JP2008203245A - X-ray analysis apparatus and x-ray analysis method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a stable behavior of an X-ray source, and stably implement quantitative analysis in an X-ray analysis apparatus, and to provide an X-ray analysis method. <P>SOLUTION: The X-ray analysis apparatus comprises an X-ray lamp 3 for irradiating a sample 1 with a primary X rays; a primary X-ray adjustment mechanism 4 for adjusting the intensity of the primary X rays; an X-ray detector 5 for detecting the characteristic X rays emitted from the sample 1, and outputting a signal that contains energy information on the characteristic X rays and scattered X rays; an analyzer 6 for analyzing the signal; and an incident X-ray adjusting mechanism 7, disposed in between the sample 1 and the X-ray detector 5 and can adjust the total intensity of the characteristic X rays and the scattered X rays that enter the X-ray detector 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an X-ray analysis apparatus and an X-ray analysis method suitable for, for example, energy dispersive fluorescent X-ray analysis.

  X-ray fluorescence analysis irradiates a sample with X-rays emitted from an X-ray source, and detects the fluorescent X-rays, which are characteristic X-rays emitted from the sample, with an X-ray detector. Acquire and perform qualitative analysis or quantitative analysis of the sample. This fluorescent X-ray analysis is widely used in processes and quality control because samples can be analyzed quickly and non-destructively. In recent years, high precision and high sensitivity have been achieved, and trace measurement has become possible. In particular, it is expected to be widely used as an analytical method for detecting harmful substances contained in materials and soil.

This fluorescent X-ray analysis can be performed using a wavelength dispersion method in which fluorescent X-rays are dispersed with a spectroscopic crystal and the wavelength and intensity of the X-rays are measured. There are energy dispersion methods for measuring the energy and intensity of X-rays.
Conventionally, for example, Patent Document 1 discloses that an X-ray source emits primary X-rays through a primary filter and irradiates the measurement sample with X-rays emitted from the measurement sample that has received the primary X-ray. A fluorescent X-ray analyzer that performs elemental analysis of a measurement sample by detecting with a detector is disclosed.
In this fluorescent X-ray analyzer, one of the tube current of the X-ray tube and a plurality of types of primary filters is selected, and the intensity of the primary X-rays from the X-ray source is adjusted by the primary filter. Thus, the background is reduced and the intensity of fluorescent X-rays incident on the X-ray detector is adjusted.

JP 2004-150990 A

The following problems remain in the conventional technology.
In the conventional X-ray analyzer, since there is a limitation on the normal operation range (maximum obtainable X-ray intensity: maximum X-ray acquisition intensity) in the X-ray detector, the tube current of the X-ray tube used as the X-ray source As described above, the intensity of fluorescent X-rays and scattered X-rays incident on the X-ray detector is adjusted by the primary filter as described above. Here, since the lower detection limit in the X-ray analyzer can be improved as the intensity of the fluorescent X-rays incident on the X-ray detector is higher, the primary X is irradiated so that the detection can be performed with almost the maximum X-ray acquisition intensity. It is set by adjusting the line strength. However, depending on the measurement sample, fluorescent X-rays and scattered X-rays incident on the X-ray detector may be too large, and in some cases, the tube current of the X-ray tube exceeds the normal operating range of the X-ray tube. There is a problem that the X-ray intensity generated from the X-ray tube becomes unstable, and quantitative analysis by the calibration curve method becomes difficult.
For example, conventionally, the maximum X-ray acquisition intensity of an X-ray detector is 200,000 cps (Counts Per Second), and the normal operating range of an X-ray tube is a range from a maximum tube current value of 1000 μA to a minimum tube current value of 200 μA. , If 100,000 cps is obtained at a tube current of 20 μA in the coarse measurement, the tube current is set to double 40 μA in this measurement to match the maximum X-ray acquisition intensity of the X-ray tube. The X-ray tube is set to obtain a maximum X-ray acquisition intensity of 200,000 cps. In this case, the tube current does not reach the normal operating range of the X-ray tube, and thus the X-ray intensity generated from the X-ray tube becomes unstable, and accordingly, the detected X-ray intensity becomes unstable. Therefore, there has been a disadvantage that quantitative analysis is difficult.

  The present invention has been made in view of the above-mentioned problems. An X-ray analysis apparatus and an X-ray analysis method capable of stably performing quantitative analysis by causing a radiation source such as an X-ray source to operate normally and stably operate. The purpose is to provide.

