μｍ）・（１／２π）・（δ／ｒ（ｍ−１））
【００４６】
励磁コイルの電流をｊとすると、部分コアの最内周部における磁束密度ｂｍｉは、次のようになる。
ｂｍｉ＝ｊ・Ｌｍｉ／（ｔ・δ）
＝ｊ・Ｎ・Ｎ（μｍ）（１／２π）・（１／ｒ（ｍ−１））
従って、磁束密度が各部分コアにかかわらず同じになるようにする条件は、
μｍ∝１／ｒ（ｍ−１）
となり、任意の環状コアの分割ｒ（ｍ−１）に対して上の式で規定される透磁率μｍのコア材を使用するのが最適となる。
【００４７】
異なる透磁率μｍのコア材は、例えば環状コア１の最外周部を構成する部分コア１６を鉄系アモルファスで製作し、環状コア１の最内周部を構成する部分コア１１をナノクリスタル材料などの高い透磁率材料で形成するなどの材料選択により行う。また、同じ材料だけを使用する場合には、材料の焼鈍条件や応力緩和度の調整により異なる透磁率μｍのコア材を製作することができる。
【００４８】
例えば、環状コアの製造工程においてコア材としてテープ状の磁性材料を環状に巻回して各部分コアを形成する際に、各部分コアごとに巻きつける張力を変化させることにより透磁率を変化させることができる。また、環状コアの製造工程において部分コアを巻回した後、焼鈍する際に、アモルファス材であれば結晶化処理の際に各部分コアごとに異なる強さの磁界を印加することにより、透磁率を変化させることが可能となる。
【００４９】
この実施の形態によれば、環状コアをその内周部から外周部にかけて複数に分割された部分コアにより構成し、かつ各部分コアそれぞれの透磁率を最適化したので、環状コアを一つの励磁コイルで励磁した場合にも、各部分コアの磁束密度が同じになり、飽和磁束密度一杯までの励磁が可能となり、加速電圧が向上するという効果がある。なお、部分コアへの分割数を増加させるほど、加速電圧を向上できる。
【００５０】
そして、この実施の形態によれば、環状コアの製造工程においてテープ状のコア材を環状に巻回して各部分コアを形成する際に、各部分コアごとに巻きつける張力を変化させることにより透磁率を変化させるようにしたので、高透磁率の高価な材料を使用することなく同じ材料でも各部分コアごとに透磁率を変化させることが可能となり、低いコストで加速電圧を向上させることができるという効果がある。
【００５１】
さらに、環状コアの製造工程において焼鈍する際に各部分コアごとに異なる強さの磁界を印加して透磁率を変化させるようにしたので、高透磁率の高価な材料を使用することなく同じ材料でも各部分コアごとに透磁率を変化させることが可能となり、低いコストで加速電圧が向上するという効果がある。
【００５２】
実施の形態７．
上記の実施例では環状コアの形状は円環状としていたが、形状が矩形状や四角形状であっても同様に実施できる。
矩形状の環状コアの各部分コアにおける透磁率をμｍとすると、各部分コアのインダクタンスＬｍは近似的に、次の式で表される。
Ｌｍ＝Ｎ・Ｎ・ｔ・（μｍ）・（１／２π）・ｌｎ（（ａ＋ｂ＋π・ｒｍ）／（ａ＋ｂ＋π・ｒ（ｍ−１））
【００５３】
部分コアにおける最内周部のインダクタンスＬｍｉは、最内周部の厚さδの部分について考えると、次式で表される。
Ｌｍｉ＝Ｎ・Ｎ・ｔ・（μｍ）・（１／２π）・ｌｎ（（ａ＋ｂ＋π・ｒｍ）／（ａ＋ｂ＋π・ｒ（ｍ−１））
＝Ｎ・Ｎ・ｔ・（μｍ）・（１／２）・（δ／（ａ＋ｂ＋π・ｒ（ｍ−１））
【００５４】
部分コアを励磁する励磁コイルの電流をｊとすると、部分コアの最内周部における磁束密度ｂｍｉは、次のようになる。
ｂｍｉ＝ｊ・Ｌｍｉ／（ｔ・δ）
＝ｊ・Ｎ・Ｎ・（μｍ）・（１／２）・（１／（ａ＋ｂ＋π・ｒ（ｍ−１））
従って、磁束密度が各部分コアにかかわらず同じになるようにする条件は、
μｍ∝１／（ａ＋ｂ＋π・ｒ（ｍ−１））
となり、任意のコア分割半径ｒ（ｍ−１）に対して上の式で規定されるμｍが最適であることが分かる。なお、部分コアのコア材の選択方法は、実施の形態６に示したものと同様にすればよい。
【００５５】
この実施の形態によれば、形状が矩形状や四角形状の環状コアであっても、実施の形態６と同様の効果を奏する。
【００５６】
実施の形態８．
図９〜図１１は、さらにこの発明の他の実施の形態を示すものであり、図９（ａ）は円環状の環状コアを有するコア装置の平面図、図９（ｂ）はコア装置の断面図、図９（ｃ）は図９（ｂ）図のコア装置を左方から見た側面図である。図１０は、各薄肉銅板の側面図である。図１１はコア装置の要部拡大図であり、図１１（ａ）はコア装置の断面図、図１１（ｂ）は図１１（ａ）のコア装置を下方から見た底面図である。
【００５７】
図９（ｂ），（ｃ）において、薄肉銅板５１〜５６の幅Ｗは、部分コア１１〜１５と同じ幅にされ、そのうちの薄肉銅板５２〜５５は、各部分コア１１〜１５の間に設けられており、図１に示した磁気絶縁板４を兼ねている（図９（ｂ）参照）。また、一番内側の薄肉銅板５１は、部分コア１１の巻芯を兼ねるために所定の強度を有するように薄肉銅板５２〜５５よりも厚さが厚くされている。薄肉銅板５６は、薄肉銅板５２等と同じ厚さのものであり、コイルの導体用として設けられている。
【００５８】
薄肉銅板５１には、図１０（ａ）に示すように、その円周上の所定の位置において所定の幅で上方へ延伸された端子５１ａと、下方に延伸された渡り用銅板５１ｂとが薄肉銅板５１と一体に形成されている。薄肉銅板５２には、図１０（ｂ）に示すように、その円周上の所定の位置において所定の幅で上方へ延伸された端子５２ａと、下方に延伸された２枚の渡り用銅板５２ｂ及び５２ｃが薄肉銅板５２と一体に形成されている。
【００５９】
薄肉銅板５３〜５５は、薄肉銅板５２と同様のものである。薄肉銅板５６には、図１０（ｃ）に示すように、その円周上の所定の位置において所定の幅で上方へ延伸された端子５６ａと、下方に延伸された渡り用銅板５６ｂとが薄肉銅板５１と一体に形成されている。
【００６０】
図１１に示すように、薄肉銅板５１に設けられた渡り用銅板５１ｂは隣接する渡り用銅板５２ｂと接続され、端子５１ａ−薄肉銅板５１−渡り用銅板５１ｂ−隣接する渡り用銅板５２ｂ−薄肉銅板５２−端子５２ａの導電回路で、部分コア１１を取り囲む１ターンのコイル２１が形成されている。同様に、他の隣接する端子同士が接続され、各部分コア１２〜１５を励磁する１ターンのコイル２２〜２５が形成されている。
【００６１】
