JP4776212B2 - Multi-X-ray generation method and apparatus - Google Patents

Description

  The present invention relates to a method and apparatus for generating multi-X-rays, and more particularly to generation of multi-X-rays having X-ray peaks in a low-energy narrow band and / or a high-energy narrow band by arranging a metal material filter. The present invention relates to a method and an apparatus thereof.

In general, X-rays generated from an X-ray generator are white X-rays having a gentle continuous X-ray energy spectrum consisting of photons of various energies. The wavelength range of this continuous X-ray is limited or separated into a plurality of wavelength ranges, a plurality of monochromatic X-rays are generated, and the X-ray absorption coefficient at each energy passing through the material is used for various substances. Attempts have been made to use it in quantitative devices.
As a method of generating high energy X-rays and low energy X-rays, for example, a method of generating X-rays generated by accelerated electrons using tungsten or the like as a target material using a diffraction grating (see, for example, Patent Document 1). ) A method of changing the tube voltage of X-rays using two types of filters (for example, see Patent Document 2), and a method of using two types of substances for the target of an X-ray generator (for example, see Patent Document 3). and so on. However, in the method of Patent Document 1, it is necessary to use a plurality of diffraction gratings. In the method of Patent Document 2, it is necessary to perform measurement twice by changing the tube voltage. In the method of Patent Document 3, the target is complicated. Therefore, there are problems that the apparatus becomes large, costs are high, and the measurement becomes complicated.

  In addition, in the method using a filter, there is a method using a K edge filter composed of not only one kind of element but also two or more kinds of elements. For example, the main part is made of a material containing at least two kinds of elements. A method of generating dual X-rays by monochromatizing an X-ray continuous spectrum using a filter having a difference in K absorption edge energy of 5 to 10 keV between at least two kinds of elements (see, for example, Patent Document 4) In particular, a Gd plate and an Er plate stacked together or a combination of Pb and Po is used. However, in the combination of these elements, since there is a certain difference in the K absorption edge of each element, the X-ray energy passed through the filter is the X-ray intensity in the vicinity of the energy separation boundary of the separated X-rays. Is not sufficiently reduced, and the low energy region and the high energy region cannot be sufficiently clearly separated. In particular, since X-rays are greatly affected by beam hardening at low energy, they are simply high energy. There is a problem that it is difficult to accurately measure the X-ray intensity as a single energy in the low energy region only by separating the region and the low energy region.

Further, the apparatus includes an X-ray source, a K edge filter that separates X-rays generated from the X-ray source into a plurality of energies, and an X-ray detector, and uses iodine and cesium as elements constituting the K edge filter. A technique using tellurium and cadmium as elements constituting the X-ray detector is disclosed (for example, see Patent Document 5). However, even if such a filter is used, the beam hardening phenomenon in the low energy region has not necessarily been suppressed. In Patent Document 5, when a filter using Sn is used, the peak of low energy is low, the peak width of high energy is wide, and the low energy region and the high energy region cannot be reliably separated.
JP-A-64-49547 JP-A-10-85208 JP-A-8-299318 JP-A-5-27043 JP-A-8-289886

  The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a method and an apparatus for generating multi-X-rays having X-ray peaks sufficiently clearly separated in a low energy region and a high energy region. .

  As a result of intensive studies to solve the above problems, the present inventors have found that the beam hardening phenomenon, particularly the phenomenon in the low energy region, is caused by the thickness of the metal element filter used and the tube voltage. By grasping the characteristics of the metal element, the present inventors have found that the low energy region and the high energy region are sufficiently clearly separated and the generation of multi-X-rays is enabled.

