JP3572333B2

JP3572333B2 - X-ray fluorescence analyzer

Info

Publication number: JP3572333B2
Application number: JP37405298A
Authority: JP
Inventors: 直樹河原; 孝庄司; 隆御園生; 光一青柳
Original assignee: 理学電機工業株式会社
Priority date: 1998-12-28
Filing date: 1998-12-28
Publication date: 2004-09-29
Anticipated expiration: 2018-12-28
Also published as: JP2000193613A

Description

【０００１】
【発明の属する技術分野】
本発明は、波長分散型としてもエネルギ分散型としても使用できる蛍光Ｘ線分析装置に関する。
【０００２】
【従来の技術】
蛍光Ｘ線分析装置は、試料の被測定部に一次Ｘ線を照射し、この被測定部から発生する蛍光Ｘ線を検出手段で検出して、被測定部における元素の分析を行うものである。検出手段としては、波長分散型検出手段と、エネルギ分散型検出手段とがある。
【０００３】
波長分散型検出手段は、波長分解能に優れているが、広範囲の波長における蛍光Ｘ線の強度を測定するには、長時間を要するという特徴がある。一方、エネルギ分散型検出手段は、分解能は波長分散型検出手段に比べて劣るが、同時的に広範囲の波長における蛍光Ｘ線の強度を測定できるという特徴がある。したがって、短時間で大まかな波長分布特性を調べるにはエネルギ分散型検出手段が適しており、狭い波長範囲において、高い分解能、つまり正確な蛍光Ｘ線分析を行うには波長分散型検出手段が適している。これにより、分析の目的に応じてエネルギ分散型検出手段と波長分散型検出手段とを使い分ければ、効率のよい分析を行うことができる。また、定性分析をエネルギ分散型検出手段で行い、この後に特定の元素の定量分析を波長分散型検出手段で行うと、全く未知の試料に対しても迅速かつ正確な蛍光Ｘ線分析ができる。
【０００４】
波長分散型検出手段とエネルギ分散型検出手段とを兼ね備え、いずれの検出手段によってもＸ線を検出できるＸ線分析装置は、既に知られている。
特開平５−２８１１６３号に開示されているＸ線分析装置は、図６に示すように、Ｘ線管４から１次Ｘ線３を照射して、試料台２上の試料１から発生する２次Ｘ線５をソーラスリット７で平行化して分光器８で分光し、検出器９で検出するとともに、２次Ｘ線５をエネルギ分散型の検出器１２にも取り込んでＸ線分析を行う。
【０００５】
また、特開平１０−２０６３５６号に開示されている蛍光Ｘ線分析装置は、図７に示すように、Ｘ線管４から１次Ｘ線３を照射して、試料台２上の試料１から発生する蛍光Ｘ線５を分光器８で分光して検出器９に取り込むが、この分光器８は、例えば矢印Ａ方向へ移動して蛍光Ｘ線５の通路から退避することができる。分光器８が蛍光Ｘ線５の通路から退避すると、エネルギ分散型の検出器１２が蛍光Ｘ線５を取り込むこととなり、波長分散型の検出がエネルギ分散型の検出に切り換わる。
【０００６】
【発明が解決しようとする課題】
しかし、図６に示したＸ線分析装置の場合、試料１と分光器８との間の第１の蛍光Ｘ線の通路８１が試料１の表面となす角度、すなわち波長分散型検出の取り出し角θ１と、試料１とエネルギ分散型の検出器１２との間の第２の蛍光Ｘ線の通路８２が試料１の表面となす角度、すなわちエネルギ分散型の取り出し角θ２とは相違する。つまり、受光面積が小さいために入射する蛍光Ｘ線の強度が低くなりがちなエネルギ分散型の検出器１２の方の強度をできる限り高くするために、エネルギ分散型の検出器１２の方の取り出し角を大きくしている。
【０００７】
ところで、Ｘ線分析において、測定するＸ線の強度は、その取り出し角に依存し、その相関関係は複雑である。したがって、このように波長分散型の取り出し角θ１とエネルギ分散型の検出器の取り出し角θ２とが相違する場合、それぞれの測定強度をそのまま対比することはできず、また、取り出し角度による補正をしても、取り出し角度に対するＸ線強度の相関関係が試料組成にも依存して複雑であるため、正確には補正されず、この不確定さから分析精度が向上しないという問題がある。さらに、試料の表面に微小な凹凸があって、試料表面が粗い場合は、たとえ取り出し角が等しくても、分光器や検出器が試料の被測定部を異なる方向から見込むと、Ｘ線の波長分布特性にばらつきがでて、それぞれの測定結果をそのまま対比することはできない。
【０００８】
これに対して、図７に示した蛍光Ｘ線分析装置の場合、第１の蛍光Ｘ線の通路８１と第２の蛍光Ｘ線の通路８２とは同一軸上であり、エネルギ分散型検出の取り出し角と波長分散型検出の取り出し角とはθ１で等しいため、エネルギ分散型のＸ線強度と波長分散型のＸ線強度とを、個別の試料に依存しないそれぞれの検出系に固有の予め求めてある感度係数を乗ずるだけで、そのまま対比して使用することができる。
【０００９】
しかし、エネルギ分解能が比較的良好な半導体検出器（ＳＳＤ）のように、一般に、エネルギ分散型の検出器はその受光面積が小さいので、エネルギ分散型の検出器１２を試料１に接近させなければ感度が低下する。エネルギ分散型の検出器のみを備えた蛍光Ｘ線分析装置では、分光器を備えないので試料に接近させることは可能であるが、この図７の蛍光Ｘ線分析装置の場合、試料１とエネルギ分散型の検出器１２との間に分光器８を位置させるので、エネルギ分散型の検出器１２を試料１に接近させることはできない。したがって、エネルギ分散型の検出において、感度が低下し、特に、試料の微小部位における蛍光Ｘ線を検出する場合には、分析に必要な感度を十分に得られないという問題がある。
【００１０】
一方、従来、定性分析を、分光素子を１つだけ備えた１結晶分光器を有する波長分散型検出手段で行い、次に化学状態の分析を、分光素子を２つ備えた２結晶分光器を有する波長分散型検出手段で行う蛍光Ｘ線分析が採用されている。このように２結晶分光器を用いるのは、２結晶分光器は１結晶分光器よりも波長分解能が高いため、化学状態分析において、化学状態による蛍光Ｘ線の波長変化を検出することができるからである。しかし、この装置の場合、１結晶分光器から、蛍光Ｘ線の通路に沿って前後１対の分光結晶を配置した２結晶分光器に変更するには、部品の入替えなどが必要であり、時間と手間がかかっていた。また、２結晶分光器を有する波長分散型検出手段では、後段側の結晶の回動範囲が制限されるという機構的な制約から、測定できる波長の範囲に制限があるため、特定の元素の化学状態のみを調べたい場合において、共存元素の組成の情報が必要な場合があるにもかかわらず、共存元素の波長領域まで走査できないために、十分な定性分析を行うことができなかった。
【００１１】
そこで本発明は、波長分散型検出手段による蛍光Ｘ線の測定強度と、エネルギ分散型検出手段による蛍光Ｘ線の測定強度とを、個別の試料に依存しないそれぞれの検出系に固有の予め求めてある感度係数を乗ずるだけで、そのまま対比して使用できるために分析精度が向上し、かつエネルギ分散型検出手段を試料に近接させて、その感度を十分に得ることができる蛍光Ｘ線分析装置を提供することを目的とする。
【００１２】
【課題を解決するための手段】