なお、図１１（ｂ）に示すように、例えば端子５１ｂと端子５２ｂとを接続する薄肉銅板５１における周方向の位置と、端子５２ｃと端子５３ｃとを接続する薄肉銅板５１における周方向の位置は、所定寸法ずらしてある（図１０（ｂ）も参照）。そして、各コイル２１〜２５の端子５１ａ〜５６ａは、ケーブル６を介して、それぞれ同じ電圧の電源装置に接続されている。
【００６２】
高周波でコアを励磁する用途に使用する場合は、薄肉銅板５２〜５５を図１に示した磁気絶縁板４と同じように磁気絶縁板として機能させることができるが、高周波の周波数に応じ、その表皮効果よる電流の浸透深さαの数倍程度の厚さに設定すればよい。この浸透深さは、
α＝√（２／ω・μ・σ）
ここに、ω：周波数　μ：透磁率　σ：電気伝導度
で表され、薄肉銅板の両面に逆方向の電流が流れ、各部分コア１１〜１５間は磁気回路的に分離される。例えば、１０ＭＨｚ近傍の周波数では、概ね１枚数百ミクロンメータ程度の厚さの銅板でよい。
【００６３】
部分コアの製作は、薄肉銅板５２よりも厚さを厚くして強度を持たせた薄肉銅板５１を巻芯にして、鉄系アモルファス材やナノクリスタル材で十ミクロンメータオーダのテープ状にロール成型されたコア材を所定巻き厚さになるまで巻き、一番内側の部分コア１１を作る。その上に、絶縁を補強するために電気絶縁の薄膜シートを巻き（図示していない、通常テープの表面が絶縁皮膜処理されているので、不可欠なものではない）、その上に薄肉銅板５２を巻きつける。この上にコア材を所定回数巻回し、次の部分コア１２を作る。
【００６４】
なお、励磁コイル２１〜２６に直流電流を流す場合は１枚の薄肉銅板５２の外側に例えばカプトンなどの絶縁薄膜テープを巻き、その上に薄肉銅板５２をもう１枚巻き、そしてコア材を巻きつけ、次の部分コア１２を作る。以上の繰り返しで、必要な個数の部分コアを製作する。最後に、外側に薄肉銅板５６を巻き、巻き方向に固定する。励磁コイルに直流電流を流すことがある場合には、上記のように薄肉銅板５２〜５５を二重にしてその間を絶縁し、互いに絶縁された励磁コイルとした方が電源との接続関係が煩わしくなくなる。
【００６５】
実施の形態９．
図１２は、さらにこの発明の他の実施の形態であるコア装置の構成図であり、図１２（ａ）は断面図、図１２（ｂ）は図１２（ａ）の左方より見た側面図である。上記実施の形態８では、薄肉銅板５１〜５６の幅Ｗを部分コア１１〜１５の幅と同じにして、端子５１ａ及び渡り部５１ｂ等を薄肉銅板から延伸して設けるものを示した。
【００６６】
これに代わり、図１２に示すように、部分コア１１〜１５の幅Ｗよりも幅広の幅Ｗ２の薄肉銅板６１〜６６を設けて、その一部が端子部６１ａや渡り部６１ｂ等を兼ねるようにしてもよい。この場合、渡り部６６ｂ（図１２（ｂ））等となる部分は、図１２（ｂ）のように下方から上方に向かって切り込みを入れ、隣接する渡り部同士を容易に接続できるようにする。その他の構成については、実施の形態８と同様のものである。
【００６７】
この実施の形態においては、薄肉銅板６１〜６６の部分コア１１〜１５から突出した部分が放熱フィンとして機能する。この薄肉銅板を自然対流あるいは強制冷却により冷却することにより、部分コアを効率よく冷却でき、部分コア内の巻き重ね方向の温度差を小さくできる。なお、冷却機能を持たせることで、温度変化による透磁率の変化を小さくでき、機械的な歪も小さく抑制される環状コアを製作できる。
【００６８】
上記各実施の形態では、部分コアは交流で励磁されるものを主に説明したが、直流で励磁されるものであってもよい。直流で励磁される場合は、図１等に示した磁気絶縁板４は、設けなくてよい。また、環状コアは、その磁気回路に空隙を有するものであってもよい。また、部分コア１１〜１６のコア材として、アモルファス材やナノクリスタル材などを使うものを示したが、これに限られるものではなく、珪素鋼板や電磁鋼板などその他の材料を使用する場合であっても、同様の効果を奏する。
【００６９】
【発明の効果】
この発明は以上説明したように、複数の環状の部分コアとこの部分コアにそれぞれ巻回され部分コアを励磁する励磁コイルとを有するものであって、部分コアは一の部分コアの外周部に別の部分コアの内周部が対向するようにして複数配設されたものであるので、各部分コアにそれぞれ設けられた励磁コイルにより各部分コアを独立に励磁可能であるので、各部分コアの内周部と外周部の磁路長の差が、複数の部分コアにて構成しない場合に比し小さくなり、各部分コアごとに飽和磁束密度近くまで励磁可能となる。
【００７０】
また、この発明に係る荷電粒子加速装置は、複数の環状の部分コアとこの部分コアにそれぞれ巻回され部分コアを励磁する励磁コイルとを有するものであって、部分コアは一の部分コアの外周部に別の部分コアの内周部が対向するようにして複数配設されたコア装置により発生する誘導起電力により荷電粒子を加速するものであるので、複数の部分コアによる加速電圧を向上させることができ、高エネルギーの荷電粒子を出射できる。
【図面の簡単な説明】
【図１】この発明の実施の一形態である円環状の環状コアを備えたコア装置の構成図である。
【図２】図１の環状コアの分割数と環状コアによる加速電圧との関係を示す特性図である。
【図３】この発明の他の実施の形態である矩形状の環状コアを備えたコア装置の構成図である。
【図４】図３の環状コアの分割数と環状コアによる加速電圧との関係を示す特性図である。
【図５】さらに、この発明の他の実施の形態である円環状の環状コアを備えたコア装置の構成図である。
【図６】図５の励磁コイルの接続図である。
【図７】さらに、この発明の他の実施の形態である円環状の環状コアを備えたコア装置の構成図である。
【図８】さらに、この発明の他の実施の形態である円環状の環状コアを備えたコア装置の構成図である。
【図９】図（ａ）は、さらにこの発明の他の実施の形態である円環状の環状コアを有するコア装置の平面図、図（ｂ）はコア装置の断面図、図（ｃ）は図９（ｂ）図のコア装置を左方から見た側面図である。
【図１０】図９の各薄肉銅板の側面図である。
【図１１】図９のコア装置の要部拡大図である。
【図１２】さらに、この発明の他の実施の形態であるコア装置の構成図である。
【符号の説明】
１　環状コア、１１〜１６　部分コア、２１〜２６　励磁コイル、
４　磁気絶縁板、５１〜５６，６１〜６６　薄肉銅板。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a core device and a charged particle accelerator used for a charged particle accelerator, for example.
