CA1220643A - Method of laser emission spectroscopic analysis of steel and apparatus therefor - Google Patents
Method of laser emission spectroscopic analysis of steel and apparatus thereforInfo
- Publication number
- CA1220643A CA1220643A CA000470410A CA470410A CA1220643A CA 1220643 A CA1220643 A CA 1220643A CA 000470410 A CA000470410 A CA 000470410A CA 470410 A CA470410 A CA 470410A CA 1220643 A CA1220643 A CA 1220643A
- Authority
- CA
- Canada
- Prior art keywords
- sample
- intensity
- light
- laser beam
- steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 30
- 239000010959 steel Substances 0.000 title claims abstract description 30
- 238000000034 method Methods 0.000 title claims description 54
- 238000004611 spectroscopical analysis Methods 0.000 title claims description 26
- 239000011261 inert gas Substances 0.000 claims abstract description 28
- 238000004458 analytical method Methods 0.000 claims abstract description 21
- 239000007787 solid Substances 0.000 claims abstract description 17
- 230000003595 spectral effect Effects 0.000 claims description 47
- 238000001228 spectrum Methods 0.000 claims description 30
- 238000012545 processing Methods 0.000 claims description 7
- 230000007246 mechanism Effects 0.000 claims description 4
- 238000004445 quantitative analysis Methods 0.000 claims description 4
- 230000001678 irradiating effect Effects 0.000 claims description 3
- 238000012544 monitoring process Methods 0.000 claims description 3
- 230000004044 response Effects 0.000 claims description 3
- 230000002463 transducing effect Effects 0.000 claims description 2
- 238000000295 emission spectrum Methods 0.000 abstract description 18
- 239000000523 sample Substances 0.000 description 46
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 11
- 238000002474 experimental method Methods 0.000 description 5
- 229910000640 Fe alloy Inorganic materials 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- 230000001174 ascending effect Effects 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 239000000428 dust Substances 0.000 description 3
- 230000005284 excitation Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000010979 ruby Substances 0.000 description 2
- 229910001750 ruby Inorganic materials 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 229910000805 Pig iron Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000011088 calibration curve Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004993 emission spectroscopy Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000001093 holography Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000013074 reference sample Substances 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/71—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light thermally excited
- G01N21/718—Laser microanalysis, i.e. with formation of sample plasma
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/30—Measuring the intensity of spectral lines directly on the spectrum itself
- G01J3/36—Investigating two or more bands of a spectrum by separate detectors
Abstract
ABSTRACT OF THE DISCLOSURE:
When a light emitted during the irradiation by a laser beam onto the surface of steel is spectrally se-parated and elements contained in the steel are analyzed quantitatively: an infrared pulse laser beam irradiates a sample such that an energy density on the surface of the sample becomes 2.0 x 109 W/mm2 or more, so that a satisfac-tory emission spectrum can be obtained; a light emitted from the surface of the sample is received through a path held under an atmosphere of inert gas by a light introducing system at a solid angle of 16 degrees or more, and there-after, caused to form its image at an inlet slit of a spectroscope so that an emission spectrum intensity being low in variations can be obtained for a long period of time;
and out of light emitted from the surface of the sample immediately after the irradiation by the laser beam, a firstly emitted light generating white noise is excluded and a subsequently emitted light is quantitatively analyzed, so that the accuracy of analysis can be improved with the influence of the white noise being avoided.
When a light emitted during the irradiation by a laser beam onto the surface of steel is spectrally se-parated and elements contained in the steel are analyzed quantitatively: an infrared pulse laser beam irradiates a sample such that an energy density on the surface of the sample becomes 2.0 x 109 W/mm2 or more, so that a satisfac-tory emission spectrum can be obtained; a light emitted from the surface of the sample is received through a path held under an atmosphere of inert gas by a light introducing system at a solid angle of 16 degrees or more, and there-after, caused to form its image at an inlet slit of a spectroscope so that an emission spectrum intensity being low in variations can be obtained for a long period of time;
and out of light emitted from the surface of the sample immediately after the irradiation by the laser beam, a firstly emitted light generating white noise is excluded and a subsequently emitted light is quantitatively analyzed, so that the accuracy of analysis can be improved with the influence of the white noise being avoided.
Description
~2~6~3 METHOD OF I~SE~< EMISSION SPECTROSCOPIC ANAI.YSIS OF STEEL
AND APPARATVS ~HEREFOR
BACKGROUND OF THE INVENTION
l. Field of the Invention This invention relates to a method of laser emission spectroscopic analysis of steel and an apparatus therefor, and more particularly to improvements in a method of laser emission spectroscopic analysis of steel and an apparatus therefor, wherein a light emitted when a laser beam irradiates the surface of steel is spectrally separated and elements contained in the steel are analy~ed quantitatively and which are suitable for use in di~ect ~uantitat.ive analysis of impurity elements in the st~el such as hot metal, molten steel, slag and the like in a pig iron production process and a steel production process.
AND APPARATVS ~HEREFOR
BACKGROUND OF THE INVENTION
l. Field of the Invention This invention relates to a method of laser emission spectroscopic analysis of steel and an apparatus therefor, and more particularly to improvements in a method of laser emission spectroscopic analysis of steel and an apparatus therefor, wherein a light emitted when a laser beam irradiates the surface of steel is spectrally separated and elements contained in the steel are analy~ed quantitatively and which are suitable for use in di~ect ~uantitat.ive analysis of impurity elements in the st~el such as hot metal, molten steel, slag and the like in a pig iron production process and a steel production process.
2. Description of the Prior A. t With the recent progress of the laser technique in various fields, attempts have been made to utilize lasers as a source of excitation for spectroscopic analysis. More specifically, when a powerful laser beam adapted to Eocus on the surEace of a sample by a focusing lens having a suitable focal length irradiates the surface of the sample, a surface l.ayer is rapidly heated. Paxticularly, if the laser beam is formed into pulse shapes of several tens of nanoseconds, then such conditions occur that energy is locally poured into the sample before heat is diffused in the sample, whereby melting and evaporation occur. Vapor is further excited ..~
~2~ L3 by the laser beam to be formed into plasma which emits a light.
According to the method of laser emission spectroscopic analysis, this light emitted from the plasma is transmitted to a spectroscope by means of a suitable light introducing system, spectrally separated by a diffraction grating or the like and formed into spectra, and thereafter detected by a photographic film, a photomultiplier tube, a photo-diode or the like, whereby the contents of target elements are determined.
However, heretofore, a ratio between the intensity of a signal and the background (hereinafter referred to as "S/B ratio") has been very low and the variations in the output intensity of lasers have been high, whereby the accuracy of analysis and the exa~ne~s have ~een considerably low. Furthermore, when the m~hod ~ laser emission spectroscopic analysis is used in p~actical process analysis or the like on site, there have been such disadvantages that mirrors in a focusing system are contaminated and so on by gases from the surface of the sample and scattered matters after the irradiation by the laser, and the method has not been practiced yet.
Aiming at making this laser emission spectroscopic analysis practicable, the applicant has proposed in Japanese Patent Laid-Open No. 100323/82 a method wherein, excludlng white noises immediately after the irradiation by the laser, subsequent line spectra are integrated to improve the accuracy of analysis.
However, the intensity of white noise is higher than the line spectrum intensity, and consequently, if a satisfactory intensity would not be given to the line spectra, then effective C` !, ~.,,~`.' improvements in accuracy would not be attained.
Furthermore, the applicant has proposed in Japanese Patent Laid-Open No. 76744/83 a method wherein an infrared pulse laser beam irradiates a sample such that an energy density on the S surface of the sample becomes2.0 x 109 W/mm2 or more. However, unless a light emitted by the laser is efficiently and sufficiently taken in, the significance has been low.
Further, the applicant has proposed in Japanese Patent Laid-Open Nos. 114746/81 and 219440/83 that mode control of a laser output and signal processing are effected so as to improve the accuracy. Likewise, unless the light emitted by the laser beam is sufficiently and efficiently taken in, it has been impossible to expect a satisfactory effect.
SUM~A~Y OF T~IE INVENTION
Th~ pr~sent invention has been developed to obviate the above-described disadvantages of the prior art and has as its object the provision of a method of laser ernission spectroscopic analysis of steel and an apparatus therefor.
The invention is practicable and usable under an adverse environment on site. Light excited and generated by a laser beam can be caused to enter a spectroscope with a satisfactory intensity, so that the accuracy of analysis can be greatly irnproved by additional use of various methods of improving the accuracy which have been proposed by the applicant.
To this end, the present invention contemplates ~' , 6~
a method of laser emission spectroscopic analysis of steel, wherein a light emitted when a laser beam irradiates the surface of the steel is spectrally separated and elements contained in the steel are quantitatively analyzed, compris-ing the steps of:
irradiating a sample with an inf~ared pulse laserbeam to turn a part of said sample into plasma such that an energy density on the surface of the sample is 2.0 x 109 W/mm or more;
receiving a light emitted from the surface of the sample by a light introducing system at a solid angle of 16 degrees or more through a path held under an atmosphere of inert gas blown into said path at a flow rate of at least 50 l/min, and thereafter, forming an image on an in-let slit of a spectroscope with said light emitted from the .~ample surface; and quanti-tatively analyæing said light e~itted from ~h~ sample surface, such that a firstly emitted portion of this light generating white noise is excluded and a sub-sequently emitted portion of this light is analyzed and an analyzed value is obtained from a spectral line intensity of an element to be measured only when an intensity of a preset spectral line or an intensity ratio between a pair of preset spectral lines is within a preset range.
In accordance with a preferred characteristic of the method o:E the present invention, an output of the infrared pulse laser beam is fixed to a gauss distribution type TEMoo mode, so that an analysis with high accuracy can be conducted in spite of variations and the like in the laser output intensity.