前記目的を達成するために、本発明にかかる蛍光Ｘ線分析装置は、試料の被測定部に一次Ｘ線を照射し、この被測定部から発生する蛍光Ｘ線を検出手段で検出して分析する蛍光Ｘ線分析装置であって、前記検出手段として、分光器および第１検出器を有する波長分散型検出手段と、エネルギ分散型の第２検出器を有するエネルギ分散型検出手段とを備え、前記試料の被測定部と前記分光器との間の第１の蛍光Ｘ線の通路が前記試料の表面となす角度と、前記試料の被測定部と前記エネルギ分散型の第２検出器との間の第２の蛍光Ｘ線の通路が前記試料の表面となす角度とが等しく、前記第２の蛍光Ｘ線の通路が前記第１の蛍光Ｘ線の通路よりも短い。
【００１３】
この構成によれば、波長分散型の取り出し角がエネルギ分散型の検出器の取り出し角と等しいので、それぞれ測定した蛍光Ｘ線強度は、個別の試料に依存しないそれぞれの検出系に固有の予め求めてある感度係数を乗ずるだけで、そのまま対比して使用できる。したがって、取り出し角度に対する蛍光Ｘ線強度の複雑な相関関係に起因する不確定さを抑制でき、分析精度が向上する。また、エネルギ分散型の第２検出器が分光器よりも試料に接近しているため、第２検出器を試料１に接近させることができる。したがって、試料の微小部位の蛍光Ｘ線を測定する場合でも、波長分散型検出手段を備えないエネルギ分散型検出手段のみの装置と同様に、十分な感度を得られ、分析精度が向上する。
【００１４】
しかも、本発明にかかる蛍光Ｘ線分析装置では、前記第１の蛍光Ｘ線の通路と前記第２の蛍光Ｘ線の通路とは同一軸上にあり、さらに、前記エネルギ分散型の第２検出器を前記第１の蛍光Ｘ線の通路に進退させる検出器用移動機構を備えている。この構成によれば、たとえ試料表面に微小な凹凸があって、試料表面が粗い場合でも、第１の蛍光Ｘ線の通路と第２の蛍光Ｘ線の通路とは同一軸上なので、エネルギ分散型検出手段の第２検出器と波長分散型検出手段の分光器とが試料の被測定部を同一の方向から見込むため、両方の測定結果にばらつきはなく、それぞれの測定結果を、個別の試料に依存しないそれぞれの検出系に固有の予め求めてある感度係数を乗ずるだけで、そのまま対比して使用できる。また、分光器と試料との間の蛍光Ｘ線の通路にエネルギ分散型の第２検出器が進退自在であるため、第２検出器を蛍光Ｘ線の通路に進入させた時に、試料１に近づけることができ、波長分散型検出手段を備えないエネルギ分散型検出手段のみの装置と同様に、十分な感度を得られ、分析精度が向上する。
【００１５】
本発明の好ましい実施形態では、前記エネルギ分散型の第２検出器と前記試料との間に、第１のコリメータが設けられ、この第１のコリメータの少なくとも１つの絞り孔を通過する蛍光Ｘ線は、前記エネルギ分散型の第２検出器で検出されるか、または前記分光器で分光されて前記第１検出器で検出される。この構成によれば、第１のコリメータの絞り孔を、エネルギ分散型検出手段および波長分散型検出手段の両方で共用するので、試料の同一の被測定部をエネルギ分散および波長分散の両方で分析することができる。したがって、微小部位からの強度の微弱な蛍光Ｘ線について、エネルギ分散型検出手段によって、短時間に波長分布特性を調べた後、必要な波長範囲においてのみ、分解能の高い波長分散型検出手段で強度を測定できるので、試料の微小部位について迅速かつ正確に分析できる。
【００１６】
本発明の好ましい実施形態では、前記第１のコリメータと前記分光器との間に絞り孔を有する第２のコリメータが設けられ、この第２のコリメータに前記エネルギ分散型の第２検出器が取り付けられている。この構成によれば、第２のコリメータの絞り孔を、試料と分光器との間の第１の蛍光Ｘ線の通路に位置させれば、第２のコリメータは視野制限絞りとしての役割を果たす。一方、第２のコリメータに取り付けられた第２検出器を、試料と分光器との間の第１の蛍光Ｘ線の通路に位置させれば、第２のコリメータは第２検出器の支持部材としての役割を果たす。また、第２のコリメータには、エネルギ分散型の第２検出器を蛍光Ｘ線通路に進退させる検出器用移動機構が取り付けられているので、第２のコリメータの絞り孔もこの移動機構によって第１の蛍光Ｘ線の通路に移動され、第２のコリメータが複数の絞り孔を有している場合でも、絞り孔相互間の切り換えは容易にできる。
【００１７】
本発明の好ましい実施形態では、前記被測定部を移動させる試料用移動機構を備える。この構成によれば、試料用移動機構によって、試料中の任意の部位である被測定部に、常に一定の強度分布で一次Ｘ線を照射することができる。したがって、試料の微小部位の迅速かつ正確な分析を、試料中の任意の部位について容易に行うことができる。
【００１８】
本発明の別の実施形態では、前記分光器が、蛍光Ｘ線の通路に沿って前後１対の分光結晶を配置した２結晶分光器である。
【００１９】
この構成によれば、エネルギ分散型の検出器で定性分析を行ってから、波長分散型の検出器で化学状態分析を行うことができる。この場合、１結晶分光器の波長分散型の検出器で定性分析を行うのに比べて、定性分析から化学状態分析への切り換えの時間が短縮され、かつ簡便となる。
【００２０】
【発明の実施の形態】
以下、本発明の基礎となる提案例および本発明の好適な実施形態を図面にしたがって説明する。
図１に、本発明の基礎となる提案例にかかる蛍光Ｘ線分析装置を示す。この装置は、試料１が固定される試料台２と、試料１の被測定部１ａに傾斜して１次Ｘ線３を照射するＸ線源４とを備える。この装置は、また、試料１の被測定部１ａから発生する蛍光Ｘ線５を検出する検出手段として、平行化のためのソーラスリット７、分光器８、第１検出器９、およびこれらを一定の位置関係で回動させる図示しないゴニオメータ等を有する波長分散型検出手段６を備える。なお、波長分散型検出手段６は、必ずしもソーラスリット７を通して平行ビームを取り出す平行法のものである必要はなく、いわゆる集中法のものでもよい。その場合は、湾曲結晶を分光器として用い、焦点の位置に検出器が設置され、平行化のためのソーラスリット７は備えない。
【００２１】
この装置は、検出手段として、さらに、エネルギ分散型の第２検出器、例えばＳＳＤ（半導体検出器）１２を有するエネルギ分散型検出手段１１も備える。ＳＳＤ１２には、ペルチェ素子を用いた冷却手段１３が設けられている。ペルチェ素子１３に接続された図示しない導線は、分析チャンバ（図示せず）の外部にまで延びており、ペルチェ素子１３に電流を流すための増幅器などの電気回路は、分析チャンバの外部に設けられている。ＳＳＤの冷却には、一般的には液体窒素が用いられので、デュアー瓶を備えるために装置の規模が大きくなるが、本提案例のようにペルチェ素子を冷却手段とすることで、装置の規模を小さくすることができる。
【００２２】
試料１の被測定部１ａと分光器８との間の第１の蛍光Ｘ線の通路８１が試料１の表面となす角度θ１は、試料１の被測定部１ａとＳＳＤ１２との間の第２の蛍光Ｘ線の通路８２が試料１の表面となす角度θ２と等しい。但し、θ１とθ２とは厳密に等しくなくてもよく、以下の（１）式を満たせばよい。
｜ｓｉｎθ１−ｓｉｎθ２｜＜０．０５×｜ｓｉｎθ１｜ …（１）
また、第２の蛍光Ｘ線の通路８２は、第１の蛍光Ｘ線の通路８１よりも短い。すなわち、ＳＳＤ１２は、分光器８よりも試料に接近している。
【００２３】
