DE102015105293A1 - Apparatus for elemental analysis on imaging devices - Google Patents

Abstract

The present invention relates to a device and a method for qualitative and quantitative elemental analysis of particular small material areas of a sample (11) by means of X-ray fluorescence at light optical magnifying imaging devices, such as a light microscope, wherein by means of the light-optical magnifying imaging device, a sample location in the sample (11) selectable and the chemical composition can be determined from this sample location by means of X-ray fluorescence, it being possible to generate primary X-ray radiation R ₁ by means of a pyroelectric, piezoelectric and / or ferroelectric effect in order to excite the sample location.

Description

The invention relates to a device for the qualitative and quantitative elemental analysis of light-optical imaging devices such as microscopes, in particular light microscopes. The qualitative and quantitative elemental analysis is preferably carried out by X-ray fluorescence.

For the elemental analysis of solids, various methods are known. For example, the X-ray fluorescence analysis (RFA), the electron beam microanalysis (ESMA) and the optical atomic emission spectroscopy (AES).

The X-ray fluorescence analysis is based on the generation of primary X-ray radiation with an X-ray tube or a radioactive isotope. The interaction of the primary X-ray radiation with the material sample produces X-radiation, which is called fluorescence radiation. This fluorescence radiation is spectroscopy wavelength or energy dispersive. As a result, the elemental composition is obtained. A major disadvantage of the known RFA methods and devices is the low lateral resolution, i. the dimension of the smallest sample area still to be characterized. Thus, no chemical assignment to the microstructure is possible.

The optical atomic emission spectroscopy is based on the light emission, for example excited by a spark and the spectroscopy of the light emitted by the sample. The diameter of the measuring location is in the range of a few millimeters. Local analyzes with an assignment of the elemental composition to components of the microstructure are therefore not possible. In addition, the sample surface is permanently changed in this process and is thus destructive. This method has the significant drawbacks that the relatively large analysis range does not allow assignment to the microstructure and that the sample is changed at the point of analysis.

The ESMA is often performed in the scanning electron microscope (SEM) and is based on the interaction of an electron beam with the sample to be examined. The emitted X-radiation is wavelength and / or energy-dispersive spectroscopy and obtained on the basis of the spectrum, the qualitative and quantitative elemental composition of the site. The advantage of the two aforementioned systems lies above all in the possibility of local analysis of the sample and thus a spatially resolved microscopic assignment of the analysis result. The lateral resolution is around 1 μm. A disadvantage of this system is the need for a vacuum or very low pressure in the sample chamber. This complicates or prevents analysis of wet samples.

DE 10 2010 034666 A1 discloses an X-ray analysis apparatus having a radiation source configured to irradiate a radiation spot on a sample with radiation, an X-ray detector configured to detect characteristic X-ray radiation emitted by the sample and output a signal containing energy information about the characteristic X-ray beam; an analyzer configured to analyze the signal, a sample stage configured to allow the sample to be placed thereon, a slide mechanism that can move the sample on the sample table, and the radiation source and the x-ray detector relative to one another; of the irradiation point on the sample, and a controller configured to control the pusher mechanism based on the measured height of the irradiation point on the sample and for adjusting the distance of the sample with respect to the radiation source and the X-ray detector.

With the above methods, either information about the elemental composition of a sample or enlarged images of the surface of a sample can be obtained. In general, however, both information is desired.

For example, light microscopes are widely used in scientific and technical facilities. These include colleges, universities, private research institutes, laboratories, departments for development or quality assurance in companies of all sizes, testing institutes or forensic institutions. In many of the areas mentioned, not only the greatly enlarged visual appearance of a surface or a sample is of interest, for example in order to evaluate the microstructure, but also the chemical composition of the examination subject. For the latter, other methods are usually needed. An example of this is the scanning electron microscope. Such devices are, however, usually not available in all of the above facilities by their purchase price and requirements for space, operators and costs for consumables and maintenance. An SEM can not replace a light microscope because of a specific contrast, such as the color of microstructure components. The user of a light microscope is therefore forced to perform the analysis not only on another device, but he must often use a third-party service. This results in the need to be able to carry out elemental analyzes directly in conjunction with optically magnifying devices, for example on the light microscope itself.

It is an object of the present invention to provide a device for the qualitative and quantitative elemental analysis of light-optical magnifying imaging devices, which overcomes the aforementioned disadvantages and allows an assignment of the elemental composition to components of the microstructure.

This object is achieved by a device according to claim 1, wherein further advantageous embodiments emerge from the subclaims. Furthermore, the present invention relates to a method for quantitative and qualitative elemental analysis using the device according to the invention.

Hereinafter, the apparatus for qualitative and quantitative elemental analysis is also abbreviated to "elemental analysis apparatus" and the light-optical magnifying imaging apparatus is referred to as "LOAV".

Examples of light-optically magnifying imaging devices which can be used according to the invention are microscopes, in particular light microscopes, but also digital image recording devices which are equipped with a device for light-optical magnification, such as a camera with a corresponding objective, smartphone or tablet with magnifying glass or microscope attachment, etc.

