JP5846469B2 - Total reflection X-ray fluorescence analyzer and total reflection X-ray fluorescence analysis method - Google Patents

Total reflection X-ray fluorescence analyzer and total reflection X-ray fluorescence analysis method Download PDF

Info

Publication number
JP5846469B2
JP5846469B2 JP2010527698A JP2010527698A JP5846469B2 JP 5846469 B2 JP5846469 B2 JP 5846469B2 JP 2010527698 A JP2010527698 A JP 2010527698A JP 2010527698 A JP2010527698 A JP 2010527698A JP 5846469 B2 JP5846469 B2 JP 5846469B2
Authority
JP
Japan
Prior art keywords
ray
rays
sample
tube
total reflection
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
JP2010527698A
Other languages
Japanese (ja)
Other versions
JPWO2010026750A1 (en
Inventor
潤 河合
潤 河合
伸祐 国村
伸祐 国村
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kyoto University
Original Assignee
Kyoto University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kyoto University filed Critical Kyoto University
Priority to JP2010527698A priority Critical patent/JP5846469B2/en
Publication of JPWO2010026750A1 publication Critical patent/JPWO2010026750A1/en
Application granted granted Critical
Publication of JP5846469B2 publication Critical patent/JP5846469B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/22Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material
    • G01N23/223Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material by irradiating the sample with X-rays or gamma-rays and by measuring X-ray fluorescence
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00Investigating materials by wave or particle radiation
    • G01N2223/07Investigating materials by wave or particle radiation secondary emission
    • G01N2223/076X-ray fluorescence

Landscapes

  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)

Description

本発明は、X線を試料に照射したときに発生する蛍光X線を検出して前記試料中の微量元素を測定する全反射蛍光X線分析装置及び全反射蛍光X線分析方法に関する。   The present invention relates to a total reflection X-ray fluorescence analyzer and a total reflection X-ray fluorescence analysis method for detecting trace X-rays generated when a sample is irradiated with X-rays and measuring trace elements in the sample.

X線を試料に照射すると、X線照射により試料中の元素が励起されて蛍光X線を発する。蛍光X線の波長は元素に固有であることから、この蛍光X線を検出することにより元素の定性・定量分析を行うことができる。
このような蛍光X線分析法による元素の検出感度を上げるためには、試料から発せられる蛍光X線を効率よく検出するだけでなく、蛍光X線のピーク強度に対するバックグランド強度の比(ピーク/バックグランド(P/B)比)を向上することが重要である。
When the sample is irradiated with X-rays, the elements in the sample are excited by X-ray irradiation and emit fluorescent X-rays. Since the wavelength of the fluorescent X-ray is unique to the element, qualitative and quantitative analysis of the element can be performed by detecting this fluorescent X-ray.
In order to increase the element detection sensitivity by such an X-ray fluorescence analysis method, not only the fluorescent X-rays emitted from the sample are efficiently detected but also the ratio of the background intensity to the peak intensity of the fluorescent X-rays (peak / It is important to improve the background (P / B) ratio.

ピーク/バックグランド比を向上する方法の一つに、単色化(モノクロ)したX線を試料に入射させる方法がある(特許文献1参照)。入射X線を単色化することにより、試料表面における散乱X線を低減することができ、バックグラウンドを低く抑えることができる。また、励起に寄与しないエネルギー成分のX線を取り除くこともできるため、さらにバックグラウンドを低く抑えることができる。   One method for improving the peak / background ratio is a method in which monochromatic (monochrome) X-rays are incident on a sample (see Patent Document 1). By making incident X-rays monochromatic, scattered X-rays on the sample surface can be reduced, and the background can be kept low. Further, since X-rays of energy components that do not contribute to excitation can be removed, the background can be further reduced.

特開平6-94653号公報(図1)JP-A-6-94653 (Fig. 1)

しかし、入射X線を単色化すると当該入射X線の強度が低下する。このため、試料から発せられる蛍光X線の強度が低下し、元素の検出感度が低下する。そこで、従来は大型の高出力X線発生装置を用いて検出感度の低下を補っているが、大型のX線発生装置を用いると、その分、蛍光X線分析装置が大型化する。また、高出力X線が外部に漏洩することを防止する遮蔽部材が必要となり、重量化する。   However, when incident X-rays are monochromatic, the intensity of the incident X-rays decreases. For this reason, the intensity | strength of the fluorescent X ray emitted from a sample falls, and the detection sensitivity of an element falls. Therefore, conventionally, a large high-power X-ray generator is used to compensate for the decrease in detection sensitivity. However, when a large X-ray generator is used, the size of the fluorescent X-ray analyzer increases accordingly. Further, a shielding member for preventing high-power X-rays from leaking to the outside is necessary, which increases the weight.

本発明が解決しようとする課題は、小型化及び軽量化を図ることができる高感度な全反射蛍光X線分析装置及び全反射蛍光X線分析方法を提供することである。   The problem to be solved by the present invention is to provide a highly sensitive total reflection X-ray fluorescence analyzer and total reflection X-ray fluorescence analysis method that can be reduced in size and weight.

上記課題を解決するために成された本発明に係る全反射蛍光X線分析装置は、試料台に水溶液試料を滴下し乾燥させ、当該試料台上に残った残渣に1次X線を照射することにより前記水溶液試料中の微量な元素分析を行うものであって、前記1次X線を照射するX線照射部と、前記X線照射部のX線照射により発生する蛍光X線を検出するX線検出部とを備え、前記X線照射部が微弱な非単色化X線を照射することを特徴とする。
ここで、「微弱な非単色化X線」とは、例えば5W以下のX線管から照射される非単色化X線をいう。
The total reflection X-ray fluorescence spectrometer according to the present invention, which has been made to solve the above problems, drops an aqueous solution sample onto a sample stage, dries it, and irradiates the residue remaining on the sample stage with primary X-rays. In this way, a small amount of elemental analysis in the aqueous solution sample is performed, and an X-ray irradiation unit that irradiates the primary X-ray and a fluorescent X-ray generated by the X-ray irradiation of the X-ray irradiation unit are detected. An X-ray detection unit, and the X-ray irradiation unit emits weak non-monochromatic X-rays.
Here, “weak non-monochromatic X-ray” refers to non-monochromatic X-rays emitted from an X-ray tube of 5 W or less, for example.

従来の全反射蛍光X線分析装置は全て単色化X線が用いられている。これは、X線管から放射された白色X線を単色化したほうが、白色X線をそのまま用いるよりも全反射蛍光X線分析装置の検出下限を改善できる、という飯田および合志によって1984年になされた報告("Total-Reflection X-Ray Fluorescence Analysis Using Monochromatic Beam"、JPN.J.APPL.PHYS.VOL.23(1984),No.11)に基づくものである。 All conventional total reflection X-ray fluorescence analyzers use monochromated X-rays. This was done in 1984 by Iida and Koshi that white X-rays radiated from the X-ray tube were made monochromatic and that the lower limit of detection of the total reflection X-ray fluorescence analyzer could be improved rather than using white X-rays as they were. ("Total-Reflection X-Ray Fluorescence Analysis Using Monochromatic Beam", JPN.J.APPL.PHYS.VOL.23 (1984), No.11).

また、1980年代当時は、X線管からシンクロトロンへの移行時期でもあり、X線強度が強ければ強いほど感度がよくなるはずである、と考えられていた。このため、単色化によるX線強度の低下を補うためには高出力のX線源を用いればよいと考えられていた。このような考えは現在まで引き継がれており、現在普及している高感度全反射蛍光X線分析装置は全て高出力のX線源とX線の単色化のためのモノクロメータを備えている。 In the 1980s, it was also the transition from X-ray tubes to synchrotrons, and it was thought that the stronger the X-ray intensity, the better the sensitivity. For this reason, it has been considered that a high-power X-ray source may be used to compensate for the decrease in the X-ray intensity due to monochromatization. Such an idea has been inherited until now, and all the high-sensitivity total reflection X-ray fluorescence analyzers that are currently popular are equipped with a high-power X-ray source and a monochromator for monochromatic X-rays.

これに対して、本発明者は、元素含有量が少ない試料について単色化X線と白色X線を用いて全反射蛍光X線分析を行ったところ、白色X線の方が単色化X線よりも検出感度が優れるという、従来の知見に反する結果を得た。このような結果が得られた理由について本発明者は次のように考えた。   In contrast, the present inventor conducted total reflection fluorescent X-ray analysis using monochromated X-rays and white X-rays on a sample having a low element content. Also obtained results contrary to the conventional knowledge that the detection sensitivity is excellent. The present inventor considered the reason why such a result was obtained as follows.

つまり、全反射蛍光X線分析装置では、オプティカルフラットからなる試料台の上の試料残渣にX線を照射することにより励起された元素から発生する蛍光X線を検出する。ところが、白色X線を用いると、白色部分、つまり広い波長範囲のX線が散乱し、元素の励起に寄与することなく検出器に入射する。 That is, in the total reflection X-ray fluorescence analyzer, X-ray fluorescence generated from an element excited by irradiating a sample residue on a sample stage made of an optical flat with X-rays is detected. However, when white X-rays are used, white portions, that is, X-rays in a wide wavelength range are scattered and enter the detector without contributing to element excitation.

1980年代は、検出下限の水準が現在ほど低くはなく、試料台上の試料残渣の量が多かったため、白色X線を用いると散乱X線が多く発生する。また、上述したように1980年代は高強度X線を用いれば検出感度が良くなると考えられていた。しかし、高強度の白色X線を用いると散乱X線が多く発生し、これが半導体検出器に入射して当該検出器を飽和させるため、検出下限を悪化させる。このため、従来は、X線を単色化して試料残渣に散乱されにくいスペクトルをもつX線を用いること、及び、単色化によるX線強度の減少を高電力のX線管を用いて補うことが、検出下限を下げるためには必須であると考えられていた。 In the 1980s, the level of the lower limit of detection was not as low as it is today, and the amount of sample residue on the sample stage was large, so a lot of scattered X-rays were generated when white X-rays were used. Further, as described above, in the 1980s, it was considered that detection sensitivity would be improved if high-intensity X-rays were used. However, when high-intensity white X-rays are used, many scattered X-rays are generated and enter the semiconductor detector to saturate the detector. For this reason, conventionally, X-rays are monochromatized and X-rays having a spectrum that is not easily scattered by the sample residue are used, and reduction of the X-ray intensity due to monochromation is compensated by using a high-power X-ray tube. It was considered essential to lower the lower detection limit.

しかし、現在の検出下限の水準はナノグラム(ng)オーダーであり、このような極微量の試料残渣に対して低出力のX線をそのまま照射してもX線の散乱が少ない。このため、X線を単色化しなくても入射X線の多くを元素の励起に有効に用いることができ、むしろ感度が向上するという結果が得られた。
従って、本発明の蛍光X線分析装置は、試料の絶対量が少ないほど、より高感度になりその有効性を発揮する。
However, the current lower limit of detection is on the order of nanograms (ng), and even if such a very small amount of sample residue is irradiated with low-power X-rays as they are, X-ray scattering is small. For this reason, even if X-rays are not monochromatic, most of the incident X-rays can be effectively used for element excitation, and rather the sensitivity is improved.
Therefore, the X-ray fluorescence analyzer of the present invention is more sensitive and effective as the absolute amount of the sample is smaller.

