JPH06300694A - Relaxation time measuring apparatus - Google Patents

Abstract

PURPOSE:To provide a relaxation time measuring apparatus which can measure a relaxation time of two-dimensional information of medium such as a flame, etc. CONSTITUTION:The relaxation time measuring apparatus comprises laser means 14 for irradiating a medium of an object to be measured with a laser sheet light of a pulse laser having a pulse width of about 20ns or less, measuring means 34 for measuring two-dimensional information of a two-dimensional distribution of a relaxation time of 20ns or less of an exciting light of the medium excited in a surface state, and timing control means 38 for controlling timing of the measurement of the means 34 from the sheet light irradiated from the means 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relaxation time measuring device such as a spectroscopic device using a pulse laser.

[0002]

2. Description of the Related Art Conventionally, various methods have been proposed for measuring a quenching time constant (relaxation time) of an intermediate substance in a flame under atmospheric pressure by using a pulse laser. If the quenching time constant is constant anywhere within the measurement area, a fluorescence signal proportional to the molecular concentration can be obtained, which is effective as data.

The relaxation time means a time constant when the signal level of the excitation light of the medium becomes 0 or close to 0 and falls from the upper level to the lower level.

[0004]

However, in a reaction field such as a flame in which the temperature distribution is wide and the chemical species are different at each measurement point, the quenching time constant does not become a constant value. Therefore, development of an effective two-dimensional clenching measurement method has been desired.

Therefore, in view of the above problems, the present invention provides a relaxation time measuring device capable of measuring the relaxation time of two-dimensional information of a medium such as a flame.

[0006]

A relaxation time measuring apparatus according to claim 1 of the present invention comprises a laser means for irradiating a medium to be measured with a laser sheet light of a pulse laser having a pulse width of 20 nsec or less, and a surface. 10n of the excitation light of the medium excited in the shape of
It comprises a measuring means for measuring two-dimensional information, which is a two-dimensional distribution of relaxation times of seconds or less, and a timing control means for controlling the measurement timing of the measuring means from the laser sheet light emitted by the laser means.

The relaxation time measuring device according to claim 2 is the device according to claim 1.
The measuring means includes two-dimensional information measuring means for measuring the two-dimensional information at predetermined time intervals, and each pixel constituting the two-dimensional information at the predetermined time intervals measured by the two-dimensional information measuring means. Storage means for storing the signal level of
Time function exp (-t / of relaxation time, which is a change until the disappearance of the signal level of each pixel stored in the storage means.
The time constant τ of τ) is calculated for each pixel.

The relaxation time measuring device of claim 3 is the same as that of claim 2.
The display means for reconstructing and displaying the two-dimensional information of the time constant τ for each pixel calculated by the calculation means.

[0009]

[Operation] A description will be given of a case where the relaxation time measuring apparatus according to claim 1 measures two-dimensional information which is a distribution of relaxation.

The medium is irradiated with laser sheet light of a pulse laser having a pulse width of 20 nsec or less from the laser means. When the laser sheet light impinges on the medium, planar excitation light occurs. Further, the timing control means controls the timing of measurement by the measurement means by the laser sheet light emitted from the laser means. The measuring means controlled by this timing measures two-dimensional information, which is a two-dimensional distribution of the relaxation time of 10 nsec or less of the excitation light, in accordance with the timing of incidence of the excitation light.

The measuring means of the relaxation time measuring device of the second aspect will be described.

The two-dimensional information measuring means measures two-dimensional information, which is a distribution of relaxation of 10 n seconds or less of the excitation light of the plane-excited medium, every predetermined time. The storage means stores the measured signal level of each pixel forming the two-dimensional information for each predetermined time. Then, the calculating means calculates, for each pixel, the time constant τ of the time function of the relaxation time, which is a change until the signal level of each pixel disappears.

With this, the time constant τ of the relaxation time can be measured.

According to the relaxation time measuring device of the third aspect, the display means reconstructs the time constant τ for each pixel calculated by the calculation means two-dimensionally and displays it.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A relaxation time measuring device 10 which is an embodiment of the present invention will be described below.

FIG. 1 is a block diagram of a measuring apparatus 10 of this embodiment.

Reference numeral 12 is an excimer laser, and reference numeral 14 is a dye laser connected to the excimer laser 12. The excimer laser 12 is operated by the trigger generator 16, and the dye laser 14 is operated by the laser light from the excimer laser 12. Then, the dye laser 14 emits a pulse laser with a pulse width of 10 nsec.

Reference numeral 18 is a half mirror provided near the irradiation port of the dye laser 14. This half mirror 1
8, the pulse laser from the dye laser 14 is 2
Divide into directions and go straight.