A device is proposed for qualitative and quantitative elemental analysis of small material areas of a sample by means of X-ray fluorescence on light-optical magnifying imaging devices, wherein a sample location in the sample is selectable by LOAV, with the LOAV the microstructure of the selected probing location can be represented, and from this sample location by means of X-ray fluorescence chemical composition is determinable. In addition, it is provided that primary X-ray radiation can be generated by means of a pyroelectric, piezoelectric effect and / or by utilizing the ferroelectric properties of such a material in order to excite the sample or the material region.

These effects describe the properties of materials that exhibit a change in the electrical polarization and, as a consequence, the occurrence of a charge or voltage when exposed to external forces. The external action may be a temperature change (pyroelectric effect), a deformation (piezoelectric effect) or the application of an external electric field (ferroelectric effect).

For the purposes of the present invention, therefore, the pyroelectric, piezoelectric and / or ferroelectric material is collectively referred to as "polarizable material".

The use of materials having pyroelectric, piezoelectric or ferroelectric properties enables the production of very small X-ray sources, preferably of the size of a 10-centimeter piece and thus integration into a housing that can be kept small and in or on a light-optical magnifying imaging device can be integrated.

It is possible to obtain energies in the range of, for example, 30 keV, which makes it possible to analyze further atomic number ranges and thus all technically relevant materials by exciting X-ray fluorescence in a sample material.

According to the invention, it is possible for the first time to examine defects or / and material inhomogeneities for their chemical composition, for example, by means of a light-optical magnifying imaging device. In many cases, this type of method coupling enables the chemical element composition to be determined at the same time on the spot of selected small areas of the microstructure on the order of a few square micrometres. In this way, a chemical analysis can be carried out directly on a sample which is optically imaged. It is no longer necessary to transport the sample to another device for chemical analysis. This results in time and cost savings for the user.

Since the X-ray sources used according to the invention require only a low supply energy, which can be provided, for example, by means of batteries, a portable use of the device is possible.

It is also advantageous that the X-ray source used according to the invention is not a permanent radiator, e.g. Radioactive isotopes, as used in other devices for RFA.

Advantageously, the device is suitable for energy dispersive X-ray fluorescence spectroscopy and evaluate qualitatively and quantitatively.

Energy-dispersive spectroscopy (EDX) allows the simultaneous detection of high signal quantities and thus the evaluation in short periods of time. Furthermore, the dimensions of modern semiconductor detectors allow them to be easily integrated into a device according to one of the variants proposed according to the invention. Energy-dispersive semiconductor detectors, with appropriate software for data analysis, generally allow qualitative analyzes of atomic numbers 5-92 and quantitative analyzes of atomic numbers 11-92. This allows all technically relevant elements to be recorded.

Advantageously, the device has a focusing unit, such as a capillary or aperture, for adapting the cross section of the exciting primary X-ray radiation, so that an analysis of measuring locations <100 μm in diameter, preferably <20 μm in diameter, is possible.

The reduction of the excitation cross section on / in the sample allows a spatially resolved chemical analysis. For example, inhomogeneities such as foreign bodies or substances or other defects in a material, including precipitates in metallic structures, are of interest. Thus, it is possible to characterize microstructure constituents smaller than 50 μm in diameter.

Hereinafter, the present invention will be explained in more detail by way of a concrete example which is a combination of the elemental analysis device with a light microscope as an example of a LOAV. It is understood, however, that the embodiments mentioned in this context are not limited to this combination, but are also applicable in an analogous manner to combinations with other light-optical magnifying imaging devices.

In one embodiment of the exemplary combination, an X-ray source and an X-ray detector may be arranged on an objective of a light microscope. It is preferably provided that the lens carrier is designed as an objective turret.

Thus, hardly any additional space is required to integrate a spectroscope into a light microscope and perform analyzes of the chemical composition in combination with the optical microstructure examination.

In addition, lenses with different magnifications can be used with a nosepiece without changing the position of the specimen.

A further embodiment provides that the X-ray source (RQ) and the X-ray detector (RD) are designed as an X-ray unit. The X-ray unit with RQ and RD can thus be exchangeable for a lens carrier of the microscope or a lens at the same and cooperate with components for receiving a sample and the sample itself so that the selected sample location is retained. As a result, selected sample areas or inhomogeneities can be investigated spatially resolved for their elemental composition.

The X-ray source and the X-ray detector can be arranged together by a non-positive and / or positive connection to the lens of a microscope, so that the additional components do not affect the use of the light microscope and in parallel the optical and chemical material characterization is possible.

In this case, optical and spectroscopic components can be located at different positions on the objective nosepiece. For example, a sample surface can first be viewed microscopically. Subsequently, by pivoting, pushing and / or moving the objective turret, the spectroscope can then be positioned at the location of the optical component, for example a lens. From The advantage here is that the considered sample area can remain in the center of the spectroscopic axis. Thus, an optically selected sample area can be investigated spatially resolved for its chemical composition.