本発明の全反射蛍光X線分析装置においては、前記X線照射部は、ロジウムをターゲット材とするX線管を含んで構成したり、タングステンをターゲット材とするX線管を含んで構成したりすることができる。
また、試料台上の残渣にX線を照射したときのX線検出部の計数率が当該X線検出部の最大積分計数率よりも小さくなるように、X線管及びX線検出部が構成されていると良い。
In the total reflection X-ray fluorescence spectrometer of the present invention, the X-ray irradiation unit is configured to include an X-ray tube using rhodium as a target material or an X-ray tube using tungsten as a target material. Can be.
In addition, the X-ray tube and the X-ray detector are configured so that the count rate of the X-ray detector when the residue on the sample stage is irradiated with X-rays is smaller than the maximum integrated count rate of the X-ray detector. Good to have been.

ここで、X線検出器の計数率をP(cps)とすると、X線検出器の計数率Pは次の式(1)で表される。
なお、I3xnは試料中の元素xから発せられる蛍光X線nの強度、I4は散乱X線の強度、I5vmは試料台の構成材料中の元素vから発せられる蛍光X線mの強度を表す。また、K5は係数、Tは測定時間を表す。
Here, if the count rate of the X-ray detector is P (cps), the count rate P of the X-ray detector is expressed by the following equation (1).
I 3xn is the intensity of fluorescent X-rays n emitted from the element x in the sample, I 4 is the intensity of scattered X-rays, I 5vm is the intensity of the fluorescent X-rays m emitted from the element v in the constituent material of the sample stage Represents. K 5 represents a coefficient, and T represents a measurement time.

上記蛍光X線nの強度I3xnは次の式(2)で表される。
なお、μ2は測定雰囲気の線吸収係数、μ3は検出器の窓材の線吸収係数、t2,t3,t4はそれぞれ入射X線が試料に照射されるまでに測定雰囲気中を通過する距離、X線がX線検出器に入射するまでに測定雰囲気中を通過する距離、X線検出器の窓材の厚さを示す。また、ρxは単位体積当たりの元素xの重量、Vは入射X線が照射する試料体積、Ifxn(E)は強度1のあるエネルギーを持つ入射X線から発生する単位重量当たりの元素xの蛍光X線nの強度、R(E)はX線の鏡面反射率、Sxnは蛍光X線の検出効率、Ωは検出器の立体角を示す。
The intensity I 3xn of the fluorescent X-ray n is expressed by the following formula (2).
Note that μ 2 is the linear absorption coefficient of the measurement atmosphere, μ 3 is the linear absorption coefficient of the window material of the detector, and t 2 , t 3 , and t 4 are each in the measurement atmosphere before the incident X-ray is irradiated to the sample. The distance that passes through, the distance that the X-ray passes through the measurement atmosphere before entering the X-ray detector, and the thickness of the window material of the X-ray detector are shown. Also, ρ x is the weight of the element x per unit volume, V is the sample volume irradiated by the incident X-ray, and I fxn (E) is the element x per unit weight generated from the incident X-ray having an intensity of 1. The intensity of fluorescent X-ray n, R (E) is the specular reflectance of X-ray, S xn is the detection efficiency of fluorescent X-ray, and Ω is the solid angle of the detector.

上記散乱X線の強度I4は次の式(3)で表される。
なお、K4は定数、φは入射X線の視射角、S(E)はエネルギーEのX線の検出効率を示す。
The intensity I 4 of the scattered X-ray is expressed by the following formula (3).
K 4 is a constant, φ is a viewing angle of incident X-rays, and S (E) is an X-ray detection efficiency of energy E.

また、試料台の構成材料中の元素vから発せられる蛍光X線mの強度I5vmは次の式(4)で表される。
なお、Ifvmは強度1のあるエネルギーを持つ入射X線から発生する元素vの単位重量当たりの蛍光X線の強度を示す。
Further, the intensity I 5vm of the fluorescent X-ray m emitted from the element v in the constituent material of the sample stage is expressed by the following formula (4).
Note that I fvm indicates the intensity of fluorescent X-rays per unit weight of the element v generated from incident X-rays having an intensity of 1.

また、上記式(4)中、X線管から発生する連続X線の強度I1は、X線のエネルギーの関数として次の式(5)で表すことができる。
なお、E0はX線エネルギーの最大値、iはX線管の管電流、ZはX線管のターゲット材の原子番号、μ1はX線管の窓材の線吸収計数、t1は窓材の厚さを示す。また、K1、K2は係数を示す。
In the above formula (4), the intensity I 1 of continuous X-rays generated from the X-ray tube can be expressed by the following formula (5) as a function of X-ray energy.
E 0 is the maximum value of X-ray energy, i is the tube current of the X-ray tube, Z is the atomic number of the target material of the X-ray tube, μ 1 is the line absorption coefficient of the window material of the X-ray tube, and t 1 is Indicates the thickness of the window material. K 1 and K 2 indicate coefficients.

X線管のターゲット材から発生する特性X線yの強度I2yは次の式(6)で表される。
なお、f3y(E)は特性X線yの強度分布、(E1-E2)は特性X線yのピーク幅、K3は定数を示す。
上記式(1)〜(6)より、X線管が放射するX線エネルギーの最大値、X線管の管電流、ターゲット材の原子番号、X線管の窓材の線吸収係数・厚さ、X線管から試料までの距離、試料からX線検出器までの距離、X線検出器の窓材の線吸収係数・厚さ、X線検出器の立体角等を、測定対象元素の原子番号に応じて適宜に設定することにより、前記X線検出器の計数率P(cps)を当該X線検出器の最大積分計数率Pmax(cps)よりも小さくすることができる。
The intensity I 2y of the characteristic X-ray y generated from the target material of the X-ray tube is expressed by the following formula (6).
Note that f 3y (E) is the intensity distribution of the characteristic X-ray y, (E 1 -E 2 ) is the peak width of the characteristic X-ray y, and K 3 is a constant.
From the above formulas (1) to (6), the maximum value of X-ray energy emitted by the X-ray tube, the tube current of the X-ray tube, the atomic number of the target material, the linear absorption coefficient and thickness of the window material of the X-ray tube , The distance from the X-ray tube to the sample, the distance from the sample to the X-ray detector, the linear absorption coefficient / thickness of the window material of the X-ray detector, the solid angle of the X-ray detector, etc. By setting appropriately according to the number, the count rate P (cps) of the X-ray detector can be made smaller than the maximum integrated count rate Pmax (cps) of the X-ray detector.

蛍光X線分析に用いられるX線検出器には半導体検出器、シリコンドリフト検出器、比例計数管、マイクロカロリーメータ、シンチレーション検出器等、様々な検出器がある。X線検出器は、その種類によって検出値の上限が異なるが、いずれの検出器においてもX線光子の全計数値が閾値を超えると不感時間を無視できなくなり、感度が低下する。
従って、X線検出器に入射するX線光子の全計数値が閾値、つまりX線検出器の最大積分計数率を超えないようにすれば、感度の低下を防ぐことができる。
X-ray detectors used for fluorescent X-ray analysis include various detectors such as a semiconductor detector, a silicon drift detector, a proportional counter, a microcalorimeter, and a scintillation detector. Although the upper limit of the detection value differs depending on the type of X-ray detector, the dead time cannot be ignored if the total count value of the X-ray photons exceeds the threshold value in any detector, and the sensitivity decreases.
Therefore, if the total count value of the X-ray photons incident on the X-ray detector does not exceed the threshold value, that is, the maximum integrated count rate of the X-ray detector, it is possible to prevent a decrease in sensitivity.

本発明によれば、X線源から放射されるX線を単色化することなくそのまま試料を照射するため、全反射蛍光X線分析装置の小型化を図ることができる。また、X線源から放射されるX線を単色化しないため、小型の低電力のX線源を用いることができる。従って、遮蔽部材を軽量にしたり不要にしたりすることができ、全反射蛍光X線分析装置の軽量化を図ることができる。   According to the present invention, since the sample is irradiated as it is without monochromatic X-rays emitted from the X-ray source, the total reflection fluorescent X-ray analyzer can be miniaturized. Further, since the X-ray emitted from the X-ray source is not monochromatic, a small, low-power X-ray source can be used. Accordingly, the shielding member can be made lighter or unnecessary, and the total reflection X-ray fluorescence spectrometer can be made lighter.

特に、近年、河川や土壌の汚染調査、農産物や食品中の有害元素の監視等への蛍光X線分析方法の利用が期待されており、現場への持ち運びが容易なように小型で軽量な蛍光X線分析装置の開発が望まれている。本発明によると、X線をモノクロ化するための構成が不要であるとともに、小型の低電力のX線源を用いることができるので、このように携行可能な蛍光X線分析装置を実現することもできる。   In particular, in recent years, the use of fluorescent X-ray analysis methods for river and soil contamination surveys, monitoring of harmful elements in agricultural products and foods, etc. is expected, and it is compact and lightweight so that it can be easily carried to the field. Development of an X-ray analyzer is desired. According to the present invention, a configuration for making X-rays monochrome is unnecessary, and a small, low-power X-ray source can be used. Thus, a portable X-ray fluorescence analyzer can be realized. You can also.

本発明の全反射蛍光X線分析装置のブロック図。1 is a block diagram of a total reflection X-ray fluorescence analyzer of the present invention. 導波路の斜視図(a)、及び分解斜視図(b)。The perspective view (a) of a waveguide, and an exploded perspective view (b). 試料台、X線管、X線検出器の概略的な位置関係を示す図。The figure which shows the schematic positional relationship of a sample stand, an X-ray tube, and an X-ray detector. 本発明の実施例1に係る全反射蛍光X線分析装置を用いたときのブランク試料の蛍光X線スペクトルを示す図。The figure which shows the fluorescence X-ray spectrum of a blank sample when using the total reflection X-ray fluorescence analyzer which concerns on Example 1 of this invention. 試料の量に応じた蛍光X線のスペクトルの変化を示す図。The figure which shows the change of the spectrum of the fluorescent X ray according to the quantity of the sample. 日本分析化学会河川水認証標準物質(JSAC 0302-3)の主要含有元素の認証値を示す図。The figure which shows the certification | authentication value of the main content element of the Japan Analytical Chemical Society river water certification reference material (JSAC 0302-3). 単色化X線、及び非単色化X線を試料に照射したときに得られる蛍光X線スペクトルを比較して示す図。The figure which compares and shows the fluorescence X-ray spectrum obtained when a sample is irradiated with the monochromatization X-ray and the non-monochromation X-ray. 鉛(Pb)を含む試料に対して非単色化X線を照射したときの蛍光X線スペクトルの視射角による変化を示す図。The figure which shows the change by the viewing angle of a fluorescent X-ray spectrum when non-monochromatic X-rays are irradiated with respect to the sample containing lead (Pb). 本発明の実施例2に係る全反射蛍光X線分析装置を用いたときの試料の量に応じた蛍光X線のスペクトルの変化を示す図。The figure which shows the change of the spectrum of the fluorescent X-ray according to the quantity of the sample when using the total reflection X-ray fluorescence analyzer which concerns on Example 2 of this invention. Sc,Cr,Co,As,Srを含む試料に対して非単色化X線を照射したときの蛍光X線スペクトルの視射角による変化を示す図。The figure which shows the change by the viewing angle of the fluorescence X-ray spectrum when the sample containing Sc, Cr, Co, As, Sr is irradiated with the non-monochromatic X-ray. 分析元素の原子番号と検出下限との関係を示す図。The figure which shows the relationship between the atomic number of an analysis element, and a detection minimum. 本発明の実施例3に係る全反射蛍光X線分析装置を用いたときの管電圧と信号対バックグラウンド比の関係を示す図。The figure which shows the relationship between a tube voltage and a signal versus background ratio when using the total reflection X-ray fluorescence spectrometer which concerns on Example 3 of this invention. 管電流と信号対バックグラウンド比との関係を示す図。The figure which shows the relationship between tube current and a signal to background ratio. ターゲット材の原子番号と信号対バックグラウンド比との関係を示す図。The figure which shows the relationship between the atomic number of a target material, and signal-to-background ratio. 視射角と信号対バックグラウンド比との関係を示す図。The figure which shows the relationship between a glancing angle and a signal to background ratio. 試料量と感度係数との関係を示す図。The figure which shows the relationship between sample amount and a sensitivity coefficient. 円板状の試料台と矩形板状の試料台のバックグラウンドの蛍光X線スペクトルを示す図。The figure which shows the fluorescence X-ray spectrum of the background of a disk-shaped sample stand and a rectangular plate-shaped sample stand. 円板状の試料台と矩形板状の試料台に非単色化X線を照射したときの散乱X線の様子を模式的に示す図。The figure which shows typically the mode of the scattered X-ray when a non-monochromated X-ray is irradiated to a disk-shaped sample stand and a rectangular plate-shaped sample stand.