[0002]
[Prior art]
As one type of accelerator using a core device, an annular annular acceleration chamber having a gap therein for forming a path of a charged particle beam and inducing an acceleration electric field of the charged particle beam, and an annular acceleration chamber are formed. A pair of closed loop sections (hereinafter, referred to as an annular core) which are provided so as to penetrate the circular space and go around the annular acceleration chamber to form a closed magnetic circuit, and are wound around the annular core to excite the annular core. There is an accelerator provided with a core device having a core coil that performs the operation (for example, see Patent Document 1). In the conventional core device used in this accelerator, a single core coil is wound around all the annular cores regardless of whether the number of annular cores is one or more, and the acceleration voltage is excited by exciting the core coils with one power supply. Had been raised.
[0003]
[Patent Document 1]
JP-A-5-335098 (page 6, FIG. 1)
[0004]
[Problems to be solved by the invention]
One of the important indicators of accelerator performance is the output beam energy, and high beam energy is required. In the case of maximizing the output beam energy in the conventional accelerator as described above, it is necessary to complete the process from the input to the output of the particles within one cycle of the operating frequency, so that the acceleration voltage V during the acceleration period in one cycle is possible. It needs to be as high as possible.
[0005]
Acceleration voltage V is given by magnetic flux φ in the annular core and magnetic flux density b = B · cos (ω · t) in the core device.
V = dφ / dt = S · db / dt = −ω · S · B
Given by
Therefore, the acceleration voltage V is determined by the amplitude B of the magnetic flux density in the core. Since the maximum value of the magnetic flux density b in the annular core is limited to the saturation magnetic flux density Bmax of various core materials, the acceleration voltage V is ultimately determined by the Bmax of the core material.
[0006]
However, the conventional annular core of the accelerator has a problem that the characteristics of the core material cannot be fully utilized. That is, when the magnetic flux density is compared between the inner peripheral portion and the outer peripheral portion of the annular core, the magnetic path length C1 of the inner peripheral portion is compared with the magnetic path length C2 of the outer peripheral portion. Short, each inductance Lc1, Lc2 is
Lc1 = N · N · μ · S / C1
Lc2 = N · N · μ · S / C2
(However, N: number of turns of the exciting coil, μ: permeability of core material, S: cross-sectional area of annular core)
Since the inductance Lc1 of the inner peripheral portion is larger, the magnetic flux density B1 = J · (Lc1) / S (J: exciting current) of the inner peripheral portion is saturated first.
[0007]
When the inner circumference of the annular core reaches saturation, problems such as (1) increase in excitation current, (2) increase in heat generation, and (3) sound generation due to increase in magnetostriction occur. Therefore, no more current can flow, and the magnetic flux density at the outer peripheral portion of the core becomes B2 = (C1 / C2) Bmax. For example, the inner / outer peripheral ratio C1 / C2 = 1 / 1.5 = 0.67. Then, only 67% of the saturation magnetic flux density Bmax could be used.
SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a core device capable of increasing the average magnetic flux density of an annular core and a charged particle accelerator capable of emitting charged particles of high energy.
[0008]
[Means for Solving the Problems]
A core device according to the present invention includes a plurality of annular partial cores and an exciting coil wound around each of the partial cores to excite the partial cores, and the partial cores are separately provided on an outer peripheral portion of one partial core. Are arranged in such a manner that the inner peripheral portions of the partial cores face each other.
[0009]
Further, a charged particle accelerator according to the present invention includes a plurality of annular partial cores and an exciting coil wound around each of the partial cores to excite the partial cores, wherein the partial cores correspond to one partial core. The charged particles are accelerated by induced electromotive force generated by a plurality of core devices arranged such that the inner peripheral portion of another partial core faces the outer peripheral portion.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
1 and 2 show an embodiment of the present invention. FIG. 1 is a configuration diagram of a core device having an annular annular core, and FIG. 2 is a diagram showing the number of divided annular cores and acceleration by the annular core. FIG. 4 is a characteristic diagram illustrating a relationship with a voltage. In FIG. 1, a plurality of (in this embodiment, six) circles of an annular annular core 1 separated in a magnetic circuit from an inner peripheral portion toward an outer peripheral portion by a magnetic insulating plate 4 in a radial direction. It has annular partial cores 11 to 16.
[0011]
Excitation coils 21 to 26 for individually exciting the respective partial cores 11 to 16 are wound around the respective partial cores 11 to 16 to form annular partial core devices 81 to 86. The number n of the respective partial cores may be an arbitrary value, but in this embodiment, n = 6. The coil 2 includes excitation coils 21 to 26 that excite the respective partial cores 11 to 16. These excitation coils 21 to 26 are connected in parallel to an AC excitation power supply 3. A core device having such an annular core 1 is used, for example, in a betatron accelerator.