In a further embodiment, a displaceable holder for receiving the X-ray unit can be arranged perpendicular to the optical axis of the microscope on the microscope. This allows a change between different lenses.

In this case, then optical and spectroscopic components can be located at different positions on this holder. Thus, a sample surface can be viewed microscopically and subsequently, by moving and / or moving the holder, the spectroscope can be positioned in place of the optical component. Also in this embodiment, the considered sample area remains in the center of the spectroscopic axis.

The objective can be arranged relative to the X-ray unit such that the location of the sample which can be selected by means of a light microscope optics is maintained on the sample by a change in the location of the specimen and the specimen can be fed and positioned to the X-ray unit. The change of location of the sample is preferably carried out by means of a sample table.

In this case, a calibration of the sample table ensures that the travel path of the table describes the exact distance of the focal point of the optical component (eg objective) to the focal point of the primary radiation. Thus, the chemical composition of a preselected sample area can be determined spatially resolved.

In one embodiment of the invention, the device can be designed such that the objective and the X-ray unit interact in such a way that X-ray radiation strikes a sample through an opening in the objective or laterally past the objective. In this case, an exchange of the components is not necessary and the determination of the elemental composition can take place simultaneously with the optical sample characterization.

Advantageously, according to another embodiment of the X-ray detector is attached to the lens, so that the X-ray radiation by X-ray, for example, a capillary, next to the lens on the sample can be conducted.

The device may comprise a positioning device, wherein by means of a distance measurement, for example by laser beams or light interference, the alignment of the focal point of the primary radiation is carried out on the selected measuring location of the surface of a sample. The positioning device ensures that the selected sample area is precisely in the focal point of the primary radiation. This ensures that the lateral resolution is as high as possible and that only the selected sample area is analyzed.

The X-ray source used according to the invention serves as a radiation source for the generation of primary X-radiation. It is based on the polarization of materials by an external action. The charge or voltage generated by the change in polarization is used to generate and accelerate electrons. The electrons hit a target and stimulate it to emit the primary x-ray radiation.

The external effect that causes the polarization is a temperature change in pyroelectric materials. Likewise, the primary x-ray radiation may be generated using the piezoelectric effect, e.g. by mechanically or acoustically induced stresses in a piezoelectric material, or by an external electric field utilizing the ferroelectric properties of such material and in conjunction with a suitable target.

Suitable pyroelectric, piezoelectric or ferroelectric material (polarizable material) are suitable materials exhibiting a corresponding effect. Typically, these are crystals and ceramics, but also plastic materials are known. Many piezoelectric materials behave at the same time pyroelectric and / or ferroelectric. An example of a material showing all three properties is barium titanate (BaTiO ₃ ). Examples of both pyroelectric and piezoelectric materials are lithium tantalate (LiTaO ₃ ) and lithium niobate (LiNbO ₃ ). Examples of other suitable piezoelectric materials are quartz, lead zirconate titanate (PZT), but also certain plastics such as polyvinylidene fluoride (PVDF) which, like piezoelectric crystals or ceramics, can be polarized and then piezoelectric.

For a pyroelectrically operated X-ray source, the pyroelectric material is subjected to a temperature change, for example, about 130 to 150 ° C. For this purpose, the material can be connected to a suitable heating device and heated, for example, an SMD (surface mounted device) resistance heating.

The temperature change causes the change of the polarization.

As a piezoelectrically operated X-ray source, a piezoelectric transformer can be used. Piezoelectric transformers and their operation are known per se.

At the heart of a piezoelectric transformer (PT) is a piezoelectric material having a first region (primary region) with a first polarization and a second region (secondary region) with a second polarization. By applying a low-voltage AC voltage (U _in ) having a frequency corresponding to a resonant frequency of the piezoelectric material to the primary region, mechanical (acoustic) vibrations are generated which are transmitted to the secondary region where a high voltage (U _out ).

According to one embodiment, a piezoelectric transformer can be used in which the primary region and the secondary region are galvanically separated from one another. For this purpose, an insulation layer between the primary and the secondary region may be provided. Examples of suitable insulating materials are in particular ceramics.

An example of a suitable PT is a so-called rose-type transformer, with which high voltage gains can be realized. Rose type transformers have a beam shape with the primary region polarized transversely and the secondary region polarized longitudinally. The voltage induced in the secondary region by applying a low voltage to the primary region is thus highest at the end of the secondary region opposite the primary region.

The charge or voltage induced by the change in the polarization of the polarizable material causes an electric field that can be used to generate a plasma. With the electrons of the plasma, a suitable target for the emission of primary X-radiation can be excited.

The X-ray source used according to the invention thus comprises the polarizable material, means for changing the polarization of the polarizable material and a target. Preferably, at least the polarizable material and the target are housed in a vacuum-tight housing. In the vacuum-tight housing, the polarizable material is in contact with a working gas to form the plasma. The pressure of the working gas is sufficiently low to allow interaction of the electrons with the target. A suitable pressure range for the working gas is, for example, 10 ^-5 to 2 × 10 ^-3 mbar. The housing preferably has means for supplying and discharging the working gas and adjusting the gas pressure.