図1は本発明の全反射蛍光X線分析装置の一例を示すブロック図である。全反射蛍光X線分析装置(以下、分析装置)10において、制御部11は、操作部12からの操作信号を受けてX線照射部13及び検出部14を制御する。X線照射部13は駆動回路131とX線管132から成り、駆動回路131によって駆動されたX線管132はX線を放射する。X線管132から放射されたX線は導波路15を通り試料台載置部16に着脱可能に装着された試料台17に入射する。検出部14はX線検出器141とX線検出器141の検出信号を増幅する増幅器142から成る。
分析装置10には、パーソナルコンピュータなどのデータ処理装置20が接続されている。データ処理装置20は、検出部14から出力される検出信号を処理する信号処理部201と、信号処理部201からの出力信号に基づきX線スペクトル等の画像を表示する表示部202等を備えている。
FIG. 1 is a block diagram showing an example of a total reflection X-ray fluorescence spectrometer of the present invention. In the total reflection fluorescent X-ray analyzer (hereinafter referred to as analyzer) 10, the control unit 11 controls the X-ray irradiation unit 13 and the detection unit 14 in response to an operation signal from the operation unit 12. The X-ray irradiation unit 13 includes a drive circuit 131 and an X-ray tube 132, and the X-ray tube 132 driven by the drive circuit 131 emits X-rays. X-rays radiated from the X-ray tube 132 pass through the waveguide 15 and enter the sample table 17 that is detachably mounted on the sample table mounting unit 16. The detection unit 14 includes an X-ray detector 141 and an amplifier 142 that amplifies the detection signal of the X-ray detector 141.
A data processing device 20 such as a personal computer is connected to the analysis device 10. The data processing device 20 includes a signal processing unit 201 that processes a detection signal output from the detection unit 14, a display unit 202 that displays an image such as an X-ray spectrum based on an output signal from the signal processing unit 201, and the like. Yes.

図2に示すように、導波路15は2枚のシリコン(Si)ウェハー151で挟持された一対のタングステン(W)箔152と、これらを保持する金属製、例えばステンレス(SUS304等)のハウジング153から構成されている。ハウジング153には幅が10mmのX線出口154が形成されている。タングステン箔152は厚さが10μmに設定されている。導波路15に入射したX線は、シリコンウェハー151及びタングステン箔152で囲まれた空間を通ってX線出口154から出射するようになっている。   As shown in FIG. 2, the waveguide 15 includes a pair of tungsten (W) foils 152 sandwiched between two silicon (Si) wafers 151 and a metal, for example, stainless steel (SUS304, etc.) housing 153 that holds them. It is composed of An X-ray outlet 154 having a width of 10 mm is formed in the housing 153. The thickness of the tungsten foil 152 is set to 10 μm. X-rays incident on the waveguide 15 are emitted from the X-ray outlet 154 through a space surrounded by the silicon wafer 151 and the tungsten foil 152.

図3は、分析装置10のX線管132、試料台17、X線検出器141の概略構成図である。X線管132から放射され、導波路15を通ったX線は1次X線として試料台17上の試料Sに入射する。このとき、1次X線は全反射する視射角度θで試料台17に照射され、このX線照射によって発生する蛍光X線はX線検出器141で検出される。X線管17から放射されたX線は単色化されずに試料Sに照射され、試料S中の元素を励起するようになっている。
なお、図3では、試料台17からX線検出器141までの距離を誇張して描いているが、実際は、前記試料台17からX線検出器141までの距離は、前記X線管132から試料台17までの距離に比べると非常に短い。例えばX線管132から試料台17までの距離が30mmのとき、試料台17からX線検出器141までの距離は1mmに設定される。
FIG. 3 is a schematic configuration diagram of the X-ray tube 132, the sample stage 17, and the X-ray detector 141 of the analyzer 10. X-rays radiated from the X-ray tube 132 and passed through the waveguide 15 enter the sample S on the sample stage 17 as primary X-rays. At this time, the primary X-ray is irradiated onto the sample table 17 at a total reflection angle θ, and the X-ray fluorescence generated by the X-ray irradiation is detected by the X-ray detector 141. The X-rays radiated from the X-ray tube 17 are irradiated with the sample S without being monochromatic, and the elements in the sample S are excited.
In FIG. 3, the distance from the sample stage 17 to the X-ray detector 141 is exaggerated, but in reality, the distance from the sample stage 17 to the X-ray detector 141 is from the X-ray tube 132. Compared to the distance to the sample stage 17, it is very short. For example, when the distance from the X-ray tube 132 to the sample stage 17 is 30 mm, the distance from the sample stage 17 to the X-ray detector 141 is set to 1 mm.

試料台17は平滑な載置面を有する例えば石英オプティカルフラットから構成されている。試料Sは、試料台17に水溶液を一定量(例えば10μl〜100μl)滴下し、乾燥させた残渣からなる。試料Sに対するX線照射により、試料S中に含まれる元素が励起され、この結果、蛍光X線が放出される。この蛍光X線をX線検出器141で検出し、得られたX線スペクトルに基づきデータ処理装置20は目的元素の定量分析を行う。
以下、本発明の全反射蛍光X線分析装置について具体的な実施例を挙げて説明する。
The sample stage 17 is made of, for example, a quartz optical flat having a smooth mounting surface. The sample S consists of a residue obtained by dropping a predetermined amount (for example, 10 μl to 100 μl) of an aqueous solution onto the sample stage 17 and drying it. X-ray irradiation on the sample S excites elements contained in the sample S, and as a result, fluorescent X-rays are emitted. The fluorescent X-ray is detected by the X-ray detector 141, and the data processing device 20 performs quantitative analysis of the target element based on the obtained X-ray spectrum.
Hereinafter, the total reflection X-ray fluorescence spectrometer of the present invention will be described with specific examples.

実施例1では、X線管として自然空冷式ロジウム(Rh)ターゲットX線管、X線検出器としてSi−PIN検出器(最大積分計数率:〜2×105cps)を用いて分析装置10を構成し、種々の測定を行った。
〔ブランク試料のX線スペクトルの測定〕
以下の測定条件で、ブランク試料(試料台3に何も滴下していない状態)に単色化していないX線(非単色化X線)を照射したときのX線スペクトルを測定した。
In Example 1, a natural air-cooled rhodium (Rh) target X-ray tube is used as the X-ray tube, and an Si-PIN detector (maximum integrated count rate: ˜2 × 10 5 cps) is used as the X-ray detector. And various measurements were performed.
[Measurement of X-ray spectrum of blank sample]
Under the following measurement conditions, an X-ray spectrum was measured when a blank sample (a state in which nothing was dropped on the sample stage 3) was irradiated with non-monochrome X-rays (non-monochromatic X-rays).

測定条件
・自然空冷式ロジウム(Rh)ターゲットX線管の電力:管電圧40kV、管電流50μA(2W)
・X線検出器:Si−PIN検出器(最大積分計数率:〜2×105cps)
・1次X線の視射角:0.05゜
・X線管と試料中心の距離:30mm
・X線検出器と試料中心の距離:1mm
Measurement conditions ・ Power of natural air-cooled rhodium (Rh) target X-ray tube: tube voltage 40 kV, tube current 50 μA (2 W)
-X-ray detector: Si-PIN detector (maximum integrated count rate: ~ 2 x 10 5 cps)
・ Primary X-ray viewing angle: 0.05 ° ・ Distance between X-ray tube and sample center: 30mm
・ Distance between X-ray detector and sample center: 1mm

図4にその結果を示す。図4から明らかなように、X線管からの特性X線由来のRh、空気中に0.93%含まれるAr、石英オプティカルフラット由来のSiのピークがそれぞれ検出された。さらに、Ni,Pb,Snの不純線が検出されたが、これらはいずれも装置の材料由来と思われた。   FIG. 4 shows the result. As is clear from FIG. 4, peaks of Rh derived from characteristic X-rays from the X-ray tube, Ar contained in the air at 0.93%, and Si derived from quartz optical flat were detected. Furthermore, impure lines of Ni, Pb, and Sn were detected, all of which seemed to be derived from the material of the apparatus.

また、上記装置を用いてブランク試料に非単色化X線を照射したときのSi−PIN検出器の積分計数率は1×103cpsであった。当該Si−PIN検出器の最大積分計数率は2×105cpsであり、ブランク試料に対して非単色化X線を照射したときのX線検出器の積分計数率は、当該X線検出器の最大積分計数率よりも十分に小さい。Moreover, the integral count rate of the Si-PIN detector was 1 × 10 3 cps when the blank sample was irradiated with non-monochromatic X-rays using the above apparatus. The maximum integral count rate of the Si-PIN detector is 2 × 10 5 cps, and the integral count rate of the X-ray detector when the non-monochromatic X-ray is irradiated to the blank sample is the X-ray detector. Is sufficiently smaller than the maximum integral count rate.

水溶液試料中の元素が微量であればあるほど当該水溶液試料を乾燥させたときの残渣が微量になる。このため、微量元素を含有する水溶液試料の残渣が載置された試料台に非単色化X線が入射しても前記残渣による散乱が少なく、ほぼ全ての入射X線は全反射するか元素を励起する。従って、微量元素を含有する水溶液試料の残渣が載置された試料台に非単色化X線を照射したときのX線スペクトルは、図4に示すブランク試料のX線スペクトルに残渣(つまり、微量元素)から発せられる蛍光X線のスペクトル線が加わるだけとなる。
以上より、微量元素を含有する水溶液試料を乾燥させた残渣が載置された試料台に対して上記した測定条件で非単色化X線を照射した場合でも、X線検出器の積分計数率が当該X線検出器の最大積分計数率を上回ることはなく、微量元素の分析が可能であると推定された。
The smaller the amount of elements in the aqueous solution sample, the smaller the residue when the aqueous solution sample is dried. For this reason, even if non-monochromatic X-rays are incident on a sample stage on which a residue of an aqueous solution sample containing a trace element is placed, there is little scattering by the residue, and almost all incident X-rays are totally reflected or elemental Excited. Therefore, the X-ray spectrum when the non-monochromated X-ray is irradiated on the sample stage on which the residue of the aqueous solution sample containing the trace element is placed is the residue (that is, a trace amount) in the X-ray spectrum of the blank sample shown in FIG. Only the spectral line of fluorescent X-rays emitted from the element is added.
From the above, even when non-monochromatic X-rays are irradiated on the sample stage on which the residue obtained by drying an aqueous solution sample containing trace elements is placed under the above-described measurement conditions, the integral count rate of the X-ray detector is It was estimated that analysis of trace elements was possible without exceeding the maximum integrated count rate of the X-ray detector.

