KR20030054084A - Method of laser-induced plasma atomic emission spectroscopy and apparatus thereof - Google Patents

Abstract

PURPOSE: A laser-induced plasma atomic emission spectroscope and a spectroscopic method thereof are provided to improve a detecting sensitivity of a light emission signal by parallel radiating dual pulse laser beam from one laser source. CONSTITUTION: A laser-induced plasma atomic emission spectroscope includes a laser source(301), optical attenuators(302,303), a dichroic mirror(305), first and second prisms(304,306), first and second lens(307,309), a spectroscope(310), an optical electron pipe(311), a power supply(312), an integrator(313), an output device(314) and a computer system. The laser source(301) generates a first laser pulse having an infrared ray wavelength and a second laser pulse having an ultraviolet ray wavelength. The optical attenuators(302,303) receive two laser pulses generated from the laser source(301). The first prism(304) receives laser beam from one optical attenuator(302) and refracts laser beam into a predetermined direction. The second prism(306) receives laser beam from the other optical attenuator and refracts laser beam into a predetermined direction.

Description

Laser organic plasma atomic emission spectroscopy and its apparatus {Method of laser-induced plasma atomic emission spectroscopy and apparatus

The present invention relates to a laser organic plasma atomic emission spectroscopy method and apparatus, and more particularly, a laser organic plasma capable of improving detection sensitivity of a light emission signal by simultaneously irradiating infrared and ultraviolet double pulse lasers generated by one laser at the same time. An atomic emission spectroscopy method and apparatus therefor.

In general, laser-induced plasma atomic emission spectroscopy is an analytical technique used for quantitative or qualitative analysis of materials, and typically uses an infrared laser. In this method, the laser pulses are irradiated to a solid, liquid or space in the atmosphere, and the light emitted from the laser organic plasma formed when the intense pulse energy is transferred to the material is determined from the form of the spectrum measured by the photometer and the spectrometer. It is a technique that analyzes the amount or type of an element in a material by looking at the peak or generation band in a particular wavelength region of the element.

1 is a schematic system diagram of a conventional single wavelength laser organic plasma atomic emission spectrometer.

Referring to FIG. 1, a conventional single wavelength laser organic plasma atomic emission spectrometer includes a laser generator 101 for generating a laser of a single wavelength, and a plane mirror 102 for reflecting the laser light generated from the laser generator 101. A light attenuator 103 that attenuates the laser light incident through the plane mirror 102, a first lens 104 that collects light passing through the light attenuator 103 and enters the material 105, and a material 105. 2nd lens 106 which focuses the emission light from the laser plasma formed in the laser beam), the spectrometer 107 which spectroscopicly injects the light incident through the 2nd lens 106, and the light which measures the light which passed through the spectroscope 107 A computer system 109 for quantitatively and qualitatively analyzing the material 105 based on the spectral results measured by the detector 108 and the photodetector 108.

In the spectroscopic method using the conventional single wavelength laser organic plasma atomic emission spectrometer having the above configuration, an infrared pulse laser having a single wavelength is mainly used. In this case, however, the reflection or scattered light of the input laser affects the spectral signal of the detection element, resulting in a poor measurement sensitivity. In order to cope with this, as shown in FIG. 2, a method of irradiating a laser pulse of the same wavelength to the material 203 in different directions with a time difference between two lasers 201 and 202 is attempted. . However, in this case, there is a disadvantage that the configuration of the device becomes complicated as the number of lasers increases. In FIG. 2, reference numeral 204 denotes an optical multichannel analyzer, and 205 denotes a charge-coupled device.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a laser organic plasma atomic emission spectroscopy method capable of improving the detection sensitivity of a light emission signal by simultaneously generating a double pulse laser from one laser source and irradiating it in parallel at the same time, and its The object is to provide a device.

1 is a schematic system diagram of a conventional single wavelength laser organic plasma atomic emission spectrometer;

2 is a schematic system diagram of a laser organic plasma atomic emission spectrometer using two conventional pulsed lasers.