  The present invention employs the following configuration in order to solve the above problems. That is, the X-ray analyzer of the present invention detects a radiation source that irradiates a sample with radiation, a radiation adjustment mechanism that can adjust the intensity of the radiation, and characteristic X-rays and scattered X-rays emitted from the sample. An X-ray detector that outputs a signal including energy information of the characteristic X-rays and scattered X-rays, an analyzer that analyzes the signal, and the X-ray disposed between the sample and the X-ray detector. And an incident X-ray adjusting mechanism that adjusts the total intensity of the characteristic X-rays and scattered X-rays incident on the detector.

  In this X-ray analyzer, the radiation intensity adjusting mechanism capable of adjusting the intensity of radiation and the total intensity of characteristic X-rays and scattered X-rays that are arranged between the sample and the X-ray detector and are incident on the X-ray detector. The incident X-ray adjustment mechanism can be adjusted so that the maximum intensity of the X-ray detector can be adjusted by adjusting both the intensity of irradiated radiation and the total intensity of incident characteristic X-rays and scattered X-rays. Measurement can be performed by taking full advantage of the radiation irradiation ability of the radiation source while taking into account the X-ray acquisition intensity.

  In the X-ray analyzer of the present invention, the total intensity of characteristic X-rays and scattered X-rays detected by the X-ray detector is substantially the maximum X-ray acquisition intensity, and the radiation intensity is the radiation irradiation capability of the radiation source. And a control unit for controlling the incident X-ray adjustment mechanism and the radiation adjustment mechanism so as to be within the normal operating range. That is, in this X-ray analyzer, the control unit controls the incident X-ray adjustment mechanism and the radiation adjustment mechanism, and the total intensity of characteristic X-rays and scattered X-rays detected by the X-ray detector is almost the maximum X-ray acquisition intensity. In addition, by setting the intensity of the radiation to be within the normal operating range of the radiation irradiation capability of the radiation source, stable radiation irradiation and high characteristic X-ray intensity at the X-ray detector can be easily obtained and quantitatively determined. Analysis can be performed stably.

また、立体角の計算は乱数を使用したモンテカルロ・シミュレーションによって求めることも可能である。
このＸ線分析装置では、入射Ｘ線調整機構として、試料から発生する特性Ｘ線及び散乱Ｘ線が検出面を見込む入射立体角を調整可能なコリメータを採用するので、特性Ｘ線及び散乱Ｘ線の入射立体角に応じてＸ線検出器の検出面に入射される特性Ｘ線及び散乱Ｘ線が制限されてその強度を容易に調整することができる。 In the X-ray analyzer of the present invention, the X-ray detector has a detection surface on which the characteristic X-rays and scattered X-rays are incident, and the incident X-ray adjustment mechanism has the characteristic X with respect to the detection surface. It is a collimator that can adjust the solid angle of incidence of X-rays and scattered X-rays. Here, the solid angle generally refers to the part delimited by a conical surface created by the movement of a half line coming out from the same point in space (vertex of the corner). Show. Specifically, it is defined as the area occupied on the surface for a sphere having a radius of 1. In practice, radiation sources and detectors are not points but have a finite extent. As shown in FIG. 5, the solid angle when the disk-shaped radiation source and the disk-shaped detector are both placed perpendicular to the common axis passing through both centers is calculated by the following calculation formula. The

The solid angle can also be calculated by Monte Carlo simulation using random numbers.
In this X-ray analyzer, as the incident X-ray adjustment mechanism, a collimator capable of adjusting the incident solid angle at which the characteristic X-rays and scattered X-rays generated from the sample look into the detection surface is adopted. The characteristic X-rays and scattered X-rays incident on the detection surface of the X-ray detector are limited according to the incident solid angle, and the intensity thereof can be easily adjusted.

  Furthermore, in the X-ray analysis apparatus of the present invention, the incident X-ray adjusting mechanism has an X-ray incident hole through which the characteristic X-ray and scattered X-ray pass and enter the detection surface, and the X-rays having different aperture diameters. It is an opening diameter changing mechanism that can be changed to a line incident hole. That is, since this X-ray analyzer employs an aperture diameter changing mechanism that can be changed to an X-ray incident hole having a different aperture diameter, the characteristic X-rays and scattered X-rays can be incident by changing the aperture diameter of the X-ray incident hole. The solid angle can be easily changed.