なお、自然空冷式ロジウムターゲットX線管以外のX線管について、管電流以外のパラメータを同じに設定した場合のブランク試料測定時の積分計数率は、計算上、以下のようになる。
強制空冷式X線管:40kV,1mA(40W):2×10cps
水冷式X線管:40kV,10mA(400W):2×10cps
回転対陰極X線管:40kV,100mA(4kW):2×10cps
In addition, regarding the X-ray tube other than the natural air-cooled rhodium target X-ray tube, the integral count rate at the time of blank sample measurement when the parameters other than the tube current are set to be the same is as follows in the calculation.
Forced air-cooled X-ray tube: 40 kV, 1 mA (40 W): 2 × 10 4 cps
Water-cooled X-ray tube: 40 kV, 10 mA (400 W): 2 × 10 5 cps
Rotating anti-cathode X-ray tube: 40 kV, 100 mA (4 kW): 2 × 10 6 cps

つまり、水冷式X線管や回転対陰極X線管を用いたときのX線検出器の積分計数率は、Si−PIN検出器の最大積分計数率と同じか上回る。従って、水冷式X線管や回転対陰極X線管とSi−PIN検出器とを組み合わせて用いる場合は、X線を単色化しなければSi−PIN検出器が飽和してしまうためX線スペクトルを検出できず、微量元素分析ができない。
また、シリコンドリフト(SDD)検出器の最大積分計数率は約1×10cpsである。従って、出力が2kWよりも大きいX線管(回転対陰極X線管)を用いる場合には、単色化X線を用いなければSDD検出器が飽和してしまうため、X線スペクトルの検出ができない。
That is, the integral count rate of the X-ray detector when using a water-cooled X-ray tube or a rotating anti-cathode X-ray tube is equal to or exceeds the maximum integral count rate of the Si-PIN detector. Therefore, when a water-cooled X-ray tube or rotating anti-cathode X-ray tube and a Si-PIN detector are used in combination, the X-ray spectrum is obtained because the Si-PIN detector is saturated unless the X-ray is monochromatic. It cannot be detected and trace element analysis cannot be performed.
The maximum integrated count rate of the silicon drift (SDD) detector is about 1 × 10 6 cps. Therefore, when using an X-ray tube (rotating anti-cathode X-ray tube) with an output greater than 2 kW, the SDD detector will be saturated unless monochromatic X-rays are used, so that the X-ray spectrum cannot be detected. .

Si(Li)検出器の最大積分計数率は約1×10cpsである。従って、出力が20Wよりも大きいX線管を用いる場合には、単色化X線を用いなければSi(Li)検出器が飽和してしまうため、X線スペクトルの検出ができない。
以上より、X線検出器の最大積分計数率とX線管の出力を適宜の関係に設定し、前記X線検出器の計数率が当該X線検出器の最大積分計数率よりも小さくなるようにすれば、非単色化X線を試料に照射して微量元素分析を行うことが可能であると推定された。
The maximum integrated count rate of the Si (Li) detector is about 1 × 10 4 cps. Therefore, when an X-ray tube having an output greater than 20 W is used, the X-ray spectrum cannot be detected because the Si (Li) detector is saturated unless monochromatic X-rays are used.
As described above, the maximum integral count rate of the X-ray detector and the output of the X-ray tube are set in an appropriate relationship so that the count rate of the X-ray detector is smaller than the maximum integral count rate of the X-ray detector. In this case, it was estimated that trace element analysis can be performed by irradiating the sample with non-monochromatic X-rays.

〔試料中の元素含有量と蛍光X線スペクトルの関係〕
元素の含有量が異なる試料について非単色化X線を照射したときに発生する蛍光X線のスペクトルの変化を調べた。その結果を図5に示す。試料には、日本分析化学会河川水認証標準物質(JSAC 0302-3)を用いた。この標準物質の主要含有元素の認証値は図6に示す通りである。
図5(a)及び(b)は、10μl及び100μl(10μl×10滴)の標準物質を試料台に滴下し、乾燥させた後の残渣に対して下記の測定条件で非単色化X線を照射したときに得られるX線スペクトルの実測例を示す。また、図5(c)は、ブランク試料としての超純水10μlを試料台に滴下し、乾燥させた後の残渣に対して下記の測定条件で非単色化X線を照射したときに得られるX線スペクトルの実測例を示す。
なお、標準物質10μlの主要含有元素の重量は合計で約0.2μgとなり、標準物質100μlの主要含有元素の重量は合計で約2μgとなる。
[Relationship between element content in sample and fluorescent X-ray spectrum]
Changes in the spectrum of fluorescent X-rays generated when non-monochromatic X-rays were irradiated on samples having different element contents were examined. The result is shown in FIG. As a sample, the Japan Society for Analytical Chemistry River Water Certified Reference Material (JSAC 0302-3) was used. The certified values of the main contained elements of this standard substance are as shown in FIG.
5 (a) and 5 (b) show that 10 μl and 100 μl (10 μl × 10 drops) of a standard substance are dropped on the sample stage and dried, and then the non-monochromic X-rays are applied to the residue under the following measurement conditions. An actual measurement example of the X-ray spectrum obtained when irradiated is shown. Further, FIG. 5 (c) is obtained when 10 μl of ultrapure water as a blank sample is dropped on the sample stage and the residue after drying is irradiated with non-monochromatic X-rays under the following measurement conditions. An example of actual measurement of the X-ray spectrum is shown.
The total weight of the main contained elements of 10 μl of the standard substance is about 0.2 μg, and the weight of the major contained elements of 100 μl of the standard substance is about 2 μg in total.

測定条件
・自然空冷式ロジウム(Rh)ターゲットX線管の電力:管電圧30kV、管電流50μA(1.5W)
・X線検出器:Si−PIN検出器(最大積分計数率:〜2×105cps)
・試料台:石英オプティカルフラット
・1次X線の視射角:0.05゜
・X線管と試料中心の距離:30mm
・X線検出器と試料中心の距離:1mm
Measurement conditions ・ Power of natural air cooled rhodium (Rh) target X-ray tube: tube voltage 30 kV, tube current 50 μA (1.5 W)
-X-ray detector: Si-PIN detector (maximum integrated count rate: ~ 2 x 10 5 cps)
・ Sample stage: Quartz optical flat ・ Primary X-ray viewing angle: 0.05 ° ・ Distance between X-ray tube and sample center: 30mm
・ Distance between X-ray detector and sample center: 1mm

図5(b)に示すように、試料中の元素総量が約2μgのときの蛍光X線のスペクトル強度(ピーク強度)は、同図(a)の約0.2μgのときに比べて増加するが、同時にバックグラウンドも増加する。このため、ピーク/バックグランド(P/B)比が悪化し、分析精度が低下する。一方、図5(a)に示すように、試料中の元素総量が約0.2μgのときのバックグラウンドは、ブランク試料のときのバックグラウンドよりもわずかに増加するだけである。従って、試料中の、分析対象(アナライト)の各元素量がそれぞれ微量(例えば、1ng以下)であるときは、1次X線を単色化しなくても含有元素が発する蛍光X線を検出することができ、元素分析を良好に行うことができる。   As shown in FIG. 5 (b), the spectrum intensity (peak intensity) of fluorescent X-rays when the total amount of elements in the sample is about 2 μg increases compared to about 0.2 μg in FIG. At the same time, the background also increases. For this reason, the peak / background (P / B) ratio deteriorates and the analysis accuracy decreases. On the other hand, as shown in FIG. 5 (a), the background when the total amount of elements in the sample is about 0.2 μg is only slightly increased compared to the background of the blank sample. Therefore, when the amount of each element of the analysis target (analyte) in the sample is very small (for example, 1 ng or less), the fluorescent X-rays emitted from the contained elements are detected even if the primary X-ray is not monochromatic. And elemental analysis can be performed well.

〔単色化X線及び非単色化X線照射による蛍光X線スペクトルの変化〕
単色化X線及び非単色化X線を下記の測定条件で試料に照射したときの蛍光X線のスペクトルを調べた。その結果を図7に示す。なお、単色化X線とは、X線源が放射するX線から一部の波長帯を取り出したものと定義され、ここでは、20keV〜25keVの波長帯を取り出して単色化X線とした。
[Changes in X-ray fluorescence spectrum due to monochromatic X-ray and non-monochromatic X-ray irradiation]
The spectrum of fluorescent X-rays when the sample was irradiated with monochromatic X-rays and non-monochromatic X-rays under the following measurement conditions was examined. The result is shown in FIG. The monochromatic X-ray is defined as a part of the wavelength band extracted from the X-ray radiated from the X-ray source. Here, the wavelength band of 20 keV to 25 keV is extracted as the monochromatic X-ray.

測定条件
・自然空冷式ロジウム(Rh)ターゲットX線管の電力:管電圧30kV、管電流50μA(1.5W)
・X線検出器:Si−PIN検出器(最大積分計数率:〜2×105cps)
・試料台:石英オプティカルフラット
1次X線の視射角:0.05゜
X線管と試料中心の距離:30mm
X線検出器と試料中心の距離:1mm
Measurement conditions ・ Power of natural air cooled rhodium (Rh) target X-ray tube: tube voltage 30 kV, tube current 50 μA (1.5 W)
-X-ray detector: Si-PIN detector (maximum integrated count rate: ~ 2 x 10 5 cps)
・ Sample stage: Quartz optical flat Primary X-ray viewing angle: 0.05 ° Distance between X-ray tube and sample center: 30mm
Distance between X-ray detector and sample center: 1mm

図7(a),(b)は、いずれも各5ngのSc,Cr,Co,Zn,As,Srを含む試料に対して単色化X線(図7(a))、非単色化X線(図7(b))を照射したときに得られるX線スペクトルの実測例を示す。また、図7(c)は、ブランク試料としての超純水10μlを試料台に滴下し、乾燥させた後の残渣に対して非単色化X線を照射したときに得られるX線スペクトルの実測例を示す。   FIGS. 7 (a) and 7 (b) show a monochromatic X-ray (FIG. 7 (a)) and a non-monochromatic X-ray for a sample containing 5 ng of Sc, Cr, Co, Zn, As, and Sr. An actual measurement example of the X-ray spectrum obtained when (FIG. 7B) is irradiated is shown. FIG. 7 (c) shows an actual measurement of an X-ray spectrum obtained when 10 μl of ultrapure water as a blank sample is dropped on a sample stage and the residue after drying is irradiated with non-monochromatic X-rays. An example is shown.

図7(a)〜(c)に示すように、単色化X線を試料に照射したとき(図7(a))のX線スペクトルのバックグラウンドは、非単色化X線を試料に照射したとき(図7(b))のバックグラウンドに比べて小さく、且つ、非単色化X線をブランク試料に照射したとき(図7(c))のX線スペクトルのバックグラウンドと同程度であった。しかし、元素Sc,Cr,Co,Zn,As,Sr,Zrについては蛍光X線のピーク強度が小さく、ピーク/バックグランド(P/B)比が低かった。   As shown in FIGS. 7A to 7C, the background of the X-ray spectrum when the sample was irradiated with monochromatic X-rays (FIG. 7A) was irradiated with non-monochromatic X-rays. When compared to the background of the X-ray spectrum (FIG. 7 (b)), it was smaller than that of the background (FIG. 7 (b)) and the same as the background of the X-ray spectrum when the non-monochromatic X-ray was irradiated to the blank sample (FIG. 7 (c)). . However, for the elements Sc, Cr, Co, Zn, As, Sr, and Zr, the peak intensity of the fluorescent X-ray was small and the peak / background (P / B) ratio was low.

