JP2009288068A - Analyzing method and analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an analyzer 11 capable of stably performing the elementary analysis of a sample 12 such as glass or a resin pervious to a pulse laser beam L, a mirror or metal reflecting the pulse laser beam L, with good reproducibility by laser beam breakdown spectral analysis. <P>SOLUTION: A laser beam absorbing layer absorbing the pulse laser beam L is provided on the surface of the sample 12. The laser beam absorbing layer is provided by either one of the plating of a gold plating material, the coating of a carbon material and the adhesion treatment of a tape. By condensing the pulse laser beam L to the sample 12 to irradiate the sample, the stable absorption of the pulse laser beam L and the formation of plasma on the surface of the sample 12 become possible by the laser beam absorbing layer. The fluorescence F discharged from the plasm P formed upon the reception of the pulse laser beam L by the sample 12 is detected to perform the elementary analysis of the sample 12 from the detected fluorescence F. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an analysis method and an apparatus for irradiating a sample with laser light to detect and quantify elements contained in the sample.

  In general, analytical techniques for detecting and quantifying various elements contained in a sample are applied in many fields. For example, it is important to improve the reliability and performance of equipment by detecting and quantifying elements of substances attached to the glass surface of electronic equipment and substances mixed inside. In addition, quality control of food and detection and quantification of elements contained in waste are important for food safety and environmental pollution prevention.

  Examples of this analysis technique include fluorescent X-ray analysis and inductively coupled plasma emission analysis. As a new analysis technique using laser light, there is laser light breakdown (LIB) spectroscopic analysis (for example, patent literature). 1 and 2).

This laser light breakdown spectroscopy is a technique that spectrally analyzes fluorescence from plasma generated by condensing and irradiating a sample with pulsed laser light, and has a feature that it can be easily applied to various elemental analysis.
Japanese Patent Laid-Open No. 11-311606 (page 3, FIG. 1-5) JP 2000-121558 A (page 4, FIG. 1)

  In conventional laser light breakdown spectroscopy, fluorescence emitted from elements is detected. However, in glass or resin that transmits pulsed laser light, or in mirrors or metals that reflect pulsed laser light, laser light breakdown occurs. A large fluctuation occurs in the generation, and the variation of the generated fluorescence intensity is large, which causes a problem in measurement accuracy and reproducibility.

  The present invention has been made in view of the above points, and a sample such as glass or resin that transmits laser light, or a mirror or metal that reflects laser light can be stably reproduced with laser beam breakdown spectroscopy. An object of the present invention is to provide an analysis method and apparatus capable of elemental analysis.

  In the analysis method of the present invention, a laser light absorption layer that absorbs laser light is provided on the surface of a sample, the sample is focused and irradiated with laser light, and the sample is emitted from plasma generated by receiving the laser light. Fluorescence is detected, and elemental analysis of the sample is performed from the detected fluorescence.

  Further, the analyzer of the present invention includes a sample provided with a laser light absorption layer for absorbing laser light on the surface, a laser oscillator for generating laser light, an optical system for condensing and irradiating the laser light on the sample, Analyzing means for detecting the fluorescence emitted from the plasma generated by the sample upon receiving the laser beam and performing elemental analysis of the sample from the detected fluorescence.

  According to the present invention, it is possible to perform elemental analysis stably with high reproducibility by laser beam breakdown spectroscopy analysis on a sample such as glass or resin that transmits laser light, or a mirror or metal that reflects laser light.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, an analysis device (element analysis device) 11 irradiates a sample 12 for elemental analysis with a pulsed laser beam L as a laser beam for laser beam breakdown, and the sample 12 is generated as a plasma. The fluorescence F to be collected is collected, and the element contained in the sample 12 and its content are quantified from the wavelength and intensity of the fluorescence F.

  The analysis apparatus 11 includes, as main components, a moving mechanism 14 for arranging the sample 12, a laser oscillator 15 for generating the pulsed laser light L, and condensing and irradiating the pulsed laser light L on the sample 12, and the sample 12 is subjected to pulsed laser light. An optical system 16 that extracts the fluorescence F emitted from the plasma P generated by receiving L, and an analysis means 17 that detects the extracted fluorescence F and performs elemental analysis of the sample 12 from the detected fluorescence F are provided.

  The moving mechanism 14 includes a stage 19 that holds the sample 12 on the upper surface and moves the laser light irradiation position. For example, an XY stage or a rotary stage is used as the stage 19 and is controlled by a stage controller 20.