As the inert gas is blown into the path of the emitted light at a flow rate of at least ~0 l/min, whereby this path is held under an atmosphere of inert gas, an ascending current can be reliably suppressed and sample dust 6~L3 generated by the irradiation of laser can be removed, and that even if the sample is in the molten state.
In accordance with another preferred characteris-tic of the present invention, the firstly emitted portion of the light is of 1.5 microsecond or less duration.
According to a further preferred characteristic of the present invention, the firstly emitted portion of the light is of 1.5 microsecond or less duration, and the sub-sequently emitted portion of the light is of up to 16 micro-seconds duration. The firstly emitted portion of the light generating the white noise can then be reliably removed and an unnecessary emitted light is not used for the analysis.
According to a still further preferred charac-teristic o~ the method of the present invention, in conduct-1~ irlg the quantitative analysis, an :Lntensity of a light havincJ
~ pr~se-t wavelen~th emi-tting no spectral llne i5 macle to be a background, and the background is subtracted from the spectral line inten.sityl so that, particularly, the influence of a continuous spectrum unavoidable when a powerful pulse laser beam is used for molten steel of high temperature can be avoided.
In accordance with yet further preferred charac-teristic of the method of the present invention, an output from the infrared pulse laser beam is fixed to a gauss distribution type TEMoo mode, and, in conducting the quanti-tative analysis, a light intensity having a preset wavelength emitting no spectral line is made to be a background, which is subtracted from the spectral line intensity, so that an analyzed value with very high accuracy can be obtained.
Also in accordance with the present invention, there is provided an apparatus for laser emission spectros-copic analysis of steel, wherein a light emitted when a laser beam irradiates the surface of the steel is spec-trally separated and elements contained in the steel are quantitatively analyzed, comprising:
z~
laser oscillating means assembled thereinto with a mode lock mechanism, for emitting an infrared pulse laser beam having an energy density of 2.0 x 109 W/mm2 or more on the surface of a sample to turn a part of said sample to plasma;
a focusing mirror for focusing alight emitted from the surface of the sample at a focusing solid angle of 16 degrees or more;
a casing and means for introducing inert gas through an inert gas introducing port in said casing at a flow rate of at least 50 l/min for holding a path of said light emitted from the sample under an atmosphere of the inert gas in said casing;
spectroscopic means wherein said light emitted from the sample whose image is formed at an inlet slit of ~he æpectroscopic means by said focusing mirror is spec~
-trally separated into spectral lines by a diffraction means;
detecting means including a group of photoelec-tric signal tranducing elements wherein preset spectrallines of target elements are converted into electric si-gnals;
a spectrum intensity monitor for monitoring an intensity of a preset spectral line or an intensity ratio 5 between a pair of preset spectral lines;
gate means to be opened during a period from 1.5 mlcrosecond after the start of the irradiation by the laser beam up to 16 microseconds and when the intensity of the preset spectral line or the intensity ratio between the pair of preset spectral lines is within a preset range, so that an output from said spectroscopic means can be adopted in the analysis; and signal processing means for obtaining an analyzed value in response to a signal inputted from said spectros-copic means when said gate means is opened.
.. .
t6~3 According to the present invention, the lightexcited and generated by the laser beam can be caused to fall into a spectroscope at a satisfactory intensity, and the additional use of the methods of improving the accuracy, which have been proposed by the applicant, makes it possible to greatly improve the accuracy of analysis, so that a practical analysis usable even under an adverse environment on the site can be conducted.
BRIEF DESCRIPTION OF THE DRAWINGS
The exact nature of this invention, as well as other objects and advanta~es thereof, will be readily appa-rent from consideration of the following non-restrictive description given for the purpose of illustration only with reference to the accompanying drawings, in which like refe-lS rence characters designate the same or similar par-ts -through-~t ~h~ ~igures thereof and wherein:
Fig. 1 is a flow chart showing a method of laser emission spectroscopic analysis of steel according to the present invention;
Fig. 2 is a graphic chart showing the relation-ship between the laser output and the emission spectrum intensity in a method of the present invention;
Fig. 3 is a graphic chart showing the relation-ship between the area of irradiation by the laser on the surface of the sample and the first laser output whose spec-trum intensity reaehes a saturated value in a method of the present invention;
Fig. 4 is an arrangement drawing showing the basic arrangement of the apparatus for laser emission spectroscopie analysis in a method of the present invention;
Fig. 5 is a graphie chart showing the relation-ship between the focusing solid angle ~ and the emission spectrum intensity in a method of the present invention;
Fig. 6 is a graphic chart showing the relation-~; ~
6~3 ship between the focusing solid angle and the coefficient of variation of the emission spectrum intensity in a method of the present invention;
Fig. 7 is a graphic chart showing the relation-ship between the repeated cycles of analysis and the changing conditions of the emission spectrum intensity in a method of the present invention;
Fig. 8 is an arrangement drawing showing the basic arrangement of the apparatus for laser emission spectroscopic analysis, to which is added a casing for holding the sample beam path under an atmosphere of inert gas in accordance with the present invention;
Fig. 9 is a graphic chart showing the relation-ship ~etween the repeated cycles of analysis and the emission spectrum intensity in the apparatus shown in Fig. 8;
F'ig. 10 is a graphic chart showing an Fe spectrum in th~ p~ximlty o:~ the wave].ength 258 nanometers between 2 microseconds before the irradiation by the laser to 16 microseconds after the irradiation by the laser;
Fig. 11 is a graphic chart showing the changing conditions of the intensity of an Fe spectrum having a wave-length of 259.8 nanometers as shown in Fig. 10;
Fig. 12 is a graphic chart showing the relation-ship between the laser output and the coefficient of varia-tion of the intensity of an Fe spectrum having a wavelength of 271.4 nanometers;
Fig. 13 is a graphic chart showing the relation-ship between the laser output, the coefficient of variation of the laser output and the coefficient of variation of the intensity of the spectral line of Fe having a wavelength of 271.4 nanometers;
Fig 14. is a graphic chart showing the waveform of the spectrum obtained through the dispersion of the light excited and generated by irradiation by the laser ; and .~ 8 --Fig. l5 is a block diagram showing the arrangement of the embodiment of an apparatus for laser emission spec-troscopic analysis, adapted to use of the method of laser emission spectroscopic analysis of steel according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
As stated hereinabove, Figure l is a flow chart of a method of laser emission spectroscopic analysis of steel according to the invention, in which a light emitted when a laser beam irradiates the surface of steel is spectrally separated and various elements contained in the steel are quantita~
tively analyzed.
In general, in laser emission spectroscopic analy-sis, a laser beam as the excitation source is focused on arld irradiates the surface of a sample, a light excited and generated is dispersed by a spectroscope, and concentration~
of various elemerlts are determined from the intensities o~
spectral lines oE the elements.
A~ the laser beam for this laser emission spec-troscopic analysis, a ruby laser beam having a wavelengthof 0.69 micrometer is used in many cases. In this case, the laser beam is formed into pulse shapes of the width of several tens of nanoseconds by use of high speed switching (Q switching) elements such as Kerr cells, Pockels cells or the like, and a portion irradiated by the laser is changed into the high energy state before thermal energy is diffused around the portion irradiated by the laser.
The inventors planned to conduct the above-described laser emission spectroscopic analysis by use of an infrared pulse .
:L~2~
laser beam further excellent in the heat transfer rate, caused an infrared pulse laser having a wavelength of l.06 micrometer emitted from an Nd glass laser to irradiate the surface of steel, and observed an emission spectrum. As the result, the inventors found the following.
~l) The emission spectrum having a satisfactorily ~xcellent S/B
ratio is obtainable without using an auxiliary electrode.
(2) The intensity of the emission spectrum increases with the increase in the laser output, but has a trend to be saturated in time as shown in Fig. 2.
~2~ L3 by the laser beam to be formed into plasma which emits a light.
According to the method of laser emission spectroscopic analysis, this light emitted from the plasma is transmitted to a spectroscope by means of a suitable light introducing system, spectrally separated by a diffraction grating or the like and formed into spectra, and thereafter detected by a photographic film, a photomultiplier tube, a photo-diode or the like, whereby the contents of target elements are determined.
However, heretofore, a ratio between the intensity of a signal and the background (hereinafter referred to as "S/B ratio") has been very low and the variations in the output intensity of lasers have been high, whereby the accuracy of analysis and the exa~ne~s have ~een considerably low. Furthermore, when the m~hod ~ laser emission spectroscopic analysis is used in p~actical process analysis or the like on site, there have been such disadvantages that mirrors in a focusing system are contaminated and so on by gases from the surface of the sample and scattered matters after the irradiation by the laser, and the method has not been practiced yet.
Aiming at making this laser emission spectroscopic analysis practicable, the applicant has proposed in Japanese Patent Laid-Open No. 100323/82 a method wherein, excludlng white noises immediately after the irradiation by the laser, subsequent line spectra are integrated to improve the accuracy of analysis.
However, the intensity of white noise is higher than the line spectrum intensity, and consequently, if a satisfactory intensity would not be given to the line spectra, then effective C` !, ~.,,~`.' improvements in accuracy would not be attained.
Furthermore, the applicant has proposed in Japanese Patent Laid-Open No. 76744/83 a method wherein an infrared pulse laser beam irradiates a sample such that an energy density on the S surface of the sample becomes2.0 x 109 W/mm2 or more. However, unless a light emitted by the laser is efficiently and sufficiently taken in, the significance has been low.
Further, the applicant has proposed in Japanese Patent Laid-Open Nos. 114746/81 and 219440/83 that mode control of a laser output and signal processing are effected so as to improve the accuracy. Likewise, unless the light emitted by the laser beam is sufficiently and efficiently taken in, it has been impossible to expect a satisfactory effect.