一方、図7(b)および(c)に示すように、非単色化X線を試料に照射したときのX線スペクトルのバックグラウンドは、非単色化X線をブランク試料に照射したときのX線スペクトルのバックグラウンドに比べてわずかに増加したが、それを補うほど高い強度の蛍光X線が元素Sc,Cr,Co,Zn,As,Sr,Zrについて検出された。つまり、非単色化X線を用いたときの方が単色化X線を用いたときよりも高いピーク/バックグランド(P/B)比が得られることが分かった。   On the other hand, as shown in FIGS. 7 (b) and (c), the background of the X-ray spectrum when the sample is irradiated with non-monochromatic X-rays is the same as that when the blank sample is irradiated with non-monochromatic X-rays. Although it slightly increased compared to the background of the line spectrum, high-intensity fluorescent X-rays were detected for the elements Sc, Cr, Co, Zn, As, Sr, and Zr. That is, it was found that a higher peak / background (P / B) ratio can be obtained when non-monochromic X-rays are used than when monochromatic X-rays are used.

〔入射X線の視射角とX線スペクトルとの関係〕
10ngの鉛(Pb)を含む試料に対して下記の測定条件で非単色化X線を照射したときのX線スペクトルを、視射角を変えて調べた。その結果を図8に示す。図8の(a)は視射角を0.05°に、図8の(b)は視射角を0.10°に、図8の(c)は視射角を0.20°に設定したときのX線スペクトルを示す。
[Relationship between incident X-ray viewing angle and X-ray spectrum]
An X-ray spectrum when a sample containing 10 ng of lead (Pb) was irradiated with non-monochromatic X-rays under the following measurement conditions was examined by changing the viewing angle. The result is shown in FIG. 8A shows the X-ray when the viewing angle is set to 0.05 °, FIG. 8B shows the viewing angle set to 0.10 °, and FIG. 8C shows the X-ray when the viewing angle is set to 0.20 °. The spectrum is shown.

測定条件
・自然空冷式ロジウム(Rh)ターゲットX線管の電力:管電圧30kV、管電流50μA(1.5W)
・X線検出器:Si−PIN検出器(最大積分計数率:〜2×105cps)
・試料台:石英オプティカルフラット
・X線管と試料中心の距離:30mm
・X線検出器と試料中心の距離:1mm
Measurement conditions ・ Power of natural air cooled rhodium (Rh) target X-ray tube: tube voltage 30 kV, tube current 50 μA (1.5 W)
-X-ray detector: Si-PIN detector (maximum integrated count rate: ~ 2 x 10 5 cps)
・ Sample stage: Quartz optical flat ・ Distance between X-ray tube and sample center: 30mm
・ Distance between X-ray detector and sample center: 1mm

図8(a)〜(c)から明らかなように、視射角が大きくなるにつれてX線スペクトルのバックグラウンドが増大する。
30keVの入射X線が石英上で全反射する臨界角は0.06°であり、入射X線のエネルギーが低くなるほど臨界角は大きくなる。入射X線の視射角が全反射臨界角よりも小さいときは当該入射X線は全反射し、視射角の増加と共にエネルギーが高い入射X線の反射率が低下する。反射率が低い入射X線は散乱X線となり、蛍光X線スペクトルのバックグラウンド成分になる。従って、入射X線の視射角が増加するとバックグラウンドが増大し、この結果、検出感度が悪化する。
As is clear from FIGS. 8A to 8C, the background of the X-ray spectrum increases as the viewing angle increases.
The critical angle at which 30 keV incident X-rays are totally reflected on quartz is 0.06 °, and the critical angle increases as the energy of incident X-rays decreases. When the viewing angle of incident X-rays is smaller than the total reflection critical angle, the incident X-rays are totally reflected, and the reflectance of incident X-rays with high energy decreases as the viewing angle increases. Incident X-rays with low reflectivity become scattered X-rays and become a background component of the fluorescent X-ray spectrum. Therefore, when the incident angle of incident X-rays increases, the background increases, and as a result, the detection sensitivity deteriorates.

非単色化X線は特定の波長帯から構成されているわけではないため、全反射臨界角はある幅を持つことになる。図8(a)は、全ての入射X線が全反射する視射角(0.05°)で非単色化X線を試料に照射したときのX線スペクトルである。図8(a)に示すように、X線スペクトルには明瞭な鉛の蛍光X線ピークが検出された。
従って、全ての入射X線が全反射する条件の視射角で照射すれば、非単色化X線を用いた場合でもバックグラウンドを低く抑えることができ、検出感度の向上を図ることができる。
Since non-monochromatic X-rays are not composed of a specific wavelength band, the total reflection critical angle has a certain width. FIG. 8A is an X-ray spectrum when a sample is irradiated with non-monochromic X-rays at a viewing angle (0.05 °) at which all incident X-rays are totally reflected. As shown in FIG. 8 (a), a clear fluorescent X-ray peak of lead was detected in the X-ray spectrum.
Therefore, if irradiation is performed at a viewing angle that allows all incident X-rays to be totally reflected, the background can be kept low even when non-monochromatic X-rays are used, and detection sensitivity can be improved.

実施例2では、X線管として自然空冷式タングステン(W)ターゲットX線管、X線検出器としてSi−PIN検出器(最大積分計数率:〜2×105cps)を用いて分析装置10を構成し、種々の測定を行った。In Example 2, the analyzer 10 uses a natural air-cooled tungsten (W) target X-ray tube as the X-ray tube and a Si-PIN detector (maximum integrated count rate: ˜2 × 10 5 cps) as the X-ray detector. And various measurements were performed.

〔試料中の元素含有量と蛍光X線スペクトルの関係〕
元素の含有量が異なる試料について非単色化X線を照射したときに発生する蛍光X線のスペクトルの変化を調べた。その結果を図9に示す。試料には、実施例1と同様、日本分析化学会河川水認証標準物質(JSAC 0302-3)を用いた。
[Relationship between element content in sample and fluorescent X-ray spectrum]
Changes in the spectrum of fluorescent X-rays generated when non-monochromatic X-rays were irradiated on samples having different element contents were examined. The result is shown in FIG. As in Example 1, the Japan Society for Analytical Chemistry River Water Certified Reference Material (JSAC 0302-3) was used as the sample.

図9(a)及び(b)は、100μl(10μl×10滴)及び200μl(10μl×20滴)の標準物質を試料台に滴下し、乾燥させた後の残渣に対して下記の測定条件で非単色化X線を照射したときに得られるX線スペクトルの実測例を示す。また、図9(c)は、ブランク試料としての超純水10μlを試料台に滴下し、乾燥させた後の残渣に対して下記の測定条件で非単色化X線を照射したときに得られるX線スペクトルの実測例を示す。
なお、標準物質100μlの主要含有元素の重量は合計で約2μgとなり、標準物質200μlの主要含有元素の重量は合計で約4μgとなる。
9 (a) and 9 (b) show that 100 μl (10 μl × 10 drops) and 200 μl (10 μl × 20 drops) of a standard substance are dropped on a sample stage and dried, and the residue is subjected to the following measurement conditions. An actual measurement example of an X-ray spectrum obtained when non-monochromatic X-rays are irradiated will be shown. Further, FIG. 9C is obtained when 10 μl of ultrapure water as a blank sample is dropped on the sample stage and the residue after drying is irradiated with non-monochromatic X-rays under the following measurement conditions. An example of actual measurement of the X-ray spectrum is shown.
The total weight of the main contained elements of 100 μl of the standard substance is about 2 μg, and the total weight of the major contained elements of 200 μl of the standard substance is about 4 μg.

測定条件
・自然空冷式タングステン(W)ターゲットX線管の電力:管電圧25kV、管電流50μA(1.25W)
・X線検出器:Si−PIN検出器(最大積分計数率:〜2×105cps)
・試料台:石英オプティカルフラット
・1次X線の視射角:0.05゜
・X線管と試料中心の距離:30mm
・X線検出器と試料中心の距離:1mm
Measurement conditions ・ Power of natural air-cooled tungsten (W) target X-ray tube: tube voltage 25 kV, tube current 50 μA (1.25 W)
-X-ray detector: Si-PIN detector (maximum integrated count rate: ~ 2 x 10 5 cps)
・ Sample stage: Quartz optical flat ・ Primary X-ray viewing angle: 0.05 ° ・ Distance between X-ray tube and sample center: 30mm
・ Distance between X-ray detector and sample center: 1mm

図9(a)〜(c)に示すように、いずれの蛍光X線スペクトルにおいてもX線管からの特性X線由来のW、空気中に0.93%含まれるAr、石英オプティカルフラット由来のSiのピークがそれぞれ検出された。また、Niの不純線が検出されたが、これらは装置の材料由来と思われた。   As shown in FIGS. 9A to 9C, in any fluorescent X-ray spectrum, W derived from the characteristic X-ray from the X-ray tube, Ar contained in the air at 0.93%, and Si derived from the quartz optical flat Each peak was detected. Further, Ni impure lines were detected, but these seemed to be derived from the material of the apparatus.

図9(a),(b)から明らかなように、試料中の元素総量が約4μgのときの蛍光X線のスペクトル強度(ピーク強度)は、約2μgのときに比べて増加するが、同時にバックグラウンドも増加した。
また、試料中の元素総量が約2μgのときの微量な元素(試料中の含有量がppbレベルの元素:Cr,Mn,Fe)の蛍光X線の分析線の信号対バックグラウンド比は、試料中の元素総量が約4μgのものより1.2〜1.8倍向上した。
以上より、試料量を少なくすることにより、1.25Wという微弱なX線源を用いても微量元素を高感度で測定できることがわかる。
As is clear from FIGS. 9 (a) and 9 (b), the spectral intensity (peak intensity) of the fluorescent X-ray when the total amount of elements in the sample is about 4 μg is increased as compared with the case of about 2 μg. The background also increased.
In addition, the signal-to-background ratio of the analysis line of fluorescent X-rays of trace elements (elements whose content is ppb level: Cr, Mn, Fe) when the total amount of elements in the sample is about 2 μg is The total amount of elements was 1.2 to 1.8 times higher than that of about 4 μg.
From the above, it can be seen that by reducing the amount of the sample, trace elements can be measured with high sensitivity even if a weak X-ray source of 1.25 W is used.