Reference numerals 20 and 22 are mirrors which are provided on the path of the pulse laser emitted from the dye laser 14 and reflect the pulse laser to a predetermined position.

Reference numerals 24 and 26 are beam expanders for expanding the pulse laser into planar laser sheet light.

Reference numeral 28 designates a beam expander 24,
The lens 26 irradiates the laser sheet light spread in a plane by 26 in parallel to a predetermined direction.

Reference numeral 30 is a beam stop provided on the path of the laser sheet light emitted by the lens 28. When the laser sheet light hits here, the laser sheet light disappears.

Reference numeral 32 denotes a medium to be measured, which is disposed between the lens 28 and the beam stop 30, that is,
In the case of this embodiment, it is a flame.

Reference numeral 34 is an image intensifier (hereinafter referred to as IIF) which receives the laser light from the flame sheet 32 and receives the excitation light excited in a plane. Light is incident on the IIF 34 via the lens 36.
The detailed structure of the IIF 34 will be described later.

Reference numeral 38 is a timing control device on which the pulse laser split by the half mirror 18 enters. With this timing control device 38, the IIF 34
The timing of the operation of is controlled.

Reference numeral 40 is a CCD camera for storing the image formed by the IIF 34.

Reference numeral 42 is a control device for controlling the CCD camera 40 and the dye laser 14. It has a device for calculating the relaxation time described below and a display 44 for displaying the calculation result.

FIG. 2 is a circuit diagram of the IIF 34 and the timing control device 38.

Reference numeral 46 denotes a light-receiving portion provided inside the IIF 34, which is provided on both sides of a microchannel plate (hereinafter, referred to as MCP) 48 and has an electron incident side terminal 50.
And an electron emission side terminal 52. Then, the light receiving unit 46
When the light enters the timing control device 38,
The electron incidence side terminal 50 is set to-and the electron emission side terminal 52 is set to +
Then, the light incident on the electron incident side terminal 50 is
It is amplified at 48 and output from the electron emission side terminal 52. The CCD camera 40 stores the signal level of the amplified and output light.

Next, the structure of the timing control device 38 will be described.

Reference numeral 54 is a photo diode, on which the pulse laser separated from the half mirror 18 enters. The anode side of the photodiode 54 is connected to the DC power supply + Vcc. The cathode side is grounded via the resistor 56.

Reference numeral 58 denotes a Schmitt trigger circuit, the input portion of which is connected to the cathode side of the photodiode 54.

Reference numeral 60 is a cable delay circuit,
One end thereof is connected to the output section of the Schmitt trigger circuit 58. This cable delay circuit can switch the delay time T1 in picosecond units.

Reference numeral 62 is a Schmitt trigger circuit, the input portion of which is connected to the other end of the cable delay circuit 60 via a resistor 64. The other end of the cable delay circuit 60 is connected to the input section of the delay circuit 66 having the delay time T3, and the output section of the delay circuit 66 is connected to the base terminal of the switching transistor 70 via the resistor 68. There is. The collector terminal of the transistor 70 is connected to the input section of the Schmitt trigger circuit 62, and the emitter terminal is grounded.

Reference numeral 72 is a cable delay circuit. This one end is connected to the other end of the cable delay circuit 60. This delay time is T2.

Reference numeral 74 is a Schmitt trigger circuit, the input portion of which is connected to the other end of the cable delay circuit 72 via the resistor 76.

Reference numeral 78 is a delay circuit having a delay time T4, one end of which is connected to the cable delay circuit 72,
The other end is connected to the base terminal of the switching transistor 82. The collector terminal of the transistor 82 is connected to the input section of the Schmitt trigger circuit 74,
The emitter terminal is grounded.

The Schmitt trigger circuit 62 includes the IIF 34
Is connected to the base terminal of a switching type transistor 86 such as an avalanche transistor via a resistor 84 provided inside. The collector terminal of the transistor 86 is connected to the DC power supply + V1 and the electron incident side terminal 50 via the resistor 88. The emitter terminal is grounded.

The output of the Schmitt trigger circuit 74 is I
A switching transistor 9 such as an avalanche transistor is provided via a resistor 90 provided inside the IF 34.
2 is connected to the base terminal. This transistor 9
The collector terminal of 2 is the DC power supply + V via the resistor 94.
2, and also to the electron emission side terminal 52. The emitter terminal is grounded.

The timing control device 38 and I having the above configuration
The operating state of the IF 34 will be described.