SUM~A~Y OF T~IE INVENTION
Th~ pr~sent invention has been developed to obviate the above-described disadvantages of the prior art and has as its object the provision of a method of laser ernission spectroscopic analysis of steel and an apparatus therefor.
The invention is practicable and usable under an adverse environment on site. Light excited and generated by a laser beam can be caused to enter a spectroscope with a satisfactory intensity, so that the accuracy of analysis can be greatly irnproved by additional use of various methods of improving the accuracy which have been proposed by the applicant.
To this end, the present invention contemplates ~' , 6~
a method of laser emission spectroscopic analysis of steel, wherein a light emitted when a laser beam irradiates the surface of the steel is spectrally separated and elements contained in the steel are quantitatively analyzed, compris-ing the steps of:
irradiating a sample with an inf~ared pulse laserbeam to turn a part of said sample into plasma such that an energy density on the surface of the sample is 2.0 x 109 W/mm or more;
receiving a light emitted from the surface of the sample by a light introducing system at a solid angle of 16 degrees or more through a path held under an atmosphere of inert gas blown into said path at a flow rate of at least 50 l/min, and thereafter, forming an image on an in-let slit of a spectroscope with said light emitted from the .~ample surface; and quanti-tatively analyæing said light e~itted from ~h~ sample surface, such that a firstly emitted portion of this light generating white noise is excluded and a sub-sequently emitted portion of this light is analyzed and an analyzed value is obtained from a spectral line intensity of an element to be measured only when an intensity of a preset spectral line or an intensity ratio between a pair of preset spectral lines is within a preset range.
In accordance with a preferred characteristic of the method o:E the present invention, an output of the infrared pulse laser beam is fixed to a gauss distribution type TEMoo mode, so that an analysis with high accuracy can be conducted in spite of variations and the like in the laser output intensity.
As the inert gas is blown into the path of the emitted light at a flow rate of at least ~0 l/min, whereby this path is held under an atmosphere of inert gas, an ascending current can be reliably suppressed and sample dust 6~L3 generated by the irradiation of laser can be removed, and that even if the sample is in the molten state.
In accordance with another preferred characteris-tic of the present invention, the firstly emitted portion of the light is of 1.5 microsecond or less duration.
According to a further preferred characteristic of the present invention, the firstly emitted portion of the light is of 1.5 microsecond or less duration, and the sub-sequently emitted portion of the light is of up to 16 micro-seconds duration. The firstly emitted portion of the light generating the white noise can then be reliably removed and an unnecessary emitted light is not used for the analysis.
According to a still further preferred charac-teristic o~ the method of the present invention, in conduct-1~ irlg the quantitative analysis, an :Lntensity of a light havincJ
~ pr~se-t wavelen~th emi-tting no spectral llne i5 macle to be a background, and the background is subtracted from the spectral line inten.sityl so that, particularly, the influence of a continuous spectrum unavoidable when a powerful pulse laser beam is used for molten steel of high temperature can be avoided.
In accordance with yet further preferred charac-teristic of the method of the present invention, an output from the infrared pulse laser beam is fixed to a gauss distribution type TEMoo mode, and, in conducting the quanti-tative analysis, a light intensity having a preset wavelength emitting no spectral line is made to be a background, which is subtracted from the spectral line intensity, so that an analyzed value with very high accuracy can be obtained.
Also in accordance with the present invention, there is provided an apparatus for laser emission spectros-copic analysis of steel, wherein a light emitted when a laser beam irradiates the surface of the steel is spec-trally separated and elements contained in the steel are quantitatively analyzed, comprising:
z~
laser oscillating means assembled thereinto with a mode lock mechanism, for emitting an infrared pulse laser beam having an energy density of 2.0 x 109 W/mm2 or more on the surface of a sample to turn a part of said sample to plasma;
a focusing mirror for focusing alight emitted from the surface of the sample at a focusing solid angle of 16 degrees or more;
a casing and means for introducing inert gas through an inert gas introducing port in said casing at a flow rate of at least 50 l/min for holding a path of said light emitted from the sample under an atmosphere of the inert gas in said casing;
spectroscopic means wherein said light emitted from the sample whose image is formed at an inlet slit of ~he æpectroscopic means by said focusing mirror is spec~
-trally separated into spectral lines by a diffraction means;
detecting means including a group of photoelec-tric signal tranducing elements wherein preset spectrallines of target elements are converted into electric si-gnals;
a spectrum intensity monitor for monitoring an intensity of a preset spectral line or an intensity ratio 5 between a pair of preset spectral lines;
gate means to be opened during a period from 1.5 mlcrosecond after the start of the irradiation by the laser beam up to 16 microseconds and when the intensity of the preset spectral line or the intensity ratio between the pair of preset spectral lines is within a preset range, so that an output from said spectroscopic means can be adopted in the analysis; and signal processing means for obtaining an analyzed value in response to a signal inputted from said spectros-copic means when said gate means is opened.
.. .
t6~3 According to the present invention, the lightexcited and generated by the laser beam can be caused to fall into a spectroscope at a satisfactory intensity, and the additional use of the methods of improving the accuracy, which have been proposed by the applicant, makes it possible to greatly improve the accuracy of analysis, so that a practical analysis usable even under an adverse environment on the site can be conducted.
BRIEF DESCRIPTION OF THE DRAWINGS
The exact nature of this invention, as well as other objects and advanta~es thereof, will be readily appa-rent from consideration of the following non-restrictive description given for the purpose of illustration only with reference to the accompanying drawings, in which like refe-lS rence characters designate the same or similar par-ts -through-~t ~h~ ~igures thereof and wherein:
Fig. 1 is a flow chart showing a method of laser emission spectroscopic analysis of steel according to the present invention;
Fig. 2 is a graphic chart showing the relation-ship between the laser output and the emission spectrum intensity in a method of the present invention;
Fig. 3 is a graphic chart showing the relation-ship between the area of irradiation by the laser on the surface of the sample and the first laser output whose spec-trum intensity reaehes a saturated value in a method of the present invention;
Fig. 4 is an arrangement drawing showing the basic arrangement of the apparatus for laser emission spectroscopie analysis in a method of the present invention;
Fig. 5 is a graphie chart showing the relation-ship between the focusing solid angle ~ and the emission spectrum intensity in a method of the present invention;
Fig. 6 is a graphic chart showing the relation-~; ~
6~3 ship between the focusing solid angle and the coefficient of variation of the emission spectrum intensity in a method of the present invention;
Fig. 7 is a graphic chart showing the relation-ship between the repeated cycles of analysis and the changing conditions of the emission spectrum intensity in a method of the present invention;
Fig. 8 is an arrangement drawing showing the basic arrangement of the apparatus for laser emission spectroscopic analysis, to which is added a casing for holding the sample beam path under an atmosphere of inert gas in accordance with the present invention;
Fig. 9 is a graphic chart showing the relation-ship ~etween the repeated cycles of analysis and the emission spectrum intensity in the apparatus shown in Fig. 8;
F'ig. 10 is a graphic chart showing an Fe spectrum in th~ p~ximlty o:~ the wave].ength 258 nanometers between 2 microseconds before the irradiation by the laser to 16 microseconds after the irradiation by the laser;
Fig. 11 is a graphic chart showing the changing conditions of the intensity of an Fe spectrum having a wave-length of 259.8 nanometers as shown in Fig. 10;
Fig. 12 is a graphic chart showing the relation-ship between the laser output and the coefficient of varia-tion of the intensity of an Fe spectrum having a wavelength of 271.4 nanometers;
Fig. 13 is a graphic chart showing the relation-ship between the laser output, the coefficient of variation of the laser output and the coefficient of variation of the intensity of the spectral line of Fe having a wavelength of 271.4 nanometers;
Fig 14. is a graphic chart showing the waveform of the spectrum obtained through the dispersion of the light excited and generated by irradiation by the laser ; and .~ 8 --Fig. l5 is a block diagram showing the arrangement of the embodiment of an apparatus for laser emission spec-troscopic analysis, adapted to use of the method of laser emission spectroscopic analysis of steel according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
As stated hereinabove, Figure l is a flow chart of a method of laser emission spectroscopic analysis of steel according to the invention, in which a light emitted when a laser beam irradiates the surface of steel is spectrally separated and various elements contained in the steel are quantita~
tively analyzed.
In general, in laser emission spectroscopic analy-sis, a laser beam as the excitation source is focused on arld irradiates the surface of a sample, a light excited and generated is dispersed by a spectroscope, and concentration~
of various elemerlts are determined from the intensities o~
spectral lines oE the elements.
A~ the laser beam for this laser emission spec-troscopic analysis, a ruby laser beam having a wavelengthof 0.69 micrometer is used in many cases. In this case, the laser beam is formed into pulse shapes of the width of several tens of nanoseconds by use of high speed switching (Q switching) elements such as Kerr cells, Pockels cells or the like, and a portion irradiated by the laser is changed into the high energy state before thermal energy is diffused around the portion irradiated by the laser.
The inventors planned to conduct the above-described laser emission spectroscopic analysis by use of an infrared pulse .
:L~2~
laser beam further excellent in the heat transfer rate, caused an infrared pulse laser having a wavelength of l.06 micrometer emitted from an Nd glass laser to irradiate the surface of steel, and observed an emission spectrum. As the result, the inventors found the following.
~l) The emission spectrum having a satisfactorily ~xcellent S/B
ratio is obtainable without using an auxiliary electrode.
(2) The intensity of the emission spectrum increases with the increase in the laser output, but has a trend to be saturated in time as shown in Fig. 2.
(3) A rectilinear relationship shown in Fig. 3 is established between the area of the irradiation by the laser on the surface of the sample and the first laser output Jmin, under which the ~mi~ n ~pectrum intensity reaches the saturated value.