That is, according to the first aspect of the present invention, an X-ray peak due to a monochromatic X-ray which is a characteristic X-ray of at least the metal by applying a tube voltage by placing a filter made of a metal material in a continuous X-ray generator. A method of generating multi-X-rays having
Step (A) of determining at least one metal according to the energy of the desired characteristic X-ray;
(B) disposing a metal material filter made of the metal having a thickness satisfying the following formula (1) in a continuous X-ray generator at a high energy position of 10 to 30 keV from the energy of the characteristic X-ray;
exp (−μρx) ≦ 0.1 (1)
(In the formula (1), μ is the mass attenuation coefficient (cm ² / g) at a specific energy of the metal element, ρ is the density (g / cm ³ ) of the metal element, and x is the thickness (cm) of the metal filter. To express.)
And, by adjusting the tube voltage applied to the continuous X-ray generator, the characteristic X-ray generated by the filter in a narrow band of low energy or the continuous X-ray in the narrow band of characteristic X-ray and high energy Generating a continuous X-ray generated by the generator (C);
A method for generating multi-X-rays is provided.

According to the second invention of the present invention, in the first invention,
In step (A), the metal is one kind ,
In the step (C), the tube voltage applied to the continuous X-ray generator is adjusted to the tube voltage necessary for generating the characteristic X-ray energy of the metal element from the filter of the metal material, and the characteristic X A multi-X-ray generation method is provided that generates single X-rays composed of lines.

According to the third invention of the present invention, in the first invention,
In step (A), the metal is one kind ,
In step (C), the tube voltage applied to the continuous X-ray generator is adjusted to a tube voltage higher than the tube voltage necessary for generating the characteristic X-ray energy of the metal element from the filter of the metal material. A multi-X-ray generation method is provided that generates dual X-rays comprising the characteristic X-rays and the continuous X-rays generated by the continuous X-ray generator.

According to the fourth invention of the present invention, in the first invention,
In step (A), there are two types of metals ,
In the step (B), the thickness of the filter made of the metal material composed of the two kinds of metals is 10-30 keV higher than the characteristic X-ray energy of the high atomic number metal element of the two kinds of metals. In the thickness that satisfies the following formula (1) ,
exp (−μρx) ≦ 0.1 (1)
(In the formula (1), μ is the mass attenuation coefficient (cm ² / g) at a specific energy of the metal element, ρ is the density (g / cm ³ ) of the metal element, and x is the thickness (cm) of the metal filter. To express.)
In the step (C), the tube voltage applied to the continuous X-ray generator is adjusted to a tube voltage necessary for generating the characteristic X-ray energy of the metal element having the high atomic number from the filter of the metal material. A multi-X-ray generation method characterized by generating dual X-rays composed of two types of characteristic X-rays is provided.

According to the fifth aspect of the present invention, in the first aspect,
In step (A), there are two types of metals ,
In the step (B), the thickness of the filter made of the metal material composed of the two kinds of metals is 10-30 keV higher than the characteristic X-ray energy of the high atomic number metal element of the two kinds of metals. In the thickness that satisfies the following formula (1) ,
exp (−μρx) ≦ 0.1 (1)
(In the formula (1), μ is the mass attenuation coefficient (cm ² / g) at a specific energy of the metal element, ρ is the density (g / cm ³ ) of the metal element, and x is the thickness (cm) of the metal filter. To express.)
In step (C), the tube voltage applied to the continuous X-ray generator is higher than the tube voltage required to generate the characteristic X-ray energy of the metal element having the high atomic number from the filter of the metal material. A multi-X-ray generation method characterized by generating triple X-rays comprising two types of characteristic X-rays and continuous X-rays generated by the continuous X-ray generator is provided.

  According to a sixth aspect of the present invention, there is provided a multi-X-ray generation method according to any one of the first to fifth aspects, wherein the metal element is an element having an atomic number of 22 to 83. Provided.

  According to a seventh aspect of the present invention, there is provided the method for generating multi-X-rays according to the fourth or fifth aspect, wherein the metal filter is a bonded filter of two kinds of metal elements. .

  According to the eighth invention of the present invention, in the fourth or fifth invention, the metal filter is a filter formed by mixing two kinds of metal element powders. A generation method is provided.

According to the ninth invention of the present invention, in any one of the first to third inventions, the metal element is Sn, the filter thickness is 0.7 to 1.7 mm, and the tube voltage is 50 to 70 kV. A method for generating multi-X-rays is provided.