When the laser pulse enters the photodiode 54, the Schmitt trigger circuit 58 outputs a pulse P1. The pulse P1 is delayed by T1 by the cable delay circuit 60, and the Schmitt trigger circuit 62
To enter. The Schmitt trigger circuit 62 outputs the pulse P2 in response to the input of the pulse P1. Also, the pulse P
1 is input to the transistor 70 after a delay time T3 via the delay circuit 66. When a pulse is input to the transistor 70, this turns on and the Schmitt trigger circuit 6
The pulse P1 input to 0 flows to the transistor 70. That is, the delay time T3 of the delay circuit 66 becomes the pulse width output from the Schmitt trigger circuit 62.
The pulse width T3 is 100 nsec.

The pulse P1 output from the cable delay circuit 60 is input to the Schmitt trigger circuit 74 after a delay time T2 via the cable delay circuit 72. When the pulse P1 is input to the Schmitt trigger circuit 74, the pulse P3 whose pulse width is adjusted by the delay circuit 78 having the delay time T4 seconds is output as described above. This pulse width T4 is also 100 nsec. The output timing of the pulse P2 output from the Schmitt trigger circuit 62 and the pulse P3 output from the Schmitt trigger circuit 74 is determined by the delay time T2 of the cable delay circuit 72. This T2 controls the time interval of the operation of the electron incident side terminal 50 and the electron emission side terminal 52. Further, the delay time T1 of the cable delay circuit 60 is for adjusting the time from the input of the pulse laser to the activation of the electron incident side terminal 50, and can be adjusted in picosecond units.

Then, when the pulse P1 is input to the transistor 86, the transistor 86 is turned on, and the electron incident side terminal 50 becomes-.
Becomes When the pulse P3 is input to the transistor 92, the electron emission side terminal 52 also becomes negative. The time from when the electron incident side terminal 50 becomes − to when the electron emission side terminal 52 becomes − is the measurement time of the IIF 34, which is determined by the delay time T2 of the cable delay circuit 72 and is 1 nsec. .

Next, a case of measuring the relaxation time by using the relaxation time measuring device 10 having the above-mentioned structure will be described.

(1) The process up to storing the signal level (hereinafter referred to as two-dimensional information) of the planar excitation light of the flame 32 excited by the laser sheet light will be described.

When a trigger is output from the trigger generator 16, laser light is emitted from the excimer laser 12, and when this laser light is input to the dye laser 14, 1
A pulse laser having a pulse width of 0 nsec is output.

The pulse laser passes through the half mirror 18 and is divided into two directions, one of which is the timing control device 38.
Is incident on the photodiode 54 of the
And then enters the beam expander 24.

The light incident on the beam expander 24 spreads in a plane through the beam expander 26 and becomes a laser sheet light. This laser sheet light is reflected by the lens 28.
And then hit the flame 32 in a plane form.

When the laser beam of light hits the flame 32, the flame 32 is excited in a plane and emits light.

Excitation light of the flame 32 reaches the IIF 34 via the lens 36.

At the same time, the timing control device 38 is controlled by the pulse laser incident on the photodiode 54.
Operates the IIF 34 to amplify the excitation light of the flame 32 and store the two-dimensional information in the CCD camera 40.

In this case, what is important is to operate the IIF 34 in synchronization with the timing at which the excitation light of the flame that has been excited planarly into the IIF 34 is incident. In the case of the present embodiment, the timing is set by the pulse laser divided into two by the half mirror 18. That is, when the pulsed laser enters the photodiode 54,
After the delay time T1, the electron incident side terminal 50 becomes negative and M
When the CP48 operates and the delay time T2 elapses, the electron emission side terminal 5
2 becomes-and the MCP 48 stops. Further, for a time period that cannot be adjusted by the timing control device 38, the path of the pulse laser is lengthened by the arrangement of the mirrors 20 and 22 to extend the incident time of the excitation light from the flame 32.

(2) Processing of measured two-dimensional information will be described.

In FIGS. 9 to 13, the two-dimensional information obtained by measuring the exposure time of 3 ns every 1 ns with the delay time T1 of 30 ns is displayed on the display 44, and is simply illustrated for the sake of explanation. It is a thing. The two-dimensional information is decomposed for each pixel in the orthogonal coordinate system (x, y), and the relaxation time is calculated for each pixel. In the following explanations 1 to 4, the case where the relaxation time τ (x1, y1) is calculated for one pixel (x1, y1) among them will be described.

The delay time T of the timing control device 38
1 is 30 ns, and T2 is 1 ns. Dye laser 1
The pulse laser is emitted from 4 to excite the flame 32.
As a result, the IIF 34 operates 30 n seconds after the excitation light from the flame 32 is incident, and the IIF 34 is activated to reduce the incident light by 3
The signal level from 0 ns to 31 ns is cut out, and CC
The D camera 40 stores the data (see FIG. 3).