~dditionally, during the experiments, the pulse width of the laser beam is made to be 15 nanosecondsand the position of the focusing lens is moved, whereby the area ofirradiation by the laser is varied. It is apparent from F-ig. 3 that, if an output density of 2.0 x lO9 W/mm2 or more is obtained, then a satisfactorily good emission spectrum can be obtained.
Subsequently, the inventors changed the area of a focusing mirror ~concave mirror) 12 for receiving an emitted light B
excited and generated in an apparatus having the arrangement shown in Fig. 4, in which an energy density of a laser beam A on the surface of the sample ~lO) is made to be 2.0 x lO9 W/mm2, and observed the changes in the spectrum intensity when the focusing solid angle ~ is changed. In Fig. 4, designated at 14 ~2~
is a focusing lens and 16A an inlet slit of a spectroscope.
Fig. 5 shows the results of experiments. In Fig. 5, broken lines show the width of variations of the emission spectrum intensity obtained by ten measurements . As apparent from Fig. 5, the variations in the emission spectrum intensity shrink with the increase in the focusing solid angle ~. Fig. 6 shows the relationship between the coefficient of variation (one obtained by dividing a standard deviation by a mean value) of the emission spectrum intensity in Fig. 5 and the focusing solid angle ~. It is found from Fig. 6 that the coefficient of variation is reduced with the increase of the focusing solid angle ~, but becomes constant when the solid angle ~ is 16 degree and thereafter. In consequence, it is ~ound ~hat if the solid angle ~ is 16 degree or more, an ernission ';pectrum intensity low in variations is obtainable.
However, in the case of the apparatus having the construction shown in Fig. 4, if the apparatus is used for a long period of time, dust of the sample scattered by the irradiation by the laser adheres to the focusing lens 14 of a laser beam A and the surface of the focusing mirror 12 of emitted light B, whereby they may be damaged or the light intensity may be lowered. Particularly, when the sample is in a molten state, an ascending current is generated, and the influence thereof is notable. Fig. 7 shows the changing conditions of the emission spectrum intensity when the apparatus shown in Fig. 4 is used for a long period of time. In the drawing, a solid line C shows the case o~ analyzing only a solid sample and a broken line D
1' ,'`;J
~2~
shows the case of analyzing a molten sample.
Then, the inventors modified the apparatus such that the apparatus is covered by a case 18 and inert gas is blown into the case 18 through an inert gas introducing port 18A as shown in Fig. 8. Fig. 9 shows the changing conditions of the emission spectrum intensity when only the molten sample is analyzed for a long period of time while inert gas is blown into the apparatus shown in Fig. 8 through the inert gas introducing port l~A. In the drawing, numerical values indicate the flowrates of the inert gas. As apparent from Fig. 9, if the inert gas having a flowrate of 50 1/min or more is caused to flow, then the ascending current can be suppressed even if the sample is in the molten state, and ~he dust of the sample generated by the ir~adi~ion by t~le l~ser can be removed. ~lrthenmore, the ~iSSiOIl IS light path is purged by this inert gas, so that a vacuum ultraviolet light can be prevented from being absorbed by oxygen in the air.
Further, the inventors caused an infrared laser beam having a wavelength of 1.06 micrometer in a pulse shape of a width of about 10 nanosecondsto irradiate the surface of Fe so as to convert part of the Fe into plasma, measured an Fe spectrum every 1 microsecond in the proximity of a wavelength of 258 nanometersfrom a light emitted by the plasma from 2 microseconds before the irradiation by the laser to 16 microseconds after the irradiation by the laser, and obtained the results shown in Figs. 10 and 11. Fig. 10 shows the relationship between the wavelength and the light intensity, and Fig. 11 shows the changes with time ~2~ L3 of the line spectrum intensity of Fe having a wavelength of 259.8 nanometersas shown in Fig. 10. From the results of experiments, the inventors have found that a continuous light (white noise) as the background is emitted for about 1.5 microsecond from the irradiation by the infrared pulse laserl the line spectrum by atoms and univalent ions, which are used in the spectroscopic analysis hardly appears for about 1.5 microsecond from the irradiation by the laser, but is observed for 15 microsecondsupto 16 microsecondsafter a lapse of about 1.5 microsecond upon the irradiation by the laser.
To put together the above-described data, it may be concluded that, by taking the following measures, a practical la~er ~mission spectroscopic analysis can be conducted under the environment on the site.
(1) The energy dens-ty of the laser beam on the surface of the sample is made to be 2.0 x 109 W/mm2 or more.
(2) The focusing solid angle ~ is made to be 16 degree or more.
(3) The emitted light path is held under an atmosphere of the inert gas.
~dditionally, during the experiments, the pulse width of the laser beam is made to be 15 nanosecondsand the position of the focusing lens is moved, whereby the area ofirradiation by the laser is varied. It is apparent from F-ig. 3 that, if an output density of 2.0 x lO9 W/mm2 or more is obtained, then a satisfactorily good emission spectrum can be obtained.
Subsequently, the inventors changed the area of a focusing mirror ~concave mirror) 12 for receiving an emitted light B
excited and generated in an apparatus having the arrangement shown in Fig. 4, in which an energy density of a laser beam A on the surface of the sample ~lO) is made to be 2.0 x lO9 W/mm2, and observed the changes in the spectrum intensity when the focusing solid angle ~ is changed. In Fig. 4, designated at 14 ~2~
is a focusing lens and 16A an inlet slit of a spectroscope.
Fig. 5 shows the results of experiments. In Fig. 5, broken lines show the width of variations of the emission spectrum intensity obtained by ten measurements . As apparent from Fig. 5, the variations in the emission spectrum intensity shrink with the increase in the focusing solid angle ~. Fig. 6 shows the relationship between the coefficient of variation (one obtained by dividing a standard deviation by a mean value) of the emission spectrum intensity in Fig. 5 and the focusing solid angle ~. It is found from Fig. 6 that the coefficient of variation is reduced with the increase of the focusing solid angle ~, but becomes constant when the solid angle ~ is 16 degree and thereafter. In consequence, it is ~ound ~hat if the solid angle ~ is 16 degree or more, an ernission ';pectrum intensity low in variations is obtainable.
However, in the case of the apparatus having the construction shown in Fig. 4, if the apparatus is used for a long period of time, dust of the sample scattered by the irradiation by the laser adheres to the focusing lens 14 of a laser beam A and the surface of the focusing mirror 12 of emitted light B, whereby they may be damaged or the light intensity may be lowered. Particularly, when the sample is in a molten state, an ascending current is generated, and the influence thereof is notable. Fig. 7 shows the changing conditions of the emission spectrum intensity when the apparatus shown in Fig. 4 is used for a long period of time. In the drawing, a solid line C shows the case o~ analyzing only a solid sample and a broken line D
1' ,'`;J
~2~
shows the case of analyzing a molten sample.
Then, the inventors modified the apparatus such that the apparatus is covered by a case 18 and inert gas is blown into the case 18 through an inert gas introducing port 18A as shown in Fig. 8. Fig. 9 shows the changing conditions of the emission spectrum intensity when only the molten sample is analyzed for a long period of time while inert gas is blown into the apparatus shown in Fig. 8 through the inert gas introducing port l~A. In the drawing, numerical values indicate the flowrates of the inert gas. As apparent from Fig. 9, if the inert gas having a flowrate of 50 1/min or more is caused to flow, then the ascending current can be suppressed even if the sample is in the molten state, and ~he dust of the sample generated by the ir~adi~ion by t~le l~ser can be removed. ~lrthenmore, the ~iSSiOIl IS light path is purged by this inert gas, so that a vacuum ultraviolet light can be prevented from being absorbed by oxygen in the air.
Further, the inventors caused an infrared laser beam having a wavelength of 1.06 micrometer in a pulse shape of a width of about 10 nanosecondsto irradiate the surface of Fe so as to convert part of the Fe into plasma, measured an Fe spectrum every 1 microsecond in the proximity of a wavelength of 258 nanometersfrom a light emitted by the plasma from 2 microseconds before the irradiation by the laser to 16 microseconds after the irradiation by the laser, and obtained the results shown in Figs. 10 and 11. Fig. 10 shows the relationship between the wavelength and the light intensity, and Fig. 11 shows the changes with time ~2~ L3 of the line spectrum intensity of Fe having a wavelength of 259.8 nanometersas shown in Fig. 10. From the results of experiments, the inventors have found that a continuous light (white noise) as the background is emitted for about 1.5 microsecond from the irradiation by the infrared pulse laserl the line spectrum by atoms and univalent ions, which are used in the spectroscopic analysis hardly appears for about 1.5 microsecond from the irradiation by the laser, but is observed for 15 microsecondsupto 16 microsecondsafter a lapse of about 1.5 microsecond upon the irradiation by the laser.
To put together the above-described data, it may be concluded that, by taking the following measures, a practical la~er ~mission spectroscopic analysis can be conducted under the environment on the site.
(1) The energy dens-ty of the laser beam on the surface of the sample is made to be 2.0 x 109 W/mm2 or more.
(2) The focusing solid angle ~ is made to be 16 degree or more.
(3) The emitted light path is held under an atmosphere of the inert gas.
(4) White noise for 1.5 microsecond immediately after the irradiation of laser beam is excluded, and the subsequent emitted light is quantitatively analyzed.
Further, the inventors have found that, in conducting the above-described laser emission spectroscopic analysis, additional use of the method of fixing the laser beam to the mode, which has been proposed in Japanese Patent Laid-Open No.
219440/83 by the applicant, and of the method of removing the .:....
~L22~ 3 background, which has been also proposed in Japanese Patent Laid-Open No. 1147~6/81 by the applicant, makes it possible to greatly improve the accuracy.
More specifically, the following are made clear by the survey of the inventors.