The working gas may be the residual air that remains after adjusting the pressure. As a working gas for the gas discharge, for example, a noble gas such as argon, nitrogen, methane, air or mixtures thereof come into question. An example of a suitable mixture is argon with methane.

In order to obtain the primary X-radiation, the generated electrons are directed onto a metallic target, which radiates the primary X-radiation by interaction with the electrons. The primary X-radiation exits the X-ray source housing through an X-ray transmissive window and is directed to the sample.

Examples of suitable metals for the target are lead, molybdenum, gold, tantalum, etc. If desired, the target can also be designed as an anode, for example connected to the political pole of a PT.

The use of a piezoelectric X-ray source is particularly advantageous if the thermal load of the sample and the optical and electronic components of the device according to the invention should be kept as low as possible.

For example, pyroelectric materials are heated in operation to a temperature of about 100 ° C. This can lead to an undesirable thermal load, in particular, if the pyroelectric material is arranged in the vicinity of the sample, in order to achieve sufficient X-ray intensity at the measuring location, and also with regard to the desired miniaturization of the system. Another advantage of a piezoelectric X-ray source over a pyroelectric source is that it can avoid the long measurement cycles that arise due to the required temperature changes of the pyroelectric material.

The peculiarity of the device according to the invention is that it is possible by the use of polarizable materials to produce comparatively small radiation sources, which however are not permanent emitters. This makes it possible to produce very small spectroscopes, which can be used for the first time for elemental analysis, especially on light microscopes or other LOAV.

An advantage of the device according to the invention in comparison with known devices results from the small and compact design and ease of use with low Kalibrieraufwand. In addition, the required space and energy requirements for this tester and for the peripheral devices is significantly lower than with conventional test equipment. Since the samples to be tested are under ambient conditions / atmosphere, i. at normal air pressure, can be tested and no vacuum such. In the scanning electron microscope is necessary, also wet and porous samples can be analyzed. The device for elemental analysis according to the invention can for example be integrated with the aid of adapter solutions in a light-optical imaging device such as a light microscope.

Since the use of the device for elemental analysis by means of battery operation is possible, the spectroscope can also be used for transport. By combining the elemental analysis device with a LOAV, for example a microscope, integral and local elemental analyzes can be performed.

• – Gehäuse mit einer pyroelektrisch, piezoelektrisch oder ferroelektrisch betreibenen Röntgenquelle zur Erzeugung von primärer Röntgenstrahlung Rö₁ zum Bestrahlen einer Probe
• – einen energiedispersiven Detektor
• – eine Vorrichtung zur Befestigung an der LOAV
• – eine Messeinheit zur Prozessüberwachung und Verarbeitung von Messdaten,
• – eine Rechen- und Steuereinheit zur Auswertung der Messdaten und Eingabe von Steuerbefehlen, wobei die Auswertung aller Messsignale mittels entsprechender Software erfolgt,
• – eine Datenspeichereinheit zur Speicherung der Prozessparameter, Messsignale und Analyseergebnisse, und
• – ein Anzeigegerät zur Ausgabe der Messdaten bzw. Spektren, Eingabe von Steuerbefehlen und Ausgabe von Analyseergebnisse, wobei
• – der Detektor mit der Signalverstärker- und Verarbeitungseinheit, der Messeinheit und Rechen- und Steuereinheit derart zusammenwirkt, dass die in der Probe enthaltenen chemischen Elemente analysierbar sind.

The device for qualitative and quantitative elemental analysis on a light-optical magnifying imaging device may comprise, for example, the following components:

• - Housing with a pyroelectric, piezoelectric or ferroelectric operated X-ray source for generating primary X-rays Rö ₁ for irradiating a sample
• - an energy dispersive detector
• - a device for attachment to the LOAV
• A measuring unit for process monitoring and processing of measured data,
• A computing and control unit for evaluating the measurement data and inputting control commands, wherein the evaluation of all measurement signals takes place by means of appropriate software,
• A data storage unit for storing the process parameters, measurement signals and analysis results, and
• - A display device for outputting the measured data or spectra, input of control commands and output of analysis results, wherein
• - The detector cooperates with the signal amplifier and processing unit, the measuring unit and computing and control unit such that the chemical elements contained in the sample are analyzable.

• – eine Einrichtung zur Abstandsmessung zwischen der Röntgenquelle oder Gehäuseunterkante und einer Probenoberfläche und
• – eine Fokussiereinheit zur Verringerung des Querschnitts der primären Röntgenstrahlung Rö₁ und / oder charakteristischen Röntgenstrahlung Rö₂ zur ortsaufgelösten Messung.

An embodiment of the invention provides that the housing with X-ray source additionally comprises:

• A device for distance measurement between the X-ray source or housing lower edge and a sample surface and
• A focussing unit for reducing the cross section of the primary X-ray radiation R ₁ and / or characteristic X-ray radiation R ₂ for spatially resolved measurement.

The focussing unit can be, for example, a fiberglass capillary optic or a diaphragm.