第１の蛍光Ｘ線の通路８１にはコリメータ２０が設けられ、第２の蛍光Ｘ線通路８２にもコリメータ２１が設けられている。それぞれのコリメータ２０，２１の絞り孔２０ａ，２１ａは同一の径で、試料１の被測定部１ａの同一部位を異なる方向から見込む。
【００２４】
次に、この装置の動作について説明する。
Ｘ線源４から１次Ｘ線３を照射して試料１から蛍光Ｘ線５が発生すると、蛍光Ｘ線５は絞り孔２０ａ，２１ａを通過する。次に、エネルギ分散型検出手段１１および波長分散型検出手段６で検出した蛍光Ｘ線５は、それぞれの波高分析器（図示せず）に接続されたコンピュータ（図示せず）で処理される。
【００２５】
本装置においては、波長分散型の取り出し角θ１がエネルギ分散型の検出器の取り出し角θ２と等しいので、それぞれ測定した蛍光Ｘ線強度は、個別の試料に依存しないそれぞれの検出系に固有の予め求めてある感度係数を乗ずるだけで、そのまま対比して使用できる。したがって、コンピュータにおける分析結果の処理は、取り出し角度に対する蛍光Ｘ線強度の複雑な相関関係を考慮せず行うことができる。これにより、取り出し角度に対する蛍光Ｘ線強度の複雑な相関関係に起因する不確定さを抑制でき、分析精度が向上する。
【００２６】
例えば、ファンダメンタル・パラメータ法は、理論から求めた蛍光Ｘ線強度と実測した蛍光Ｘ線強度とを対比して、試料の被測定部の元素の含有率を決める方法である。コンピュータでは、実測した蛍光Ｘ線強度に物理定数や装置定数による補正を加えて理論強度と対比し、試料の被測定部の元素の含有率を求めて、分析結果を処理する。本提案例では、エネルギ分散型検出手段１１および波長分散型検出手段６のそれぞれによって測定した蛍光Ｘ線強度に、同一の補正を加えて理論強度と対比すればよいので、コンピュータにおける処理が簡易になる。また、ＳＳＤ１２が分光器８よりも試料１に接近しているので、試料１の被測定部１ａが微小でも、ＳＳＤ１２にとって十分な感度を得られ、分析精度が向上する。
【００２７】
試料台２は、図示しないＸＹテーブル上に載置されて移動し、被測定部１ａを最適な照射位置に設定する。ＸＹテーブルについては、後述の第１実施形態で詳しく説明する。
【００２８】
次に、本発明の第１実施形態について説明する。
図２に示すように、この装置も前記提案例と同様に、試料１が固定される試料台２と、Ｘ線源４と、ソーラスリット７、分光器８、および第１検出器９等を有する波長分散型検出手段６とを備える。試料１と検出手段６との間の蛍光Ｘ線の通路８１には、平板状の第１のコリメータ３０が設けられている。図３に示すように、第１のコリメータ３０は、異なる径の絞り孔３１ａ，３１ｂ，３１ｃを有する。第１のコリメータ３０は平板状に限らず、試料１から発生する蛍光Ｘ線のＳ／Ｎ比を向上させるために、特願平１０−３１００５６号に示すように、上壁を有するものや、試料側の壁が段状のものなど、いかなる形状でもよい。また、第１のコリメータ３０と分光器８との間には、絞り孔４１ａ，４１ｂを有する平板状の第２のコリメータ４０が設けられている。
【００２９】
さらに、この装置は、検出手段として、エネルギ分散型の第２検出器であるＳＳＤ１２を有するエネルギ分散型検出手段１１も備える。ＳＳＤ１２は、第２のコリメータ４０において、絞り孔４１ａ，４１ｂの側方に取り付けられている。このＳＳＤ１２は、第１のコリメータ３０の絞り孔３１ａ，３１ｂ，３１ｃのいずれかで絞った蛍光Ｘ線５を検出することができる。ＳＳＤ１２には、前記提案例と同様に、ペルチェ素子を用いた冷却手段１３が設けられている。絞り孔４１ａ，４１ｂの両方を備えた第２のコリメータ４０を割愛し、ＳＳＤ１２のみを第１のコリメータ３０の後方で第１の蛍光Ｘ線の通路８１に進退自在に配置してもよい。
【００３０】
図２に示すように、ＳＳＤ１２には、第１の蛍光Ｘ線の通路８１に進退自在とするための検出器用移動機構５０が取り付けられている。検出器用移動機構５０は、第２のコリメータ４０の下部に取り付けられたラック５１と、パルスモータ５３に連結されたピニオン５２とからなる。第２のコリメータ４０は図示しないガイド体に移動自在に取り付けられ、ラック５１がピニオン５２とかみ合っているので、パルスモータ５３の駆動によって、図示しないガイド体に沿って第２のコリメータ４０はＹ方向にスライドすることができる。これにより、試料１の被測定部１ａと分光器８との間の第１の蛍光Ｘ線の通路８１と、試料１の被測定部１ａとエネルギ分散型の検出器であるＳＳＤ１２との間の第２の蛍光Ｘ線の通路８２とは同一軸上となる。
【００３１】
第１のコリメータ３０も紙面垂直方向Ｙに延びた図示しないガイド体に移動自在に取り付けられている。コリメータ３０の下部にはラック６１が取り付けられ、パルスモータ６３に連結されたピニオン６２とかみ合っている。したがって、第１のコリメータ３０も、第２のコリメータ４０と同様に、パルスモータ６３の駆動によって、図示しないガイド体に沿ってＹ方向にスライドすることができる。
【００３２】
この装置は、試料１の被測定部１ａを移動させるＸＹステージのような試料用移動機構７０を備え、試料台２は、試料用移動機構７０の上部７０ａに固定されている。ＸＹステージ上部７０ａは、下部７０ｂに対して左右方向Ｘに移動自在に設置され、ＸＹステージ下部７０ｂは、その下のベース７１に対し、Ｙ方向に移動自在に設置されている。つまり、ＸＹは、仮想照射面内に設定された直交座標である。なお、試料用移動機構７０は、ｒθステージでもよい。この場合、ｒθは、仮想照射面内に設定されて、試料表面１ａの中心点を極とする極座標である。
【００３３】
第２のコリメータ４０、第１のコリメータ３０、およびＸＹステージ７０は、制御手段７２によって制御される。まず、制御手段７２は、エネルギ分散型検出手段１１によって蛍光Ｘ線を検出するか、または波長分散型検出手段６によって蛍光Ｘ線を検出するかに応じて、第２のコリメータ４０を制御する。すなわち、エネルギ分散型検出手段１１によって検出するのであれば、第２のコリメータ４０に取り付けられたＳＳＤ１２を第１の蛍光Ｘ線の通路８１に進入させる。一方、波長分散型検出手段６によって検出するのであれば、第２のコリメータ４０を第１の蛍光Ｘ線の通路８１から退避させる。
【００３４】
また、制御手段７２は、試料１の被測定部１ａの大きさに応じて、被測定部１ａから発生した蛍光Ｘ線５のみを検出手段６に入射させるように、コリメータの絞り孔を選択して、第１および第２のコリメータ３０，４０の位置を制御する。エネルギ分散型検出手段１１による検出であれば、第１のコリメータ３０の絞り孔３１ａ，３１ｂ，３１ｃのいずれかを選択し、波長分散型検出手段６による検出であれば、第１のコリメータ３０の絞り孔３１ａ，３１ｂ，３１ｃまたは第２のコリメータ４０の絞り孔４１ａ，４１ｂのいずれかを選択して、第１のコリメータ３０または第２のコリメータ４０を移動させるパルスモータ５３，６３を制御する。
【００３５】
さらに、制御手段７２は、試料１被測定部１ａを移動させるために、試料台２を移動させるようにＸＹステージ７０を制御する。
【００３６】
次に、この装置の動作について説明する。
ここで、試料１の被測定部１ａは微小部位であり、その未知の元素の蛍光Ｘ線分析を行うこととする。すなわち、被測定部１ａの定性分析をした後、定量分析を行う。
まず、図２に示すように、試料１を試料台２に中心を一致させて固定する。そして、試料１の被測定部１ａを決定し、その旨を制御手段７２に入力する。また、定性分析、つまりエネルギ分散型の検出を行う旨、および被測定部の径の大きさも制御手段７２に入力する。