  In the X-ray analysis apparatus of the present invention, the opening diameter changing mechanism has a plurality of the X-ray incident holes having different opening diameters, and any one of the X-ray incident holes is detected. It can be arbitrarily arranged between a surface and the sample. That is, in this X-ray analyzer, since the aperture diameter changing mechanism arbitrarily selects and installs one of a plurality of X-ray incident holes having different aperture diameters, a plurality of incident solid angles are prepared in advance. Therefore, the incident solid angle can be easily switched.

  Moreover, the X-ray analyzer of the present invention is characterized in that the incident X-ray adjusting mechanism has a position adjusting mechanism capable of adjusting an interval between the X-ray incident hole and the detection surface. That is, in this X-ray analyzer, the position adjustment mechanism changes the distance between the X-ray incident hole and the detection surface, and therefore, even if there is only one X-ray incident hole according to the distance, the characteristic X-ray is continuously obtained. The incident solid angle of scattered X-rays can be changed, and the total intensity of incident characteristic X-rays and scattered X-rays can be adjusted with high accuracy. If a plurality of X-ray incident holes having different opening diameters can be arbitrarily selected, a high degree of freedom in changing the incident solid angle can be obtained in a wider range by adjusting the interval by the position adjusting mechanism.

  The X-ray analysis method of the present invention includes a step of irradiating a sample with radiation from a radiation source at a preset intensity of radiation for rough measurement, and a total intensity of characteristic X-rays and scattered X-rays emitted from the sample. A step of detecting a coarse measurement value with an X-ray detector, and a total intensity of characteristic X-rays and scattered X-rays detected by the X-ray detector based on the intensity of the radiation for coarse measurement and the coarse measurement value The intensity of the radiation is adjusted by a radiation adjustment mechanism so that the intensity of the X-ray acquisition is approximately the maximum and the intensity of the radiation is within a normal operating range of the radiation irradiation capability of the radiation source, and the sample and the X-ray detector are adjusted. Adjusting the total intensity of the characteristic X-rays and scattered X incident on the X-ray detector by an incident X-ray adjusting mechanism disposed between the X-ray detector and the X-ray in the main measurement. Characteristic X-ray and scattering obtained by a ray detector And outputting a signal containing energy information about the line, characterized in that it has the steps of: analyzing said signal in analyzer.

  In this X-ray analysis method, by performing the above-described rough measurement, the relationship in the default condition is obtained in advance for the level of the intensity of irradiation radiation in the sample and the total intensity of characteristic X-rays and scattered X-rays. The total intensity of the characteristic X-rays and scattered X-rays detected by the X-ray detector by the radiation adjustment mechanism and the incident X-ray adjustment mechanism is almost the maximum X-ray acquisition intensity, and the radiation intensity is the radiation irradiation ability of the radiation source. Both the intensity of radiation to be irradiated and the total intensity of characteristic X-rays and scattered X-rays incident on the X-ray detector are adjusted so as to be within the normal operating range. Therefore, in this measurement, since the radiation irradiation capability is within the normal operating range, stable radiation irradiation of the radiation source can be obtained, and quantitative analysis can be performed stably.

The present invention has the following effects.
That is, according to the X-ray analysis apparatus and the X-ray analysis method of the present invention, the intensity of radiation irradiated by the radiation adjustment mechanism is adjusted, and the characteristic X-ray incident on the X-ray detector by the incident X-ray adjustment mechanism In addition, the total intensity of the scattered X-rays is adjusted, so that the maximum X-ray acquisition intensity of the X-ray detector can be taken into account, making it possible to make the best use of the radiation irradiation capability of the radiation source, and the quantitative analysis can be performed stably. Will be able to.

  Hereinafter, a first embodiment of an X-ray analysis apparatus and an X-ray analysis method according to the present invention will be described with reference to FIGS. 1 to 3.

  The X-ray analyzer of this embodiment is an energy dispersive fluorescent X-ray analyzer, and as shown in FIGS. 1 to 3, a sample stage 2 for fixing a sample 1 and primary X-rays (radiation). X-ray tube (radiation source) 3 that irradiates sample 1 with light, primary X-ray adjustment mechanism (radiation adjustment mechanism) 4 that can adjust the intensity of primary X-rays, and characteristic X-rays emitted from sample 1 An X-ray detector 5 that detects scattered X-rays and outputs a signal including energy information of the characteristic X-rays and scattered X-rays, an analyzer 6 that is connected to the X-ray detector 5 and analyzes the signals, and a sample 1 and an X-ray detector 5, an incident X-ray adjustment mechanism 7 capable of adjusting the total intensity of characteristic X-rays and scattered X-rays incident on the X-ray detector 5 and primary X-ray adjustment A control unit C that controls the mechanism 4 and the incident X-ray adjustment mechanism 7, and an analysis processor 8 that is connected to the analyzer 6 and the control unit C It is equipped with a.