With the focusing unit, it is also possible to perform spatially resolved elemental analysis. The energy-dispersive detector and / or the device for distance measurement and / or the focusing unit can be arranged outside or inside the housing and communicate with it.

According to one embodiment of the invention, the device additionally has a power supply device. This makes the portable application of the device possible. Accordingly, non-destructive chemical composition studies can be carried out in the field.

In a further embodiment, the device additionally has an interface for data transfer. Thus, in the laboratory use existing devices (laptop, PC, etc.) or in field use portable devices (laptop, tablet PC, smartphone or the like) can be used. The devices can be used to enter control commands and / or to output measured values, spectra and analysis results.

• – die Signalverstärker- und Verarbeitungseinheit,
• – die Messeinheit,
• – die Rechen- und Steuereinheit,
• – die Energieversorgungseinrichtung und
• – die Datenspeichereinheit

angeordnet sind.Advantageously, the device comprises a controller box in which at least

• The signal amplifier and processing unit,
• - the measuring unit,
• - the computing and control unit,
• - the power supply device and
• - the data storage unit

are arranged.

The controller box is used to control the measuring system itself, as well as the processing, transfer and evaluation of measuring signals, the data line and power supply and as an interface for data output.

For this purpose, additional interfaces for data transfer can be arranged in the controller box.

The device according to the invention can be coupled by the adapter device to any LOAV, such as a camera or a microscope. By means of the adapter device, for example, a special adaptation to the respective thread types of conventional microscopes, especially light microscopes, can take place.

A distance measurement can be carried out, for example, in the execution of light-optical measurement methods with visual evaluation.

• – Bauteile, und/oder archäologische, mineralogische und/oder geologische Proben,
• – Werkstoffe
• – feuchte und / oder porige und / oder ölige Materialien.

With the device for elemental analysis, the chemical composition of a wide variety of materials can be tested. These can be:

• - components, and / or archaeological, mineralogical and / or geological samples,
• - Materials
• - Moist and / or porous and / or oily materials.

According to the method, a sample location in the sample can be selected by means of the LOAV for the qualitative and quantitative elemental analysis of small material areas of a sample by means of X-ray fluorescence at LOAV and the chemical composition can be determined from this sample location by means of X-ray fluorescence.

According to the method, the excitation of the sample or of the material region is effected by primary X-radiation, which is generated by means of a pyroelectric, piezoelectric and / or ferroelectric effect.

Preferably, X-ray radiation is energy-dispersively spectroscopically and evaluated qualitatively and / or quantitatively. For the implementation of the method, a device for elemental analysis of LOAV is preferably used, as it is also the subject of the present invention.

• – Erzeugung einer Röntgenstrahlung Rö₁ mittels einer pyroelektrischen, piezoelektrischen und/oder ferroelektrischen Röntgenquelle und Bestrahlen einer Probe,
• – Detektierung einer von der Probe emittierten charakteristischen Röntgenstrahlung Rö₂ vorzugsweise mittels eines energiedispersiven Detektors,
• – Wandlung, Verstärkung, Weiterleitung und Verarbeitung der durch die Röntgenstrahlung Rö₂ im Detektor erzeugten Messsignale mittels einer Signalverstärker- und Verarbeitungseinheit,
• – Ermittlung von Messdaten mittels entsprechender Messsensorik zur Prozessüberwachung mittels einer Messeinheit,
• – Auswertung der Messdaten und Eingabe von Steuerbefehlen mittels einer Rechen- und Steuereinheit, und Auswertung aller Messsignale mittels entsprechender Software,
• – Speicherung der Messdaten/Spektren, und Analyseergebnisse mittels einer Datenspeichereinheit und
• – Ausgabe der Messdaten, Spektren und Analyseergebnisse mittels eines Anzeigegeräts, wobei
• – der Detektor mit der Signalverstärker- und Verarbeitungseinheit, der Messeinheit und Rechen- und Steuereinheit derart zusammenwirkt, dass die in der Probe enthaltenen chemischen Elemente analysierbar werden.

The method for qualitative and / or quantitative elemental analysis of LOAV may include at least the following method steps:

• Generation of an X-ray radiation R ₁ by means of a pyroelectric, piezoelectric and / or ferroelectric X-ray source and irradiation of a sample,
• Detecting a characteristic X-radiation Ro ₂ emitted by the sample, preferably by means of an energy-dispersive detector,
• Conversion, amplification, transmission and processing of the measurement signals generated by the X-ray radiation R ₂ in the detector by means of a signal amplifier and processing unit,
• Determination of measured data by means of corresponding measuring sensors for process monitoring by means of a measuring unit,
• - Evaluation of the measured data and input of control commands by means of a computing and control unit, and evaluation of all measured signals by means of appropriate software,
• Storage of the measured data / spectra and analysis results by means of a data storage unit and
• - Output of measurement data, spectra and analysis results by means of a display device, wherein
• - The detector cooperates with the signal amplifier and processing unit, the measuring unit and computing and control unit such that the chemical elements contained in the sample are analyzable.