【００３７】
これらを入力すると、制御手段７２は、一次Ｘ線３の照射位置に試料１の被測定部１ａが合致する位置に試料台２を移動させるように、ＸＹステージ７０を制御する。制御手段７２は、また、ＳＳＤ１２が第１の蛍光Ｘ線の通路８１に位置するように、第２のコリメータ４０を進入させるためにパルスモータ５３を制御する。パルスモータ５３の回転により、第２のコリメータ４０はＹ方向に移動して試料１と波長分散型検出手段６との間の第１の蛍光Ｘ線の通路８１に進入する。また、制御手段７２は、入力された被測定部の径の大きさに対応する第１のコリメータ３０の絞り孔３１ａ（図３）が選択されるよう、すなわち、試料１の被測定部１ａから発生した蛍光Ｘ線５のみをＳＳＤ１２に入射させるようにパルスモータ６３を制御する。パルスモータ６３の回転により、第１のコリメータ３０の孔３１ａは試料１と波長分散型検出手段６との間の第１の蛍光Ｘ線の通路８１に進入する。
【００３８】
図３に示すように、この状態でＸ線源４から１次Ｘ線３を照射して試料１から蛍光Ｘ線５が発生すると、蛍光Ｘ線５は第１のコリメータ３０の絞り孔３１ａを通過して、ＳＳＤ１２で検出される。この検出した蛍光Ｘ線強度は、図示しないコンピュータで処理され、短時間に波長分布特性が得られ、定性分析を行うことができる。被測定部１ａは微小部位であるが、ＳＳＤ１２が分光器８よりも試料１に接近しているので、ＳＳＤ１２において十分な感度を得られ、分析精度が向上する。
【００３９】
このように波長分布特性を調べた後は、図４に示すように、第２のコリメータ４０を第１の蛍光Ｘ線の通路８１から退避させる。次に、この波長分布特性を基に測定が必要な波長が決定され、その波長に応じた蛍光Ｘ線を分光して検出するために、分光器８と第１検出器９の位置を図示しないゴニオメータが調節する。この状態で、試料１から発生した蛍光Ｘ線５は、第１のコリメータ３０の絞り孔３１ａを通過し、ソーラスリット７で平行化され、分光器８で分光されて、第１検出器９で検出される。この検出した蛍光Ｘ線強度は、図示しないコンピュータで処理され、所望の詳細に分析すべき波長範囲における分析、つまり、定量分析をすることができる。
【００４０】
以上のように定性分析をエネルギ分散型検出手段１１で行い、この後に特定の元素の定量分析を波長分散型検出手段６で行うので、迅速かつ正確な蛍光Ｘ線分析ができる。
【００４１】
このように、第１の蛍光Ｘ線の通路８１と第２の蛍光Ｘ線の通路８２とは同一軸上にあるので、たとえ試料１の表面に微小な凹凸があって、試料１の表面が粗い場合でも、エネルギ検出手段１１の第２検出器であるＳＳＤ１２と波長分散型検出手段６の分光器８とが試料１の被測定部１ａを同一の方向から見込むため、両方の測定結果にばらつきはなく、それぞれの測定結果を、個別の試料に依存しないそれぞれの検出系に固有の予め求めてある感度係数を乗ずるだけで、そのまま対比して使用できる。これにより、分析精度が向上する。その上、第１のコリメータ３０の絞り孔３１ａを、エネルギ分散型検出手段１１および波長分散型検出手段６の両方で共用するので、上述のように、エネルギ分散型検出手段１１による定性分析の結果に基づいて、波長分散型検出手段６による定量分析を行うことができる。
【００４２】
また、本実施形態において、試料１の大きい被測定部位１ａから発生する蛍光Ｘ線を波長分散型検出手段８で検出して分析する場合は、第１のコリメータ３０は第１の蛍光Ｘ線の通路８１から退避させ、第２のコリメータ４０の絞り孔４１ａまたは４１ｂのいずれかを第１の蛍光Ｘ線の通路８１に進入させる。これは、第２のコリメータ４０をＹ方向へ移動させるために、ＳＳＤ１２を第１の蛍光Ｘ線の通路８１に進入させる場合と同様に、移動機構５０を制御手段７２が制御して行うので、絞り孔４１ａ，４１ｂの相互間の切り換えは容易である。
【００４３】
次に、本発明の第２実施形態について説明する。
図５に示すように、本実施形態の装置が第１実施形態と異なる点は、波長分散型検出手段６が１結晶分光器ではなく、第１分光結晶素子８ａおよび第２分光結晶素子８ｂを第１の蛍光Ｘ線の通路８１に沿って前後１対に配置した２結晶分光器８を有することである。２結晶分光器８は、第１分光結晶素子８ａで分光された蛍光Ｘ線を第２分光結晶素子８ｂでさらに分光するので、波長分解能が非常に高く、化学状態による蛍光Ｘ線波長の微小な変化を検出できるので、化学状態分析に用いることができる。本装置では、エネルギ分散型検出手段１１で定性分析を行うことができるとともに、２結晶分光器８を有する波長分散型検出手段６で化学状態分析を行うことができる。この場合、１結晶分光器の波長分散型の検出器で定性分析を行うのに比べて、定性分析から化学状態分析への切り換えの時間が短縮され、かつ簡便となる。また、２結晶分光器のみでは、後段側の結晶の回動範囲が制限されるという機構的な制約から、測定できる波長の範囲に制限があったが、このようにエネルギ分散型検出手段１１を組み合わせることで、特定の元素の化学状態のみを調べたい場合であっても、共存元素の波長領域まで分析が可能であるため、共存元素の組成の情報も得ることができ、十分な定性分析が可能である。
【００４４】
【発明の効果】
以上のように、本発明によれば、波長分散型の取り出し角がエネルギ分散型の検出器の取り出し角と等しいので、それぞれ測定した蛍光Ｘ線強度は、個別の試料に依存しないそれぞれの検出系に固有の予め求めてある感度係数を乗ずるだけで、そのまま対比して使用できる。したがって、取り出し角度に対する蛍光Ｘ線強度の複雑な相関関係に起因する不確定さを抑制でき、分析精度が向上する。また、エネルギ分散型の第２検出器が分光器よりも試料に接近しているため、第２検出器を試料１に接近させることができる。したがって、試料の微小部位の蛍光Ｘ線を測定する場合でも、波長分散型検出手段を備えないエネルギ分散型検出手段のみの装置と同様に、十分な感度を得られ、分析精度が向上する。
【図面の簡単な説明】
【図１】本発明の基礎となる提案例にかかる蛍光Ｘ線分析装置の斜視図である。
【図２】本発明の第１実施形態にかかる蛍光Ｘ線分析装置の概略側面図である。
【図３】同蛍光Ｘ線分析装置のエネルギ分散型検出を示す斜視図である。
【図４】同蛍光Ｘ線分析装置の波長分散型検出を示す斜視図である。
【図５】本発明の第２実施形態にかかる蛍光Ｘ線分析装置の概略側面図である。
【図６】従来の蛍光Ｘ線分析装置の概略側面図である。
【図７】従来の蛍光Ｘ線分析装置の概略側面図である。
【符号の説明】
１…試料、１ａ…被測定部、３…一次Ｘ線、５…蛍光Ｘ線、６…波長分散型検出手段、８…分光器、９…第１検出器、１１…エネルギ分散型検出手段、１２…第２検出器、３０…第１のコリメータ、３１ａ，３１ｂ，３１ｃ…第１のコリメータの絞り孔、４０…第２のコリメータ、４１ａ，４１ｂ…第２のコリメータの絞り孔、５０…検出器用移動機構、７０…試料用移動機構、８１…第１の蛍光Ｘ線の通路、８２…第２の蛍光Ｘ線の通路。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an X-ray fluorescence spectrometer that can be used both as a wavelength dispersive type and an energy dispersive type.