3 is a schematic system diagram of a laser organic plasma atomic emission spectrometer according to the present invention;

4 is a schematic diagram of formation of a laser plasma by laser-material interaction at a material surface during double laser pulse simultaneous parallel irradiation by the apparatus of the present invention.

Fig. 5 shows the laser organic plasma atomic emission spectroscopy spectra upon laser irradiation of Na 13% -containing glass by the apparatus of the present invention.

FIG. 6 is a diagram showing the results of measuring the emission intensity of 589 nm of Na element detection wavelength using an oscilloscope in laser irradiation of Na 13% -containing glass by the apparatus of the present invention; FIG.

<Explanation of symbols for the main parts of the drawings>

101,201,202,301 ... Laser source 102 ... Flat mirror

103,302,303 ... light attenuator 104,307 ... first lens

105,203,308 ... Material 106,309 ... Second Lens

107,310 ... Spectrum 108 ... Photodetector

109,315 Computer system 304,306 First, second prism

305 Dichroic mirror 311 Optoelectronic multiplier

Power supplies 313 Integrators

314 ... output device

Laser organic plasma atomic emission spectroscopy method according to the present invention to achieve the above object,

Generating laser pulses in the infrared and ultraviolet regions from one laser source respectively;

Synthesizing the laser pulses in the infrared and ultraviolet regions in the form of double parallel light on the same axis;

Irradiating the laser pulse in the form of the double parallel light to the material to be tested; And

And detecting the light emitted from the laser organic plasma formed on the material by the irradiation of the laser pulses.

In addition, the laser organic plasma atomic emission spectrometer according to the present invention in order to achieve the above object,

A laser generation source for generating two pulse lasers of different wavelengths;

A plurality of optical attenuators each receiving two pulse lasers output from the laser source and attenuating and outputting the same to a predetermined size;

A first prism which receives an output laser light of one of the plurality of optical attenuators and refracts it in a specific direction;

A dichroic mirror which receives the light emitted from the first prism and the output laser light of the other light attenuator among the plurality of light attenuators and reflects or passes light having a specific wavelength;

A second prism that receives the light emitted from the dichroic mirror and refracts the light in a specific direction;

A first lens receiving incident light from the second prism and focusing the incident light on the sample;

A second lens for collecting and emitting light emitted from a laser organic plasma formed on the sample;

A spectrometer for spectroscopy and outputting emission light having a specific wavelength from light incident through the second lens;

An photomultiplier tube that multiplies the number of electrons of the light that has passed through the spectrometer;

A power supply for supplying power required for electron multiplication to the photomultiplier;

An integrator which integrates a periodic signal waveform of minute amplitude of light output through the photomultiplier;

An output device for outputting a signal integrated by the integrator; And

It is characterized in that it comprises a computer system for receiving the data of the signal waveform integrated by the integrator and analyzing the sample.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a schematic system configuration diagram of a laser organic plasma atomic emission spectrometer according to the present invention.

Referring to FIG. 3, the laser organic plasma atomic emission spectrometer according to the present invention includes a laser source 301, a light attenuator 302 and 303, a dichroic mirror 305, and first and second prisms 304. 306, first and second lenses 307 and 309, spectrometer 310, photomultiplier tube 311, power supply 312, integrator 313, output device 314, computer system ( 315).

The laser generating source 301 is a Nd (neodymium): YAG (yttrium aluminum garnet) laser having a laser pulse having a wavelength of 1064 nm in the infrared region, which is the fundamental wavelength, and a laser having a wavelength (266 nm) of the ultraviolet region, which is the fourth harmonic. Generate pulses respectively. Here, the laser pulse in the ultraviolet region can be generated using a nonlinear optical element installed in the laser device.

The optical attenuators 302 and 303 receive two pulsed lasers output from the laser generation source 301, respectively, and attenuate and output a laser radiation flux density by absorbing or scattering a predetermined amount of laser radiation flux.

The first prism 304 receives the output laser light of one of the two optical attenuators 302 and 303, and refracts it in a specific direction (a 90 ° upward direction in the drawing) and emits the light.