The sample stage 2 includes a stepping motor (not shown) or the like that enables horizontal movement while the sample 1 is fixed.
In the X-ray tube 3, thermoelectrons generated from a filament (anode) in the tube are accelerated by a voltage applied between the filament (anode) and a target (cathode), and the target W (tungsten), Mo X-rays generated by colliding with (molybdenum), Cr (chromium), etc. are emitted as primary X-rays from a window such as beryllium foil.

The primary X-ray adjustment mechanism 4 is capable of adjusting the tube voltage and tube current of the X-ray tube 3 and is attached to the X-ray emission surface of the X-ray tube 3 as shown in FIG. A secondary filter 9, an output side collimator 11 having a plurality of X-ray emission holes 10 having different opening diameters, which is installed before the primary filter 9, that is, between the primary filter 9 and the sample 1, and an X-ray tube And an emission side collimator moving mechanism (not shown) that slides the emission side collimator 11 with respect to 3 and positions any one of the plurality of X-ray emission holes 10 in front of the primary filter 9. ing. In addition, this output side collimator 11 is comprised by drive means, such as a stepping motor. The primary filter 9 is a metal thin film or a metal thin plate such as Cu (copper), Zr (zirconium), or Mo selected according to the sample. The primary filter 9 is not limited to the one attached to the X-ray emission surface of the X-ray tube 3, and may be between the X-ray tube 3 and the sample 1.
In the present embodiment, the X-ray tube 3 having a normal operating range of 1000 μA to 200 μA is used, but the present invention is not limited to this.

The X-ray detector 5 includes a semiconductor detection element 12 installed with a detection surface 12a facing an X-ray incident window. The semiconductor detection element 12 is an Si (silicon) element that is a pin structure diode, and when one X-ray photon is incident, a current pulse corresponding to the one X-ray photon is generated. The instantaneous current value of this current pulse is proportional to the energy of the incident characteristic X-ray. The X-ray detector 5 is set to convert the current pulse generated in the semiconductor detection element 12 into a voltage pulse, amplify it, and output it as a signal.
In the present embodiment, the X-ray detector 5 having a maximum X-ray acquisition intensity of 200,000 cps (Counts Per Second) is used. However, the present invention is not limited to this.

The analyzer 6 is a wave height analyzer (multi-channel pulse height analyzer) that generates a voltage pulse wave height from the signal and generates an energy spectrum.
As shown in FIG. 3, the incident X-ray adjusting mechanism 7 has a plurality of X-ray incident holes 13 that allow X-rays to pass through and enter the detection surface 12a, and can be changed to X-ray incident holes 13 having different opening diameters. It is a simple opening diameter changing mechanism.

  That is, the incident X-ray adjusting mechanism 7 is installed in front of the detection surface 12a of the semiconductor detection element 12 in the X-ray detector 5, that is, between the detection surface 12a and the sample 1, and has a plurality of X-ray incident holes having different opening diameters. The incident-side collimator 14 having 13 and the incident-side collimator 14 are slidably moved with respect to the X-ray detector 5 so that any one of the plurality of X-ray incident holes 13 is in front of the detection surface 12a, that is, detected. An incident-side collimator moving mechanism 15 that is arbitrarily positioned between the surface 12a and the sample is provided. Thus, the incident X-ray adjusting mechanism 7 can adjust the incident solid angle of the characteristic X-ray and scattered X-ray with respect to the detection surface 12a by selecting one of the X-ray incident holes 13 having different aperture diameters. This is a collimator. In addition, this incident side collimator moving mechanism 15 is comprised by drive means, such as a stepping motor. Furthermore, between the sample 1 and the detection surface 12a, a secondary filter 16 is attached for the purpose of reducing scattered X-rays generated from the sample 1. The secondary filter 16 is a metal thin film or metal thin plate such as Ni (nickel) selected according to the sample.

  The control unit C is configured such that the total intensity of characteristic X-rays and scattered X-rays detected by the X-ray detector 5 is approximately the maximum X-ray acquisition intensity, and the intensity of the primary X-ray is the primary X-ray of the X-ray tube 3. A processing circuit for controlling the incident X-ray adjusting mechanism 7 and the primary X-ray adjusting mechanism 4 is provided so that the irradiation capability is within a normal operating range. Further, the control unit C controls the tube current of the X-ray tube 3.