〔入射X線の視射角とX線スペクトルとの関係〕
Sc,Cr,Co,As,Srをそれぞれ1ngずつ含む試料に対して下記の測定条件で非単色化X線を照射したときのX線スペクトルを、視射角を変えて調べた。その結果を図10に示す。図10の(a)は視射角を0.05°に、図10の(b)は視射角を0.20°に設定したときのX線スペクトルを示す。また、図10の(c)はブランク試料(超純粋10μlを滴下乾燥した試料)の視射角を0.05°に設定したときのX線スペクトルを示す。
測定条件
・自然空冷式タングステン(W)ターゲットX線管の電力:管電圧25kV、管電流50μA(1.25W)
・X線検出器:Si−PIN検出器(最大積分計数率:〜2×105cps)
・試料台:石英オプティカルフラット
・X線管と試料中心の距離:30mm
・X線検出器と試料中心の距離:1mm
[Relationship between incident X-ray viewing angle and X-ray spectrum]
A sample containing 1 ng of each of Sc, Cr, Co, As, and Sr was examined for X-ray spectra obtained by irradiating non-monochromatic X-rays under the following measurement conditions with different viewing angles. The result is shown in FIG. 10A shows an X-ray spectrum when the viewing angle is set to 0.05 °, and FIG. 10B shows the X-ray spectrum when the viewing angle is set to 0.20 °. FIG. 10 (c) shows an X-ray spectrum when the viewing angle of a blank sample (sample obtained by dripping and drying 10 μl of ultrapure) is set to 0.05 °.
Measurement conditions ・ Power of natural air-cooled tungsten (W) target X-ray tube: tube voltage 25 kV, tube current 50 μA (1.25 W)
-X-ray detector: Si-PIN detector (maximum integrated count rate: ~ 2 x 10 5 cps)
・ Sample stage: Quartz optical flat ・ Distance between X-ray tube and sample center: 30mm
・ Distance between X-ray detector and sample center: 1mm

図10(a),(b)から明らかなように、視射角が大きい程、X線スペクトルのバックグラウンドが増大する。
25keVの入射X線が石英上で全反射する臨界角は約0.08°であり、この臨界角は入射X線のエネルギーが低いほど大きくなる。従って、視射角の増加と共にエネルギーが高い入射X線の反射率から減少していく。反射率が低いエネルギーを持つ入射X線は散乱され、スペクトルのバックグラウンド成分となる。
As is clear from FIGS. 10A and 10B, the background of the X-ray spectrum increases as the viewing angle increases.
The critical angle at which 25 keV incident X-rays are totally reflected on quartz is about 0.08 °, and this critical angle increases as the incident X-ray energy decreases. Accordingly, the reflectance of incident X-rays with high energy decreases as the viewing angle increases. Incident X-rays with low reflectivity energy are scattered and become the background component of the spectrum.

入射X線として単色化X線を用いれば、単色化X線として取り出したある波長帯のX線のバックグラウンドのみが視射角の増加に伴い増加する。
入射X線として非単色化X線を用いると、視射角の増加に伴いより広い波長帯のバックグラウンドが増大し、検出感度が低下する。しかし、全ての入射X線が全反射する視射角で測定を行えば、非単色化X線を用いてもバックグラウンドは低くなり、高感度分析が可能になる。
従って、全ての入射X線が全反射する条件の視射角(Φ=0.05°)で照射すれば、非単色化X線を用いた場合でもバックグラウンドを低く抑えることができ、1ngのSc,Cr,Co,As,Srを検出することができる。
If monochromatic X-rays are used as incident X-rays, only the background of X-rays in a certain wavelength band extracted as monochromatic X-rays increases as the viewing angle increases.
When non-monochromatic X-rays are used as incident X-rays, the background of a wider wavelength band increases with an increase in the viewing angle, and the detection sensitivity decreases. However, if measurement is performed at a viewing angle at which all incident X-rays are totally reflected, the background becomes low even when non-monochromatic X-rays are used, and high-sensitivity analysis is possible.
Therefore, if irradiation is performed at a viewing angle (Φ = 0.05 °) where all incident X-rays are totally reflected, the background can be kept low even when non-monochromatic X-rays are used, and 1 ng of Sc, Cr, Co, As, Sr can be detected.

図11はロジウムターゲット、タングステンターゲットのX線管を用いたときの分析対象元素の原子番号と検出下限との相関関係を示す。ロジウムターゲットについては、単色化X線及び非単色化X線を試料に照射したときの検出下限を、タングステンターゲットについては、非単色化X線を照射したときの検出下限を示す。   FIG. 11 shows the correlation between the atomic number of the element to be analyzed and the detection lower limit when an X-ray tube of a rhodium target or a tungsten target is used. For the rhodium target, the detection lower limit when the sample is irradiated with monochromatic X-rays and non-monochromatic X-ray is shown, and for the tungsten target, the detection lower limit when non-monochromatic X-ray is irradiated is shown.

ロジウムターゲットのX線管は、非単色化X線、単色化X線のいずれについても電力が、管電圧30kV、管電流50μA(1.5W)のものを、タングステンターゲットのX線はその電力が、管電圧25kV、管電流50μA(1.25W)のものを用いた。また、ロジウムターゲットのX線管を用いたときの測定時間は600秒、タングステンターゲットのX線管を用いたときの測定時間は1800秒とした。その他の条件は、上述した実施例1、2と同じである。   The rhodium target X-ray tube has a power of 30 kV and a tube current of 50 μA (1.5 W) for both non-monochromatic X-ray and monochromatic X-ray. A tube voltage of 25 kV and a tube current of 50 μA (1.25 W) were used. The measurement time when using a rhodium target X-ray tube was 600 seconds, and the measurement time when using a tungsten target X-ray tube was 1800 seconds. Other conditions are the same as in the first and second embodiments.

図11に示すように、タングステンターゲットX線管を用いたときの測定時間はロジウムターゲットX線管を用いたときの3倍であるが、測定時間を3倍にしても検出下限は1/√3に改善されるだけである。従って、タングステンターゲットのX線管を用いた方が、同じ測定時間(600秒)に換算しても検出下限が低くなる。
また、ロジウムターゲットのX線管を用いた場合において、非単色化X線を照射したときの方が、単色化X線を照射したときよりも検出下限が低くなった。タングステンターゲットのX線管を用いたときも同様の結果が得られると考えられる。
As shown in FIG. 11, the measurement time when using a tungsten target X-ray tube is three times that when using a rhodium target X-ray tube, but even if the measurement time is tripled, the detection lower limit is 1 / √. It is only improved to 3. Therefore, the lower limit of detection is lower when the tungsten target X-ray tube is used even when converted to the same measurement time (600 seconds).
Further, in the case of using a rhodium target X-ray tube, the lower limit of detection was lower when irradiated with non-monochromatic X-rays than when irradiated with monochromatic X-rays. It is considered that the same result can be obtained when using a tungsten target X-ray tube.

なお、ここでは、原子番号が20〜38の元素について測定したが、これらの原子番号の元素について得られた結果は、他の原子番号の元素についても一般化できることは良く知られている。   In addition, although it measured about the element of atomic number 20-38 here, it is well known that the result obtained about the element of these atomic numbers can be generalized also about the element of other atomic numbers.

以上より、非単色化X線を用いる方が単色化X線を用いるよりも微量元素の分析に適しており、タングステンターゲットX線管を用いた方がロジウムターゲットX線管を用いたときよりも微量元素の分析に適していることが分かる。   From the above, the use of non-monochromic X-rays is more suitable for analysis of trace elements than the use of monochromatized X-rays, and the use of a tungsten target X-ray tube is more suitable than the use of a rhodium target X-ray tube. It turns out that it is suitable for the analysis of trace elements.

実施例3では、分析感度を向上させるために最適な管電圧、管電流、ターゲット材、視射角、試料量、試料台の形状について検討した。ここでは、最大管電圧,最大管電流がそれぞれ50 kV,200μA のタングステンターゲットX線管(50 kV Magnum(Moxtek))を用いて蛍光X線分析装置を構成し、非単色化X線を試料に照射して以下の実験を行った。   In Example 3, the optimum tube voltage, tube current, target material, viewing angle, sample amount, and sample stage shape were studied in order to improve analysis sensitivity. Here, a fluorescent X-ray analyzer is constructed using a tungsten target X-ray tube (50 kV Magnum (Moxtek)) with a maximum tube voltage and a maximum tube current of 50 kV and 200 μA, respectively. The following experiments were conducted after irradiation.

〔管電圧と分析感度の関係〕
まず、X線管の管電流を50μA とし、管電圧を20,25,30,35 kV と変えて試料の蛍光X線スペクトルを測定した。入射X 線の視射角は,35 keV の全反射臨界角度(0.05°)よりも小さい0.04°とした。試料には、超純水を滴下乾燥した試料(ブランク試料)、及びそれぞれ0.5 ppmのSc,Cr,Co,As を含む混合標準試料溶液を1μl滴下乾燥したものを用いた。得られたブランク試料および混合標準試料の蛍光X線スペクトルから、管電圧と蛍光X線分析線の信号対バックグラウンド比の関係を求めた。その結果を図12に示す。
図12に示すように、管電圧が25kVのときにCr,Co,AsKα線の信号対バックグラウンド比が最も高くなった。また、管電圧が20から25kV辺りでScKα線の信号対バックグラウンド比が最も高くなった。
[Relationship between tube voltage and analysis sensitivity]
First, the fluorescent X-ray spectrum of the sample was measured by changing the tube current of the X-ray tube to 50 μA and changing the tube voltage to 20, 25, 30, 35 kV. The incident X-ray viewing angle was set to 0.04 °, which is smaller than the 35 keV total reflection critical angle (0.05 °). The sample used was a sample obtained by dripping and drying ultrapure water (blank sample), and a sample obtained by dripping and drying 1 μl of a mixed standard sample solution containing 0.5 ppm of Sc, Cr, Co, and As, respectively. The relationship between the tube voltage and the signal to background ratio of the fluorescent X-ray analysis line was determined from the fluorescent X-ray spectra of the obtained blank sample and mixed standard sample. The result is shown in FIG.
As shown in FIG. 12, when the tube voltage is 25 kV, the signal to background ratio of the Cr, Co, AsKα line is the highest. Further, the signal to background ratio of the ScKα line was the highest when the tube voltage was around 20 to 25 kV.

管電圧を上げるとX線管から発生するX線のエネルギー範囲が広くなり、管電圧の2乗に比例して連続X線の強度が強くなる。また、管電圧の上昇に伴い、試料台や試料からの入射X線の散乱が増加するため、管電圧を上げすぎると蛍光X線分析線の信号対バックグラウンド比が低下する。つまり、分析感度を改善するためには、最適な管電圧に設定することが重要である。   When the tube voltage is increased, the energy range of X-rays generated from the X-ray tube is widened, and the intensity of continuous X-rays increases in proportion to the square of the tube voltage. Further, as the tube voltage increases, scattering of incident X-rays from the sample stage and the sample increases. Therefore, if the tube voltage is increased too much, the signal to background ratio of the fluorescent X-ray analysis line decreases. That is, in order to improve the analysis sensitivity, it is important to set an optimum tube voltage.

以上から、広範囲の元素をK線励起で同時に高感度分析するための本装置の最適な管電圧は25kVあたりであると考えられる。また、この管電圧を25kVとして測定すれば、K線及びL線励起により、周期表上でベリリウムからウランまでの元素を分析することが可能であると考えられる。   From the above, it is considered that the optimum tube voltage of this apparatus for simultaneously analyzing a wide range of elements with high sensitivity by K-ray excitation is around 25 kV. If this tube voltage is measured at 25 kV, it is considered that elements from beryllium to uranium can be analyzed on the periodic table by K-line and L-line excitation.