The dichroic mirror 305 receives the light emitted from the first prism 304 and the output laser light of the other light attenuator 303 among the two light attenuators to reflect or pass light having a specific wavelength. That is, the dichroic mirror 305 is a laser pulse having an ultraviolet region wavelength (266 nm) incident through the first prism 304 and an infrared region incident through the other optical attenuator 303 of the two optical attenuators. Each laser pulse having a wavelength (1064 nm) is incident, the laser pulse having an ultraviolet region wavelength (266 nm) is reflected, and the laser pulse having an infrared region wavelength (1064 nm) passes. Accordingly, the two laser pulses have a double compound laser structure.

The second prism 306 receives the light emitted from the dichroic mirror 305 and refracts it in a specific direction (90 ° right angle downward in the drawing) and emits the light.

The first lens 307 receives incident light from the second prism 306, and focuses the incident light on the sample 308 as shown in FIG. 4.

The second lens 309 collects and emits light emitted from the laser organic plasma formed on the sample 308.

The spectroscope 310 spectroscopically outputs the emission light of a specific wavelength from the light incident through the second lens 309.

The photomultiplier tube 311 multiplies the number of photoelectrons of the light passed through the spectroscope 310.

The power supply device 312 supplies power to the photomultiplier tube 311 for the photoelectron multiplication.

The integrator 313 integrates the periodic signal waveform of the small amplitude of the light output through the photomultiplier tube 311. Here, a boxcar integrator is used as this integrator.

The output device 314 outputs the signal integrated by the integrator 313. An oscilloscope is used as this output device 314.

The computer system 315 receives data of the signal waveform integrated by the integrator 313 to quantitatively and qualitatively analyze the sample.

Then, the laser organic plasma atomic emission spectroscopy method by the laser organic plasma atomic emission spectrometer according to the present invention having the above configuration will be briefly described with reference to FIGS. 3 and 4.

Referring to FIGS. 3 and 4, first, a laser pulse having a wavelength (1064 nm) in the infrared region, which is the fundamental wavelength, and a laser pulse having a wavelength (266 nm) in the ultraviolet region, the fourth harmonic, are generated from the Nd: YAG laser source 301. Each will be generated. At this time, particularly in order to improve the sensitivity of the light emission signal, preferably the energy intensity of the laser pulse in the ultraviolet region generated from the laser generation source 301 is set below the value at which the atomic emission signal by the ultraviolet laser.

In this way, the laser pulse having the wavelength (1064 nm) in the infrared region and the laser pulse having the wavelength (266 nm) in the ultraviolet region generated from the Nd: YAG laser source 301 pass through the optical attenuators 302 and 303, respectively. 1064 nm infrared pulses go straight, and 266 nm ultraviolet pulses are redirected by the first prism 304 and incident on the dichroic mirror 305, respectively. The incident infrared rays are reflected from the rear surface of the dichroic mirror 305, and the ultraviolet pulses are passed through as they are, so that the two pulses are synthesized in the form of double parallel light on the same axis. Then, the laser pulses having the two wavelengths thus merged are irradiated to the sample 308 by changing the direction by the second prism 306. At this time, the sample is focused by the first lens 307 and irradiated onto the sample 308. Of the two laser pulses irradiated onto the sample 308, 266 nm ultraviolet pulses interact with the laser-material on the surface of the sample (308) to form a laser plasma, and simultaneously irradiated 1064 nm infrared pulses The formed laser plasma is reheated to excite the atomized elements to higher levels. As a result, the atomic density of the excitation level is increased, and the signal intensity of the emitted light generated when returning to the base level is significantly increased.

On the other hand, the emitted light from the laser plasma formed on the sample 308 is focused by the second lens 309 is incident to the spectrometer 310, the spectrometer 310 spectroscopically outputs the emitted light of a specific wavelength from the incident light. Then, the photomultiplier tube 311 receives the output light from the spectroscope 310 to multiply the number of photoelectrons, and the integrator 313 integrates the periodic signal waveform of the small amplitude of the light output from the photomultiplier tube 311. . At this time, the signal integrated by the integrator 313 is displayed via an oscilloscope, which is an output device 314, and is simultaneously input to the computer system 315. The computer system 315 then quantitatively and qualitatively analyzes the sample (material) 308 based on the input signal. At this time, the Q-switch output signal from the laser source 301 is also input to the integrator 313 as a trigger signal, and the integrator 313 adjusts the integral section so that an optimal state of the atomic emission signal can be observed. This enables time domain adjustment with the light emission signal generated after laser irradiation.