According to a tenth aspect of the present invention, in any one of the first to third aspects, the metal element is Ti, the filter thickness is 60 to 80 μm, and the tube voltage is 8 kV or more. A method for generating multi-X-rays is provided.

According to the eleventh aspect of the present invention, in the first, fourth or fifth aspect , the metallic element is Sn and Gd, the Sn filter thickness is 0.3 to 0.8 mm, and the Gd filter A method for generating multi-X-rays is provided in which the thickness is 0.2 to 0.5 mm and the tube voltage is 50 to 75 kV.

According to a twelfth aspect of the present invention, there is provided an apparatus for performing the method of any one of the first to eleventh aspects,
Generation of X-ray peaks consisting of characteristic X-rays in a narrow band of low energy , or multi-X-rays having X-ray peaks consisting of the characteristic X-rays and X-ray peaks consisting of continuous X-rays in a narrow band of high energy an apparatus, multi X-ray generator, characterized in that the continuous X-ray generator and a filter comprising at least one metal material is provided.

  According to the present invention, multi-X-rays having X-ray peaks in a low energy region and / or a high energy region can be generated.

  The method for generating multi-X-rays according to the present invention is a method for generating multi-X-rays by applying a tube voltage by arranging a filter of a metal element made of at least one metal in a continuous X-ray generator, By adjusting the thickness and tube voltage of the metal filter, it is a method of generating multi-X-rays composed of a monochromatic X-ray peak which is a characteristic X-ray of the metal and a continuous X-ray peak appearing at a higher energy position. . Details will be described below.

  As a metal material that can be used for the filter of the metal material used in the present invention, a metal element having an atomic number of 22 to 83 is preferable. These metal elements are properly used in applications of characteristic X-ray energy possessed by each metal. The metal material is formed into a filter shape by a known method and installed in a continuous X-ray generator. If a collimator for focusing X-rays is used, it is installed before or after the collimator.

  In the method for generating multi-X-rays according to the present invention, an X-ray peak is generated in a narrow band of low energy and / or a narrow band of high energy by placing a tube of metal material on a continuous X-ray generator and applying a tube voltage. However, it is necessary to control the thickness of the filter made of a metal material used for the filter and the tube voltage for generating X-rays.

The thickness of the metal material filter satisfies the following formula (1) at a high energy position of 10 to 30 keV from the characteristic X-ray energy of the metal element used,
exp (−μρx) ≦ 0.1 (1)
Preferably, it is necessary to satisfy the following formula (1 ′).
exp (−μρx) ≦ 0.05 (1 ′)
(In the formulas (1) and (1 ′), μ is the mass attenuation coefficient (cm ² / g) at a specific energy of the metal element, ρ is the density (g / cm ³ ) of the metal element, and x is the thickness of the metal filter Represents (cm)
The thickness of the metal filter is set so that the value of exp (−μρx) is 0.1 or less, and by controlling the tube voltage, continuous X-rays in the vicinity of the energy generated by the characteristic X-rays of the metal filter are shielded, In addition, continuous X-ray peaks in a high energy region can be unified. When the value of exp (−μρx) exceeds 0.1, continuous X-rays overlap characteristic X-rays.

Here, exp (−μρx) is an expression for obtaining the intensity of ordinary X-rays, μ is a mass attenuation coefficient (cm ² / g) at a specific energy of the metal, and is described in the literature (for example, NSRDS-NBS29 (1969) by JH Hubbell), ρ is the metal density (g / cm ³ ), and x is the thickness (cm) of the metal filter.

  The tube voltage must be several kV or higher than the voltage required to generate the characteristic X-ray energy of the metal element, and it must be 10 kV or higher when the characteristic X-ray energy is several tens of keV. . Nothing appears when the tube voltage is lower than the voltage required to generate the characteristic X-ray energy of the metal element.