The advantage over other methods is that for the first time it is possible to determine the chemical composition of a sample directly at any LOAV. For example, if the LOAV is a microscope such as a light microscope, the described device can be arranged in a lens changing device.

The flexibility, compactness and analytical advantages of the device for elemental analysis form significant unique features over already known systems. By means of such a spectroscope, important technical progress can be achieved in the field of correlative microscopy and transportable analytics.

The device is characterized by low energy consumption and can be supplied via energy storage media, such as accumulators or batteries, or transportable energy sources, e.g. Solar modules to be fed.

The device may be used for portable or mobile applications, i. Measurements in the field, but also for stationary applications, such as measurements on the microscope, are used especially at the light microscope.

By way of example, embodiments of the invention will be illustrated and described in more detail in the following figures, but the invention is not limited thereto.

Show it:

1 schematically a device for qualitative and quantitative elemental analysis of LOAV in its operation;

2 schematically a device for qualitative and quantitative elemental analysis of LOAV without focusing in its operation with further embodiments.

3 schematically a device for qualitative and quantitative elemental analysis of LOAV with focusing in its operation with further embodiments, and

4 FIG. 1 schematically shows a flowchart of a device for qualitative and quantitative elemental analysis.

The operation of the device according to the invention is made with reference to 1 with the schematic representation of the device according to the invention with LOAV using the example of a piezoelectrically operated X-ray source explained in more detail.

Shown is in 1 a housing 1' in which an X-ray source 2 and a target 15 are housed. The piezoelectrically operated X-ray source 2 may be a conventional piezoelectric transformer such as a rose type transformer.

The housing 1' is vacuum tight and contains a working gas for gas discharge to generate a plasma with electrons. Upon collision of these electrons with the target 15 arises primary X-radiation Rö ₁ . The primary X-radiation exits the housing 1' through an X-ray permeable window 16 out and through a focusing unit 14 to a selected location of the sample 11 directed. Exposure of the primary X-ray radiation to the sample site causes characteristic X-ray radiation R _{2 to be} emitted by the detector 3 is detected by generating a measurement signal. In the in 1 schematically illustrated embodiment is the detector 3 on a lens of a LOAV 17 appropriate.

The PT can typically be excited with an electrical voltage in the range of 2V to 20V. Thus, an electrical voltage in the order of 20 kV to 100 kV can be generated. Typical resonance frequencies are in a range of 2 Hz to 10 kHz.

The PT is provided in a known manner with electrical lines for voltage application, which are not shown here. By applying the excitation voltage to the primary region of the PT, mechanical (acoustic) vibrations are generated, which are transmitted to the secondary region and induce a high voltage there. The induced high voltage or the associated electric field causes the discharge of the working gas. The electrons of the plasma formed are used to generate the primary X-radiation.

In an analogous manner, the electrons which are used for the formation of the primary X-radiation can be detected by means of a pyroelectric and / or ferroelectrically operated X-ray source 2 be generated.

The device according to the invention for the qualitative and quantitative elemental analysis of LOAV and its mode of operation is described in 2 further described, wherein in 2 in particular embodiments for the processing of the detector 3 generated measuring signal are shown.

• – eine pyroelektrische, piezoelektrische und/oder ferroelektrischen Röntgenquelle 2 zur Erzeugung einer Röntgenstrahlung Rö₁ zum Bestrahlen einer Probe 11, wobei die Röntgenquelle 2 (mit einem in der Figur nicht gezeigten Target) in einem Gehäuse 1‘ angeordnet ist,
• – einen energiedispersiven Detektor 3, der an oder in dem Gehäuse 1‘ zur Detektierung einer von der Probe 11 emittierten Röntgenstrahlung Rö₂ angeordnet ist, wobei das Gehäuse 1‘ eine Einrichtung 12, in Form eines Adapters, zur Adaption des Gehäuses 1‘ an ein nicht in der 2 gezeigtes Mikroskop aufweist,
• – eine Signalverstärker- und Verarbeitungseinheit 4 zur Wandlung, Verstärkung, Weiterleitung und Verarbeitung des im Detektor 3 durch die charakteristische Röntgenstrahlung Rö₂ erzeugten Messsignals,
• – eine Messeinheit 5 zur Prozessüberwachung und Verarbeitung von Messdaten,
• – eine Rechen- und Steuereinheit 6 zur Auswertung der Messdaten und Eingabe von Steuerbefehlen,
• – eine Datenspeichereinheit 8 zur Speicherung der Prozessparameter, Messsignale und Analyseergebnisse und
• – ein Anzeigegerät 10 zur Ausgabe der Messdaten, Eingabe von Steuerbefehlen und Ausgabe von Analyseergebnisse, wobei
• – der Detektor 3 mit der Signalverstärker- und Verarbeitungseinheit 4, der Messeinheit 5 und Rechen- und Steuereinheit 6 derart zusammenwirkt, dass die in der Probe 11 enthaltenen chemischen Elemente analysierbar sind.