On the other hand, Figure 5 is a measurement result of the emission spectroscopy spectrum obtained by irradiating a laser pulse on the optical glass containing 13% Na (sodium) element, Na element contained in the glass has the largest peak value at a wavelength of 588.9nm Is showing.

FIG. 6 shows that when the radiation of only 588.9 nm is passed through the spectrometer 310 in the same glass material, the glass material is irradiated with the fundamental wave of 1064 nm, the fourth harmonic of 266 nm, and the fundamental wave and the fourth harmonic simultaneously. Shows the results of measuring the luminous intensity of each with an oscilloscope. As shown in FIG. 6, when the pulse of the 1064 nm wavelength which is the fundamental wave of the Nd: YAG laser and the pulse of the 266 nm wavelength which is the fourth harmonic are irradiated separately, the emission signal is not measured at all, but the pulse of the 1064 nm wave and the 266 nm wavelength When irradiating the pulses simultaneously, it can be seen that a signal having a sufficiently high intensity is generated while the light emission signal for the input laser pulse and the Na element are separated.

As described above, in the case of using the laser organic plasma atomic emission spectroscopy method according to the present invention, it is possible to precisely analyze the trace elements in a simple manner without the need for pretreatment of the sample.

As described above, the laser organic plasma atomic emission spectroscopy method according to the present invention generates two laser pulses of infrared rays and ultraviolet rays having different wavelengths in one laser, and condenses them and irradiates the material in parallel directions at the same time. Compared with the conventional short wavelength infrared laser pulse, the input energy density for generating the laser organic plasma can be reduced, thereby sufficiently reducing the influence of the reflected light or scattered light due to the laser irradiation on the spectral signal of the detection element. The signal-to-noise ratio can be improved. In addition, since one laser generates two pulses of different wavelengths, there is an advantage of simplifying the device configuration.

Claims (4)

(a) generating laser pulses in the infrared and ultraviolet regions, respectively, from one laser source; (b) synthesizing the laser pulses in the infrared and ultraviolet regions in the form of double parallel light on the same axis; (c) irradiating the laser pulse in the form of the double parallel light to the material to be tested; And (d) detecting the emitted light from the laser organic plasma formed on the material by irradiation of the laser pulses and analyzing the material. The method of claim 1, Synthesis of the laser pulse in the step (b) is characterized in that the laser pulses in the infrared and ultraviolet regions generated from the laser source is synthesized in the form of double parallel light on the same axis using a prism and a dichroic mirror Organic Plasma Atomic Emission Spectroscopy. The method of claim 1, The energy intensity of the laser pulse in the ultraviolet region generated from the laser source in the step (a) is set to less than the value of the atomic emission signal by the ultraviolet laser. A laser generation source for generating two pulse lasers of different wavelengths; A plurality of optical attenuators each receiving two pulse lasers output from the laser source and attenuating and outputting the same to a predetermined size; A first prism which receives an output laser light of one of the plurality of optical attenuators and refracts it in a specific direction; A dichroic mirror which receives the light emitted from the first prism and the output laser light of the other light attenuator among the plurality of light attenuators and reflects or passes light having a specific wavelength; A second prism that receives the light emitted from the dichroic mirror and refracts the light in a specific direction; A first lens receiving incident light from the second prism and focusing the incident light on the sample; A second lens for collecting and emitting light emitted from a laser organic plasma formed on the sample; A spectrometer for spectroscopy and outputting emission light having a specific wavelength from light incident through the second lens; An photomultiplier tube that multiplies the number of electrons of the light that has passed through the spectrometer; A power supply for supplying power required for electron multiplication to the photomultiplier; An integrator which integrates a periodic signal waveform of minute amplitude of light output through the photomultiplier; An output device for outputting a signal integrated by the integrator; And And a computer system for receiving data of signal waveforms integrated by the integrator and analyzing a sample.