JPH084605Y2 - Filter exchange device for X-ray fluorescence analyzer - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter exchanging device for exchanging a plurality of types of filters for removing impure rays from an X-ray tube in a fluorescent X-ray analyzer.

[0002]

2. Description of the Related Art Conventionally, in an X-ray fluorescence analyzer, a filter may be provided in front of an X-ray tube. By installing a filter, impurities in the X-ray tube for microanalysis can be removed, characteristic X-rays in the X-ray tube can be removed, or P
By reducing the background in the analysis of b and As, the effect of improving the S / N ratio can be obtained.

The characteristic X-rays that can be removed from the filter differ depending on the type. Therefore, conventionally, there is a filter exchanging device capable of exchanging a filter by providing a plurality of types of filters on one filter substrate and slidingly moving the filter substrate. An example of this is shown in FIGS. 3 and 4.

In FIG. 3, an X-ray tube 50 has a tip portion inserted into an irradiation chamber 51, and a primary X-ray is directed toward a sample 52.
Emit B1. The primary X-ray B1 passes through a filter 61 provided between the X-ray tube 50 and the sample 52, so that a predetermined characteristic X-ray is removed and enters the sample 52. Incident primary X
The line B1 excites the atoms of the sample 52 to generate a fluorescent X-ray B2 specific to the element. The fluorescent X-ray B2 from the sample 52 passes through the solar slit 55 in the analysis chamber 54, is dispersed by the spectroscope 56, is incident on the X-ray detector 57, and is detected. Elemental analysis of the sample 52 is performed based on this detected value.

The axis line C of the X-ray tube 50 is set obliquely with respect to the sample surface 53 in order to obtain a predetermined incident angle. Further, in order to increase the intensity (X-ray brightness) of the primary X-ray B1 per unit area on the sample surface 53, the tip surface 58 of the X-ray tube 50 is arranged close to the sample 52.

As shown in FIG. 4, the filter 61 is provided on the filter substrate 60 together with the other filters 62 and 63. The filter substrate 60 is a tip surface of the X-ray tube 50 of FIG.
The filters 61 to 63 are arranged movably in the direction (perpendicular to the paper surface) in a state of being close to 58. The filter substrate 60 is moved by a driving machine (not shown),
Each of the filters 61 to 63 is selectively stopped at a position facing the tip surface 58 of the X-ray tube 50.

[0007]

In the above prior art, since the filter substrate 60 of FIG. 4 moves linearly as shown by the chain double-dashed line, the moving space of the filter substrate 60 becomes large, and therefore the fluorescent substrate The entire X-ray analyzer becomes large.

Therefore, it is conceivable to make the filter substrate 60 circular and rotate it. However, as described above, the tip surface 58 of the X-ray tube 50 in FIG. 3 and the sample 52 are close to each other, and the axis C of the X-ray tube 50 is set obliquely with respect to the sample surface 53. Therefore, even if an attempt is made to arrange a circular filter substrate along the tip surface 58 of the X-ray tube 50, it interferes with the sample 53.
Therefore, with a circular filter substrate, the X-ray tube 50 and sample
Cannot be placed between 53 and.

This invention has been made in view of the above-mentioned drawbacks of the prior art.
An object of the present invention is to provide a filter exchanging device that can downsize the entire fluorescent X-ray analyzer.

[0010]

In order to achieve the above-mentioned object, the present invention forms a filter substrate arranged between an X-ray tube and a sample with an annular flat plate, and The filter substrate is rotatably supported by providing three or more support rollers that are in sliding contact with the outer peripheral edge.

[0011]

According to this invention, since the filter substrate is composed of the annular flat plate, the sample can be inserted into the central hole portion of the filter substrate to prevent the interference between the filter substrate and the sample.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, a filter substrate 10 composed of an annular flat plate is arranged between the X-ray tube 50 and the sample 52. Part of the sample 52 has entered the large hole 17 in the center of the filter substrate 10.

FIG. 2 is a view taken along the line 2-2 of FIG. As shown in this figure, the filter substrate 10 is provided with four different kinds of first to fourth filters 11 to 14, an X-ray passage hole 15 and a shield portion 16 at an equal angular pitch. ing. Each of the filters 11 to 14 is made of a foil such as Ni, Al, Ti or Zr, and a filter plate (not shown) is used to close the portion of the small X-ray aperture window 18 formed by cutting the filter substrate 10 in a circular shape. It is fixed to. In addition, the shielding part 16
Is composed of the filter substrate 10 itself.

Three support rollers 20 are in sliding contact with the inner peripheral edge 19 of the filter substrate 10, and the filter substrate 10 is rotatably supported. The support roller 20 is rotatably supported by the case 59 of the irradiation chamber 51 shown in FIG. The support roller 20 has a V-shaped groove 21 on the outer circumference, and the inner peripheral line 19 of the filter substrate 10 is fitted into the V-shaped groove 21 so that the filter substrate 10 is axially (up and down). ) Supported by S.