[0012]
For each of the partial cores 11 to 16, an iron-based amorphous material, a nanocrystal material, an electromagnetic steel plate, or the like is used as a core material. When an iron-based amorphous material or a nanocrystal material is used, the partial core is formed in a wound tape shape. For example, a tape-shaped core material is wound around a cylindrical winding core a predetermined number of times to form a partial core 11, and an exciting coil 21 is wound around this partial core 11 for one turn, thereby manufacturing an annular partial core device 81. Then, the magnetic insulating plate 4 is wound around the outside thereof. Further, a tape-shaped core material is wound a predetermined number of times to form the partial core 12, and the exciting coil 22 is wound around the partial core 12 for one turn, thereby manufacturing the annular partial core device 82. By repeating this operation, a core device having the annular partial core devices 81 to 86 is manufactured.
[0013]
The number of turns N of the exciting coils 21 to 26 wound around the respective partial cores 11 to 16 can be arbitrarily selected. In this embodiment, N = 1. The power supply voltage v0 of the excitation power supply 3 is equal to v0 = v / n (v / 6 in this embodiment), assuming that the accelerating voltage required for the annular core 1 is v = | V | cos (ω · t). Set to be. The magnetic insulating plate 4 is made of a material having a sufficiently small magnetic permeability as compared with the core material in order to effectively perform magnetic insulation between the partial cores 11 to 16. A conductor about twice as thick is used. In this embodiment, a copper plate having a thickness of 1 mm is used.
[0014]
The number of turns of the tape-shaped core material when forming each of the partial cores 11 to 16 is determined by the amplitude of the magnetic flux density B in each of the partial cores 11 to 16 when the same voltage v0 is applied to each of the partial cores 11 to 16 | It is determined so as to satisfy the condition that B | is equal to the saturation magnetic flux density Bmax of the core material (the condition for keeping the applied voltage constant).
[0015]
Here, the inner radius r0 and the outer radius r1 of the partial core 11 and the inner radius r1 and the outer radius r2 of the partial core 12 are defined. Similarly, the inner radius r (n-1) and the outer radius of the outermost partial core are similarly defined. rn. R0 corresponding to the inner radius of the annular core 1 and rn corresponding to the outer radius are values determined by the specifications of the accelerator. In this embodiment, r0 = 1 and rn = 1.5. Here, since the thickness of the magnetic insulating plate 4 is thin, it is ignored, and the outer radius of the partial core 11 and the inner radius of the adjacent partial core 12 are set to the same r1.
[0016]
The values r1 to r (n-1) are determined by solving the following function equation satisfying the constant applied voltage condition for r1, the function r (m) is determined, and therefore rm = r (m) and (m = 1 to n-1).
r (n) = rn
However, the function r (m) is defined as a recursive function as in the following Expression 1.
[0017]
(Equation 1)

[0018]
In this embodiment, r0 = 1, r1 = 1.1, r2 = 1.20, r3 = 1.30, r4 = 1.40, and r5 = 1.5. That is, in this case, the difference between the inner and outer diameters of the partial cores 11 to 16 is substantially constant.
[0019]
The voltage v0 is applied to the annular core 1 configured as described above, that is, each annular partial core device. Calculation of the magnetic flux density Bmi at the innermost circumference inside each of the partial cores 11 to 16 is as follows.
Using the function r (m), the inductance Lm of each partial core is
Lm = N · N · μ · t / (2π) · ln (rm / r (m−1))
= N ・ N ・ μ ・ t ・ r0 ・ ln (r1 / r0) / (2π ・ r (m-1))
Here, t is the thickness of the partial core, and μ is the magnetic permeability of the core material of the partial core.
[0020]
The current jm when the voltage v0 is applied to the excitation coil of each partial core is:
jm = -v0 / Lm
= (− 2π · r (m−1)) / (ω · NN · μ · t · r0 · ln (r1 / r0)) | V | (sin (ω · t)) / n
Considering the portion of thickness δ at the innermost periphery, the inductance Lmi is
Lmi = N · N · μ · t / (2π) · ln (rm / r (m−1))
= N ・ N ・ t ・ μ ・ (1 / 2π) ・ (δ / r (m-1))
The magnetic flux density bmi at the innermost periphery of the thickness δ of each partial core is:
bmi = jm · Lmi / (t · δ)
= −V · (sin (ω · t)) / (n · ω · t · r0 · ln (r1 / r0))
[0021]
Considering the amplitude,
Bmi = | bmi | = V / (ω · nt · r0 · ln (r1 / r0))
That is, a magnetic flux density Bmi having a constant amplitude is obtained in the innermost peripheral portion of all the partial cores.
The maximum amplitude Vmax of the acceleration voltage is obtained when | Bmi | = Bmax when the saturation magnetic flux density of the core material is Bmax.
Vmax (n) = (ω · nt · r0 · ln (r1 / r0)) · Bmax
If the number of divisions n is sufficiently large, the partial cores are considered to be equally divided, so if r1 → r0 + (rn−r0) / n,
Vmax (∞) = (rn−r0) · t · ω · Bmax
It becomes.
[0022]
In the above embodiment, the number of divisions n of the annular core 1 is set to 6. However, the inside of each partial core first reaches the saturation magnetic flux density Bmax at the innermost periphery, and the outer peripheral portion is used at a saturation magnetic flux density Bmax or less. However, there is room for further utilizing the characteristics of the partial core. Therefore, theoretically, if the division is made infinitely, the characteristics of the core can be used completely, but this is not realistic. Actually, an appropriate number of divisions is set in consideration of cost and the like.
[0023]
FIG. 2 shows the result of plotting the number of divisions on the horizontal axis and plotting the acceleration voltage Vmax (n) / Vmax (n → ∞) by the annular core 1 on the vertical axis. However, the ratio of the outer peripheral length / inner peripheral length of the annular core 1 was 1.5. As shown in FIG. 2, Vmax (n = 1) / Vmax (n∞) = 0.81 in the case of no division, and Vmax (n = 5) / Vmax (n → ∞) = 0.96, which makes it possible to increase the acceleration voltage V by about 18% compared to the related art.
