JPS6064236A - Fluorescent-x-ray analyzing apparatus - Google Patents

Abstract

PURPOSE:To broaden the measuring range of elements in a sample and to improve detecting sensitivity and analyzing accuracy, by using an alloy target for an X ray tube, obtaining a specified wavelength by a spectroscopic crystal plate, and thereafter projecting X rays on the sample. CONSTITUTION:An alloy of heavy metal is used as an anode target of an X ray tube 1. The generated primary X rays X1 are inputted to a spectroscopic crystal 3 at an angle theta through a solar slit 2, and only the specified wavelength is reflected. Then the spectroscopic X rays X2 can be set at an arbitrary wavelength by the angle theta. Thus a monochromatic color is formed. Then, the spectroscopic X rays X2, which are made to be the monochromatic color, are projected on a sample 6 through a solar slit 5. Elements in the sample are excited, and the characteristic X rays for each element is generated. Fluorescent X rays X3 are detected by a detector 8. Energy is divided by a system 9, and the qualities and quantities of many elements are determined. In this way, sensitivity is improved, background of the fluorescent X rays X3 become less at the same time, and the detecting limit is improved. Analyzing accuracy is also improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluorescent X-ray analyzer, and more particularly to a novel improvement in monochromating excited X-rays to improve sample limits and analytical accuracy.

Conventionally, an X-ray tube used in a fluorescent X-ray analyzer has a target of w, A J M O+ C"r Cr
X-rays are generated using high-purity metals such as rRh. For this reason, the excited X-rays include continuous X-rays such as Compton scattering in addition to the characteristic X-rays of the target metal, so to remove the background, a secondary target was placed between the X-ray tube and the sample to make it monochromatic. Next Characteristics of target metal X-ray α, β.

Because it contains multiple peaks such as Lα and β2M rays, and continuous X-rays such as Compton scattering cannot be completely removed, when the sample is irradiated with X-rays that have passed through this secondary target, the characteristic X-rays of the secondary target metal , the range of measurement elements in the sample is limited, the optimum excitation conditions for the measurement elements cannot be achieved, the detection sensitivity is poor,
There was a drawback that it affected analysis accuracy. The method of monochromating the excited X-rays from an X-ray tube through a spectroscopic crystal did not have good folding accuracy.

The purpose of this invention is to provide an extremely effective means for eliminating the above-mentioned drawbacks.The purpose of this invention is to provide an extremely effective means for eliminating the above-mentioned drawbacks. The objective is to realize a fluorescent X-ray analyzer that irradiates the sample after it has been oxidized.

Hereinafter, preferred embodiments of the fluorescent X-ray analyzer according to the present invention will be described in detail with reference to the drawings.

In the drawing, 1 is an X-ray tube that generates the primary X-ray beam X1, 2 is a hat for converting the X-ray beam X into a parallel X-ray bundle, and 3 is the primary Xg! It is a spectroscopic crystal that is irradiated with beam Xl (Graphai)! It is.

The spectroscopic X-ray beam X2 reflected from this spectroscopic crystal is -
Black's condition nλ = 2dSinθ is satisfied between the wavelength λ of the -order x Hx, the angle formed by the order X-ray beam and the spectral surface of the spectrometer crystal 3 (incident angle 0), and the lattice spacing d of the spectrometer crystal. , and spectral X-rays of wavelength λ at that position are reflected. The buniometer 4 is configured to rotate around a center 3a so that the angle (incident angle θ) between the -order X-ray beam x1 and the spectral plane of the spectroscopic crystal 3 can be arbitrarily changed.

However, since the reflection of the spectral X-ray beam X2 has an angle of 2θ with respect to the incident direction, X#i! The tube 1 is designed to rotate at a double angle so that the spectroscopic crystal is also located at twice the angular position. At the same time, along with this buniometer 4, the solar slit 2 mentioned above, the solar slit 5 described later, and the collimator 6 also move according to the angle. 5 is a solar slit for converting the spectral X-ray beam x2 into a parallel X-ray flux, 6 is a collimator for narrowing down the spectral X-ray beam X2, and 7 is a sample irradiated with the spectral X-ray beam X2 via the collimator 6. , 8 is sample 7
A detector 9 is a system that separates the energy of the X-ray signal 8a from the detector 8 and displays it.

The X-ray tube 1 is constructed as shown in FIG. 2, and includes a target 11 provided on the anode and a filament 12 on the cathode side.
I'm confused. Target 11 is heavy metal (W, A
g, Or, Mo, C! u, Rh), and the electron beam 12a from the filament 12
When irradiated, primary X-rays X1 consisting of characteristic X-rays and continuous X-rays of each constituent element are generated.

Next, regarding the operation, when Or-W-Ag is used as the X-ray tube 10 alloy target, the -order Xi It becomes a spectrum. This -order X-ray X passes through the Solar slit 2, enters the spectroscopic crystal 6 at an angle θ, and reflects only a specific wavelength.