(1) If an output from a laser oscillator is increased, then the coefficient of variation of the spectral line intensity decreases. ~owever, an amplifier is provided at a stage posterior to the laser oscillator and, if an output thereof is further increased, then the coefficient of variation increases.
(2) Even when the laser beam is obtained only by use of the l~çr o~cillator without using the amplifier, the varlation oE
the spectral line intensity is higher than the variation of the laser output.
Figs. 12 and 13 show the results of experiments. The sample used in the experiments is an Fe alloy, and, as the laser beam, an infrared laser beam having a wavelength of 1.06 micrometer and a pulse width of 15 nanosecondSis used. As apparent from Fig. 12, when the laser output becomes an output 2 joule or more with an amplifier being utilized~ the coefficient of variation suddenly increases. The cause seems to reside in the intensity distribution of the laser pulses. Namely, in general, there are various symmetries in the intensity distribution (mode) in the direction of the vertical section of the laser beam emitted from a laser oscillator. When such a high output is re~uired as used in the emission spectroscopic analysis, multi-mode ~22~ 3 oscillation, in which the mode is varied with every pulse, is adopted. However, when several peaks of the intensity distribution are present in a beam as described above, if an amplifier is actuated, then a specified peak is amplified preferentially. In conse~uence, if a laser beam having the above-described intensity distribution is converged onto the surface of the sample, then, within this spot caliber, a local area, which is high in laser irradiation dPnsity, is generated.
Such wide fluctuations in the irradiation density as described above vary with every pulse, whereby the emission spectrum intensity is subjected to the variat~ions. Then, the inventors thought of fixing the laser used in the emission spectroscopic ~nalysis to TEMoo mode, from which the gauss distribution type ~ pu~ can be obtained, by utilizing the mode lock technique used in holography or the like. As the mode, TEMo1 mode or the like, from which an annular distribution can be obtained, may be adopted except the above-described mode, however, the qauss distribution seems optimal to the emission spectroscopic analysis. Additionally, if the mode lock is effected, the laser output decreases, however, this decrease can be made up for by an increase in the output of the laser oscillator and use of an additional amplifier. Needless to say, when the laser beam is fixed to TEMoo mode, the mode will not be changed even if an amplifier is used.
On the other hand, Fig. 13 shows a comparison between the coefficient of variation (solid line E) of a spectral line intensity of Fe having a wavelength of 271.4 nanometersand the ,",~ ,., ~22iO ~
coe~ficient of variation (solid line F) of the laser output when the same laser beam as shown in Fig. 12 irradiates an Fe alloy.
In spite of the fact that no amplifier is used, the change in the spectral line intensity is higher than the width of varia-tions of the laser output. The above-described change in the emission spectrum intensity is tolerably improved by the mode lock;
however, in addition thereto, the influence of the wide fluctuations in the evaporation and excitation processes, which occur on the surface of the sample during the irradiationby the laser cannot be disregarded.
Since the latter cannot be removed only by controlling the laser output and the mode, as the preset spectral line or lines, which can be ~btained during the irradiation by-the Laser, one or ~w~ Fe spectral lines each having a suitable wavelength are lS selected in the exemplary case of an Fe alloy, an intensity of the preset spectral line or an intensity ratio between the two preset spectral lines is constantly monitored, and a spectral line intensity of an element to be measured is read only when the intensity or the intensity ratio is within a preset range of variations. Particularly, the latter method of regulating the intensity ratio makes it possible to restrict the temperature of plasma generated by the irradiation by the laser, thus proving effective in improving the accuracy of analysis.
As a method to further improve the accuracy of analysis, a beam intensity having a specified wavelength emitting no spectral line as the background is subtracted from the 3 ~2~6~3 spectral line intensity. Fig. 14 shows the results of spectrally separating a light emitted by the irradiation by the laser and of observing the spectra. In Fig. 14, a point G
indicates the spectrum of the element and a point H the background emitting no spectral line. In consequence, the pure spectral line i~tensity is represented by a ~ifference obtained by subtracting the intensity at the point H from the intensity at the point G. This method is also an effective one applicable to a sample in the molten state where the background intensity varies greatly.
In consequence, when the requirements of the present invention are satisfied and further the above described methods of improving the accuracy are additionally used, all the probl~ms, which have been occurring on the site during the plication, are solved and a useful accuracy of analysis can be provided.
Detailed description will hereunder be given of one embodiment of the analyzing apparatus, to which is applied the method of laser emission spectroscopic analysis of steel according to the present invention, with reference to the drawing.
As shown in Fig. 15, this embodiment comprises:
a laser oscillator 22 assembled thereinto with a mode lock mechanism, not shown, for emitting an infrared pulse laser beam 25 having an energy density of 2.0 x 109 W/mm2 or more on the surface of a sample 10;
a switching circuit 24 for actuating a high speed switching ~Z;~ 3 element, not shown, assembled in the laser oscillator 22;
a rectangular prism 26 for diverting the irradiating direction of a laser beam emitted from the laser oscillator 22;
a focusing mirror (concave mirror) 12 for focusing a light emitted from the surface of the sample 10 at a focusing solid angle ~ of 16 degrees or more;
a casing 18, into which is introduced inert gas for holding a path of the light emitted from the sample under an atmosphere of the inert gas, through an inert gas introduc-ng port 18A;
a spectroscope 16 wherein the light emitted from the sample whose image is formed at an inlet slit 16A of the spectroscope by the focusing mirror 12, is spectrally separated into spectral lines by a diffraction grating 16B or the like, and the spe~tral lines are converted into electric signals for the target ~p~r~l lines b,y a yroup o~ photo el.ectric signal ~ran~ducing elements 16C;
a spectrum intensity monitor 28 for monitoring an intensity of a preset spectral line or an intensity ratio between a pair of preset spectral lines, all of which are emitted from a group of output terminals 16D of the spectroscope 16;
a gate circuit 30 to be opened during a period from 1.5 microsecond after the start of the irradiation by the laser u~ to 16 microseconds thereafter and when the intensity of the prese,t spectral line or the intensity ratio between the pair of preset spectral lines is within the preset range, so that an output from the spectroscope 16 can be adopted in the analysis;
a signal processing section 32 for obtaining an analyzed , ., ,~
~22~3 value in response to a signal inputted from the group of output terminals 16D of the spectroscope 16 when the gate circuit 30 is opened, and an indication section 34 for indicating the analyzed value obtained by the signal processing section 32.
As the laser oscillator 22, for example, a ruby laser having a wavelength of 0.69 micrometer or an infrared laser having a wavelength 1.05 to 1.06 micrometer may be used.
The rectangular prism 26 is intended to cause a laser beam A
to irradiate the surface of the sample 10 at a predetermined ange, and, when a laser emitting section including the laser oscillator 22 is provided in a predetermined direction, the rectangular prism 26 may be dispensed with.
As the group of photo-electric signal transducing elements 16C, or example, a photo-diode or a photomultiplier tube may be u~ed.
Description will hereunder be given of action of this embodiment.
The laser beam A fixed to TEMoo mode is emitted from the laser oscillator 22 controlled by the switching circuit 24, passed through the rectangular prism 26 and the focusing lens 14, and focused onto the surface of the sample 10. At this time, the energy density on the surface of the sample 10 is made to be 2.0 x 109 W/mm2 or more.
The emitted light B excited and emitted by the laser beam is caused to form its image at the inlet slit 16A of the spectroscope 16 by the focusing mirror 12 having the focusing :i ~
6~3 solid angle ~ of 16 degree or more. At this time, the inert gas is blown into the light introducing system in the casing 18 through the inert gas introducing port 18A and the light introducing system is held under the atmosphere of the inert gas. The inert gas is also blown onto the surface of the sample 10 .
The light introduced into the spectroscope 16 through the inlet slit 16A is diffused by ordinary means such for example as the diffraction grating 16B. Out of the spectra thus diffused, spectrum intensity or intensities tone or two) for regulating data, a base constituent element spectrum intensity Sigl, a background intensity BGl thereof, a measured element spectrum intensity Sig2 and a background intensity ~G2 thereof are converted into electric slgnals by the group of photo-electric n~1 ~ransducing elements 16C and outputted to the group of ~u~put terminals 16D.
Out of the above-mentioned signals, the spectrum intensity signal for regulating data is delivered to the spectrum intensity monitor 28, where judgment as to whether the intensity thereof or the intensity ratio between the pair of spectral line intensities is within the preset range or not is made. In the case of being within the preset range, the gate circuit 30 is actuated, whereby the respective spectrum intensity signals for the analysis and measurement are inputted to the signal processing section 32.
At the same time, a signal is delivered to the gate circuit 30 from the switching circuit 24 when the laser beam is ~2;~ 3 oscillated. And a gate is operatedr being referenced from the aforesaid signal, to exclude the emitted light for 1.5 microsecond immediately after the irradiation by the laser and to signal-process the subsequent emitted light upto 16 microseconds, out of the respective spectrum intensity signals for the analysis and measurement.
In the signal processing section 32, the spectrum intensity ratio obtained by subtractin~ the background therefrom (Sig2 -BG2)/~Sigl - BGl~ is calculated, a concentration of the element to be measured is worked out on the basis of a calibration curve prepared in advance by use of a reference sample and indicated in the indication section 34.