  As the laser oscillator 15, for example, a YAG laser oscillator that oscillates YAG (Yttrium Aluminum Garnet) laser light is used. A laser power source 22 is connected to the laser oscillator 15, and a laser control signal that defines the timing for oscillating the pulsed laser light L is input from the timing controller 23 to the laser power source 22. Oscillates the pulsed laser beam L.

  The optical system 16 includes a cylindrical optical system main body 25, and a laser transmission optical fiber 26 that transmits the pulsed laser light L oscillated from the laser oscillator 15 is connected to the side of the optical system main body 25. In addition, a fluorescence transmission optical fiber 27 for transmitting the extracted fluorescence F to the analysis means 17 is connected.

  The optical system body 25 reflects the pulsed laser light L transmitted from the side of the optical system body 25 by the laser transmission optical fiber 26 toward the distal end side of the optical system body 25 and the distal end of the optical system body 25. The dichroic mirror 28 that transmits visible light captured from the side to separate the pulsed laser light L and visible light, transmits the pulsed laser light L toward the distal end side of the optical system body 25, and from the distal end side of the optical system body 25 A dichroic mirror 29 that reflects the captured fluorescence F toward the fluorescence transmission optical fiber 27 on the side of the optical system body 25 to separate the pulsed laser light L and the fluorescence F is disposed at the tip of the optical system body 25. The sample 12 is focused and irradiated with the pulsed laser light L and the fluorescence F reflected by the dichroic mirror 29 is collected by collecting the fluorescence F and the fluorescence transmission optical fiber is collected. Fluorescence condenser lens 31 to be introduced into the server 27 is installed.

  Visible light that has passed through the dichroic mirror 28 is incident on the base end of the optical system body 25, and a camera 32 is provided for photographing the surface state of the sample 12 and the occurrence of laser light breakdown.

  The analyzing means 17 includes a spectroscope 34 that splits the fluorescence F transmitted by the fluorescence transmission optical fiber 27, a fluorescence detector 35 that converts the fluorescence F dispersed by the spectrometer 34 into an electrical signal, and the fluorescence. A data recording computer 36 that records the wavelength and intensity of the fluorescence F converted into an electrical signal by the detector 35 and quantifies the elements contained in the sample 12 and the contents thereof by elemental analysis from the wavelength and intensity of the fluorescence F I have.

  The fluorescence detector 35 and the data recording computer 36 are input with a detection control signal that defines the timing of fluorescence detection at a timing with a certain delay from the timing of outputting the laser control signal described above from the timing controller 23, and for a predetermined time. Only the fluorescence F generated in the band is measured.

  The data recording computer 36 controls the stage 19 through the stage controller 20 and moves the sample 12 relative to the optical system 16, thereby moving the laser light irradiation position of the sample 12. Then, the data recording computer 36 obtains the element distribution on the surface of the sample 12 from the measurement result measured by moving the laser beam irradiation position of the sample 12.

  Next, a sample 12 is shown in FIG.

  The sample 12 is, for example, glass or resin through which the pulse laser beam L is transmitted, or a mirror or metal from which the pulse laser beam L is reflected. A laser beam absorption layer 41 is formed on the surface of the sample 12. The laser light absorbing layer 41 is formed by a plating process of a gold plating material as a laser light absorbing material, a coating process of a carbon material as a laser light absorbing material, and a tape bonding process as a laser light absorbing material.

  Then, a method for analyzing the sample 12 will be described.

  The sample 12 with the laser light absorption layer 41 formed on the surface is set on the stage 19.

  The pulse laser beam L oscillated by the laser oscillator 15 is condensed and irradiated on the surface of the sample 12 by the laser condenser lens 30 of the optical system body 25.

  When the surface of the sample 12 is irradiated with the pulsed laser light L, the elements present on the surface of the sample 12 are instantaneously vaporized, and a part thereof is turned into plasma. If the pulse laser beam L is a YAG laser beam having a pulse energy of about several tens of mJ and a pulse width of several ns, the output is 1 MW in terms of pulse. When such a pulsed laser beam L is condensed and irradiated on the surface of the sample 12, so-called breakdown occurs, and elements present on the surface of the sample 12 are ionized to generate plasma P.

  Fluorescence F is emitted from the plasma P. The fluorescence F is taken into the optical system main body 25 from the laser condenser lens 30, reflected by the dichroic mirror 29, and introduced into the fluorescence transmission optical fiber 27 by the fluorescence condenser lens 31. And transmitted to the spectroscope 34.

  The spectroscope 34 separates the fluorescence F, and the fluorescence F dispersed by the spectroscope 34 is converted into an electric signal by the fluorescence detector 35. Then, the data recording computer 36 records the wavelength and intensity of the fluorescence F converted into an electrical signal, and quantifies the elements contained in the sample 12 and their contents by performing elemental analysis from the wavelength and intensity of the fluorescence F. .