[0024]
As described above, according to this embodiment, the annular core is constituted by a plurality of divided partial cores, and an excitation coil is provided for each of the partial cores to form a plurality of annular partial core devices. The core is excited independently. Therefore, the difference in the magnetic path length between the inner and outer peripheral portions of each partial core is smaller than when the annular core is not divided, and it is possible to excite each partial core to near the saturation magnetic flux density. When used in a charged particle accelerator, the acceleration voltage by a plurality of partial cores can be improved, and high energy charged particles can be emitted. Also, when the same voltage is applied to the excitation coil provided in each partial core, the magnetic flux density of each partial core becomes almost the same, and a plurality of partial cores can be excited in parallel by a single power supply. There is an effect that it can be reduced.
[0025]
Embodiment 2 FIG.
3 and 4 show another embodiment of the present invention. FIG. 3 is a configuration diagram of a core device having a rectangular annular core, and FIG. 4 is a diagram showing the number of divided annular cores and the annular core. FIG. 4 is a characteristic diagram showing a relationship with an acceleration voltage. In the first embodiment, the shape of the annular core is an annular shape. However, the annular core 1 may have a rectangular shape or a rectangular shape with a corner formed in an arc shape as shown in FIG.
[0026]
In this case, the method of forming the partial cores 11 to 15 and the material to be used are the same as in the first embodiment. The same applies to the case where the excitation coils 21 to 25 are provided on the respective partial cores 11 to 15 to form the annular partial core devices 81 to 86. In addition, for convenience of illustration, five annular partial core devices are illustrated.
When the annular core is divided into the respective partial cores, the division ratio of each partial core is obtained by solving the following equation. Note that the dimensions of each linear portion of the rectangular annular core 1 are a and b, and the inner radius of the arc portion is r0.
r (n) = rn
However, the function r (m) is defined as a recursive function as in the following Expression 2.
[0027]
(Equation 2)

[0028]
In this embodiment, when a = 1, b = 1.5, r0 = 1, rn = 2.5, and n = 5, the calculation is as follows.
The division ratios are obtained as r0 = 1, r1 = 1.31, r2 = 1.61, r3 = 1.91, r4 = 2.20, and r5 = 2.5. That is, the dimensional difference between the inner and outer peripheries of each partial core may be made substantially constant.
When the maximum amplitude Vmax of the acceleration voltage is obtained in the same manner as in the above embodiment,
Vmax (n) = (ω · nt · (a + b + r0) · ln ((a + b + r1) / (a + b + r0))) · Bmax
Vmax (n → ∞) = (rn−r0) · t · ω · Bmax
It becomes.
[0029]
FIG. 4 shows a calculation result obtained by plotting the division number n on the horizontal axis and the acceleration voltage Vmax (n) / Vmax <n = ∞) on the vertical axis. As shown in FIG. 4, Vmax (n = 1) / Vmax (n = ∞) = 0.83 in the case of no division, and Vmax (n = 5) / Vmax (n = ∞) in the case of five divisions. ) = 0.98, which is almost 100%, which makes it possible to increase the acceleration voltage V by about 18% as compared with the related art.
[0030]
According to this embodiment, the same effects as those of the first embodiment can be obtained even with a rectangular or square annular core.
[0031]
Embodiment 3 FIG.
FIGS. 5 and 6 show still another embodiment of the present invention. FIG. 5 is a configuration diagram of a core device having an annular core, and FIG. 6 is a connection diagram of excitation coils. In each of the above embodiments, the power supply voltage v0 = v / n is used as the power supply voltage, which is equal to the conventional voltage v for exciting the undivided annular core, divided into n equal parts of the annular core. . Therefore, the power supply current is n times as large. Normally, in a betatron as an accelerator, the voltage v is as high as several kV, and the above-described embodiments in which the power supply voltage is reduced are desirable directions.
[0032]
However, since the current capacity of the power supply is limited, when it is desired to increase the applied power by increasing the voltage, a predetermined number of exciting coils are connected in series and parallel to the power supply. That is, in this embodiment, as shown in FIGS. 5 and 6, two-turn excitation coils 21 to 26 are connected in parallel with the excitation coil 21 and the excitation coil 26, and the excitation coil 22 and the excitation coil 25 are connected in parallel, the exciting coil 23 and the exciting coil 24 are connected in parallel, and three sets of these exciting coils connected in parallel are connected in series and connected to the power supply 3. With such a configuration, the voltage of the power supply 3 can be driven at the same voltage v as in the related art.
[0033]
According to this embodiment, in applying a voltage to each excitation coil provided in each partial core, parallel connection and series connection are appropriately combined, so that the current flowing through the excitation coil can be arbitrarily selected. In this case, the degree of freedom in manufacturing the power supply is increased, so that there is an effect that the cost can be reduced.
[0034]
Embodiment 4 FIG.
FIG. 7 is a configuration diagram of an electromagnet device having an annular core according to another embodiment of the present invention. In each of the above embodiments, when the same voltage is applied to each partial core to excite the annular core by one power supply device, the annular core is divided so that the characteristics of the annular core can be used to the maximum. The method has been adopted. On the other hand, in this embodiment, as shown in FIG. 7, the partial dimensions of the partial cores 11 to 16 are arbitrarily set, and the excitation coils 21 to 26 are respectively provided to form the annular partial core devices 81 to 86. Power supplies 31 to 36 are provided corresponding to the exciting coils 21 to 26 so that optimum voltages can be respectively applied to the partial cores 11 to 16.
[0035]
The inductance Lm in each partial core is approximately expressed as follows.
Lm = N · N · t · (μm) · (1 / 2π) · ln (rm / r (m−1))
≒ N ・ N ・ t ・ (μm) ・ (1 / 2π) ・ (rm / r (m-1) -1)
Assuming that the voltage applied to each partial core is vm = Vm · cos (ω · t), the current jm flowing through the exciting coil is
jm = vm / Lm
It becomes.
[0036]
The inductance Lmi of the innermost peripheral portion in the partial core is expressed by the following equation when considering the portion having the thickness δ of the innermost peripheral portion.
Lmi = N · N · t · (μm) · (1 / 2π) · ln (rm / r (m−1))
= N ・ N ・ t ・ (μm) ・ (1 / 2π) ・ (δ / r (m-1))
The magnetic flux density bmi at the innermost peripheral portion of the partial core is as follows.
bmi = −jm · Lmi / (t · δ) = − Vm / {t · (rm−r (m−1))}
[0037]
Therefore, the condition that the magnetic flux density is the same regardless of each partial core is
Vm∝rm-r (m-1)
It can be seen that Vm defined by the above equation is optimal for an arbitrary core division radius rm.