~ hc ~ollowing is the coefficient oE variation obtained by ~n~lyzing ~h~ concentration o~ contained silicon in a sample of lS an Fe alloy in the apparatus shown in Fig. 15 by various methods. Namely, according to the conventional method, the coefficient of variation was 11.4~. According to a first method Oc the present invention, wherein the energy density on the surface of the sample was made to be 2.0 x 109 W/~n2, argon as the inert gas was caused to flow at a flowrate of 50 l/min, the light for 1.5 microsecond immediately after the irradiation by the laser was exclude-d and the subsequent emitted light signalsup to 16 microsecondswere integrated, the coefficient of variation was 9.0%. ~ccording to a second method of the present invention, wherein, in addition to the first method, the mode lock mechanism was additionally provided in the laser oscillator 22 and the laser output mode was fixed to TEMoo , ~
~L2;~6~3 mode, the coefficient of variation was 7.3%. According to a third method of the present invention, wherein, in addition to the first method, the background intensity was subtracted, the coefficient of variation was 5.9~. According to a fourth method of the present invention, wherein, in addition to the first method, two spectrum intensities of Fe having wavelengths of 271.4 nanometersand 273.1 nanometerswere monitored and the spectral line intensity of silicon (288.2 nanometers)was read only when the intensity ratio between the aforesaid two spectrum intensities are within plus-minus 5% of the preset value, the coefficient of variation was 5.3%. According to a fifth method of the p~esent invention, wherein all of the first to fourth m~thods were conducted at the same time, the coefficient of varia~ion was 3.2~. It was ascertained that each of the aforesaid five methods was improved better than the conventional method. Particularly, it was proved that, according to the fifth method, wherein all of the methods were conducted simultaneously, the coefficient of variation was greatly improved to 3.2% as compared with 11.4% of the conventional method.
Further, the inventors have found that, in conducting the above-described laser emission spectroscopic analysis, additional use of the method of fixing the laser beam to the mode, which has been proposed in Japanese Patent Laid-Open No.
219440/83 by the applicant, and of the method of removing the .:....
~L22~ 3 background, which has been also proposed in Japanese Patent Laid-Open No. 1147~6/81 by the applicant, makes it possible to greatly improve the accuracy.
More specifically, the following are made clear by the survey of the inventors.
(1) If an output from a laser oscillator is increased, then the coefficient of variation of the spectral line intensity decreases. ~owever, an amplifier is provided at a stage posterior to the laser oscillator and, if an output thereof is further increased, then the coefficient of variation increases.
(2) Even when the laser beam is obtained only by use of the l~çr o~cillator without using the amplifier, the varlation oE
the spectral line intensity is higher than the variation of the laser output.
Figs. 12 and 13 show the results of experiments. The sample used in the experiments is an Fe alloy, and, as the laser beam, an infrared laser beam having a wavelength of 1.06 micrometer and a pulse width of 15 nanosecondSis used. As apparent from Fig. 12, when the laser output becomes an output 2 joule or more with an amplifier being utilized~ the coefficient of variation suddenly increases. The cause seems to reside in the intensity distribution of the laser pulses. Namely, in general, there are various symmetries in the intensity distribution (mode) in the direction of the vertical section of the laser beam emitted from a laser oscillator. When such a high output is re~uired as used in the emission spectroscopic analysis, multi-mode ~22~ 3 oscillation, in which the mode is varied with every pulse, is adopted. However, when several peaks of the intensity distribution are present in a beam as described above, if an amplifier is actuated, then a specified peak is amplified preferentially. In conse~uence, if a laser beam having the above-described intensity distribution is converged onto the surface of the sample, then, within this spot caliber, a local area, which is high in laser irradiation dPnsity, is generated.
Such wide fluctuations in the irradiation density as described above vary with every pulse, whereby the emission spectrum intensity is subjected to the variat~ions. Then, the inventors thought of fixing the laser used in the emission spectroscopic ~nalysis to TEMoo mode, from which the gauss distribution type ~ pu~ can be obtained, by utilizing the mode lock technique used in holography or the like. As the mode, TEMo1 mode or the like, from which an annular distribution can be obtained, may be adopted except the above-described mode, however, the qauss distribution seems optimal to the emission spectroscopic analysis. Additionally, if the mode lock is effected, the laser output decreases, however, this decrease can be made up for by an increase in the output of the laser oscillator and use of an additional amplifier. Needless to say, when the laser beam is fixed to TEMoo mode, the mode will not be changed even if an amplifier is used.
On the other hand, Fig. 13 shows a comparison between the coefficient of variation (solid line E) of a spectral line intensity of Fe having a wavelength of 271.4 nanometersand the ,",~ ,., ~22iO ~
coe~ficient of variation (solid line F) of the laser output when the same laser beam as shown in Fig. 12 irradiates an Fe alloy.
In spite of the fact that no amplifier is used, the change in the spectral line intensity is higher than the width of varia-tions of the laser output. The above-described change in the emission spectrum intensity is tolerably improved by the mode lock;
however, in addition thereto, the influence of the wide fluctuations in the evaporation and excitation processes, which occur on the surface of the sample during the irradiationby the laser cannot be disregarded.
Since the latter cannot be removed only by controlling the laser output and the mode, as the preset spectral line or lines, which can be ~btained during the irradiation by-the Laser, one or ~w~ Fe spectral lines each having a suitable wavelength are lS selected in the exemplary case of an Fe alloy, an intensity of the preset spectral line or an intensity ratio between the two preset spectral lines is constantly monitored, and a spectral line intensity of an element to be measured is read only when the intensity or the intensity ratio is within a preset range of variations. Particularly, the latter method of regulating the intensity ratio makes it possible to restrict the temperature of plasma generated by the irradiation by the laser, thus proving effective in improving the accuracy of analysis.
As a method to further improve the accuracy of analysis, a beam intensity having a specified wavelength emitting no spectral line as the background is subtracted from the 3 ~2~6~3 spectral line intensity. Fig. 14 shows the results of spectrally separating a light emitted by the irradiation by the laser and of observing the spectra. In Fig. 14, a point G
indicates the spectrum of the element and a point H the background emitting no spectral line. In consequence, the pure spectral line i~tensity is represented by a ~ifference obtained by subtracting the intensity at the point H from the intensity at the point G. This method is also an effective one applicable to a sample in the molten state where the background intensity varies greatly.
In consequence, when the requirements of the present invention are satisfied and further the above described methods of improving the accuracy are additionally used, all the probl~ms, which have been occurring on the site during the plication, are solved and a useful accuracy of analysis can be provided.
Detailed description will hereunder be given of one embodiment of the analyzing apparatus, to which is applied the method of laser emission spectroscopic analysis of steel according to the present invention, with reference to the drawing.
As shown in Fig. 15, this embodiment comprises:
a laser oscillator 22 assembled thereinto with a mode lock mechanism, not shown, for emitting an infrared pulse laser beam 25 having an energy density of 2.0 x 109 W/mm2 or more on the surface of a sample 10;
a switching circuit 24 for actuating a high speed switching ~Z;~ 3 element, not shown, assembled in the laser oscillator 22;
a rectangular prism 26 for diverting the irradiating direction of a laser beam emitted from the laser oscillator 22;
a focusing mirror (concave mirror) 12 for focusing a light emitted from the surface of the sample 10 at a focusing solid angle ~ of 16 degrees or more;
a casing 18, into which is introduced inert gas for holding a path of the light emitted from the sample under an atmosphere of the inert gas, through an inert gas introduc-ng port 18A;
a spectroscope 16 wherein the light emitted from the sample whose image is formed at an inlet slit 16A of the spectroscope by the focusing mirror 12, is spectrally separated into spectral lines by a diffraction grating 16B or the like, and the spe~tral lines are converted into electric signals for the target ~p~r~l lines b,y a yroup o~ photo el.ectric signal ~ran~ducing elements 16C;
a spectrum intensity monitor 28 for monitoring an intensity of a preset spectral line or an intensity ratio between a pair of preset spectral lines, all of which are emitted from a group of output terminals 16D of the spectroscope 16;
a gate circuit 30 to be opened during a period from 1.5 microsecond after the start of the irradiation by the laser u~ to 16 microseconds thereafter and when the intensity of the prese,t spectral line or the intensity ratio between the pair of preset spectral lines is within the preset range, so that an output from the spectroscope 16 can be adopted in the analysis;
a signal processing section 32 for obtaining an analyzed , ., ,~
~22~3 value in response to a signal inputted from the group of output terminals 16D of the spectroscope 16 when the gate circuit 30 is opened, and an indication section 34 for indicating the analyzed value obtained by the signal processing section 32.
As the laser oscillator 22, for example, a ruby laser having a wavelength of 0.69 micrometer or an infrared laser having a wavelength 1.05 to 1.06 micrometer may be used.
The rectangular prism 26 is intended to cause a laser beam A
to irradiate the surface of the sample 10 at a predetermined ange, and, when a laser emitting section including the laser oscillator 22 is provided in a predetermined direction, the rectangular prism 26 may be dispensed with.
As the group of photo-electric signal transducing elements 16C, or example, a photo-diode or a photomultiplier tube may be u~ed.
Description will hereunder be given of action of this embodiment.
The laser beam A fixed to TEMoo mode is emitted from the laser oscillator 22 controlled by the switching circuit 24, passed through the rectangular prism 26 and the focusing lens 14, and focused onto the surface of the sample 10. At this time, the energy density on the surface of the sample 10 is made to be 2.0 x 109 W/mm2 or more.
The emitted light B excited and emitted by the laser beam is caused to form its image at the inlet slit 16A of the spectroscope 16 by the focusing mirror 12 having the focusing :i ~
6~3 solid angle ~ of 16 degree or more. At this time, the inert gas is blown into the light introducing system in the casing 18 through the inert gas introducing port 18A and the light introducing system is held under the atmosphere of the inert gas. The inert gas is also blown onto the surface of the sample 10 .
The light introduced into the spectroscope 16 through the inlet slit 16A is diffused by ordinary means such for example as the diffraction grating 16B. Out of the spectra thus diffused, spectrum intensity or intensities tone or two) for regulating data, a base constituent element spectrum intensity Sigl, a background intensity BGl thereof, a measured element spectrum intensity Sig2 and a background intensity ~G2 thereof are converted into electric slgnals by the group of photo-electric n~1 ~ransducing elements 16C and outputted to the group of ~u~put terminals 16D.