In the 2 shown embodiment of the device 1 includes at least:

• - A pyroelectric, piezoelectric and / or ferroelectric X-ray source 2 for generating an X-radiation Rö ₁ for irradiating a sample 11 , wherein the X-ray source 2 (with a target, not shown in the figure) in a housing 1' is arranged
• - an energy dispersive detector 3 , on or in the case 1' for detecting one of the sample 11 emitted X-radiation Rö _{2 is} arranged, wherein the housing 1' An institution 12 , in the form of an adapter, for adapting the housing 1' to a not in the 2 has shown microscope,
• A signal amplifier and processing unit 4 for conversion, amplification, transmission and processing of the detector 3 measurement signal generated by the characteristic X-ray radiation R ₂ ,
• - a measurement unit 5 for process monitoring and processing of measurement data,
• - a computing and control unit 6 for evaluation of the measured data and input of control commands,
• - a data storage unit 8th for storing the process parameters, measurement signals and analysis results and
• - a display device 10 to output the measured data, input of control commands and output of analysis results, where
• - the detector 3 with the signal amplifier and processing unit 4 , the measurement unit 5 and computing and control unit 6 interacts in such a way that in the sample 11 contained chemical elements are analyzable.

The device 1 additionally includes a power supply device 7 and an interface 9 for data transfer. The power supply device 7 can also be an energy storage.

Here, in all figures, the dashed lines each represent a flow of data and information. The lines with dots indicate the respective energy flow from the energy supply device 7 to the respective device component.

The device 1 additionally includes a controller box 1'' in which at least the signal amplifier and processing unit 4 , the measurement unit 5 , the computing and control unit 6 , the energy supply device 7 , the data storage unit 8th and the interface 9 are arranged.

In the 3 schematically the device 1 out 2 supplemented with a focusing unit 14 shown. In this case, the housing comprises 1' in addition a facility 13 for distance measurement between the X-ray source 2 or a housing lower edge 1a and a sample surface 11 ' the sample 11 and the focusing unit 14 for focusing the primary X-radiation Rö ₁ and / or characteristic X-radiation Rö ₂ .

Accordingly, a distance measurement between the x-ray source 2 or the lower edge of the housing 1a and the sample surface by means of this device 13 respectively. A focusing of the primary x-ray radiation R ₁ and / or characteristic x-ray radiation R ₂ can thus be effected by means of this focussing unit 14 for spatially resolved measurement.

• – Erzeugung einer Röntgenstrahlung Rö₁ mittels einer pyroelektrischen, piezoelektrischen und/oder ferroelektrischen Röntgenquelle 2 und Bestrahlen einer Probe 11 mit einer Probenoberfläche 11‘,
• – Detektierung einer von der Probe 11 emittierten charakteristischen Röntgenstrahlung Rö₂ mittels eines energiedispersiven Detektors 3,
• – Wandlung, Verstärkung, Weiterleitung und Verarbeitung der durch die Rö₂ im Detektor 3 erzeugten Messsignale mittels einer Signalverstärker- und Verarbeitungseinheit 4,
• – Ermittlung von Messdaten zur Prozessüberwachung mittels einer Messeinheit 5,
• – Auswertung der Messdaten und Eingabe von Steuerbefehlen mittels einer Rechen- und Steuereinheit 6, und Auswertung aller Messsignale,
• – Speicherung der Messdaten und/oder Spektren und Analyseergebnisse mittels einer Datenspeichereinheit 8, und
• – Ausgabe der Messdaten, Spektren und Analyseergebnisse mittels eines Anzeigegeräts 10, wobei
• – der Detektor mit der Signalverstärker- und Verarbeitungseinheit 4, der Messeinheit 5 und Rechen- und Steuereinheit 6 derart zusammenwirkt, dass die in der Probe enthaltenen chemischen Elemente analysierbar werden.

In 4 A flowchart of an elemental analysis with a device according to the invention is shown schematically, wherein at least the following method steps are used in a qualitative and quantitative elemental analysis on LOAV:

• - Generation of an X-ray radiation Rö ₁ by means of a pyroelectric, piezoelectric and / or ferroelectric X-ray source 2 and irradiating a sample 11 with a sample surface 11 ' .
• - Detecting one of the sample 11 emitted characteristic X-ray Rö ₂ by means of an energy-dispersive detector 3 .
• - Conversion, amplification, transmission and processing by the Rö ₂ in the detector 3 generated measuring signals by means of a signal amplifier and processing unit 4 .
• - Determination of measurement data for process monitoring by means of a measuring unit 5 .
• - Evaluation of the measured data and input of control commands by means of a computing and control unit 6 , and evaluation of all measurement signals,
• - Storage of the measured data and / or spectra and analysis results by means of a data storage unit 8th , and
• - Output of measured data, spectra and analysis results by means of a display device 10 , in which
• - The detector with the signal amplifier and processing unit 4 , the measurement unit 5 and computing and control unit 6 cooperates in such a way that the chemical elements contained in the sample become analyzable.