A driven gear is provided on the outer periphery of the filter substrate 10.
10a is integrally formed. The driven gear 10a meshes with the drive gear 22, and the filters 11 to 14 selectively oppose the tip surface 58 of the X-ray tube 50 when the filter substrate 10 is rotationally driven. The drive gear 22 is rotationally driven by a drive machine such as a motor (not shown) provided outside the irradiation chamber 51.

Analysis chamber side 54 around the outside of the X-ray tube 50
A shielding plate 23 is provided on the. This shield 23
Is for preventing fluorescent X-rays generated from the filter 14 and the filter substrate 10 itself from entering the solar slit 55 in the analysis chamber 54. As shown in FIG.
It is formed of an arc-shaped plate along the outer periphery of 10.

The other construction is similar to that of the conventional example shown in FIG. 3, and the same portions or corresponding portions are designated by the same reference numerals, and detailed description and illustration thereof will be omitted.

Next, the operation of the above configuration will be described. First, when the Cd-Kα ray is measured, the Rh-Kα ray can be removed by making the fourth filter 14 made of Zr in FIG. 1 face the tip surface 58 of the X-ray tube 50. . On the other hand, when the Pb-Lα ray is measured, a motor (not shown) is driven at a predetermined rotation speed to rotate the filter substrate 10 by 180 °, and the first filter 11 made of Ni is attached to the tip surface of the X-ray tube 50.
Oppose 58. This can reduce the background.

In the above structure, according to the present invention, since the filter substrate 10 is formed by the annular flat plate, the filter substrate 10
A part of the sample 52 can be made to enter the large hole 17 in the center of. Therefore, since the filter substrate 10 does not interfere with the sample 52, the filter substrate 10 is rotated and each filter 11 is rotated.
Since ~ 14 can be exchanged, the space for moving the filter substrate 10 becomes unnecessary. Therefore, the entire device becomes compact.

By the way, the primary X-ray B1 is filtered by the filters 11-14.
And the filter substrate 10, the fluorescent X-rays are also generated from the filters 11 to 14 and the like, so it is necessary to shield them. On the other hand, in this embodiment, since the shield plate 23 is provided on the outer periphery of the X-ray tube 50 on the side of the analysis chamber 54, the fluorescent X-rays can be shielded.

The filters 11 to 14 also serve as masks for the X-ray tube 50 and the sample 52, and also have an effect of determining the effective irradiation range of the primary X-ray B1 incident on the sample 52.

By the way, in the above embodiment, the filter substrate
Although the inner peripheral edge 19 of 10 is supported by the support roller 20 and the driven gear 10a is formed on the outer peripheral edge, it may be reversed. That is, the outer peripheral edge of the filter substrate 10 may be supported by the support roller 20 to form the driven gear 10a on the inner peripheral edge.

Further, in the above embodiment, the driven gear 10a is integrally formed with the filter substrate 10 and the filter substrate 10 is rotated, but it is not always necessary to do so. For example, the filter substrate 10 may be driven by a timing belt. Further, although the filter substrate 10 is supported by the three support rollers 20 in the above embodiment, four or more support rollers 20 may be provided.

[0024]

As described above, according to the present invention, since the filter substrate to which the filter is attached is formed of an annular flat plate, a part of the sample enters the hole portion at the center of the filter substrate. Therefore, the interference between the filter substrate and the sample can be prevented. Therefore, since the filter substrate can be rotated and the filter can be exchanged, a space for moving the filter substrate is not required, and the fluorescent X-ray analysis apparatus is downsized.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a filter exchanging device according to an embodiment of the present invention.

FIG. 2 is a view taken along the line 2-2 of FIG.

FIG. 3 is a schematic configuration diagram showing a conventional X-ray fluorescence analyzer.

FIG. 4 is a plan view showing a conventional filter substrate.

[Explanation of symbols]

10 ... Filter substrate, 11-14 ... Filter, 19 ... Inner peripheral edge, 20
... Support roller, 50 ... X-ray tube, 51 ... Irradiation chamber, 52 ... Sample, 53
... Sample surface, 58 ... Tip surface, B1 ... Primary X-ray, C ... Axis.

Claims (1)

[Scope of utility model registration request] 1. The tip of an X-ray tube for irradiating a sample with primary X-rays is inserted into an irradiation chamber, and the axis of the X-ray tube is set obliquely with respect to the surface of the sample and provided on a filter substrate. In a filter exchanging device for an X-ray fluorescence analyzer equipped with a driving device that selectively opposes a plurality of types of filters to the tip surface of the X-ray tube, the filter substrate is formed of an annular flat plate, and the filter substrate 3. A filter exchange device for an X-ray fluorescence analyzer, comprising three or more support rollers slidably contacting an inner peripheral edge or an outer peripheral edge to rotatably support the filter substrate.