[0038]
According to this embodiment, an excitation power supply capable of individually exciting each of the excitation coils is provided, and the excitation voltage is set independently.Therefore, even when it is necessary to divide each partial core arbitrarily, Excitation up to near the saturation magnetic flux density becomes possible, and there is an effect that the acceleration voltage is improved. Note that, as in the first and second embodiments, the acceleration voltage can be improved as the number of divisions into partial cores is increased.
[0039]
Embodiment 5 FIG.
In the fourth embodiment, the case where the annular core is annular has been described. In the fifth embodiment, a case will be described in which the shape of the annular core is rectangular. The dimensions of the inner and outer peripheries of the rectangular annular core are the same as those shown in FIG. 3, but the dimensions of the division of the partial cores 11 to 16 are arbitrary.
[0040]
The inductance Lm in each partial core of the rectangular annular core is approximately expressed by the following equation.
Lm = N · N · t · (μm) · (1 / 2π) · ln ((a + b + π · rm) / (a + b + π · r (m−1))
≒ N · N · t · (μm) · (1/2) · (rm−r (m−1)) / ((a + b + π · r (m−1))
Assuming that the voltage applied to each partial core is vm = Vm · cos (ω · t), the current flowing through the exciting coil is jm:
jm = vm / Lm
It becomes.
[0041]
The inductance Lmi of the innermost peripheral portion in the partial core is expressed by the following equation when considering the portion having the thickness δ of the innermost peripheral portion.
Lmi = N · N · t · (μm) · (1 / 2π) · ln ((a + b + π · rm) / (a + b + π · r (m−1))
= N ・ N ・ t ・ (μm) ・ (1/2) ・ (δ / (a + b + π ・ r (m-1))
[0042]
The magnetic flux density bmi at the innermost peripheral portion of the partial core is as follows.
bmi = −jm · Lmi / (t · δ)
= −Vm / {t · (rm−r (m−1))}
Therefore, the condition that the magnetic flux density is the same regardless of each partial core is
Vm∝rm-r (m-1)
It can be seen that the voltage Vm defined by the above equation is optimal for an arbitrary core division radius rm.
[0043]
According to this embodiment, the same effects as those of the fifth embodiment can be obtained even with a rectangular or square annular core.
[0044]
Embodiment 6 FIG.
FIG. 8 is a configuration diagram of a core device having an annular core according to another embodiment of the present invention. In each of the above embodiments, the core material used for the partial core is the same, and the magnetic permeability μ is constant. In this embodiment, as shown in FIG. 8, the core material is divided into partial cores 11 to 16 at an arbitrary radius rm, and a core material having a different magnetic permeability μm for each of the partial cores 11 to 16 is used, in particular, the inner circumference of the annular core. A material having a higher magnetic permeability is used as the partial core is positioned at the portion. That is, the magnetic permeability μ1 of the core material of the partial core 11 is the largest, and the magnetic permeability μ6 of the core material of the partial core 16 is the smallest among the partial cores. Then, the excitation coils 21 to 26 are provided, and the annular partial core devices 81 to 86 are manufactured.
[0045]
When the magnetic permeability of each partial core is μm, the inductance Lm of each partial core is approximately expressed by the following equation.
Lm = N · N · t · μm · (1 / 2π) · ln (rm / r (m−1))
The inductance Lmi of the innermost peripheral portion in the partial core is expressed by the following equation when considering the portion having the thickness δ of the innermost peripheral portion.
Lmi = N · N · t · (μm) · (1 / 2π) · ln (rm / r (m−1))
= N ・ N ・ t ・ (μm) ・ (1 / 2π) ・ (δ / r (m-1))
[0046]
Assuming that the current of the exciting coil is j, the magnetic flux density bmi at the innermost peripheral portion of the partial core is as follows.
bmi = j · Lmi / (t · δ)
= J ・ N ・ N (μm) (1 / 2π) ・ (1 / r (m-1))
Therefore, the condition that the magnetic flux density is the same regardless of each partial core is
μm∝1 / r (m-1)
It is optimal to use a core material having a magnetic permeability μm defined by the above equation for an arbitrary division r (m−1) of the annular core.
[0047]
For the core material having a different magnetic permeability μm, for example, the partial core 16 constituting the outermost peripheral portion of the annular core 1 is made of an iron-based amorphous material, and the partial core 11 constituting the innermost peripheral portion of the annular core 1 is formed of a nanocrystal material. This is performed by selecting a material such as a material having a high magnetic permeability. When only the same material is used, core materials having different magnetic permeability μm can be manufactured by adjusting the annealing conditions and the stress relaxation degree of the material.
[0048]
For example, in the process of manufacturing an annular core, when a tape-shaped magnetic material is annularly wound as a core material to form each partial core, the magnetic permeability is changed by changing the tension wound around each partial core. Can be. In addition, when the partial core is wound in the manufacturing process of the annular core and then annealed, if the material is an amorphous material, a magnetic field having a different strength is applied to each partial core during the crystallization process, so that the magnetic permeability is increased. Can be changed.
[0049]
According to this embodiment, the annular core is constituted by a plurality of partial cores divided from the inner peripheral portion to the outer peripheral portion thereof, and the magnetic permeability of each partial core is optimized. Even when the coils are excited by the coils, the magnetic flux densities of the respective partial cores become the same, and excitation can be performed up to the full saturation magnetic flux density, and there is an effect that the acceleration voltage is improved. The acceleration voltage can be improved as the number of divisions into partial cores increases.
[0050]
According to this embodiment, when forming the respective partial cores by winding the tape-shaped core material in the annular shape in the manufacturing process of the annular core, the tension applied to each partial core is changed to change the transparency. Since the magnetic permeability is changed, the magnetic permeability can be changed for each partial core even with the same material without using an expensive material having a high magnetic permeability, and the acceleration voltage can be improved at a low cost. This has the effect.
[0051]
Furthermore, during annealing in the manufacturing process of the annular core, a magnetic field having a different strength is applied to each partial core to change the magnetic permeability, so that the same material is used without using an expensive material having a high magnetic permeability. However, the magnetic permeability can be changed for each of the partial cores, and the acceleration voltage can be improved at low cost.
[0052]
Embodiment 7 FIG.
In the above embodiment, the shape of the annular core is an annular shape, but the present invention can be similarly implemented even if the shape is a rectangular shape or a square shape.
Assuming that the magnetic permeability of each partial core of the rectangular annular core is μm, the inductance Lm of each partial core is approximately expressed by the following equation.