By switching the cable delay circuit 60,
The delay time T1 is 31 ns. In this state, the dye laser 14 emits a pulse laser again to excite the flame 32. As a result, 31 n of the relaxation portion of the incident excitation light
The signal level after 32 seconds from the second is cut out and stored in the CCD camera 40 (see FIG. 4).

By switching the cable delay circuit 60,
The delay time T1 is set to 32 ns. In this state, the dye laser 14 emits a pulse laser again to excite the flame 32. 32n of the relaxation portion of the incident excitation light by this
The signal level after 33 seconds from the second is cut out and stored in the CCD camera 40 (see FIG. 5).

By switching the cable delay circuit 60,
The delay time T1 is 33 ns. In this state, the dye laser 14 emits a pulse laser again to excite the flame 32. As a result, 33n of the relaxation portion of the incident excitation light
The signal level after 34 ns after the second is cut out and stored in the CCD camera 40 (see FIG. 6).

By switching the cable delay circuit 60,
The delay time T1 is 34 ns. In this state, the dye laser 14 emits a pulse laser again to excite the flame 32. As a result, 34n of the relaxation portion of the incident excitation light
The signal level after 35 ns after the second is cut out and stored in the CCD camera 40 (see FIG. 7).

FIG. 8 is a graph in which the signal levels stored each time the delay times T1 are switched are arranged on the time axis along the measured time and displayed. The time function of the slope of this signal level extinction time is k × exp (−t / τ)
Is. However, K is a constant and τ is a time constant. From this slope, the time constant τ (x1, y1) which is the relaxation time (quenching time constant) is calculated.

The processes from to are performed for each pixel of the two-dimensional information. FIG. 14 shows the relaxation times τ (x, y) of the calculation results, which are again arranged as two-dimensional information in the orthogonal coordinate system (x, y).

Then, the molecular concentration is determined from the two-dimensional information of the relaxation time τ (x, y).

As described above, the relaxation time measuring device 10 of this embodiment can display the relaxation time τ of the two-dimensional information of the flame 32.

[0064]

As described above, with the relaxation time measuring device of the present invention, it is possible to measure the relaxation distribution of the excitation light of the medium excited in a plane for 10 nsec or less.

[Brief description of drawings]

FIG. 1 is a block diagram of a relaxation time measuring device showing an embodiment of the present invention.

FIG. 2 is a block diagram of a timing control device and an IIF.

FIG. 3 is a graph of signal levels measured after 30 ns.

FIG. 4 is a graph of signal level measured after 31 ns.

FIG. 5 is a graph of signal level measured after 32 ns.

FIG. 6 is a graph of signal level measured after 33 ns.

FIG. 7 is a graph of signal level measured after 34 ns.

FIG. 8 is a graph showing the relationship between signal level and delay time.

FIG. 9 is two-dimensional information measured after 30 ns.

FIG. 10 is two-dimensional information measured after 31 ns.

FIG. 11 is two-dimensional information measured after 32 ns.

FIG. 12 is two-dimensional information measured after 33 ns.

FIG. 13 is two-dimensional information measured after 34 ns.

FIG. 14 is a diagram in which relaxation time is reconstructed into two-dimensional information.

[Explanation of symbols]

 10 Measuring Device 12 Excimer Laser 14 Dye Laser 16 Trigger Generator 18 Half Mirror 20 Mirror 22 Mirror 24 Beam Expander 26 Beam Expander 28 Lens 30 Beam Stop 32 Flame 34 IIF 36 Lens 38 Timing Controller 40 CCD Camera 42 Controller 44 Display

Claims (3)

[Claims] 1. A laser means for irradiating a medium to be measured with a laser sheet light of a pulse laser having a pulse width of 20 nsec or less, and a relaxation time of 10 nsec or less of excitation light of a plane-excited medium. A relaxation time measuring device comprising: a measuring unit that measures two-dimensional information that is a dimensional distribution; and a timing control unit that controls the timing of measurement by the measuring unit from the laser sheet light emitted by the laser unit. . 2. The measuring means comprises two-dimensional information measuring means for measuring the two-dimensional information at predetermined time intervals, and two at the predetermined time intervals measured by the two-dimensional information measuring means.
A storage unit that stores the signal level of each pixel that constitutes the dimension information, and a time function exp (-t / of the relaxation time that is a change until the disappearance of the signal level of each pixel stored in the storage unit.
The relaxation time measuring device according to claim 1, characterized in that the relaxation time measuring device comprises a calculation means for calculating a time constant τ of τ) for each pixel. 3. The relaxation time measuring device according to claim 2, further comprising display means for reconstructing and displaying the time constant τ of each pixel calculated by the calculation means into two-dimensional information.