DE202007000756U1 - Calibration standard, for an X-ray fluorescence analysis apparatus, has a drilling in an ebony sample holder to take a calibration sample fixed by an adhesive and/or clamping - Google Patents

Abstract

The calibration standard (10), for an X-ray fluorescence analysis apparatus, has a metallic calibration sample (12) and a container with a non-metal sample holder (14) preferably of ebony, within a metallic ring (18). The sample holder has a surface with a drilling to take the calibration sample, held in place by an adhesive and/or clamping.

Description

The The invention relates to a calibration standard for use in X-ray fluorescence analyzers Claim 1.

X-ray fluorescence analyzers are well known in the art and are used for example in the jewelry industry used, where they serve, the elemental composition of finished pieces of jewelry or of raw material. Such an X-ray fluorescence analyzer operates as follows: An exciting x-ray (rarely also an electron beam) is applied to the surface of the directed to the object to be examined, which thereupon characteristic X-ray fluorescence radiation sending out. The determined spectrum consists primarily of Kα- and Kβ-lines of existing elements, with the location of the respective lines characteristic for each is an element. Thus lets by comparing the intensities of the individual lines close the percent elemental composition. To the accuracy of a measurement To improve, it is known before the measurement, the X-ray fluorescence analyzer by means of a Calibrate calibration standards. The one before a measurement Calibration standard used contains a calibration sample, which a similar, However, exactly known elemental composition contains as the object to be measured. It is therefore necessary to have a set of such Calibration standards with different calibration samples vorzuhalten.

It Calibration standards have become known in which the calibration sample to a thin sheet rolled, which is applied to a carrier. The carrier serves then mostly to the necessary data, such as to note the composition of the calibration sample.

It has been found that previously available calibration samples often no provide satisfactory results.

The The present invention therefore has as its object, a calibration standard to create precise measurement results in a simple way can achieve.

These Task is performed by a calibration standard with the characteristics of Claim 1 solved.

Calibration standards in which the calibration sample is rolled into a thin sheet therefore often do not appear to give satisfactory results because the alloy homogeneity is not sufficiently constant within the calibration sample. The stimulating X-ray beam is usually collimated to a few mm ² area, resulting in different results depending on the exact positioning of the calibration standard in the meter.

It Therefore, it is proposed a sample holder with a first surface provided with a bore extending from this first surface, in which recorded the calibration sample, namely glued and / or jammed is. This allows a calibration sample with a very small cross-section may be used, wherein the calibration sample is preferably a wire section is. It can thus be easily achieved that the area of the Calibration sample of the same order of magnitude as the cross-sectional area of the stimulating X-ray, so again inhomogeneity effects play only a minor role. Furthermore, it has been found that wires over their Cross section usually are quite homogeneous anyway.

By the chosen one Arrangement, it is imperative that the material of the sample holder immediately after the calibration sample. especially if the calibration sample has a relatively small cross section, which is preferred, therefore, there is a risk that characteristic X-ray fluorescence zenzstrahlung is excited in the sample holder. The suggestion can be, for example, by scattered stimulating X-rays respectively. To exclude, that thereby falsifies the result the sample holder must be made of a non-metallic material. Preferred materials for the sample holder is plastic or wood, again here Wood, especially ebony, is preferable. Ebony has beside good mechanical properties and good durability further advantage that it is black. The positioning of the calibration sample in terms of the X-ray source usually happens by means of a target laser, which those Spot illuminates which the X-ray source irradiated during operation. Since the calibration sample is metallic shiny, can be achieved when using ebony a very good contrast, so that the correct positioning of the calibration sample is easy.

In a further preferred embodiment lie the first surface the sample holder and the surface of the calibration sample in one plane, which preferably generated by a common grinding process becomes.

Further preferred embodiments arise from the other dependent claims and from the now with Reference to the figures closer illustrated embodiment. Hereby show:

1 A calibration standard in a plan view,

2 the calibration standard 1 along the cutting plane AA,

3 the calibration standard from the 1 and 2 during operation in an X-ray fluorescence analyzer of a first embodiment and

4 the calibration standard from the 1 and 2 during operation in an X-ray fluorescence analyzer of a second embodiment.