The path of the respective data and information flow is marked here by I ₁ to I ₆ . For example, the symbol I ₁ indicates the path of the data and information flow from the computing and control unit 6 to the X-ray source 2 ,

In the 4 not shown, in addition, a distance measurement between the X-ray source 2 or the lower edge of the housing 1a and the sample surface 11 ' by means of a device 13 take place and a focusing of the primary X-ray Rö ₁ and / or characteristic X-ray Rö ₂ by means of a focusing 14 be made for spatially resolved measurement.

In Table 1, the advantages of the device are listed as product benefits and set out the resulting customer benefit. Table 1: Advantages of the invention user benefits Focusing the primary radiation - Spatially resolved material analysis Use of the pyroelectric, piezoelectric and / or ferroelectric effect - no permanent spotlight - transportable application with, for example, battery operation - compact design - robust system Use of EDX and primary radiation - all technically relevant materials can be analyzed Use of SDDs (silicon drift detector) - short analysis time - no nitrogen cooling No evacuation of the sample needed - Analysis of moist, oily and porous samples Analysis by X-ray fluorescence - Non-destructive examination possible - low preparation effort Combination with a LOAV, such as a light microscope - technical expansion of already acquired equipment - direct implementation of elemental analysis - no cost for external analysis Low costs for most of the components - Low purchase price compared to alternative systems

LIST OF REFERENCE NUMBERS

1

 Device (without microscope)

1'

 casing

1a

 Housing bottom

1''

 Controllerbox

2

 X-ray source

3

 detector

4

 Signal amplification and processing unit

5

 measuring unit

6

 Computing and control unit

7

 Power supply unit

8th

 Data storage unit

9

 interface

10

 display

11

 sample

12

 adapter

13

 Device for distance measurement

14

 focusing

15

 target

16

 X-ray permeable window

17

 LOAV

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010034666 A1 [0006]

Claims (15)

Device for the qualitative and quantitative elemental analysis of small material areas of a sample ( 11 ) by means of X-ray fluorescence on optical imaging apparatuses, characterized in that a sample location in the sample ( 11 ) can be selected by means of the optical imaging device and the chemical composition can be determined from this sample location by means of X-ray fluorescence, and primary X-ray radiation can be generated by means of a pyroelectric, piezoelectric and / or ferroelectric effect to excite the sample / material area. Apparatus according to claim 1, characterized in that X-ray fluorescence radiation is energy-dispersible spectroscopically and qualitatively and / or quantitatively evaluated. Apparatus according to claim 1 or 2, characterized in that the light-optical magnifying imaging device is selected from a microscope, light microscope and a digital image recording apparatus having a means for light optical magnification. Device according to one of the preceding claims, comprising means for adjusting the cross section of the primary X-radiation. Device according to one of the preceding claims, characterized in that the light-optical magnifying imaging device is a microscope, wherein an X-ray source ( 2 ) and an x-ray detector ( 3 ) can be arranged on an objective of the microscope, and wherein a lens carrier is designed in the form of an objective revolver. Apparatus according to claim 5, wherein the X-ray source ( 2 ) and the X-ray detector ( 3 ) are formed as an X-ray unit, wherein the X-ray unit is so interchangeable with the lens carrier or a lens of the microscope and cooperates with components for receiving a sample and the sample itself so that the selected sample location is retained. Apparatus according to claim 6, wherein on the microscope a displaceable holder for receiving the X-ray unit is arranged perpendicular to the optical axis of the microscope. Device according to claim 6, wherein the objective is arranged relative to the X-ray unit in such a way that a change of the location of the sample ( 11 ) the location of the sample which can be selected by means of a microscope optics is maintained on the sample, and the sample ( 11 ) of the X-ray unit can be fed and positioned. Device according to one of the preceding claims 5 to 8, wherein the objective and the X-ray unit with X-ray source ( 2 ) and X-ray detector ( 3 ) cooperate in such a way that X-ray radiation passes through an opening in the objective or laterally past the objective onto the sample ( 11 ) meets. Device according to one of the preceding claims 5 to 9, wherein the X-ray detector ( 3 ) is attached to the lens and the X-ray radiation by X-ray guide to the sample ( 11 ) is conductive. Device according to one of the preceding claims, comprising a positioning device, wherein by means of a distance measurement, the alignment of the focal point of the primary X-radiation to a selected measuring location of the surface of a sample ( 11 ) he follows. Apparatus according to any one of the preceding claims, wherein the apparatus comprises a piezoelectric transformer for forming electrons for generating the primary x-ray radiation. Device according to one of the preceding claims, wherein the electrons are generated by a gas discharge. Method for the qualitative and quantitative elemental analysis of a sample ( 11 ) and / or selected material regions of a sample ( 11 ) by means of X-ray fluorescence at imaging devices which enlarge the light optical system, wherein a sample location in the sample ( 11 ), the chemical composition is determined from this sample location by means of X-ray fluorescence, primary X-radiation being generated by means of a pyroelectric, piezoelectric and / or feroelectric effect for exciting the sample location, and additionally the microstructure of the sample location being displayed. The method of claim 14, wherein the method is performed with a device according to any one of claims 1 to 13.

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