  Usually, X-rays generated from an X-ray generator are composed of various energy photons, and therefore have a gentle continuous X-ray spectrum energy spectrum as shown in FIG. Here, when a metal filter having a specific thickness is used, X-rays transmitted through the filter sufficiently attenuate the X-ray energy below the K absorption edge depending on the attenuation coefficient of the metal, and the characteristic X of the metal The amount of transmission in the energy region of the line rapidly decreases and the continuous spectrum does not appear. The present invention succeeded in generating multi X-rays by controlling the thickness of the filter and the tube voltage for generating X-rays.

When one type of metal is used as the metal element and the filter thickness and tube voltage are controlled, the characteristic X-ray energy peak of the metal used in the low energy region is obtained, and the continuous X-ray peak is obtained in the high energy region. And two types of X-ray peaks can be generated.
Here, by setting the tube voltage to the tube voltage necessary to generate the characteristic X-ray energy of the metal filter, it is possible to suppress the occurrence of continuous X-ray peaks in the high energy region, and in the low energy region. Only a monochromatic peak of characteristic X-rays of the metal used as a filter can be obtained.

For example, when Sn is used as the metal element, its X-ray spectrum will be described with reference to FIGS. Since the characteristic X-ray energy of Sn is 28.5 keV, the filter thickness at which exp (−μρx) at the high energy position of 10 to 30 keV is 0.1 or less is set, and the tube voltage is the characteristic of Sn. When a voltage of 50 to 75 kV capable of generating X-ray energy ( 28.5 keV ) is obtained, a single characteristic peak of Sn characteristic X-ray at 28.5 keV and a continuous X-ray peak at about 65 keV as shown in FIG. Dual X-rays are generated.
At this time, by setting the tube voltage to 50 kV or less that can suppress the occurrence of continuous X-ray peaks in the high energy region, the appearance of continuous X-ray peaks can be suppressed, as shown in FIG. A single peak of the monochromatic spectrum of Sn can be obtained.

  Here, when Sn is used as a filter, when the thickness of Sn is 0.7 to 1.7 mm and the tube voltage is 50 to 75 kV, the value of exp (−μρx) at 60 keV is 0.039 to 0. .00039, and dual X-rays can be obtained. Further, when the tube voltage is set to 30 to 50 kV, only Sn monochromatic X-rays can be obtained.

  When Ti is used as a filter, if the thickness of Ti is set to 60 to 80 μm and the tube voltage is set to 8 kV or more, the value of exp (−μρx) at 10 keV is 0.049 to 0.018. A line is obtained.

When two or more kinds of metals are used as the filter metal, if the above filter thickness and tube voltage are controlled for the metal having the highest atomic number, the characteristic X-ray energy of the two or more kinds of metals used in the low energy region It is possible to generate three or more types of X-ray peaks, that is, peaks and continuous X-ray peaks in a high energy region.
Here, the generation of continuous X-ray peaks in the high energy region can be suppressed by setting the tube voltage to the tube voltage necessary for generating the characteristic X-ray energy of the metal filter having the higher atomic number. It is possible to obtain only monochromatic peaks of characteristic X-rays of two or more kinds of metals used as filters in the low energy region.

  For example, an X-ray spectrum in the case where two kinds of metals, Sn and Gd, are used as metal elements will be described with reference to FIGS. The characteristic X-ray energy of Sn is 28.5 keV, and the characteristic X-ray energy of Gd is 48.7 keV. Of the two kinds of metals, the characteristic X-ray energy of the metal Gd with the higher atomic number is reduced to a filter thickness where the value of exp (−μρx) at a high energy position of 10 to 30 keV of 48.7 keV is 0.1 or less. The tube voltage may be 28.4 keV as shown in FIG. 3 and Sn characteristic X-ray as shown in FIG. 3 when a voltage higher than 48.7 kV, which can generate Gd characteristic X-ray energy of 48.7 keV, is applied. And a monochromatic peak of Gd appear at 48.7 keV, and a continuous X-ray peak appears at a position of 60 keV, resulting in a triple X-ray. At this time, by suppressing the tube voltage to a voltage of energy that generates the characteristic X-ray energy of the metal and to 10 kV or less, the appearance of continuous X-ray peaks can be suppressed, and Sn as shown in FIG. Dual X-rays of the monochromatic spectrum of Gd and the monochromatic spectrum of Gd can be obtained.