The analysis processing device 8 is a computer composed of a CPU or the like, displays an energy spectrum sent from the analyzer 6 on a display, and gives the maximum X-ray acquisition intensity, X-ray tube to the control unit C. The normal operating range of the tube current 3 and the X-ray irradiation capability 3 can be input and set. Note that the control unit C may be provided in a processing circuit in the analysis processing apparatus 8.
The sample stage 2, the X-ray tube 3, the primary X-ray adjusting mechanism 4, the X-ray detector 5, and the incident X-ray adjusting mechanism 7 are housed in a sample chamber 16 that can be depressurized, and the X-rays are brought into an atmosphere in the atmosphere. During measurement, the inside of the sample chamber 16 is depressurized so as not to be absorbed.

  Next, an X-ray analysis method using the X-ray analysis apparatus of this embodiment will be described.

First, the sample 1 is irradiated with primary X-rays from the X-ray tube 3 under preset default conditions for rough measurement. That is, the primary X-ray is irradiated to the sample 1 with a tube current for rough measurement (for example, 20 μA) from the X-ray emission hole 10, the X-ray incident hole 13, and the X-ray tube 3 having a preset opening diameter. Then, characteristic X-rays and scattered X-rays emitted from the sample 1 are detected by the X-ray detector 5 in a short time (for example, 2 seconds), and a current pulse generated in the semiconductor detection element 12 is converted into a voltage pulse and amplified. And output as a signal.
Next, the signal from the X-ray detector 5 is sorted into X-ray intensity for each energy by the analyzer 6 to generate an energy spectrum in rough measurement.

  Next, based on the rough measurement default conditions obtained through the analysis processing device 8 and the total intensity of the characteristic X-rays and scattered X-rays in the rough measurement obtained by the analyzer 6, the control unit C The total intensity of characteristic X-rays and scattered X-rays detected by the detector 5 is almost the maximum X-ray acquisition intensity and the intensity of the primary X-ray is within the normal operating range of the primary X-ray irradiation ability of the X-ray tube 3. The primary X-ray adjusting mechanism 4 adjusts the intensity of the primary X-ray so that the following condition is satisfied, and the incident X-ray adjusting mechanism 7 adjusts the characteristic X-rays and scattered X-rays incident on the X-ray detector 5. Adjust the total strength.

  That is, based on the total intensity of characteristic X-rays and scattered X-rays in rough measurement, the opening diameter of the X-ray exit hole 10 satisfying the above conditions, the tube current of the X-ray tube 3 and the opening diameter of the X-ray incident hole 13 The optimal condition of is calculated. Furthermore, the primary X-ray adjusting mechanism 4 and the incident X-ray adjusting mechanism 7 are used to move the exit-side collimator 11 and the incident-side collimator 14 so that the X-ray exit hole 10 and the X-ray entrance hole 13 selected according to the optimum conditions are moved. Each is installed at a predetermined position. Further, the control unit C sets the X-ray tube 3 to the calculated tube current. And this measurement is performed according to this optimal condition.

The optimum condition is calculated based on rough measurement information so as to realize an incident X-ray intensity equivalent to the maximum X-ray acquisition intensity of the X-ray detector 5 with the X-ray incident hole 13 having the smallest possible aperture diameter. . In this calculation method, first, the ratio of the incident solid angle at the aperture diameter of the X-ray incident hole 13 under the default condition to the incident solid angle at the other aperture diameters of the X-ray incident hole 13 and the characteristic X in the rough measurement are used. From the total intensity of the X-rays and scattered X-rays, the theoretical value of the total intensity of the characteristic X-rays and scattered X-rays incident for each X-ray incident hole 13 in the tube current for rough measurement is calculated as follows.
I ₀ × (Ω _k / Ω ₀ )
(I ₀ : Total intensity of characteristic X-rays and scattered X-rays under default conditions)
(Ω ₀ : solid angle of incidence at the X-ray incident hole 13 with an aperture diameter of φ ₀ under default conditions)
(Ω _k : solid angle of incidence at the X-ray incident hole 13 having an aperture diameter φ _{k in} this measurement)