  In the data recording computer 36, the element content of the sample 12 is corrected by the emission intensity of the plasma P generated by the pulsed laser beam L for breakdown or the emission line intensity of the specific element. This is because the size and temperature characteristics of the plasma P when the sample 12 generates the plasma P by the pulsed laser light L are affected by fine irregularities on the surface of the sample 12.

  In general, when measuring glass or resin through which the pulse laser beam L is transmitted, the pulse laser beam L is transmitted even when the pulse laser beam L is irradiated from the surface of the sample 12, as shown in the comparative example of FIG. Therefore, stable measurement is difficult. Further, when measuring a mirror or metal that reflects the pulse laser beam L, the pulse laser beam L is reflected even when the pulse laser beam L is irradiated from the surface of the sample 12, as shown in the comparative example of FIG. Therefore, stable measurement is difficult.

  In order to stably measure these samples 12, it is effective to stably absorb the pulsed laser beam L and generate plasma on the surface of the sample 12.

  In FIG. 5, the measurement result which measured about the glass-made sample 12 with which carbon has adhered to the surface is shown. The location where the fluorescence intensity of silicon Si, which is the main component of glass, is measured is only the location where carbon C, which is a deposit, is present, and the portion where no carbon C is deposited is transmitted by pulsed laser light L. Since the fluorescence of the main component silicon Si is not obtained, the fluorescence intensity is high in the portion where the amount of laser light absorption due to the density of carbon C is large. For this reason, the measurement results at the location where the pulse laser beam L is transmitted and the location where the carbon C adheres and the pulse laser beam L is absorbed vary greatly. Therefore, the measurement is difficult when the carbon C is less adhered.

  Therefore, as shown in FIG. 2, by forming the laser light absorption layer 41 on the surface of the sample 12, it is possible to stably absorb the pulsed laser light L on the surface of the sample 12 and generate plasma. Element can be measured stably and elemental analysis can be performed stably with good reproducibility by laser light breakdown spectroscopy.

  At this time, even if the element of the laser light absorption layer 41 may be detected by irradiation with the pulsed laser light L, the composition element of the laser light absorption layer 41 is clear. It is possible to distinguish it from elements of other substances.

  In addition, when analyzing the adhesion of a substance within a predetermined range of the surface of the sample 12, the sample 12 is moved by the stage 19, and the laser beam irradiation position on the surface of the sample 12 is changed sequentially or continuously. By measuring, the element distribution on the surface of the sample 12 can be measured.

  The spectroscope 34 is generally used for fluorescence measurement. However, if only a specific element is measured, measurement using a photomultiplier tube provided with an interference filter is also possible. Further, the content of the element to be detected in the sample 12 can be analyzed by the intensity ratio of the wavelength by measurement in parallel with the standard sample.

  The laser oscillator 15 is not limited to YAG laser light, and laser light such as excimer laser light is applicable as long as the pulse laser light L is capable of laser light breakdown.

It is a block diagram of the analyzer which shows one embodiment of this invention. It is a side view of the sample which provided the laser beam absorption layer in the analyzer same as the above. It is a side view of the sample which is a comparative example and permeate | transmits a laser beam. It is a side view of the sample which is a comparative example and reflects a laser beam. It is a graph which shows the measurement result of the fluorescence intensity of silicon and carbon with respect to the position of a sample.

Explanation of symbols

11 Analyzer
12 samples
15 Laser oscillator
16 optics
17 Analytical tools
41 Laser light absorption layer F Fluorescence L Pulse laser light as laser light P Plasma

Claims (4)

A laser light absorption layer that absorbs laser light is provided on the surface of the sample,
The sample is focused and irradiated with laser light,
An analysis method comprising: detecting fluorescence emitted from plasma generated by the sample upon receiving the laser beam; and performing elemental analysis of the sample from the detected fluorescence. The analysis method according to claim 1, wherein the laser light absorption layer is provided on the surface of the sample by any one of a plating process, a coating process, and an adhesion process of the laser light absorbing material. A sample provided with a laser light absorption layer for absorbing laser light on the surface;
A laser oscillator for generating laser light;
An optical system for condensing and irradiating the sample with the laser beam;
An analysis apparatus comprising: an analysis unit that detects fluorescence emitted from plasma generated by the sample receiving the laser beam, and performs elemental analysis of the sample from the detected fluorescence. 4. The analyzer according to claim 3, wherein the laser light absorbing layer is provided on the surface of the sample by any one of a plating process, a coating process, and an adhesion process of the laser light absorbing material.

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