The 1 and 2 show a calibration standard 10 , where the 2 a section along the plane AA in 1 is. The calibration standard 10 has a calibration sample 12 and a sample holder, wherein this sample holder again to two components, namely from the sample holder 14 and the ring 18 consists. The sample holder 14 is a flat cylinder of ebony, which has a first surface 14a and a second surface 14b Has. From the first surface 14a extends a hole 15 which completely from the calibration sample 12 is completed. The calibration sample 12 is a section of a wire which enters the hole 15 was pressed or glued. The calibration sample is usually made of a precious metal alloy. The ring 18 is preferably made of stainless steel and serves primarily as a labeling element. In particular, the ring may carry on its outer lateral surface the information for calibration sample, which information may be engraved for example by means of a laser.

The production of the calibration standard 10 is preferably as follows: First, the flat cylinder of the sample holder 14 Made of ebony, the two surfaces 14a . 14b at least roughly flat and ground parallel to each other. Subsequently, in the first surface 14a the hole 15 introduced, wherein the bore preferably has a diameter between 2 and 5 mm. In this hole 15 now becomes the calibration sample 12 , which is present as the front portion of a wire, and which is substantially the same diameter as the bore 15 even introduced, whereby it can be pressed, for example; an additional bond at the bottom of the hole 15 is possible. Now the sample is taken 14 in the ring 18 inserted and connected to this, for example, pressed or glued. Finally, the two end faces 10a . 10b of the calibration standard 10 ground plan, leaving the first surface 14a the robe shot 14 , the surface of the calibration sample 12 and the front end of the ring 18 lie in one plane. The other side is also subjected to a grinding process, so that the second surface 14b the sample intake 14 and the second end of the ring 18 lie in one plane.

Even if a ring 18 As labeling element offers advantages, so it can be dispensed with in principle. However, it is important that the surface of the calibration sample 12 and the first surface 14a the sample intake 14 lie in one plane so that a common grinding process after introduction of the calibration sample 12 always to be preferred.

The 3 shows schematically the use of the calibration standard 10 with a first embodiment of an X-ray fluorescence analyzer. This is the calibration standard 10 with its second face 10b on a work table 26 on. Above this work table 26 are an X-ray source 20 , an X-ray fluorescence detector 22 and a collimator 24 arranged, which from the X-ray source 20 coming excitation radiation collimates. Because of that, first and second face 10a . 10b of the calibration standard 10 parallel to each other, the calibration sample can be 12 not only exactly position, but also orient their surface exactly (it is always parallel to the surface of the also flat work table 26 ).

The 4 shows the use of the calibration standard 10 in an X-ray fluorescence analyzer according to a second embodiment. Here are X-ray source, X-ray fluorescence detector and collimator below the work table 26 arranged, which therefore a recess 26a having. Again, it is important that the calibration standard 10 a flat first end face 10a so that also here position and orientation of the calibration sample 12 are reproducible.

10

calibration Standard

10a

first face

10b

second face

12

calibration sample

14

specimen collection

14a

first surface

14b

second surface

15

drilling

18

ring

20

X-ray source

22

X-ray fluorescence detector

24

collimator

26

worktable

26a

recess

Claims (11)

Calibration standard ( 10 ) for use in X-ray fluorescence analyzers consisting of a metallic calibration sample ( 12 ) and a pro wherein the sample holder comprises a sample holder made of a non-metallic material ( 14 ) with a first surface ( 14a ), from which a bore ( 15 ) and the calibration sample ( 12 ) in this hole ( 15 ) is glued and / or jammed. Calibration standard according to claim 1, characterized in that the first surface ( 14a ) of the sample receiver ( 14 ) and the surface of the calibration sample ( 12 ) lie in one plane. Calibration standard according to claim 2, characterized that the plane is generated by a common grinding process. Calibration standard according to one of the preceding claims, characterized in that the sample holder ( 14 ) consists of wood. Calibration standard according to Claim 4, characterized that the wood is ebony. Calibration standard according to one of the preceding claims, characterized in that the calibration sample ( 12 ) is a wire section. Calibration standard according to claim 6, characterized the wire section has a diameter between 2 and 5 mm. Calibration standard according to one of the preceding claims, characterized characterized in that the sample holder further comprises a labeling element having. Calibration standard according to claim 8, characterized in that the sample holder ( 14 ) has a cylindrical shape and the inscription element as a metallic ring ( 18 ) is formed, which surrounds the sample holder. Calibration standard according to claim 9, characterized that one end face of the metal ring lies in the first plane of the sample receiver. Calibration standard according to one of claims 8 to 10, characterized in that the labeling element made of stainless steel consists.