[0002]
[Prior art]
The X-ray fluorescence analyzer irradiates a measurement target portion of a sample with primary X-rays, detects fluorescent X-rays generated from the measurement target portion by a detecting means, and analyzes elements in the measurement target portion. . As the detection means, there are a wavelength dispersion type detection means and an energy dispersion type detection means.
[0003]
The wavelength dispersion type detection means is excellent in wavelength resolution, but has a feature that it takes a long time to measure the intensity of fluorescent X-rays in a wide range of wavelengths. On the other hand, the energy dispersive detection means is inferior in resolution to the wavelength dispersive detection means, but is characterized in that it can simultaneously measure the intensity of fluorescent X-rays in a wide range of wavelengths. Therefore, the energy dispersive type detecting means is suitable for examining the rough wavelength distribution characteristics in a short time, and the wavelength dispersive type detecting means is suitable for performing high resolution X-ray fluorescence analysis in a narrow wavelength range. ing. Thus, if the energy dispersion type detection means and the wavelength dispersion type detection means are properly used according to the purpose of the analysis, efficient analysis can be performed. If the qualitative analysis is performed by the energy dispersive detector and the quantitative analysis of a specific element is performed by the wavelength dispersive detector after that, X-ray fluorescence analysis can be performed quickly and accurately even on a completely unknown sample.
[0004]
An X-ray analyzer that has both a wavelength dispersion type detection unit and an energy dispersion type detection unit and can detect X-rays by any of the detection units is already known.
The X-ray analyzer disclosed in Japanese Patent Application Laid-Open No. 5-281163 irradiates primary X-rays 3 from an X-ray tube 4 as shown in FIG. The secondary X-rays 5 are collimated by the solar slit 7, separated by the spectroscope 8 and detected by the detector 9, and the secondary X-rays 5 are also taken into the energy dispersive detector 12 to perform X-ray analysis.
[0005]
The X-ray fluorescence analyzer disclosed in Japanese Patent Application Laid-Open No. H10-206356 irradiates primary X-rays 3 from an X-ray tube 4 as shown in FIG. The generated fluorescent X-rays 5 are separated by the spectroscope 8 and taken into the detector 9. The spectroscope 8 can be moved, for example, in the direction of arrow A and retracted from the path of the fluorescent X-rays 5. When the spectroscope 8 retreats from the path of the fluorescent X-rays 5, the energy-dispersive detector 12 takes in the fluorescent X-rays 5, and the wavelength-dispersive detection is switched to the energy-dispersive detection.
[0006]
[Problems to be solved by the invention]
However, in the case of the X-ray analyzer shown in FIG. 6, the angle formed by the first fluorescent X-ray passage 81 between the sample 1 and the spectroscope 8 with the surface of the sample 1, that is, the take-out angle of the wavelength-dispersive detection. The angle θ1 is different from the angle formed by the second fluorescent X-ray path 82 between the sample 1 and the energy dispersive detector 12 with the surface of the sample 1, that is, the energy dispersive take-out angle θ2. In other words, in order to increase the intensity of the energy dispersive detector 12, which tends to decrease the intensity of the incident fluorescent X-ray due to the small light receiving area, as much as possible, the extraction of the energy dispersive detector 12 is performed. The corner is enlarged.
[0007]
By the way, in the X-ray analysis, the intensity of the X-ray to be measured depends on the extraction angle, and the correlation is complicated. Therefore, when the wavelength dispersion type take-out angle θ1 and the energy dispersion type detector take-out angle θ2 are different from each other, the respective measured intensities cannot be directly compared, and correction based on the take-out angle is performed. However, since the correlation of the X-ray intensity with respect to the take-out angle is complicated depending on the sample composition, it is not accurately corrected, and the analysis accuracy is not improved due to the uncertainty. Furthermore, when the sample surface has minute irregularities and the sample surface is rough, even if the take-out angles are the same, if the spectroscope or the detector looks at the part to be measured of the sample from different directions, the X-ray wavelength Since the distribution characteristics vary, the respective measurement results cannot be directly compared.
[0008]
On the other hand, in the case of the fluorescent X-ray analyzer shown in FIG. 7, the first fluorescent X-ray passage 81 and the second fluorescent X-ray passage 82 are on the same axis, and the energy-dispersive detection is performed. Since the take-out angle is equal to the take-out angle of the wavelength-dispersive detection at θ1, the energy-dispersive X-ray intensity and the wavelength-dispersive X-ray intensity are obtained in advance in a manner unique to each detection system independent of an individual sample. By simply multiplying by a certain sensitivity coefficient, it can be used as it is for comparison.
[0009]
However, like a semiconductor detector (SSD) having a relatively good energy resolution, an energy dispersive detector generally has a small light receiving area, so that the energy dispersive detector 12 must be brought close to the sample 1. The sensitivity decreases. In an X-ray fluorescence spectrometer equipped only with an energy dispersive detector, it is possible to approach the sample because it does not have a spectroscope. However, in the case of the X-ray fluorescence spectrometer shown in FIG. Since the spectroscope 8 is located between the dispersive detector 12 and the dispersive detector 12, the energy dispersive detector 12 cannot be brought close to the sample 1. Therefore, in the energy dispersive type detection, the sensitivity is lowered. In particular, when detecting fluorescent X-rays in a minute portion of the sample, there is a problem that the sensitivity required for the analysis cannot be sufficiently obtained.
[0010]
On the other hand, conventionally, qualitative analysis has been performed by a wavelength-dispersion detecting means having a single crystal spectroscope having only one spectroscopic element, and then analysis of the chemical state has been performed by using a two crystal spectroscope having two spectroscopic elements. X-ray fluorescence analysis performed by the wavelength dispersive detection means is employed. The use of the two-crystal spectrometer in this manner is because the two-crystal spectrometer has a higher wavelength resolution than the one-crystal spectrometer, and thus can detect a change in the wavelength of the fluorescent X-ray due to the chemical state in the chemical state analysis. It is. However, in the case of this apparatus, in order to change from a single-crystal spectroscope to a two-crystal spectroscope in which a pair of front and rear spectroscopic crystals are arranged along the path of fluorescent X-rays, it is necessary to exchange parts and the like. It was troublesome. In the wavelength dispersion type detection means having a two-crystal spectroscope, the range of wavelengths that can be measured is limited due to the mechanical restriction that the rotation range of the subsequent crystal is limited. When it is desired to examine only the state, it is not possible to perform a sufficient qualitative analysis because it is not possible to scan up to the wavelength region of the coexisting element, although information on the composition of the coexisting element may be required.
[0011]
Therefore, the present invention obtains in advance the measurement intensity of the fluorescent X-rays by the wavelength dispersion type detection means and the measurement intensity of the fluorescent X-rays by the energy dispersion type detection means, which is unique to each detection system independent of an individual sample. An X-ray fluorescence spectrometer that can improve the analysis accuracy because it can be used as it is by simply multiplying it by a certain sensitivity coefficient, and can obtain sufficient sensitivity by bringing the energy dispersive detection means close to the sample The purpose is to provide.
[0012]
[Means for Solving the Problems]
To achieve the above objectives,ClearlySuch an X-ray fluorescence spectrometer is an X-ray fluorescence spectrometer that irradiates primary portions of a sample to be measured with primary X-rays and detects and analyzes the fluorescent X-rays generated from the portion to be measured by a detection means, As a detection means, a wavelength dispersion type detection means having a spectroscope and a first detector, and an energy dispersion type detection means having an energy dispersion type second detector are provided. And the angle between the first fluorescent X-ray path and the surface of the sample, and the path of the second fluorescent X-ray between the measured portion of the sample and the energy dispersive second detector The angle formed by the surface of the sample is equal, and the path of the second fluorescent X-ray is shorter than the path of the first fluorescent X-ray.