Lm = N · N · t · (μm) · (1 / 2π) · ln ((a + b + π · rm) / (a + b + π · r (m−1))
[0053]
The inductance Lmi of the innermost peripheral portion in the partial core is expressed by the following equation when considering the portion having the thickness δ of the innermost peripheral portion.
Lmi = N · N · t · (μm) · (1 / 2π) · ln ((a + b + π · rm) / (a + b + π · r (m−1))
= N ・ N ・ t ・ (μm) ・ (1/2) ・ (δ / (a + b + π ・ r (m-1))
[0054]
Assuming that the current of the exciting coil for exciting the partial core is j, the magnetic flux density bmi at the innermost peripheral portion of the partial core is as follows.
bmi = j · Lmi / (t · δ)
= J ・ NＮN ・ (μm) ・ (１ ／) ・ (1 / (a + b + π ・ r (m-1))
Therefore, the condition that the magnetic flux density is the same regardless of each partial core is
μm∝1 / (a + b + π · r (m-1))
It can be seen that μm defined by the above equation is optimal for an arbitrary core division radius r (m−1). The method for selecting the core material of the partial core may be the same as that described in the sixth embodiment.
[0055]
According to this embodiment, even if the shape is a rectangular or square annular core, the same effects as in the sixth embodiment can be obtained.
[0056]
Embodiment 8 FIG.
9 to 11 show still another embodiment of the present invention. FIG. 9A is a plan view of a core device having an annular core, and FIG. 9B is a plan view of the core device. 9 (c) is a side view of the core device of FIG. 9 (b) viewed from the left. FIG. 10 is a side view of each thin copper plate. 11 is an enlarged view of a main part of the core device, FIG. 11 (a) is a cross-sectional view of the core device, and FIG. 11 (b) is a bottom view of the core device of FIG. 11 (a) viewed from below.
[0057]
9 (b) and 9 (c), the width W of the thin copper plates 51 to 56 is set to be the same as that of the partial cores 11 to 15, and the thin copper plates 52 to 55 are disposed between the respective partial cores 11 to 15. It also serves as the magnetic insulating plate 4 shown in FIG. 1 (see FIG. 9B). In addition, the innermost thin copper plate 51 is thicker than the thin copper plates 52 to 55 so as to have a predetermined strength so as to also serve as a winding core of the partial core 11. The thin copper plate 56 has the same thickness as the thin copper plate 52 and the like, and is provided for a conductor of a coil.
[0058]
As shown in FIG. 10A, the thin copper plate 51 includes a terminal 51a extending upward with a predetermined width at a predetermined position on the circumference thereof and a crossover copper plate 51b extending downward. It is formed integrally with the copper plate 51. As shown in FIG. 10 (b), the thin copper plate 52 has a terminal 52a extending upward at a predetermined position at a predetermined position on the circumference thereof, and two connecting copper plates 52b extending downward. And 52 c are formed integrally with the thin copper plate 52.
[0059]
The thin copper plates 53 to 55 are the same as the thin copper plate 52. As shown in FIG. 10 (c), the thin copper plate 56 includes a terminal 56a extending upward with a predetermined width at a predetermined position on the circumference thereof and a transition copper plate 56b extending downward. It is formed integrally with the copper plate 51.
[0060]
As shown in FIG. 11, the transition copper plate 51b provided on the thin copper plate 51 is connected to the adjacent transition copper plate 52b, and the terminal 51a-the thin copper plate 51-the transition copper plate 51b-the adjacent transition copper plate 52b-the thin copper plate A one-turn coil 21 surrounding the partial core 11 is formed by the conductive circuit of the 52-terminal 52a. Similarly, other adjacent terminals are connected to each other, and one-turn coils 22 to 25 for exciting the respective partial cores 12 to 15 are formed.
[0061]
As shown in FIG. 11B, for example, the circumferential position on the thin copper plate 51 connecting the terminal 51b and the terminal 52b and the circumferential position on the thin copper plate 51 connecting the terminal 52c and the terminal 53c are Are shifted by a predetermined dimension (see also FIG. 10B). The terminals 51 a to 56 a of the coils 21 to 25 are connected to power supply devices having the same voltage via the cable 6.
[0062]
When used for exciting the core at a high frequency, the thin copper plates 52 to 55 can function as a magnetic insulating plate in the same manner as the magnetic insulating plate 4 shown in FIG. The thickness may be set to about several times the penetration depth α of the current due to the skin effect. This penetration depth is
α = √ (2 / ω ・ μ ・ σ)
Where, ω: frequency μ: magnetic permeability σ: electric conductivity
The current flows in opposite directions on both surfaces of the thin copper plate, and the partial cores 11 to 15 are separated from each other in a magnetic circuit. For example, at a frequency in the vicinity of 10 MHz, a single copper plate having a thickness of about one hundred micrometers can be used.
[0063]
The partial core is manufactured by rolling the thin copper plate 51, which is thicker than the thin copper plate 52 to give strength, to the core, and using iron-based amorphous material or nanocrystal material to form a tape in the order of 10 micrometers. The core material thus obtained is wound up to a predetermined winding thickness to form the innermost partial core 11. An electrically insulating thin film sheet is wound thereon to reinforce the insulation (not shown, which is not indispensable since the surface of the tape is usually treated with an insulating film), and a thin copper plate 52 is placed thereon. Wrap around. A core material is wound thereon a predetermined number of times to form the next partial core 12.
[0064]
When a direct current is applied to the excitation coils 21 to 26, an insulating thin film tape such as Kapton is wound around one thin copper plate 52, another thin copper plate 52 is wound thereon, and a core material is wound. Then, the next partial core 12 is formed. By repeating the above, a required number of partial cores are manufactured. Finally, the thin copper plate 56 is wound around the outside and fixed in the winding direction. In the case where a DC current is supplied to the exciting coil, the thin copper plates 52 to 55 are doubled as described above to insulate them from each other, and the exciting coils are insulated from each other, so that the connection relationship with the power supply is troublesome. Disappears.
[0065]
Embodiment 9 FIG.
FIG. 12 is a configuration diagram of a core device according to still another embodiment of the present invention. FIG. 12 (a) is a cross-sectional view, and FIG. 12 (b) is a side view seen from the left side of FIG. 12 (a). FIG. In the eighth embodiment, the width W of the thin copper plates 51 to 56 is set to be the same as the width of the partial cores 11 to 15, and the terminals 51a and the crossover portions 51b are provided to extend from the thin copper plates.