Out of the above-mentioned signals, the spectrum intensity signal for regulating data is delivered to the spectrum intensity monitor 28, where judgment as to whether the intensity thereof or the intensity ratio between the pair of spectral line intensities is within the preset range or not is made. In the case of being within the preset range, the gate circuit 30 is actuated, whereby the respective spectrum intensity signals for the analysis and measurement are inputted to the signal processing section 32.
At the same time, a signal is delivered to the gate circuit 30 from the switching circuit 24 when the laser beam is ~2;~ 3 oscillated. And a gate is operatedr being referenced from the aforesaid signal, to exclude the emitted light for 1.5 microsecond immediately after the irradiation by the laser and to signal-process the subsequent emitted light upto 16 microseconds, out of the respective spectrum intensity signals for the analysis and measurement.
In the signal processing section 32, the spectrum intensity ratio obtained by subtractin~ the background therefrom (Sig2 -BG2)/~Sigl - BGl~ is calculated, a concentration of the element to be measured is worked out on the basis of a calibration curve prepared in advance by use of a reference sample and indicated in the indication section 34.
~ hc ~ollowing is the coefficient oE variation obtained by ~n~lyzing ~h~ concentration o~ contained silicon in a sample of lS an Fe alloy in the apparatus shown in Fig. 15 by various methods. Namely, according to the conventional method, the coefficient of variation was 11.4~. According to a first method Oc the present invention, wherein the energy density on the surface of the sample was made to be 2.0 x 109 W/~n2, argon as the inert gas was caused to flow at a flowrate of 50 l/min, the light for 1.5 microsecond immediately after the irradiation by the laser was exclude-d and the subsequent emitted light signalsup to 16 microsecondswere integrated, the coefficient of variation was 9.0%. ~ccording to a second method of the present invention, wherein, in addition to the first method, the mode lock mechanism was additionally provided in the laser oscillator 22 and the laser output mode was fixed to TEMoo , ~
~L2;~6~3 mode, the coefficient of variation was 7.3%. According to a third method of the present invention, wherein, in addition to the first method, the background intensity was subtracted, the coefficient of variation was 5.9~. According to a fourth method of the present invention, wherein, in addition to the first method, two spectrum intensities of Fe having wavelengths of 271.4 nanometersand 273.1 nanometerswere monitored and the spectral line intensity of silicon (288.2 nanometers)was read only when the intensity ratio between the aforesaid two spectrum intensities are within plus-minus 5% of the preset value, the coefficient of variation was 5.3%. According to a fifth method of the p~esent invention, wherein all of the first to fourth m~thods were conducted at the same time, the coefficient of varia~ion was 3.2~. It was ascertained that each of the aforesaid five methods was improved better than the conventional method. Particularly, it was proved that, according to the fifth method, wherein all of the methods were conducted simultaneously, the coefficient of variation was greatly improved to 3.2% as compared with 11.4% of the conventional method.
Claims (7)
1. A method of laser emission spectroscopic analysis of steel, wherein a light emitted when a laser beam irradiates the surface of the steel is spectrally separated and elements contained in the steel are quanti-tatively analyzed, comprising the steps of:
irradiating a sample with an infrared pulse laser beam to turn a part of said sample into plasma such that an energy density on the surface of the sample is 2.0 x 109 W/mm2 or more;
receiving a light emitted from the surface of the sample by a light introducing system at a solid angle of 16 degrees or more throuhg a path held under an atmosphere of inert gas blown in-to said path at a flow rate of at least 50 1/min, and thereafter, forming an image on an in-let slit of a spectroscope with said light emitted from the sample surface; and quantitatively analyzing said light emitted from the sample surface, such that a firstly emitted portion of this light generating white noise is excluded and a subse-quently emitted portion of this light is analyzed and an analyzed value is obtained from a spectral line intensity of an element to be measured only when an intensity of a preset spectral line or an intensity ratio between a pair of preset spectral lines is within a preset range.
irradiating a sample with an infrared pulse laser beam to turn a part of said sample into plasma such that an energy density on the surface of the sample is 2.0 x 109 W/mm2 or more;
receiving a light emitted from the surface of the sample by a light introducing system at a solid angle of 16 degrees or more throuhg a path held under an atmosphere of inert gas blown in-to said path at a flow rate of at least 50 1/min, and thereafter, forming an image on an in-let slit of a spectroscope with said light emitted from the sample surface; and quantitatively analyzing said light emitted from the sample surface, such that a firstly emitted portion of this light generating white noise is excluded and a subse-quently emitted portion of this light is analyzed and an analyzed value is obtained from a spectral line intensity of an element to be measured only when an intensity of a preset spectral line or an intensity ratio between a pair of preset spectral lines is within a preset range.
2. A method as set forth in claim 1, wherein an output of said infrared pulse laser beam is fixed to a gauss distribution type TEM00 mode.
3. A method as set forth in claim 1, wherein said firstly emitted portion of said light is of 1.5 micro-second orless duration.
4. A method as set forth in claim 1, wherein said firstly emitted portion of said light is of 1.5 micro-second or less duration, and said subsequently emitted portion of said light is of up to 16 microseconds duration.
5. A method as set forth in claim 1, wherein, in conducting said quantitative analysis, an intensity of a light having a preset wavelength emitting no spectral line is made to be a background which is subtracted from said spectral line intensity.
6. A method as set forth in claim 1, wherein:
an output of said infrared pulse laser beam is fixed to a gauss distribution type TEM00 mode; and in conducting the quantitative analysis, a light intensity having a preset wavelength emitting no spectral line is made to be a background, which is subtracted from said spectral line intensity.
an output of said infrared pulse laser beam is fixed to a gauss distribution type TEM00 mode; and in conducting the quantitative analysis, a light intensity having a preset wavelength emitting no spectral line is made to be a background, which is subtracted from said spectral line intensity.
7. An apparatus for laser emission spectroscopic analysis of steel, wherein a light emitted when a laser beam irradiates the surface of the steel is spectrally separated and elements contained in the steel are quanti-tatively analyzed, comprising:
laser oscillating means assembled thereinto with a mode lock mechanism, for emitting an infrared pulse laser beam having an energy density of 2.0 x 109 W/mm2 or more on the surface of a sample to turn a part of said sample to plasma;
a focusing mirror for focusing a light emitted from the surface of the sample at a focusing solid angle of 16 degrees or more;
a casing and means for introducing inert gas through an inert gas introducing port in said casing at a flow rate of at least 50 1/min for holding a path of said light emitted from the sample under an atmosphere of the inert gas in said casing;
spectroscopic means wherein said light emitted from the sample whose image is formed at an inlet slit of the spectroscopic means by said focusing mirror is spec-trally separated into spectral lines by a diffraction means;
detecting means including a group of photoelec-tric signal transducing elements wherein preset spectral lines of target elements are converted into electric si-gnals;
a spectrum intensity monitor for monitoring an intensity of a preset spectral line or an intensity ratio between a pair of preset spectral lines;
gate means to be opened during a period from 1.5 microsecond after the start of the irradiation by the laser beam up to 16 microseconds and when the intensity of the preset spectral line or the intensity ratio between the pair of preset spectral lines is within a preset range, so that an output from said spectroscopic means can be adopted in the analysis; and signal processing means for obtaining an analyzed value in response to a signal inputted from said spectros-copic means when said gate means is opened.