〔管電流と分析感度の関係〕
タングステンターゲットX線管の管電圧を上述の最適値(25 kV)とし、管電流を20,50,100,150,200μAに変えて試料の全反射蛍光X線スペクトルを測定した。入射X線の視射角は,35 keV の全反射臨界角度(0.05°)よりも小さい0.04°とした。上述の管電圧の最適値を求めたときと同様、試料には、それぞれ0.5 ppmのSc,Cr,Co,As を含む混合標準試料溶液を1μl滴下乾燥したものを用いた。得られた試料の蛍光X線スペクトルから、管電流と蛍光X線分析線の信号対バックグラウンド比の関係を求めた。その結果を図13に示す。
[Relationship between tube current and analytical sensitivity]
The total reflection fluorescent X-ray spectrum of the sample was measured by changing the tube voltage of the tungsten target X-ray tube to the above optimum value (25 kV) and changing the tube current to 20, 50, 100, 150, and 200 μA. The incident X-ray viewing angle was 0.04 °, which is smaller than the 35 keV total reflection critical angle (0.05 °). As in the case of obtaining the optimum value of the tube voltage described above, 1 μl of a mixed standard sample solution containing 0.5 ppm of Sc, Cr, Co, and As was used as the sample. From the fluorescent X-ray spectrum of the obtained sample, the relationship between the tube current and the signal to background ratio of the fluorescent X-ray analysis line was determined. The result is shown in FIG.

管電流に比例してX線管から発生する連続X線の強度は大きくなるので、蛍光X線面積強度及びバックグラウンド強度は管電流にほぼ比例して強くなる。従って、図13に示すように、各試料の蛍光X線分析線の信号対バックグラウンド比は管電流によらず略一定であった。   Since the intensity of continuous X-rays generated from the X-ray tube increases in proportion to the tube current, the fluorescent X-ray area intensity and the background intensity increase in proportion to the tube current. Therefore, as shown in FIG. 13, the signal to background ratio of the fluorescent X-ray analysis line of each sample was substantially constant regardless of the tube current.

〔ターゲット材と分析感度の関係〕
X線管から発生する連続X線の強度はターゲット材の原子番号に比例して大きくなる。そこで、ターゲット材と分析感度の関係を調べた。実験は、タングステンターゲットX線管(タングステンの原子番号:74)及びロジウムターゲットX線管(ロジウムの原子番号:45)を用い、ロジウムターゲットX線管では管電圧を30kV、管電流を50μAとして、タングステンターゲットX線管では管電圧を25 kV、管電流を50μAとして試料の全反射蛍光X線スペクトルを測定することにより行った。入射X 線の視射角は0.04°とした。また試料には、それぞれ0.1 ppmのSc,Cr,Co,As, Sr を含む混合標準試料溶液を10μl滴下乾燥したものを用いた。得られた試料の蛍光X線スペクトルから、ターゲット材の原子番号と蛍光X線分析線の信号対バックグラウンド比の関係を求めた。その結果を図14に示す。
[Relationship between target material and analysis sensitivity]
The intensity of continuous X-rays generated from the X-ray tube increases in proportion to the atomic number of the target material. Therefore, the relationship between the target material and analysis sensitivity was examined. In the experiment, a tungsten target X-ray tube (atomic number of tungsten: 74) and a rhodium target X-ray tube (atomic number of rhodium: 45) were used. The tungsten target X-ray tube was measured by measuring the total reflection fluorescent X-ray spectrum of the sample at a tube voltage of 25 kV and a tube current of 50 μA. The incident angle of incident X-rays was 0.04 °. The sample used was a 10 μl drop-dried mixed standard sample solution containing 0.1 ppm of Sc, Cr, Co, As, and Sr. From the fluorescent X-ray spectrum of the obtained sample, the relationship between the atomic number of the target material and the signal to background ratio of the fluorescent X-ray analysis line was determined. The result is shown in FIG.

タングステン管から発生する連続X線の強度はロジウム管よりも大きく、発生する特性X線の強度も大きくなるため、タングステン管を用いる方が元素の励起効率が高くなる。以上から、タングステン管を用いることにより、蛍光X線分析線の信号対バックグラウンド強度比を改善することができる。   The intensity of continuous X-rays generated from a tungsten tube is higher than that of a rhodium tube, and the intensity of generated characteristic X-rays is also increased. Therefore, the use of a tungsten tube increases the element excitation efficiency. From the above, the signal to background intensity ratio of the fluorescent X-ray analysis line can be improved by using the tungsten tube.

〔入射角(視射角)と分析感度の関係〕
視射角の増大に伴い、試料台からの入射X線の散乱が増加し、スペクトルのバックグラウンドが高くなる。そこで、入射X線の視射角と分析感度との関係を調べた。実験は、タングステンターゲットX線管を用い、管電圧を25kV、管電流を50μAとした。そして、入射X線の視射角を0.00, 0.05, 0.10, 0.15, 0.20°に変えて試料の全反射蛍光X線スペクトルを測定した。試料には、0.1 ppmのSc,Cr,Co,As をそれぞれ含む混合標準試料溶液を10 μl滴下乾燥したものを用いた。得られた試料の蛍光X線スペクトルから、入射X線の視射角と蛍光X線分析線の信号対バックグラウンド比の関係を求めた。その結果を図15に示す。
[Relationship between incident angle (sight angle) and analysis sensitivity]
As the viewing angle increases, the scattering of incident X-rays from the sample stage increases and the spectral background increases. Therefore, the relationship between the incident X-ray viewing angle and the analysis sensitivity was examined. In the experiment, a tungsten target X-ray tube was used, the tube voltage was 25 kV, and the tube current was 50 μA. Then, the total reflection fluorescent X-ray spectrum of the sample was measured while changing the viewing angle of the incident X-ray to 0.00, 0.05, 0.10, 0.15, 0.20 °. The sample used was a 10 μl drop-dried mixed standard sample solution containing 0.1 ppm of Sc, Cr, Co, and As. From the fluorescent X-ray spectrum of the obtained sample, the relationship between the incident angle of the incident X-ray and the signal to background ratio of the fluorescent X-ray analysis line was determined. The result is shown in FIG.

図15に示すように、AsKα線の信号対バックグラウンド強度比は視射角が0.00°のときに最も高くなったが、Sc,Cr,Co,Kα線の信号対バックグラウンド強度比は視射角0.05°辺りで最も高くなった。以上から、広範囲の元素を高感度で同時に分析するために最適な視射角は0.05°辺りであると考えられた。   As shown in FIG. 15, the signal-to-background intensity ratio of the AsKα line was the highest when the viewing angle was 0.00 °, but the signal-to-background intensity ratio of the Sc, Cr, Co, Kα line was It was the highest around an angle of 0.05 °. From the above, the optimal viewing angle for analyzing a wide range of elements simultaneously with high sensitivity was considered to be around 0.05 °.

〔試料量と元素の励起効率の関係〕
試料量を少なくすると、試料残渣から入射X線の散乱が減少し、蛍光X線の励起への反射X線の寄与が増加するため、感度係数(counts/ng)が改善されると考えられる。このことを調べるために、ロジウムターゲットX線管を用い、管電圧を30kV、管電流を50μAとして試料の全反射蛍光X線スペクトルを測定し、感度係数(counts/ng)を求めた。試料には、超純水を滴下乾燥した試料(ブランク試料)及びSc,Cr,Co,As, Sr, Zn をそれぞれ0.1〜10ppm含む混合標準試料溶液を10μl滴下乾燥したものを用いた。例えば、それぞれ0.1ppmのSc,Cr,Co,As, Sr, Znを含む混合標準溶液を10 μlを滴下乾燥すると、その乾燥残渣中にはそれぞれ1 ngのSc,Cr,Co,As, Sr, Znが含まれる。その結果を図16に示す。
[Relationship between sample volume and element excitation efficiency]
When the sample amount is reduced, the scattering of incident X-rays from the sample residue is reduced, and the contribution of reflected X-rays to the excitation of fluorescent X-rays is increased, so the sensitivity coefficient (counts / ng) is considered to be improved. In order to investigate this, a total reflection fluorescent X-ray spectrum of the sample was measured using a rhodium target X-ray tube, a tube voltage of 30 kV, a tube current of 50 μA, and a sensitivity coefficient (counts / ng) was obtained. The sample used was a sample obtained by dripping and drying ultrapure water (blank sample) and a sample obtained by dripping and drying 10 μl of a mixed standard sample solution containing 0.1 to 10 ppm of Sc, Cr, Co, As, Sr, and Zn, respectively. For example, when 10 μl of a mixed standard solution containing 0.1 ppm of Sc, Cr, Co, As, Sr, Zn is dropped and dried, 1 ng of Sc, Cr, Co, As, Sr, Zn is included. The result is shown in FIG.

図16に示すように、いずれの試料についても含有元素の量が1ng辺りのときに感度係数が最も高くなった。従って、含有元素の量を1ngとすれば、検出感度を向上できる。   As shown in FIG. 16, the sensitivity coefficient was the highest when the amount of the contained element was around 1 ng for any sample. Accordingly, if the amount of the contained element is 1 ng, the detection sensitivity can be improved.

〔試料台の形状の最適化〕
試料台の形状により分析感度が変化するかを調べるために、直径3cmの円板状の石英ガラス製の試料台(円形試料台)及び3cm四方の矩形(正方形)板状の石英ガラス製の試料台(正方形試料台)を用いて蛍光X線スペクトルを測定した。測定には、タングステンターゲットX線管を用い、管電圧を25 kV、管電流を200μA、視射角を0.04°とした。また、試料台には何も滴下せずに測定した。従って、得られたスペクトルはバックグラウンドの蛍光X線スペクトルに相当する。その結果を図17に示す。
図17中、黒く塗りつぶしたスペクトルが正方形試料台の蛍光X線スペクトルを、実線で示したスペクトルが円形試料台の蛍光X線スペクトルを示している。図17から、円形試料台を用いた方がバックグラウンドが大きくなることが分かる。
[Optimization of sample stage shape]
In order to investigate whether the analytical sensitivity changes depending on the shape of the sample stage, a sample plate made of quartz glass (circular sample stage) with a diameter of 3 cm and a sample made of quartz glass with a square (square) plate shape of 3 cm square A fluorescent X-ray spectrum was measured using a table (square sample table). For the measurement, a tungsten target X-ray tube was used, the tube voltage was 25 kV, the tube current was 200 μA, and the viewing angle was 0.04 °. Moreover, it measured, without dripping anything on a sample stand. Therefore, the obtained spectrum corresponds to the background fluorescent X-ray spectrum. The result is shown in FIG.
In FIG. 17, the blacked-out spectrum indicates the fluorescent X-ray spectrum of the square sample stage, and the spectrum indicated by the solid line indicates the fluorescent X-ray spectrum of the circular sample stage. It can be seen from FIG. 17 that the background becomes larger when the circular sample stage is used.

この理由を図18を用いて説明する。図18に示すように、試料台の端部(エッジ部分)に当たった入射X線は散乱する。このエッジからの散乱X線は様々な方向に進むが、円形試料台の方が正方形試料台よりも、多くの散乱X線がX線検出器に向かう。すなわち、X線管と試料台との距離が一定の場合、正方形試料台であれば、円形試料台と比較してエッジと検出器の距離が遠くなる。例えば、正方形試料台であれば、円形試料台の場合にエッジであった部分も試料台上であるため、入射X線が全反射し、円形試料台と比較してエッジからの散乱X線が検出器に入射し辛い。このため、円形試料台の方が正方形試料台よりもバックグラウンドが増大する。従って、分析感度を改善するためには、エッジと検出器の距離が遠くなるよう、例えば矩形の試料台、正方形試料台を用いることが好ましい。   The reason for this will be described with reference to FIG. As shown in FIG. 18, the incident X-rays that hit the end (edge portion) of the sample stage are scattered. Although scattered X-rays from this edge travel in various directions, more scattered X-rays are directed to the X-ray detector in the circular sample stage than in the square sample stage. That is, when the distance between the X-ray tube and the sample stage is constant, the distance between the edge and the detector is longer in the case of the square sample stage as compared with the circular sample stage. For example, in the case of a square sample table, since the portion that was an edge in the case of a circular sample table is also on the sample table, the incident X-rays are totally reflected, and the scattered X-rays from the edge are compared with the circular sample table. Difficult to enter the detector. For this reason, the background of the circular sample stage increases more than the square sample stage. Therefore, in order to improve the analysis sensitivity, it is preferable to use, for example, a rectangular sample stand or a square sample stand so that the distance between the edge and the detector is increased.