[0013]
According to this configuration, since the take-out angle of the wavelength dispersion type is equal to the take-out angle of the energy dispersive type detector, the measured fluorescent X-ray intensity can be obtained in advance, which is unique to each detection system independent of an individual sample. By simply multiplying by a certain sensitivity coefficient, it can be used as it is. Therefore, it is possible to suppress uncertainty due to a complicated correlation of the fluorescent X-ray intensity with respect to the take-out angle, and to improve the analysis accuracy. Further, since the energy dispersive second detector is closer to the sample than the spectroscope, the second detector can be closer to the sample 1. Therefore, even in the case of measuring the fluorescent X-rays of a minute portion of the sample, sufficient sensitivity can be obtained and the analysis accuracy can be improved, as in the case of the apparatus having only the energy dispersive type detecting means without the wavelength dispersive type detecting means.
[0014]
Moreover, the fluorescent X-ray analyzer according to the present inventionIn the above, the path of the first fluorescent X-ray and the path of the second fluorescent X-ray are on the same axis, and the energy dispersive type second detector is connected to the path of the first fluorescent X-ray. And a detector moving mechanism for moving forward and backward. According to this configuration, even if the sample surface has minute irregularities and the sample surface is rough, the path of the first fluorescent X-ray and the path of the second fluorescent X-ray are on the same axis. Since the second detector of the type detection means and the spectroscope of the wavelength dispersion type detection means look at the portion to be measured of the sample from the same direction, there is no variation in both measurement results. Can be used as it is by simply multiplying by a previously obtained sensitivity coefficient unique to each detection system that does not depend on. In addition, since the energy dispersive type second detector can freely move in and out of the fluorescent X-ray path between the spectroscope and the sample, when the second detector enters the fluorescent X-ray path, the sample 1 In this case, sufficient sensitivity can be obtained and the analysis accuracy can be improved, as in the case of the apparatus having only the energy dispersive type detecting means which does not include the wavelength dispersive type detecting means.
[0015]
In a preferred embodiment of the present invention, a first collimator is provided between the energy dispersive second detector and the sample, and a fluorescent X-ray passing through at least one aperture of the first collimator is provided. Is detected by the energy dispersive type second detector, or separated by the spectroscope and detected by the first detector. According to this configuration, since the aperture of the first collimator is shared by both the energy dispersive type detecting means and the wavelength dispersive type detecting means, the same measured portion of the sample is analyzed by both the energy dispersive type and the wavelength dispersive type. can do. Therefore, for the fluorescent X-rays having weak intensity from the minute part, the wavelength distribution characteristics are examined in a short time by the energy dispersive type detecting means, and then, only in the necessary wavelength range, the intensity is detected by the wavelength dispersive type detecting means having a high resolution. Can be measured, so that a minute portion of the sample can be analyzed quickly and accurately.
[0016]
In a preferred embodiment of the present invention, a second collimator having an aperture is provided between the first collimator and the spectroscope, and the energy dispersive type second detector is attached to the second collimator. Have been. According to this configuration, if the aperture of the second collimator is located in the path of the first X-ray fluorescence between the sample and the spectroscope, the second collimator plays a role as a field limiting aperture. . On the other hand, if the second detector attached to the second collimator is located in the path of the first X-ray fluorescence between the sample and the spectroscope, the second collimator can support the second detector. Play a role. Further, since the second collimator is provided with a detector moving mechanism for moving the energy dispersive type second detector into and out of the fluorescent X-ray path, the aperture of the second collimator is also moved to the first collimator by the first moving mechanism. And the second collimator has a plurality of apertures, it is possible to easily switch between the apertures.
[0017]
In a preferred embodiment of the present invention, a sample moving mechanism for moving the measured portion is provided. According to this configuration, the measurement portion, which is an arbitrary portion in the sample, can always be irradiated with the primary X-ray with a constant intensity distribution by the sample movement mechanism. Therefore, quick and accurate analysis of a micro site of a sample can be easily performed for any site in the sample.
[0018]
Of the present inventionIn another embodimentIsThe spectroscope is a two-crystal spectroscope in which a pair of front and rear spectroscopic crystals are arranged along a fluorescent X-ray path.
[0019]
According to this configuration, the qualitative analysis can be performed by the energy dispersive detector, and then the chemical state analysis can be performed by the wavelength dispersive detector. In this case, the time for switching from qualitative analysis to chemical state analysis is shorter and simpler than performing qualitative analysis with a wavelength-dispersive detector of a single crystal spectrometer.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Less than,Proposal examples based on the present invention andA preferred embodiment of the present invention will be described with reference to the drawings.
FIG.Examples of basic proposals1 shows a fluorescent X-ray analyzer according to the first embodiment. This apparatus includes a sample table 2 on which a sample 1 is fixed, and an X-ray source 4 for irradiating a measured portion 1a of the sample 1 with a primary X-ray 3 while being inclined. This device also includes a solar slit 7 for collimation, a spectroscope 8, a first detector 9, and a fixed unit for detecting X-ray fluorescence 5 generated from the measured portion 1a of the sample 1. Is provided with a wavelength dispersion type detecting means 6 having a goniometer and the like (not shown) to be rotated in the positional relationship of (1). The wavelength dispersion type detection means 6 does not necessarily need to be a parallel method for extracting a parallel beam through the solar slit 7, but may be a so-called concentrated method. In that case, a curved crystal is used as a spectroscope, a detector is installed at the position of the focal point, and the solar slit 7 for parallelization is not provided.
[0021]
The apparatus further includes an energy dispersive type detector 11 having an energy dispersive type second detector, for example, an SSD (semiconductor detector) 12, as a detector. The SSD 12 is provided with a cooling unit 13 using a Peltier device. A lead (not shown) connected to the Peltier element 13 extends to the outside of the analysis chamber (not shown), and an electric circuit such as an amplifier for flowing a current to the Peltier element 13 is provided outside the analysis chamber. ing. Since liquid nitrogen is generally used for cooling the SSD, the size of the device becomes large to provide a Dewar bottle.Proposal exampleBy using the Peltier element as the cooling means as described above, the size of the apparatus can be reduced.
[0022]
The angle θ1 formed by the first fluorescent X-ray path 81 between the measured portion 1a of the sample 1 and the spectroscope 8 with the surface of the sample 1 is the second angle between the measured portion 1a of the sample 1 and the SSD 12. Is equal to the angle θ2 formed by the fluorescent X-ray path 82 with the surface of the sample 1. However, θ1 and θ2 do not have to be strictly equal, and may satisfy the following expression (1).
| Sin θ1−sin θ2 | <0.05 × | sin θ1 | (1)
The second fluorescent X-ray path 82 is shorter than the first fluorescent X-ray path 81. That is, the SSD 12 is closer to the sample than the spectroscope 8.
[0023]
The collimator 20 is provided in the first fluorescent X-ray path 81, and the collimator 21 is also provided in the second fluorescent X-ray path 82. The apertures 20a and 21a of the respective collimators 20 and 21 have the same diameter, and look at the same part of the measured portion 1a of the sample 1 from different directions.
[0024]
Next, the operation of this device will be described.
When the primary X-ray 3 is irradiated from the X-ray source 4 and the fluorescent X-ray 5 is generated from the sample 1, the fluorescent X-ray 5 passes through the apertures 20a and 21a. Next, the fluorescent X-rays 5 detected by the energy dispersive type detecting means 11 and the wavelength dispersive type detecting means 6 are processed by computers (not shown) connected to respective wave height analyzers (not shown).
[0025]
In the present apparatus, since the wavelength-dispersion type take-out angle θ1 is equal to the energy-dispersion type detector take-out angle θ2, the measured fluorescent X-ray intensities are determined in advance by each of the detection systems peculiar to each detection system independent of an individual sample. By simply multiplying by a given sensitivity coefficient, it can be used as it is. Therefore, the processing of the analysis result by the computer can be performed without considering the complicated correlation of the fluorescent X-ray intensity with respect to the extraction angle. As a result, uncertainty due to a complicated correlation of the fluorescent X-ray intensity with respect to the extraction angle can be suppressed, and the analysis accuracy is improved.