  Here, in the case of using two kinds of metal filters, when Sn and Gd are used as a filter, a filter is formed for each metal and is used as a single filter by overlapping the thickness of Sn. When the thickness is 0.3 to 0.8 mm, the thickness of Gd is 0.2 to 0.5 mm, and the tube voltage is 65 to 75 kV, the value of exp (−μρx) at 60 keV is 0.034 to 0.00. As a result, triple X-rays are obtained. Further, when the tube voltage is set to 50 to 65 kV, dual X-rays only of Sn and Gd monochromatic X-rays can be obtained.

When two types of metals are used, the filter may be a filter in which filters of two types of metal elements are bonded together, or a filter formed by mixing powders of two types of metal elements.
When two types of metal filters are used together, the thickness of the two types of metal filters and the tube voltage are mainly adjusted, but when using two types of metals, the thickness of the metal filter with the higher atomic number The thickness ratio of the filter with the lower atomic number is determined by the ratio of the peaks on the low energy side and the high energy side.

  The apparatus for generating multi-X-rays according to the present invention comprises an X-ray generator of a conventionally known X-ray apparatus and a collimator for narrowing down X-rays used as necessary. This is an apparatus in which a metal material filter to be taken out is arranged in contact with an X-ray generator.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples.

Example 1
Toshiba's I311 was used as the X-ray generator, NaI detector (50.8φ × 50.8 mm) was used as the X-ray detector, and 1 mm thick Sn metal was used as the filter. An X-ray spectrum was obtained by applying a tube voltage of 63 kV and a tube current of 0.5 mA. The X-ray spectrum is shown in FIG. A single characteristic peak of Sn characteristic X-rays appeared at 28.4 keV, and a continuous X-ray peak appeared at about 62 keV, resulting in dual X-rays. The value of exp (−μρx) at 60 keV was 0.0098.

(Example 2)
XB150CP-10 manufactured by Rigaku Corporation was used as the X-ray generator, a CdTe detector (4 × 4 × 0.3 mm) was used as the X-ray detector, and 0.7 mm thick Sn metal was used as the filter. An X-ray spectrum was obtained by applying a tube voltage of 75 kV and a tube current of 0.5 mA. The X-ray spectrum is shown in FIG. A single characteristic peak of Sn characteristic X-rays at 28.4 keV and a continuous X-ray peak at about 67 keV appeared, resulting in dual X-rays. The value of exp (−μρx) at 60 keV was 0.039.

(Comparative Example 1)
In Example 2, X-rays were generated in the same manner as in Example 2 except that the thickness of the Sn metal filter was 0.3 mm. The X-ray spectrum is shown in FIG. Only a gentle pile-up continuous X-ray peak appeared. The value of exp (−μρx) at 60 keV was 0.25.

(Example 3)
In Example 2, X-rays were generated in the same manner as in Example 2 except that the thickness of the Sn metal filter was 1 mm and the tube voltage was 50 kV. The X-ray spectrum is shown in FIG. Only a monochromatic peak of characteristic X-rays of Sn metal appeared.

(Comparative Example 2)
In Example 2, X-rays were generated in the same manner as in Example 3 except that the tube voltage was set to 30 kV. The X-ray spectrum is shown in FIG. Only a few monochromatic peaks of characteristic X-rays of Sn metal appeared.

Example 4
Using X-ray generator RE-1030 specially made by Softex, using NaI detector (50.8φ × 3mm) as X-ray detector, using 72μm thick Ti metal filter as metal filter, tube voltage X-rays were generated at 10 kV and a tube current of 0.02 mA. The X-ray spectrum is shown in FIG. A monochromatic peak of Ti characteristic X-rays appeared at 4.9 keV and a continuous X-ray peak at about 8.5 keV, resulting in dual X-rays. The value of exp (−μρx) at 10 keV was 0.027.