Therefore, the spectral X-rays X2 can be set to any wavelength by adjusting the angle θ and can be monochromatic. For example, in FIG. 4, the incident angle θ is adjusted to bring the spectroscopic X-ray X2 to a peak at 3·ke9. (When trying to use θV excitation X-rays at 3 with the conventional secondary target method, A
If this is done using g, the spectrum shown in FIG. 5 will be obtained. For this reason, there are many characteristic X-rays and continuous X-rays of the metal of the -order target secondary target, which poses a big problem when exciting the sample. ) Next, the monochromatic spectral X-rays X2 pass through the solar slit 5, irradiate the sample 6, excite the elements in the sample, generate characteristic X-rays of each element, and are detected by the 5i (Li) detector 8. The system 9 detects the optical X-rays and performs energy separation to finally obtain the spectrum shown in FIG. Since the excitation X-rays are 60%, the excitation efficiency is very high for light elements below Ar. In addition, for heavy element analysis, a buniometer 4 is used to change the incident angle θ to the spectroscopic crystal 5, and the spectroscopic X-ray
It is possible to irradiate by changing 2. In this way, qualitative and quantitative analysis of multiple elements can be performed.

In particular, when the device of this invention is used, the X-rays generated in the X-ray tube can emit powerful continuous X-rays with a low current. By changing the angle of this -order x 1m By irradiating, each element in the sample is irradiated under the best excitation conditions, which improves sensitivity. At the same time, since spectral X-rays Less ground and better detection limits. Unlike conventional methods, quantification using a calibration curve can reduce the effects of excitation and absorption due to coexisting elements and overlapping lines, resulting in fewer corrections and improved analytical accuracy.

As described above, according to the present invention, the sample is irradiated after setting it to a specific wavelength using a spectroscopic crystal plate.
The wavelength of the X-rays for sample irradiation can be selected as desired, which has the effect of improving the detection limit and improving the analysis precision and accuracy in qualitative and quantitative analysis using a fluorescent X-ray analyzer.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram showing a fluorescent X-ray analyzer according to the present invention, Fig. 2 is a sectional view showing an X-ray tube, and Figs. 5 and 6 are characteristic diagrams showing spectra of X-rays in each state. be. 1... X-ray tube 2... Solar Slit 6... Spectroscopic crystal 4... Pniometer 5... Solar Slit 6... Collimator 7... Sample 8... 5i (Li) Detector +Preamplifier 9...Linear amplifier+Multiple wave height discriminator+CRTX,...-order X
Ray x2... Spectral X-ray X3... Fluorescent X-ray 7a...
・Preamplifier signal 3a... Pniometer rotating shaft 11... Alloy target 12... Filament X
1... -order X-ray 12a... electron beam a1--
Ag-L line (L(Z, 2.984kev, Lβ+
3.151key) a2=-Ag- line (Kα, 22
．． 162key, Kβ, 24.942kev) a3
・=W-L line (Lα, 8.396kev, Li, 9
．． 670key) a 4-WM line (Mα, 1.77
5key, Mβ21.855kev) a5...-0r-
line (Kα, -5,41kev, Kβ, 5.94
6kov) a6... Compton scattering a7... W- line ('k(,, 59. U10kev,
β to 67.233, θV to 67.233) However, excitation voltage is 50KV
In the case of Drawing 4 Spectral X-ray spectrum a8...monochromatic peak a9...A g-1, line a10.・Rh-X-ray (Kα120.214kev,
Kβ(22,721kev) ail...Ag- to line α12...Compton scattering a 15-Na- to line K(t 1.041 Kβ, 1.
067 keva 14 ・-Mg- line Kα 1.
254 Kβ 1.297 keva 15 ・-A7
- line Kα, 1.487 I(β, 1.555 k
eva16-8i- to α11.740 to β, 1.8
32 keva 17・-P- to line α, 2.015
Kβ12゜136 keva 1a・= α to s−x, 2.338 Kβ, 2.464 keva 19
-= CL- to line α, 2.622 Kβ, 2.81
5 keva20...Compton scattering + Thomson scattering and above Applicant: Daini Seikosha Co., Ltd. Patent Attorney Mogami Tsutomu

Claims (2)

[Claims] (1) An X-ray analysis device consisting of an X-ray tube that generates X-rays, a spectrometer that monochromates the X-rays from the X-ray tube, and a detector that detects fluorescent X-rays from the sample. In the X-ray tube, a heavy metal alloy is used as an anode target of the X-ray tube, and the X-ray tube is configured such that the X-ray tube is made monochromatic by a spectroscopic crystal provided in the spectrometer and then enters the detector through the sample. Line analyzer. (2) Claims characterized in that the spectroscopic crystal is configured to be rotatable around its X-ray irradiation position.
4. The X-ray spectrometer according to item 1.