[0026]
For example, the fundamental parameter method is a method of comparing the fluorescent X-ray intensity obtained from the theory and the actually measured fluorescent X-ray intensity to determine the content of the element in the measured portion of the sample. The computer corrects the measured fluorescent X-ray intensity with a physical constant or a device constant, compares the corrected X-ray intensity with the theoretical intensity, obtains the content of the element in the measured portion of the sample, and processes the analysis result. BookProposal exampleThen, the fluorescent X-ray intensity measured by each of the energy dispersive type detecting means 11 and the wavelength dispersive type detecting means 6 can be compared with the theoretical intensity by adding the same correction to the fluorescent X-ray intensity. Further, since the SSD 12 is closer to the sample 1 than the spectroscope 8, even if the measured portion 1a of the sample 1 is minute, sufficient sensitivity for the SSD 12 can be obtained, and the analysis accuracy is improved.
[0027]
The sample stage 2 is placed on an XY table (not shown) and moves, and sets the measured section 1a to an optimal irradiation position. Regarding the XY table,1The embodiment will be described in detail.
[0028]
Next, the second embodiment of the present invention1An embodiment will be described.
As shown in FIG.Proposed exampleIn the same manner as described above, the apparatus includes a sample stage 2 on which the sample 1 is fixed, an X-ray source 4, and a wavelength dispersion type detection unit 6 having a solar slit 7, a spectroscope 8, a first detector 9, and the like. A flat plate-shaped first collimator 30 is provided in a fluorescent X-ray path 81 between the sample 1 and the detection means 6. As shown in FIG. 3, the first collimator 30 has apertures 31a, 31b, and 31c having different diameters. The first collimator 30 is not limited to a flat plate, but has an upper wall as shown in Japanese Patent Application No. 10-310056 in order to improve the S / N ratio of fluorescent X-rays generated from the sample 1, The sample side wall may have any shape such as a stepped wall. Further, between the first collimator 30 and the spectroscope 8, there is provided a plate-shaped second collimator 40 having aperture holes 41a and 41b.
[0029]
Further, this device also includes, as a detecting means, an energy dispersive detecting means 11 having an SSD 12, which is an energy dispersive second detector. In the second collimator 40, the SSD 12 is attached to the side of the apertures 41a and 41b. The SSD 12 can detect the fluorescent X-ray 5 narrowed by one of the apertures 31a, 31b, 31c of the first collimator 30. In SSD12,Proposed exampleSimilarly to the above, a cooling means 13 using a Peltier element is provided. The second collimator 40 having both the apertures 41a and 41b may be omitted, and only the SSD 12 may be disposed behind the first collimator 30 in the first fluorescent X-ray passage 81 so as to be able to advance and retreat.
[0030]
As shown in FIG. 2, the SSD 12 is provided with a detector moving mechanism 50 for allowing the first fluorescent X-ray path 81 to advance and retreat. The detector moving mechanism 50 includes a rack 51 mounted below the second collimator 40 and a pinion 52 connected to a pulse motor 53. Since the second collimator 40 is movably attached to a guide body (not shown) and the rack 51 is engaged with the pinion 52, the second collimator 40 moves in the Y direction along the guide body (not shown) by driving the pulse motor 53. You can slide to. Thus, the first fluorescent X-ray path 81 between the measured section 1a of the sample 1 and the spectroscope 8 and the path between the measured section 1a of the sample 1 and the SSD 12 which is an energy dispersive detector. The second fluorescent X-ray path 82 is on the same axis.
[0031]
The first collimator 30 is also movably attached to a guide body (not shown) extending in the direction Y perpendicular to the paper surface. A rack 61 is attached to a lower portion of the collimator 30 and meshes with a pinion 62 connected to a pulse motor 63. Therefore, similarly to the second collimator 40, the first collimator 30 can slide in the Y direction along the guide body (not shown) by driving the pulse motor 63.
[0032]
This apparatus includes a sample moving mechanism 70 such as an XY stage for moving the measured portion 1a of the sample 1, and the sample table 2 is fixed to an upper portion 70a of the sample moving mechanism 70. The XY stage upper part 70a is installed movably in the left-right direction X with respect to the lower part 70b, and the XY stage lower part 70b is installed movably in the Y direction with respect to the base 71 thereunder. That is, XY is the orthogonal coordinates set in the virtual irradiation plane. The sample moving mechanism 70 may be an rθ stage. In this case, rθ is a polar coordinate set in the virtual irradiation plane and having the center point of the sample surface 1a as a pole.
[0033]
The second collimator 40, the first collimator 30, and the XY stage 70 are controlled by the control means 72. First, the controller 72 controls the second collimator 40 according to whether the energy dispersive detector 11 detects fluorescent X-rays or the wavelength dispersive detector 6 detects fluorescent X-rays. That is, if the energy is to be detected by the energy dispersive detector 11, the SSD 12 attached to the second collimator 40 is caused to enter the first fluorescent X-ray path 81. On the other hand, if it is to be detected by the wavelength dispersion type detection means 6, the second collimator 40 is retracted from the first fluorescent X-ray path 81.
[0034]
Further, the control means 72 selects the aperture of the collimator according to the size of the measured part 1a of the sample 1 so that only the fluorescent X-rays 5 generated from the measured part 1a enter the detecting means 6. Thus, the positions of the first and second collimators 30 and 40 are controlled. If the detection is performed by the energy dispersive detector 11, one of the apertures 31a, 31b, and 31c of the first collimator 30 is selected. The pulse motors 53 and 63 for moving the first collimator 30 or the second collimator 40 are controlled by selecting one of the apertures 31a, 31b and 31c or the apertures 41a and 41b of the second collimator 40.
[0035]
Further, the control means 72 controls the XY stage 70 so as to move the sample stage 2 in order to move the sample 1 measured section 1a.
[0036]
Next, the operation of this device will be described.
Here, the measured portion 1a of the sample 1 is a minute portion, and the unknown element is subjected to X-ray fluorescence analysis. That is, after performing the qualitative analysis of the measured section 1a, the quantitative analysis is performed.
First, as shown in FIG. 2, the sample 1 is fixed to the sample table 2 so that the centers thereof are aligned. Then, the portion to be measured 1a of the sample 1 is determined, and the fact is input to the control means 72. In addition, the fact that qualitative analysis, that is, energy dispersion type detection is to be performed, and the size of the diameter of the measured part are also input to the control means 72.
[0037]
When these are input, the control means 72 controls the XY stage 70 so as to move the sample stage 2 to a position where the measured portion 1a of the sample 1 matches the irradiation position of the primary X-ray 3. The control means 72 also controls the pulse motor 53 to make the second collimator 40 enter so that the SSD 12 is located in the first fluorescent X-ray path 81. By the rotation of the pulse motor 53, the second collimator 40 moves in the Y direction and enters the first fluorescent X-ray path 81 between the sample 1 and the wavelength dispersion type detection means 6. Further, the control means 72 selects the aperture 31a (FIG. 3) of the first collimator 30 corresponding to the input diameter of the measured part, that is, from the measured part 1a of the sample 1. The pulse motor 63 is controlled so that only the generated fluorescent X-rays 5 are incident on the SSD 12. By the rotation of the pulse motor 63, the hole 31a of the first collimator 30 enters the first fluorescent X-ray path 81 between the sample 1 and the wavelength dispersion type detection means 6.
[0038]
As shown in FIG. 3, in this state, when the primary X-ray 3 is irradiated from the X-ray source 4 and the fluorescent X-ray 5 is generated from the sample 1, the fluorescent X-ray 5 passes through the aperture 31 a of the first collimator 30. It passes and is detected by the SSD 12. The detected fluorescent X-ray intensity is processed by a computer (not shown), whereby a wavelength distribution characteristic can be obtained in a short time, and qualitative analysis can be performed. Although the measured portion 1a is a minute portion, since the SSD 12 is closer to the sample 1 than the spectroscope 8, sufficient sensitivity can be obtained in the SSD 12, and the analysis accuracy is improved.