Further, the total intensity of characteristic X-rays and scattered X-rays incident on the X-ray detector 5 when the tube current of the X-ray tube 3 is used at the maximum rating is calculated. Here, the total intensity of characteristic X-rays and scattered X-rays is directly proportional to the tube current. While this value exceeds the maximum X-ray acquisition intensity of the X-ray detector 5, the X-ray incident hole 13 having the smallest aperture diameter is selected for the main measurement.
The solid angle of incidence Ω in this X-ray analyzer is, when the distance between the sample and the detection surface 12a is constant, the diameter φ of the X-ray incident hole 13, the thickness h of the X-ray incident hole, the X-ray incident hole 13 The distance d between the detection surface 12a and the radius S of the detection surface 12a are obtained as a function. Here, if the distance d between the X-ray incident hole 13 and the detection surface 12a, the thickness h of the X-ray incident hole, and the radius S of the detection surface 12a are constant, the incident solid angle Ω is the opening diameter φ of the X-ray incident hole 13. Is a function of

When the aperture diameter of each X-ray incident hole 13 is set to φ ₀ to φ _k (φ ₀ > φ ₁ > φ ₂ >...> Φ _k ),
I _max ≦ I ₀ × (Ω _k / Ω ₀ ) × (i _max / i ₀ )
(I _max : Maximum X-ray acquisition intensity)
(I ₀ : Total intensity of characteristic X-rays and scattered X-rays under default conditions)
(Ω ₀ : solid angle of incidence at the X-ray incident hole 13 with an aperture diameter of φ ₀ under default conditions)
(Ω _k : solid angle of incidence at the X-ray incident hole 13 having an aperture diameter φ _{k in} this measurement)
(I ₀ : tube current under default conditions)
(I _max : Maximum rating of tube current)
The minimum opening diameter φ _k that satisfies the above is _obtained . Here, the calculated value of the incident solid angle ratio Ω _k / Ω ₀ is previously incorporated as a constant. The tube current i is
I _max = I ₀ × (Ω _k / Ω ₀ ) × (i / i ₀ )
It is adjusted to become. Here, even if the maximum aperture diameter of the X-ray incident hole 13 does not satisfy the above conditions for optimizing the aperture diameter, the X-ray incident hole 13 is the maximum aperture diameter, and the tube current is Use the maximum rating.

  When the X-ray detector 5 is a silicon drift detector (SSD) or the like, when the total intensity of the incident characteristic X-ray and the scattered X-ray is the same, the smaller the opening diameter of the X-ray incident hole 13 is, the more the characteristic becomes. Since the peak back ratio, which is the ratio between the peak intensity of the target detection element by X-rays and the background intensity by scattered X-rays, is improved, the detection lower limit can be improved, so that more accurate measurement can be performed. It becomes possible.

Specifically, for example, when the maximum X-ray acquisition intensity of the X-ray detector 5 is 200,000 cps and the normal operation range of the X-ray tube 3 is 200 to 1000 μA, the default condition for rough measurement is one. Assuming that 100,000 cps is obtained at a tube current of 20 μA of the X-ray tube 3 using the X-ray incident hole 13 having the largest aperture diameter, the optimal aperture diameter of the X-ray incident hole 13 is
200,000 ≦ 100,000 × Ω _k / Ω ₀ ) × (1000 μA / 20 μA)
Among those satisfying the requirements, the one having the smallest opening diameter is selected. For example, when the ratio of the solid angle of incidence (Ω _k / Ω ₀ ) between the minimum opening diameter φ _k and the opening diameter φ ₀ under the default condition is 0.05, the tube current is
200,000 = 100,000 × 0.05 × (i / 20)
To 800 μA.

  Thereby, in this measurement, the maximum X-ray acquisition intensity of 200,000 cps can be obtained in the X-ray detector 5. The condition is preferably set so as to match the maximum X-ray acquisition intensity, but may be a value near the maximum X-ray acquisition intensity that can be said to be approximately the maximum X-ray acquisition intensity.

In this measurement set to the optimum conditions in this way, a signal including characteristic X-ray and scattered X-ray energy information obtained by the X-ray detector 5 is output to the analyzer 6, and this signal is further output by the analyzer 6. By sending the energy spectrum obtained by the analysis to the analysis processing device 8, the energy spectrum is displayed on the analysis processing device 8.
In this measurement, a predetermined measurement time was measured in, for example, 100 seconds in order to obtain sufficient energy information.

  In the present embodiment, the primary X-ray adjusting mechanism 4 that can adjust the intensity of the primary X-ray and the characteristic X that is disposed between the sample 1 and the X-ray detector 5 and is incident on the X-ray detector 5. Since the incident X-ray adjustment mechanism 7 capable of adjusting the total intensity of the rays and scattered X-rays is provided, both the intensity of primary X-rays to be irradiated and the total intensity of incident characteristic X-rays and scattered X-rays are provided. By adjusting the X, the X-ray irradiation ability of the X-ray tube 3 can be utilized to the maximum while taking into account the maximum X-ray acquisition intensity of the X-ray detector 5. Therefore, in this measurement, since the radiation irradiation capability is within the normal operating range, stable radiation irradiation of the radiation source can be obtained, and quantitative analysis can be performed stably.