[0066]
Instead, as shown in FIG. 12, thin copper plates 61 to 66 having a width W2 wider than the width W of the partial cores 11 to 15 are provided, and a part thereof also serves as the terminal portion 61a, the crossover portion 61b, and the like. It may be. In this case, the portion serving as the transition portion 66b (FIG. 12 (b)) is cut upward from below as shown in FIG. 12 (b) so that the adjacent transition portions can be easily connected to each other. . Other configurations are the same as those of the eighth embodiment.
[0067]
In this embodiment, the portions of the thin copper plates 61 to 66 projecting from the partial cores 11 to 15 function as heat radiation fins. By cooling this thin copper plate by natural convection or forced cooling, the partial core can be efficiently cooled, and the temperature difference in the winding direction in the partial core can be reduced. By providing a cooling function, a change in magnetic permeability due to a change in temperature can be reduced, and an annular core with reduced mechanical distortion can be manufactured.
[0068]
In each of the above-described embodiments, the partial core is mainly described as being excited by alternating current, but may be excited by direct current. In the case of excitation by direct current, the magnetic insulating plate 4 shown in FIG. 1 and the like need not be provided. The annular core may have a gap in its magnetic circuit. In addition, as the core material of the partial cores 11 to 16, a material using an amorphous material, a nanocrystal material, or the like has been described. However, the present invention is not limited to this, and other materials such as a silicon steel plate or an electromagnetic steel plate may be used. However, the same effect can be obtained.
[0069]
【The invention's effect】
As described above, the present invention includes a plurality of annular partial cores and an exciting coil wound around each of the partial cores to excite the partial cores. Since a plurality of partial cores are arranged so that the inner peripheral portions thereof face each other, each partial core can be independently excited by an excitation coil provided for each partial core. The difference between the magnetic path lengths of the inner peripheral portion and the outer peripheral portion is smaller than that in the case where a plurality of partial cores are not used, and it becomes possible to excite each partial core to near the saturation magnetic flux density.
[0070]
Further, a charged particle accelerator according to the present invention includes a plurality of annular partial cores and an exciting coil wound around each of the partial cores to excite the partial cores, wherein the partial cores correspond to one partial core. Charged particles are accelerated by induced electromotive force generated by multiple core devices arranged so that the inner peripheral portion of another partial core faces the outer peripheral portion, so the acceleration voltage by multiple partial cores is improved. And high-energy charged particles can be emitted.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a core device including an annular core according to an embodiment of the present invention.
FIG. 2 is a characteristic diagram showing a relationship between the number of divisions of the annular core in FIG. 1 and an acceleration voltage by the annular core.
FIG. 3 is a configuration diagram of a core device having a rectangular annular core according to another embodiment of the present invention.
FIG. 4 is a characteristic diagram showing a relationship between the number of divisions of the annular core in FIG. 3 and an acceleration voltage by the annular core.
FIG. 5 is a configuration diagram of a core device having an annular core according to another embodiment of the present invention.
FIG. 6 is a connection diagram of the excitation coil of FIG.
FIG. 7 is a configuration diagram of a core device including an annular core according to another embodiment of the present invention.
FIG. 8 is a configuration diagram of a core device including an annular core according to another embodiment of the present invention.
9A is a plan view of a core device having an annular core according to another embodiment of the present invention, FIG. 9B is a cross-sectional view of the core device, and FIG. It is the side view which looked at the core device of Drawing 9 (b) from the left.
FIG. 10 is a side view of each thin copper plate of FIG. 9;
FIG. 11 is an enlarged view of a main part of the core device of FIG. 9;
FIG. 12 is a configuration diagram of a core device according to another embodiment of the present invention.
[Explanation of symbols]
1 annular core, 11-16 partial core, 21-26 excitation coil,
4 Magnetic insulating plate, 51-56, 61-66 Thin copper plate.

Claims (13)

It has a plurality of annular partial cores and an exciting coil wound around each of the partial cores to excite the partial cores, wherein the partial cores are provided on an outer peripheral portion of one partial core and an inner peripheral portion of another partial core. A core device in which a plurality of units are provided so as to face each other. 2. The core device according to claim 1, wherein each of the partial cores is formed in an annular shape or a rectangular shape. 3. 3. The core device according to claim 1, wherein each of the partial cores has an average magnetic flux density substantially equal. Each of the partial cores is formed of a magnetic material having the same magnetic permeability, and has the same average magnetic flux density when the same voltage is applied to each of the excitation coils. The core device according to claim 3, wherein: 5. The core device according to claim 4, wherein each of the partial cores has a substantially constant difference between an inner peripheral length and an outer peripheral length. 4. The device according to claim 3, wherein each of the partial cores is formed of a magnetic material having the same magnetic permeability, and a voltage is applied to each of the excitation coils so that the average magnetic flux density becomes substantially the same. A core device as described. 4. The core device according to claim 3, wherein each of the partial cores is formed of a magnetic material having a different magnetic permeability. Each of the partial cores is formed by winding a band-shaped magnetic material whose magnetic permeability changes according to an applied tension while changing the tension so that the magnetic permeability differs for each of the partial cores. The core device according to claim 7, wherein Each of the partial cores is formed by heat-treating a band-shaped magnetic material whose magnetic permeability changes by heat treatment so that the magnetic permeability differs for each of the partial cores. 8. The core device according to 7. Each of the partial cores is characterized in that an AC voltage is applied to the excitation coil and AC excitation is applied, and a conductive magnetic insulating member is provided between the inner peripheral portion and the outer peripheral portion facing each other. The core device according to claim 1 or 2, wherein The inner peripheral side of the innermost partial core of the partial cores, between the inner peripheral portion and the outer peripheral portion of each of the partial cores facing each other, and the outermost portion of the partial cores 3. The core device according to claim 1, wherein a conductor is provided on an outer peripheral side of the core, and each of the exciting coils uses the conductor as a conductive circuit. 4. An AC voltage is applied to the excitation coil to excite each of the partial cores, and the conductor provided between the inner peripheral portion and the outer peripheral portion of each of the partial cores is provided with the magnetic insulation. The core device according to claim 11, wherein the core device also serves as a member. A charged particle accelerator for accelerating charged particles by induced electromotive force generated by the core device according to claim 1.

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