10…全反射蛍光X線分析装置
13…X線照射部
132…X線管
14…検出部
15…導波路
17…試料台
DESCRIPTION OF SYMBOLS 10 ... Total reflection fluorescent X-ray analyzer 13 ... X-ray irradiation part 132 ... X-ray tube 14 ... Detection part 15 ... Waveguide 17 ... Sample stand

Claims (7)

試料台に水溶液試料を滴下して乾燥させ、当該試料台上に残った残渣に1次X線を照射することにより前記水溶液試料中の微量な元素分析を行う全反射蛍光X線分析装置であって、
前記1次X線を照射するX線照射部と、
前記X線照射部のX線照射により発生する蛍光X線を検出するX線検出部とを備え、
前記X線照射部が、ロジウムをターゲット材とするX線管、又はタングステンをターゲット材とするX線管を含んで構成されており、前記X線管の管電圧が20kV以上、35kV以下であり、且つ、出力が5W以下であることを特徴とする全反射蛍光X線分析装置。
This is a total reflection X-ray fluorescence spectrometer that performs an elemental analysis of a trace amount in the aqueous solution sample by dropping an aqueous solution sample onto the sample stage and drying it, and irradiating the residue remaining on the sample stage with primary X-rays. And
An X-ray irradiation unit for irradiating the primary X-ray;
An X-ray detection unit that detects fluorescent X-rays generated by X-ray irradiation of the X-ray irradiation unit,
The X-ray irradiation unit is configured to include an X-ray tube using rhodium as a target material or an X-ray tube using tungsten as a target material, and the tube voltage of the X-ray tube is 20 kV or more and 35 kV or less. A total reflection fluorescent X-ray analyzer having an output of 5 W or less .
前記X線照射部から照射された1次X線を前記試料台に導く導波路を備え、
前記導波路は、2枚のシリコンウェハーと、これらシリコンウェハーで挟持され前記シリコンウェハーとの間に1次X線の通路を形成する一対のタングステン箔と、前記シリコンウェハー及び前記タングステン箔を保持する金属製のハウジングから構成されていることを特徴とする請求項1に記載の全反射蛍光X線分析装置。
A waveguide for guiding primary X-rays irradiated from the X-ray irradiation unit to the sample stage;
The waveguide holds two silicon wafers, a pair of tungsten foils sandwiched between the silicon wafers to form a primary X-ray path between the silicon wafers, and the silicon wafers and the tungsten foils. The total reflection X-ray fluorescence spectrometer according to claim 1, comprising a metal housing.
前記導波路は、幅が10mmのX線出口を備えることを特徴とする請求項2に記載の全反射蛍光X線分析装置。   The total reflection X-ray fluorescence spectrometer according to claim 2, wherein the waveguide includes an X-ray exit having a width of 10 mm. 前記タングステン箔は厚さが10μmであることを特徴とする請求項2又は3に記載の全反射蛍光X線分析装置。   The total reflection X-ray fluorescence spectrometer according to claim 2 or 3, wherein the tungsten foil has a thickness of 10 µm. 前記X線管の管電圧が、20kV以上30kV以下であることを特徴とする請求項1〜4のいずれかに記載の全反射蛍光X線分析装置。 The total reflection fluorescent X-ray analyzer according to any one of claims 1 to 4, wherein a tube voltage of the X-ray tube is 20 kV or more and 30 kV or less. 前記試料台上の残渣にX線を照射したときの前記X線検出部の計数率が当該X線検出部の最大積分計数率よりも小さくなるように、前記X線管及び前記X線検出部が構成されていることを特徴とする請求項1〜5のいずれかに記載の全反射蛍光X線分析装置。 The X-ray tube and the X-ray detector so that the count rate of the X-ray detector when the residue on the sample stage is irradiated with X-rays is smaller than the maximum integrated count rate of the X-ray detector. The total reflection fluorescent X-ray analyzer according to claim 1 , wherein: 前記試料台が矩形板状であることを特徴とする1〜のいずれかに記載の全反射蛍光X線分析装置。 The total reflection fluorescent X-ray analyzer according to any one of 1 to 6 , wherein the sample stage is a rectangular plate.
JP2010527698A 2008-09-02 2009-09-02 Total reflection X-ray fluorescence analyzer and total reflection X-ray fluorescence analysis method Active JP5846469B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2010527698A JP5846469B2 (en) 2008-09-02 2009-09-02 Total reflection X-ray fluorescence analyzer and total reflection X-ray fluorescence analysis method

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2008225046 2008-09-02
JP2008225046 2008-09-02
JP2010527698A JP5846469B2 (en) 2008-09-02 2009-09-02 Total reflection X-ray fluorescence analyzer and total reflection X-ray fluorescence analysis method
PCT/JP2009/004328 WO2010026750A1 (en) 2008-09-02 2009-09-02 Total-reflection fluorescent x-ray analysis device, and total-reflection fluorescent x-ray analysis method

Publications (2)

Publication Number Publication Date
JPWO2010026750A1 JPWO2010026750A1 (en) 2012-02-02
JP5846469B2 true JP5846469B2 (en) 2016-01-20

Family

ID=41796934

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2010527698A Active JP5846469B2 (en) 2008-09-02 2009-09-02 Total reflection X-ray fluorescence analyzer and total reflection X-ray fluorescence analysis method

Country Status (2)

Country Link
JP (1) JP5846469B2 (en)
WO (1) WO2010026750A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2706445C1 (en) * 2019-01-09 2019-11-19 Акционерное общество "Научные приборы" Device for waveguide-resonance x-ray fluorescence element analysis

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6378056A (en) * 1986-09-20 1988-04-08 Rigaku Denki Kogyo Kk Total reflection fluorescent x-ray analyzer
JPH052057U (en) * 1991-06-24 1993-01-14 理学電機工業株式会社 Dummy for height adjustment in total reflection X-ray fluorescence analyzer
JPH0961382A (en) * 1995-08-24 1997-03-07 Hitachi Ltd Total reflection fluorescent x-ray analyzer
JP2000214107A (en) * 1998-11-18 2000-08-04 Rigaku Industrial Co X-ray fluorescence analyzer
JP2000298107A (en) * 1999-04-14 2000-10-24 Sony Corp Holding device for analytical sample and analytical method for sample
JP2008122144A (en) * 2006-11-09 2008-05-29 Rigaku Industrial Co Specimen drip substrate for total-reflection fluorescence x-ray analysis, total reflection fluorescent x-ray analyzer, and total reflection fluorescent x-ray analysis method

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0610660B2 (en) * 1984-10-05 1994-02-09 川崎製鉄株式会社 Method for measuring film thickness and composition of alloy film
JPH0627056A (en) * 1992-07-09 1994-02-04 Ricoh Co Ltd Method for alalyzing composition and structure of substance
JP2001124711A (en) * 1999-10-27 2001-05-11 Fujitsu Ltd Fluorescence x-ray analysis method and evaluation method of sample structure
JP5159068B2 (en) * 2005-09-01 2013-03-06 独立行政法人科学技術振興機構 Total reflection X-ray fluorescence analyzer
JP4759750B2 (en) * 2005-12-21 2011-08-31 国立大学法人京都大学 Method of manufacturing curvature distribution crystal lens, polarization control device, X-ray reflectivity measuring device, and X-ray reflectivity measuring method

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6378056A (en) * 1986-09-20 1988-04-08 Rigaku Denki Kogyo Kk Total reflection fluorescent x-ray analyzer
JPH052057U (en) * 1991-06-24 1993-01-14 理学電機工業株式会社 Dummy for height adjustment in total reflection X-ray fluorescence analyzer
JPH0961382A (en) * 1995-08-24 1997-03-07 Hitachi Ltd Total reflection fluorescent x-ray analyzer
JP2000214107A (en) * 1998-11-18 2000-08-04 Rigaku Industrial Co X-ray fluorescence analyzer
JP2000298107A (en) * 1999-04-14 2000-10-24 Sony Corp Holding device for analytical sample and analytical method for sample
JP2008122144A (en) * 2006-11-09 2008-05-29 Rigaku Industrial Co Specimen drip substrate for total-reflection fluorescence x-ray analysis, total reflection fluorescent x-ray analyzer, and total reflection fluorescent x-ray analysis method

Also Published As

Publication number Publication date
JPWO2010026750A1 (en) 2012-02-02
WO2010026750A1 (en) 2010-03-11

Similar Documents

Publication Publication Date Title
JP4874118B2 (en) X-ray fluorescence analyzer
US7023955B2 (en) X-ray fluorescence system with apertured mask for analyzing patterned surfaces
US7680243B2 (en) X-ray measurement of properties of nano-particles
WO2006060347A1 (en) Portable and on-line x-ray analyzer
Vanhoof et al. Energy-dispersive X-ray fluorescence systems as analytical tool for assessment of contaminated soils
Kunimura et al. Polychromatic excitation improves detection limits in total reflection X-ray fluorescence analysis compared with monochromatic excitation
Kunimura et al. Trace elemental analysis of commercial bottled drinking water by a portable total reflection X-ray fluorescence spectrometer
Sanyal et al. Drastic improvement in detection limits in energy dispersive X-ray fluorescence geometry utilizing micro-focused bremsstrahlung excitation in thin-film sample specimen
EP0464671A2 (en) System for analyzing metal impurity on the surface of a single crystal semiconductor by using total reflection of x-rays fluorescence
JP5846469B2 (en) Total reflection X-ray fluorescence analyzer and total reflection X-ray fluorescence analysis method
Kujala et al. High resolution short focal distance Bent Crystal Laue Analyzer for copper K edge x-ray absorption spectroscopy
Harada et al. K-line X-ray fluorescence analysis of high-Z elements
Das et al. Effect of synchrotron polarization on grazing incidence X-ray fluorescence analysis
Liu et al. Multi-element analysis by portable total reflection X-ray fluorescence spectrometer
JP2006038822A (en) Fluorescent x-ray analyzer
Maderitsch et al. Feasibility study of total reflection X-ray fluorescence analysis using a liquid metal jet X-ray tube
JP4537149B2 (en) X-ray fluorescence analysis method
JP2006030018A (en) X-ray fluorescence analyzer
JP4473246B2 (en) X-ray fluorescence analyzer and X-ray fluorescence analysis method
Brown X-ray fluorescence analysis. A review
JPH11248653A (en) Method and device for analyzing total reflection fluorescent x-ray
JPH03160353A (en) Fluorescent x-ray analysis and fluorescent x-ray spectrometer
KR950010390B1 (en) Total reflection of x-rays fluorescence analyzing apparatus
Wobrauschek et al. Txrf-Sources-Samples and Detectors
JP2759922B2 (en) Method for measuring high-order X-ray intensity

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20120831

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20130618

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20140304

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A821

Effective date: 20140604

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20151019

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20151112

R150 Certificate of patent or registration of utility model

Ref document number: 5846469

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250