Specifically, the control unit C controls the incident X-ray adjustment mechanism 7 and the primary X-ray adjustment mechanism 4 including tube current adjustment, and the total of characteristic X-rays and scattered X-rays detected by the X-ray detector 5. Stable primary X-ray irradiation by setting the intensity to be the maximum X-ray acquisition intensity and the primary X-ray intensity to be within the normal operating range of the primary X-ray irradiation ability of the X-ray tube 3 And a high characteristic X-ray intensity at the X-ray detector 5 can be easily obtained.
In particular, the incident X-ray adjusting mechanism 7 can be adjusted by changing the incident solid angles of characteristic X-rays and scattered X-rays to the detection surface 12a of the X-ray detector 5 to X-ray incident holes 13 having different aperture diameters. Since the collimator 14 is employed, the characteristic X-rays incident on the detection surface 12a of the X-ray detector 5 are limited according to the solid angle of incidence of the characteristic X-rays and scattered X-rays, and the intensity thereof can be easily adjusted. it can.

  Next, a second embodiment of the X-ray analysis apparatus and the X-ray analysis method according to the present invention will be described below with reference to FIG. Note that, in the following description of the embodiment, the same components described in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The difference between the second embodiment and the first embodiment is that, in the first embodiment, the incident X-ray adjusting mechanism 7 selects a plurality of X-ray incident holes 13 having different aperture diameters that meet the conditions. In the X-ray analyzer according to the second embodiment, which is used in this measurement, as shown in FIG. 4, the incident X-ray adjusting mechanism 7 includes an X-ray incident hole 13, a detection surface 12 a of the X-ray detector 5, and the like. It is the point which has the position adjustment mechanism 21 which can adjust the space | interval d.

  That is, the X-ray analysis apparatus of the second embodiment includes a position adjustment mechanism 21 that moves the incident-side collimator 14 in which the X-ray incident hole 13 is formed so as to be close to or away from the detection surface 12 a of the X-ray detector 5. have. As described above, the incident solid angle Ω in this X-ray analyzer is such that the distance between the sample and the detection surface 12a is constant, the opening diameter φ of the X-ray incident hole 13, the X-ray incident hole 13 and the detection surface 12a. The distance d, the thickness h of the X-ray incident hole, and the radius S of the detection surface 12a are obtained as functions. Therefore, if the aperture diameter φ of the X-ray incident hole 13, the thickness h of the X-ray incident hole, and the radius S of the detection surface 12a are constant, the incident solid angle Ω is the distance between the OLE_LINK1 X-ray incident hole 13 and the detection surface 12a. This is a function of dOLE_LINK1.

  In this second embodiment, the incident solid angle Ω of the optimum condition is obtained by rough measurement in the same manner as in the first embodiment, and the distance d between the X-ray incident hole 13 and the detection surface 12a corresponding to this incident solid angle Ω is set. calculate. The control unit C moves the incident side collimator 14 by the position adjusting mechanism 21 so as to obtain the calculated interval d, and sets the position of the X-ray incident hole 13 with respect to the detection surface 12a.

  As described above, in the second embodiment, since the distance d between the X-ray incident hole 13 and the detection surface 12a is changed by the position adjusting mechanism 21, only one X-ray incident hole 13 is provided according to the distance d. The incident solid angle Ω of the characteristic X-rays and scattered X-rays can be changed continuously, and the total intensity of the incident characteristic X-rays and scattered X-rays can be adjusted with high accuracy. As in the first embodiment, if a plurality of X-ray incident holes 13 having different opening diameters are arbitrarily selected, the incident solid angle Ω can be changed in a wider range by adjusting the distance d by the position adjusting mechanism 21. Is possible.

  The technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

For example, each of the above embodiments is an energy dispersive X-ray fluorescence analyzer, but may be applied to other analysis methods, for example, a wavelength dispersive X-ray fluorescence analyzer.
In each of the above embodiments, X-rays from the X-ray tube 3 as an X-ray source are used as radiation for irradiating the sample, but other radiation, for example, radiation for irradiating an electron beam or the like is used. It doesn't matter.