laser oscillating means assembled thereinto with a mode lock mechanism, for emitting an infrared pulse laser beam having an energy density of 2.0 x 109 W/mm2 or more on the surface of a sample to turn a part of said sample to plasma;
a focusing mirror for focusing a light emitted from the surface of the sample at a focusing solid angle of 16 degrees or more;
a casing and means for introducing inert gas through an inert gas introducing port in said casing at a flow rate of at least 50 1/min for holding a path of said light emitted from the sample under an atmosphere of the inert gas in said casing;
spectroscopic means wherein said light emitted from the sample whose image is formed at an inlet slit of the spectroscopic means by said focusing mirror is spec-trally separated into spectral lines by a diffraction means;
detecting means including a group of photoelec-tric signal transducing elements wherein preset spectral lines of target elements are converted into electric si-gnals;
a spectrum intensity monitor for monitoring an intensity of a preset spectral line or an intensity ratio between a pair of preset spectral lines;
gate means to be opened during a period from 1.5 microsecond after the start of the irradiation by the laser beam up to 16 microseconds and when the intensity of the preset spectral line or the intensity ratio between the pair of preset spectral lines is within a preset range, so that an output from said spectroscopic means can be adopted in the analysis; and signal processing means for obtaining an analyzed value in response to a signal inputted from said spectros-copic means when said gate means is opened.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59-209096 | 1984-10-05 | ||
| JP59209096A JPS6186636A (en) | 1984-10-05 | 1984-10-05 | Emission spectrochemical analysis method of steel using laser |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1220643A true CA1220643A (en) | 1987-04-21 |
Family
ID=16567217
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000470410A Expired CA1220643A (en) | 1984-10-05 | 1984-12-18 | Method of laser emission spectroscopic analysis of steel and apparatus therefor |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4645342A (en) |
| EP (1) | EP0176625B1 (en) |
| JP (1) | JPS6186636A (en) |
| KR (1) | KR880001527B1 (en) |
| BR (1) | BR8406819A (en) |
| CA (1) | CA1220643A (en) |
| DE (1) | DE3481642D1 (en) |
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| DE3617869A1 (en) * | 1986-05-27 | 1987-12-03 | Hoesch Stahl Ag | SPECTRAL ANALYZER DEVICE ON A CONVERTER |
| JPS63193038A (en) * | 1987-02-06 | 1988-08-10 | Idemitsu Petrochem Co Ltd | Method and apparatus for analyzing solid element |
| US4885070A (en) * | 1988-02-12 | 1989-12-05 | Leybold Aktiengesellschaft | Method and apparatus for the application of materials |
| DE3911329A1 (en) * | 1989-04-07 | 1990-10-11 | Dornier Luftfahrt | METHOD FOR UNPAINTING WORKPIECES, IN PARTICULAR FIBER COMPOSITE WORKPIECES |
| DE3911965A1 (en) * | 1989-04-12 | 1990-10-18 | Krupp Gmbh | METHOD FOR DETERMINING THE CONCENTRATION RATIO OF TWO ELEMENTS OF A SUBSTANCE FROM THE INTENSITY OF TWO SPECTRALLINES OF THESE ELEMENTS IN A PLASMA OF THIS FABRIC |
| US4986658B1 (en) * | 1989-04-21 | 1996-06-25 | Univ Lehigh | Transient spectroscopic method and apparatus for in-process analysis of molten metal |
| US5009099A (en) * | 1989-05-09 | 1991-04-23 | Varian Associates, Inc. | Background correction method for use in gas chromatography |
| DE3942375A1 (en) * | 1989-12-21 | 1991-06-27 | Guenter Knapp | DEVICE FOR SIMULTANEOUS DETECTION OF SEVERAL WAVELENGTH RANGES |
| DE4004627C2 (en) * | 1990-02-15 | 1994-03-31 | Krupp Ag Hoesch Krupp | Method for determining material properties of polymer materials and device for carrying out the method |
| US5252834A (en) * | 1990-11-13 | 1993-10-12 | Union Oil Company Of California | Pulsed and gated multi-mode microspectrophotometry device and method |
| US5141314A (en) * | 1991-03-01 | 1992-08-25 | Thermo Jarrell Ash Corporation | Spectroanalytical system |
| DE4118518C2 (en) * | 1991-06-06 | 1994-03-17 | Fraunhofer Ges Forschung | Process for carrying out laser emission spectroscopy and device for carrying out the process |
| DE4138157A1 (en) * | 1991-11-21 | 1993-05-27 | Krupp Ag | Measuring thickness of coating, e.g. of zinc@ on steel, - counting repeatedly applied laser pulses until spectral lines in plasma generated changes |
| FR2712697B1 (en) * | 1993-11-19 | 1995-12-15 | Commissariat Energie Atomique | Elementary analysis method by optical emission spectrometry on plasma produced by laser in the presence of argon. |
| DE4341462C2 (en) * | 1993-11-30 | 1999-02-11 | Hartmut Dr Rer Nat Lucht | Method for determining the material composition of samples and device for carrying out the method |
| DE4443407C2 (en) * | 1993-12-08 | 1999-07-22 | Fraunhofer Ges Forschung | Device for the qualitative and / or quantitative chemical analysis of a substance, in particular for the analysis of a molten metal |
| DE4415381A1 (en) * | 1994-05-02 | 1995-11-09 | Nis Ingenieurgesellschaft Mbh | Laser-based method for the determination of precious metal concentrations in metals |
| DE19531988A1 (en) * | 1995-08-30 | 1997-03-06 | Europaeische Kommission | Remote measurement of U (Pu) in glasses |
| DE19537796B4 (en) * | 1995-10-11 | 2005-08-25 | Specialty Minerals Michigan Inc., Bingham Farms | Non-destructive analysis method for the chemical elements of ceramic materials and glasses and / or components made from these materials and glasses and their use |
| US5781289A (en) * | 1996-11-05 | 1998-07-14 | Sabsabi; Mohamad | Method and apparatus for rapid in situ analysis of preselected components of homogeneous solid compositions, especially pharmaceutical compositions |
| US6034768A (en) * | 1997-09-26 | 2000-03-07 | Physical Sciences Inc. | Induced breakdown spectroscopy detector system with controllable delay time |
| US6008896A (en) * | 1998-07-01 | 1999-12-28 | National Research Council Of Canada | Method and apparatus for spectroscopic analysis of heterogeneous materials |
| US6400787B2 (en) * | 1998-07-06 | 2002-06-04 | Euratom | Telemetering of uranium of plutonium in glass |
| GB2340598A (en) * | 1998-08-07 | 2000-02-23 | British Steel Plc | Determining composition of galvanised metal coating |
| AT409553B (en) * | 2000-09-28 | 2002-09-25 | Voest Alpine Ind Anlagen | DEVICE FOR CHEMICAL ANALYSIS OF MATERIAL SAMPLES AND METALLURGICAL VESSEL THEREFOR |
| EP1223423A3 (en) | 2001-01-16 | 2004-01-28 | National Research Council of Canada | Method and apparatus for enhanced laser-induced plasma spectroscopy using mixed-wavelength laser pulses |
| DE10304337A1 (en) * | 2003-02-03 | 2004-08-19 | Luk Laser-Und Umweltmesstechnik Kiel Gmbh | Process and sensor head for the contactless classification of materials |
| US7016035B2 (en) * | 2003-09-25 | 2006-03-21 | General Electric Company | Fiber optical apparatus and system for in situ laser plasma spectroscopy |
| EP1720002A1 (en) * | 2005-05-04 | 2006-11-08 | Oxford Instruments Analytical Oy | Method and arrangement for non-destructive composition analysis of delicate samples |
| JP4749890B2 (en) * | 2006-02-27 | 2011-08-17 | 株式会社四国総合研究所 | Hydrogen gas visualization method and system using Raman scattered light |
| US7440097B2 (en) * | 2006-06-27 | 2008-10-21 | General Electric Company | Laser plasma spectroscopy apparatus and method for in situ depth profiling |
| US7573570B2 (en) | 2006-08-21 | 2009-08-11 | Jingyun Zhang | Compact Raman or fluorescence excitation system |
| JP4634413B2 (en) * | 2007-04-23 | 2011-02-16 | テクノシステム株式会社 | measuring device |
| RU2520944C2 (en) * | 2011-09-13 | 2014-06-27 | Юрий Александрович Чивель | Method for optical monitoring of surface in laser impact area and device for its implementation |
| CN104204782B (en) | 2011-12-07 | 2016-08-17 | 牛津仪器工业产品有限公司 | Analytical equipment |
| RU2518292C1 (en) * | 2013-01-24 | 2014-06-10 | Нина Валерьевна Молчан | Control over steel structure |
| DE102018128754B4 (en) * | 2018-11-15 | 2021-02-18 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Device and method for element analysis of materials |
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| GB772250A (en) * | 1953-11-21 | 1957-04-10 | Nat Res Dev | Spectral analysis by electrical light-sensitive means |
| BE574024A (en) * | 1957-12-21 | 1959-04-16 | Renault | Device for the chemical analysis of materials by spectral route by means of photoelectric cells. |
| FR2063713A5 (en) * | 1969-10-28 | 1971-07-09 | Instr Controle Ana | |
| FR2193200B1 (en) * | 1972-07-19 | 1975-03-07 | Ctre Etu Rech Liants H | |
| JPS5272285A (en) * | 1975-12-12 | 1977-06-16 | Nat Res Inst Metals | Apparatus for directly measuring fused substance by giant pulse laser beam |
| FR2348486A1 (en) * | 1976-04-15 | 1977-11-10 | Commissariat Energie Atomique | METHOD AND DEVICE FOR SAMPLE ANALYSIS BY EMISSION SPECTROGRAPHY USING A LASER BEAM |
| US4182574A (en) * | 1976-05-27 | 1980-01-08 | Jenoptik Jena G.M.B.H. | Arrangement for carrying out laser spectral analysis |
| DD160523A1 (en) * | 1977-11-08 | 1983-08-17 | Winfried Quillfeldt | METHOD FOR IMPROVING THE SPECTROCHEMICAL DETECTION METHOD FOR LASER SPECTRAL ANALYZERS |
| JPS54162297A (en) * | 1978-05-15 | 1979-12-22 | Kotsukamu Indasutori Ab | Gang saw |
| JPS56114746A (en) * | 1980-02-14 | 1981-09-09 | Kawasaki Steel Corp | Direct analyzing method for molten metal with pulse laser light |
| JPS57100323A (en) * | 1980-12-15 | 1982-06-22 | Kawasaki Steel Corp | Method for spectrochemical analysis of steel by using laser beam |
| JPS5876744A (en) * | 1981-10-30 | 1983-05-09 | Kawasaki Steel Corp | Laser emission spectrochemical analysis |
| JPS58219438A (en) * | 1982-06-15 | 1983-12-20 | Kawasaki Steel Corp | Spectrochemical analysis device using laser light |
| JPS58219440A (en) * | 1982-06-15 | 1983-12-20 | Kawasaki Steel Corp | Method for spectrochemical analysis using laser light |
-
1984
- 1984-10-05 JP JP59209096A patent/JPS6186636A/en active Pending
- 1984-12-14 DE DE8484115416T patent/DE3481642D1/en not_active Revoked
- 1984-12-14 EP EP84115416A patent/EP0176625B1/en not_active Expired
- 1984-12-18 US US06/682,897 patent/US4645342A/en not_active Expired - Fee Related
- 1984-12-18 CA CA000470410A patent/CA1220643A/en not_active Expired
- 1984-12-19 KR KR1019840008100A patent/KR880001527B1/en not_active IP Right Cessation
- 1984-12-19 BR BR8406819A patent/BR8406819A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| DE3481642D1 (en) | 1990-04-19 |
| KR880001527B1 (en) | 1988-08-19 |
| EP0176625B1 (en) | 1990-03-14 |
| KR860003508A (en) | 1986-05-26 |
| EP0176625A3 (en) | 1986-12-30 |
| JPS6186636A (en) | 1986-05-02 |
| BR8406819A (en) | 1986-07-08 |
| EP0176625A2 (en) | 1986-04-09 |
| US4645342A (en) | 1987-02-24 |
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