[0039]
After examining the wavelength distribution characteristics in this manner, as shown in FIG. 4, the second collimator 40 is retracted from the first fluorescent X-ray passage 81. Next, the wavelength that needs to be measured is determined based on this wavelength distribution characteristic, and the positions of the spectroscope 8 and the first detector 9 are not shown in order to spectrally detect the fluorescent X-ray corresponding to the wavelength. Goniometer adjusts. In this state, the fluorescent X-rays 5 generated from the sample 1 pass through the aperture 31a of the first collimator 30, are collimated by the solar slit 7, are separated by the spectroscope 8, and are separated by the first detector 9. Is detected. The detected X-ray fluorescence intensity is processed by a computer (not shown), and analysis in a desired wavelength range to be analyzed in detail, that is, quantitative analysis can be performed.
[0040]
As described above, since the qualitative analysis is performed by the energy dispersive detector 11 and the quantitative analysis of a specific element is performed by the wavelength dispersive detector 6 after that, rapid and accurate X-ray fluorescence analysis can be performed.
[0041]
As described above, since the first fluorescent X-ray path 81 and the second fluorescent X-ray path 82 are on the same axis, even if the surface of the sample 1 has minute irregularities, Even in a rough case, the SSD 12 as the second detector of the energy detecting means 11 and the spectroscope 8 of the chromatic dispersion detecting means 6 look at the measured portion 1a of the sample 1 from the same direction, so that both measurement results vary. Instead, each measurement result can be used as it is by simply multiplying it by a predetermined sensitivity coefficient unique to each detection system independent of an individual sample. Thereby, the analysis accuracy is improved. In addition, since the aperture 31a of the first collimator 30 is shared by both the energy dispersive detector 11 and the wavelength dispersive detector 6, the result of the qualitative analysis by the energy dispersive detector 11 is as described above. The quantitative analysis by the wavelength dispersion type detection means 6 can be performed based on
[0042]
Further, in the present embodiment, when the fluorescent X-rays generated from the large measurement site 1a of the sample 1 are detected and analyzed by the wavelength-dispersive detection means 8, the first collimator 30 detects the first fluorescent X-rays. The second collimator 40 is retracted from the passage 81, and one of the apertures 41a or 41b of the second collimator 40 enters the first fluorescent X-ray passage 81. This is performed by controlling the moving mechanism 50 by the control means 72 in the same manner as when the SSD 12 enters the first fluorescent X-ray passage 81 in order to move the second collimator 40 in the Y direction. Switching between the apertures 41a and 41b is easy.
[0043]
Next, the second embodiment of the present invention2An embodiment will be described.
As shown in FIG. 5, the device of this embodiment is1The difference from the present embodiment is that the wavelength dispersion type detection means 6 is not a single crystal spectroscope but a pair of first and second spectral crystal elements 8a and 8b along the first fluorescent X-ray path 81. Is provided with the two-crystal spectroscope 8 arranged in the above. Since the two-crystal spectroscope 8 further separates the fluorescent X-rays separated by the first separating crystal element 8a with the second separating crystal element 8b, the wavelength resolution is very high and the fluorescent X-ray wavelength due to the chemical state is very small. Since the change can be detected, it can be used for chemical state analysis. In this apparatus, qualitative analysis can be performed by the energy dispersive detector 11 and chemical state analysis can be performed by the wavelength dispersive detector 6 having the two-crystal spectroscope 8. In this case, the time for switching from qualitative analysis to chemical state analysis is shorter and simpler than performing qualitative analysis with a wavelength-dispersive detector of a single crystal spectrometer. Further, with the two-crystal spectroscope alone, the range of wavelengths that can be measured was limited due to the mechanical restriction that the rotation range of the subsequent crystal was limited. By combining them, even when it is desired to investigate only the chemical state of a specific element, it is possible to analyze up to the wavelength range of the coexisting element, so that information on the composition of the coexisting element can also be obtained, and sufficient qualitative analysis can be performed. It is possible.
[0044]
【The invention's effect】
As mentioned above,ClearlyAccording to this, since the wavelength-dispersion type take-out angle is equal to the energy-dispersion type detector take-out angle, the measured fluorescent X-ray intensities are determined in advance by a sensitivity unique to each detection system independent of an individual sample. Simply multiply by a coefficient and use it as it is. Therefore, it is possible to suppress uncertainty due to a complicated correlation of the fluorescent X-ray intensity with respect to the take-out angle, and to improve the analysis accuracy. Further, since the energy dispersive second detector is closer to the sample than the spectroscope, the second detector can be closer to the sample 1. Therefore, even in the case of measuring the fluorescent X-rays of a minute portion of the sample, sufficient sensitivity can be obtained and the analysis accuracy can be improved, as in the case of the apparatus having only the energy dispersive type detecting means without the wavelength dispersive type detecting means.
[Brief description of the drawings]
FIG. 1 of the present invention.Examples of basic proposals1 is a perspective view of a fluorescent X-ray analyzer according to the embodiment.
FIG. 2 of the present invention.11 is a schematic side view of a fluorescent X-ray analyzer according to an embodiment.
FIG. 3 is a perspective view showing energy dispersive detection of the X-ray fluorescence spectrometer.
FIG. 4 is a perspective view showing wavelength-dispersive detection of the X-ray fluorescence analyzer.
FIG. 5 of the present invention.21 is a schematic side view of a fluorescent X-ray analyzer according to an embodiment.
FIG. 6 is a schematic side view of a conventional fluorescent X-ray analyzer.
FIG. 7 is a schematic side view of a conventional X-ray fluorescence analyzer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Sample, 1a ... Measurement part, 3 ... Primary X-ray, 5 ... Fluorescence X-ray, 6 ... Wavelength dispersion type detection means, 8 ... Spectroscope, 9 ... First detector, 11 ... Energy dispersion type detection means, 12 ... second detector, 30 ... first collimator, 31a, 31b, 31c ... first collimator aperture, 40 ... second collimator, 41a, 41b ... second collimator aperture, 50 ... detection Dice moving mechanism, 70: sample moving mechanism, 81: passage of first fluorescent X-ray, 82: passage of second fluorescent X-ray.

Claims

A fluorescent X-ray analyzer for irradiating a measurement target portion of a sample with primary X-rays, detecting and analyzing fluorescent X-rays generated from the measurement target portion by a detection means,
The detection means includes a wavelength dispersion type detection means having a spectroscope and a first detector, and an energy dispersion type detection means having an energy dispersion type second detector,
The angle formed by the path of the first fluorescent X-ray between the measured portion of the sample and the spectroscope with the surface of the sample, and the angle between the measured portion of the sample and the energy dispersive second detector. the second X-ray fluorescence of the passage is equal to the angle formed between the surface of the sample during, passage of the second X-ray fluorescence is rather shorter than the passage of the first X-ray fluorescence,
The path of the first fluorescent X-ray and the path of the second fluorescent X-ray are on the same axis, and the energy-dispersive second detector moves back and forth to the path of the first fluorescent X-ray. An X-ray fluorescence analyzer provided with a moving mechanism for a detector to be activated .

2. The apparatus according to claim 1 , wherein a first collimator is provided between the energy-dispersive second detector and the sample, and the fluorescent X-rays passing through at least one aperture of the first collimator are An X-ray fluorescence spectrometer that is detected by an energy dispersive second detector or separated by the spectroscope and detected by the first detector.

3. The second collimator according to claim 2 , wherein a second collimator having an aperture is provided between the first collimator and the spectroscope, and the energy dispersive second detector is attached to the second collimator. X-ray fluorescence analyzer.

The X-ray fluorescence spectrometer according to any one of claims 1 to 3 , further comprising a sample moving mechanism for moving the measured portion.

2. The X-ray fluorescence spectrometer according to claim 1, wherein the spectroscope is a two-crystal spectroscope in which a pair of front and rear spectroscopic crystals are arranged along a path of the X-ray fluorescence.