  Further, as the incident X-ray adjusting mechanism 7 which is an aperture diameter changing mechanism, a mechanism which can select and change any one of the X-ray incident holes 13 having different aperture diameters is adopted. As the mechanism, for example, a single X-ray incident hole such as a diaphragm mechanism of a camera may be used, and the opening diameter of the X-ray incident hole can be changed to an arbitrary size.

1 is a schematic overall configuration diagram showing an X-ray analyzer in a first embodiment of an X-ray analyzer and an X-ray analysis method according to the present invention. In 1st Embodiment, it is explanatory drawing which shows the positional relationship of an output side collimator and an X-ray tube. In 1st Embodiment, it is explanatory drawing which shows the positional relationship of an incident side collimator and an X-ray detector. In 2nd Embodiment of the X-ray-analysis apparatus and X-ray-analysis method which concern on this invention, it is explanatory drawing which shows the positional relationship of an X-ray detector and an incident side collimator. It is explanatory drawing about a solid angle.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Sample, 3 ... X-ray tube (radiation source), 4 ... Primary X-ray adjustment mechanism (radiation adjustment mechanism), 5 ... X-ray detector, 6 ... Analyzer, 7 ... Incident X-ray adjustment mechanism, 11 DESCRIPTION OF SYMBOLS ... Output side collimator, 12 ... Semiconductor detection element, 12a ... Detection surface, 13 ... X-ray entrance hole, 14 ... Incident side collimator, 21 ... Position adjustment mechanism, C ... Control part

Claims (7)

A radiation source for irradiating the sample with radiation;
A radiation adjustment mechanism capable of adjusting the intensity of the radiation;
An X-ray detector that detects characteristic X-rays and scattered X-rays emitted from the sample and outputs a signal including energy information of the characteristic X-rays and scattered X-rays;
An analyzer for analyzing the signal;
An incident X-ray adjustment mechanism that is disposed between the sample and the X-ray detector and adjusts the total intensity of the characteristic X-rays and scattered X-rays incident on the X-ray detector; A featured X-ray analyzer. The X-ray analyzer according to claim 1,
The total intensity of characteristic X-rays and scattered X-rays detected by the X-ray detector is approximately the maximum X-ray acquisition intensity, and the intensity of the radiation is within a normal operating range of the radiation irradiation capability of the radiation source. An X-ray analysis apparatus comprising an incident X-ray adjustment mechanism and a control unit that controls the radiation adjustment mechanism. In the X-ray analyzer according to claim 1 or 2,
The X-ray detector has a detection surface on which the characteristic X-rays and scattered X-rays are incident;
The X-ray analyzer according to claim 1, wherein the incident X-ray adjusting mechanism is a collimator capable of adjusting an incident solid angle of the characteristic X-ray and scattered X-ray with respect to the detection surface. In the X-ray analyzer according to claim 3,
The incident X-ray adjusting mechanism has an X-ray incident hole that allows the characteristic X-ray and scattered X-ray to pass through and enter the detection surface, and can be changed to the X-ray incident hole having a different opening diameter. An X-ray analyzer characterized by the above. The X-ray analyzer according to claim 4,
The opening diameter changing mechanism has a plurality of the X-ray incident holes having different opening diameters, and any one of the X-ray incident holes is arbitrarily disposed between the detection surface and the sample. An X-ray analyzer characterized by being capable. In the X-ray analyzer according to any one of claims 3 to 5,
The X-ray analyzer according to claim 1, wherein the incident X-ray adjusting mechanism has a position adjusting mechanism capable of adjusting a distance between the X-ray incident hole and the detection surface. Irradiating the sample with radiation from a radiation source at a predetermined intensity of radiation for coarse measurement;
Detecting a coarse measurement value, which is a total intensity of characteristic X-rays and scattered X-rays emitted from the sample, with an X-ray detector;
Based on the intensity of the radiation for coarse measurement and the coarse measurement value, the total intensity of characteristic X-rays and scattered X-rays detected by the X-ray detector is almost the maximum X-ray acquisition intensity, and the intensity of the radiation is An incident X-ray adjustment mechanism disposed between the sample and the X-ray detector and adjusting the intensity of the radiation with a radiation adjustment mechanism so that the radiation irradiation capability of the radiation source is within a normal operating range. Adjusting the total intensity of the characteristic X-rays and scattered X incident on the X-ray detector, and performing this measurement;
Outputting a signal including energy information of characteristic X-rays and scattered X-rays obtained by the X-ray detector in the main measurement;
And analyzing the signal with an analyzer.

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