(Example 5)
Example 1 except that a 1 mm thick Cd metal filter is used as the metal filter, a NaI detector (50.8φ × 50.8 mm) is used as the X-ray detector, the tube voltage is 60 kV, and the tube current is 0.5 mA. X-rays were generated as in 2. The X-ray spectrum is shown in FIG. A monochromatic peak of Cd characteristic X-rays appeared at 26.1 keV and a continuous X-ray peak at about 56 keV, resulting in dual X-rays. The value of exp (−μρx) at 60 keV was 0.0065.

(Example 6)
X-rays were generated in the same manner as in Example 5 except that a 1 mm thick Ag metal filter was used as the metal filter, the tube voltage was changed to 60 kV, and the tube current was set to 0.5 mA. The X-ray spectrum is shown in FIG. A monochromatic peak of Ag characteristic X-rays appeared at 24.9 keV and a continuous X-ray peak appeared at about 56 keV, resulting in dual X-rays. The value of exp (−μρx) at 60 keV was 0.0030.

(Example 7)
X-rays are generated in the same manner as in Example 2 except that a 0.25 mm thick Gd metal filter and a 0.5 mm thick Sn metal filter are used as the metal filter, the tube voltage is set to 70 kV, and the tube current is set to 0.5 mA. I let you. The X-ray spectrum is shown in FIG. A monochromatic peak of Sn characteristic X-ray and a Gd monochromatic peak at 48.7 keV appeared at 28.5 keV, and a continuous X-ray peak appeared at about 60 keV, resulting in a triple X-ray. The value of exp (−μρx) at 60 keV was 0.017.

(Example 8)
X-rays are generated in the same manner as in Example 2 except that a 0.25 mm thick Gd metal filter and a 0.5 mm thick Sn metal filter are used as the metal filter, and the tube voltage is 60 kV and the tube current is 0.5 mA. I let you. The X-ray spectrum is shown in FIG. A monochromatic peak of Sn characteristic X-rays appeared at 28.5 keV and a monochromatic peak of Gd at 48.7 keV, and a dual X-ray of continuous X-ray peaks appeared at about 60 keV. The value of exp (−μρx) at 60 keV was 0.017.

According to the multi-X-ray generation method and apparatus of the present invention, it is possible to generate multi-X-rays having X-ray peaks sufficiently clearly separated in a low energy region and a high energy region. It can be applied to the field of non-destructive inspection, such as a measuring device, a measuring device for fat content in dairy products, a measuring device for additives in gasoline, and a measuring device for the thickness of each film layer of a laminate film.

It is an example of the spectrum of the dual X-ray obtained by the method of the present invention. It is an example of the spectrum of a single X-ray obtained by the method of the present invention. It is an example of the spectrum of the triple X-ray obtained by the method of the present invention. It is an example of the spectrum of the dual X-ray obtained by the method of the present invention. It is a spectrum of continuous X-rays. 2 is an X-ray spectrum using the Sn filter of Example 1. FIG. It is an X-ray spectrum of Example 2 and Comparative Example 1. It is an X-ray spectrum of Example 3 and Comparative Example 2. 7 is an X-ray spectrum of Example 4. It is an X-ray spectrum of Example 5 and Example 6. 7 is an X-ray spectrum of Example 7. 10 is an X-ray spectrum of Example 8.

Claims (12)

A method for generating multi-X-rays having X-ray peaks due to monochromatic X-rays which are characteristic X-rays of the metal at least by applying a tube voltage by placing a filter made of a metal material in a continuous X-ray generator,
Step (A) of determining at least one metal according to the energy of the desired characteristic X-ray;
(B) disposing a metal material filter made of the metal having a thickness satisfying the following formula (1) in a continuous X-ray generator at a high energy position of 10 to 30 keV from the energy of the characteristic X-ray;
exp (−μρx) ≦ 0.1 (1)
(In the formula (1), μ is the mass attenuation coefficient (cm ² / g) at a specific energy of the metal element, ρ is the density (g / cm ³ ) of the metal element, and x is the thickness (cm) of the metal filter. To express.)
And, by adjusting the tube voltage applied to the continuous X-ray generator, the characteristic X-ray generated by the filter in a narrow band of low energy or the continuous X-ray in the narrow band of characteristic X-ray and high energy Generating a continuous X-ray generated by the generator (C);
A method for generating multi-X-rays. In step (A), the metal is one kind ,
In the step (C), the tube voltage applied to the continuous X-ray generator is adjusted to the tube voltage necessary for generating the characteristic X-ray energy of the metal element from the filter of the metal material, and the characteristic X 2. The method of generating multi X-rays according to claim 1, wherein a single X-ray consisting of a line is generated. In step (A), the metal is one kind ,
In step (C), the tube voltage applied to the continuous X-ray generator is adjusted to a tube voltage higher than the tube voltage necessary for generating the characteristic X-ray energy of the metal element from the filter of the metal material. 2. The multi-X-ray generation method according to claim 1, wherein dual X-rays composed of the characteristic X-rays and the continuous X-rays generated by the continuous X-ray generator are generated . In step (A), there are two types of metals ,
In the step (B), the thickness of the filter made of the metal material composed of the two kinds of metals is 10-30 keV higher than the characteristic X-ray energy of the high atomic number metal element of the two kinds of metals. In the thickness that satisfies the following formula (1) ,
exp (−μρx) ≦ 0.1 (1)
(In the formula (1), μ is the mass attenuation coefficient (cm ² / g) at a specific energy of the metal element, ρ is the density (g / cm ³ ) of the metal element, and x is the thickness (cm) of the metal filter. To express.)
In the step (C), the tube voltage applied to the continuous X-ray generator is adjusted to a tube voltage necessary for generating the characteristic X-ray energy of the metal element having the high atomic number from the filter of the metal material. 2. The multi X-ray generation method according to claim 1, wherein dual X-rays composed of two types of characteristic X -rays are generated. In step (A), there are two types of metals ,
In the step (B), the thickness of the filter made of the metal material composed of the two kinds of metals is 10-30 keV higher than the characteristic X-ray energy of the high atomic number metal element of the two kinds of metals. In the thickness that satisfies the following formula (1) ,
exp (−μρx) ≦ 0.1 (1)
(In the formula (1), μ is the mass attenuation coefficient (cm ² / g) at a specific energy of the metal element, ρ is the density (g / cm ³ ) of the metal element, and x is the thickness (cm) of the metal filter. To express.)
In step (C), the tube voltage applied to the continuous X-ray generator is higher than the tube voltage required to generate the characteristic X-ray energy of the metal element having the high atomic number from the filter of the metal material. The method of generating multi-X-rays according to claim 1, wherein triple X-rays are generated by adjusting to two types of characteristic X-rays and continuous X-rays generated by the continuous X-ray generator.   The method for generating multi-X-rays according to any one of claims 1 to 5, wherein the metal element is an element having an atomic number of 22 to 83.   6. The method for generating multi-X-rays according to claim 4, wherein the metal filter is a bonded filter of two kinds of metal elements.   The method for generating multi-X-rays according to claim 4 or 5, wherein the metal filter is a filter formed by mixing powders of two kinds of metal elements. The generation of multi-X-rays according to any one of claims 1 to 3 , wherein the metal element is Sn, the filter thickness is 0.7 to 1.7 mm, and the tube voltage is 50 to 70 kV. Method. Metal element is that Ti, method generation according multi X-ray to any one of claims 1 to 3, wherein the filter thickness 60 to 80 m, is the tube voltage is 8kV or more. The metal elements are Sn and Gd, the Sn filter thickness is 0.3 to 0.8 mm, the Gd filter thickness is 0.2 to 0.5 mm, and the tube voltage is 50 to 75 kV. The method for generating multi-X-rays according to claim 1, 4 or 5 . An apparatus for performing the method according to claim 1,
Generation of X-ray peaks consisting of characteristic X-rays in a narrow band of low energy , or multi-X-rays having X-ray peaks consisting of the characteristic X-rays and X-ray peaks consisting of continuous X-rays in a narrow band of high energy an apparatus, multi X-ray generator, characterized in that the continuous X-ray generator and a filter comprising at least one metal material.

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