CN101728207B - Method for correcting nonlinear response of photomultiplier and photoelectric detector and spectrophotometer obtained based on same - Google Patents

Abstract

The invention relates to a method for correcting nonlinear response of a photomultiplier and a photoelectric detector and a spectrophotometer obtained based on the same, solving the problem of nonlinear response of the current photomultipliers and the problem of low transmittance accuracy of the spectrophotometer caused by the previous problem. The method is characterized by obtaining a correction equation by correcting the photo-electric response curve of the photomultiplier, thereby correcting the electric signal output by the photomultiplier. The photoelectric detector comprises the photomultiplier and a nonlinear response corrector. The spectrophotometer comprises a light source, a monochrometer, a sample cell, the photoelectric detector and a calculation and display device. The photoelectric detector can be used for high accuracy photoelectric detection, and the spectrophotometer can be used for qualitative and quantitative analysis and corresponding optical measurement of the substances.

Description

Method and the photodetector of implementing this method and spectrophotometer that the nonlinear response of photomultiplier tube is revised

Technical field

The present invention relates to a kind of method, a kind of photodetector and a kind of spectrophotometer that the nonlinear response of photomultiplier is revised.

Background technology

Because due to the semiconductor material characteristic of photomultiplier; Make photomultiplier not convert the light signal of varying strength into the signal of telecommunication by linear scale; The response of Here it is photomultiplier non-linear; Because the non-linear systematic error that causes of photomultiplier self is generally about 0.3～0.5%.And photomultiplier mainly is used in the spectrophotometer, but because non-linear the failing of the response of photomultiplier eliminated, makes that spectrophotometric transmittance accuracy is low, can only reach 0.3～0.5% level.Transmittance is defined as: the ratio that sees through light intensity with the light intensity that incides sample of sample.

Summary of the invention

The objective of the invention is to solve the low problem of spectrophotometric transmittance accuracy that there is nonlinear problem in the response of present photomultiplier and causes thus, a kind of method and the photodetector of implementing this method and spectrophotometer that the nonlinear response of photomultiplier tube is revised is provided.

One, the light signal of 400nm～500nm to input carries out length scanning, and in scanning process, exports the light signal of G different single wavelength successively, in real time, and G is a positive integer;

Each light signal in the light signal of G different single wavelength that two, one by one step 1 obtained is handled as follows, obtains the nonlinear response update equation of G different single wavelength:

21, the light signal to pending single wavelength carries out intensity modulation, obtains the light signal of K different light intensity;

The light signal of K the different light intensity that two or two, step 2 one is obtained is input in the photomultiplier successively; Make photomultiplier export K the signal of telecommunication successively, write down the pairing light intensity value that is input to the light signal in the photomultiplier of each signal of telecommunication in intensity level and this K the signal of telecommunication of a said K signal of telecommunication;

Two or three, the pairing light intensity value that is input to the optical signal in the photomultiplier of each signal of telecommunication in the intensity level of K the signal of telecommunication that obtains based on step 2 two and this K the signal of telecommunication; Draw light-electroresponse curve; Said light-electroresponse curve ordinate is the intensity that incides the optical signal of photomultiplier, and abscissa is the electrical signal intensity of photomultiplier output;

Two or four, the light-electroresponse curve that step 2 three is obtained carries out linearity correction, obtains the non-linear fair curve that is used to revise, utilizes least square method to carry out match to non-linear fair curve again, obtains the nonlinear response update equation of this list wavelength;

Three, the light signal with specific single wavelength is input in the photomultiplier; In the nonlinear response update equation of G different single wavelength that step 2 obtains, select the equation that is complementary with this specific single wavelength; And utilize the equation of selecting that the signal of telecommunication of photomultiplier output is revised, then with revised signal of telecommunication output.

Implement the photodetector of this method; It comprises photomultiplier and nonlinear response corrector; The light signal input of photomultiplier is as the light signal input of photodetector; The electrical signal of photomultiplier connects the electric signal input end of nonlinear response corrector, and the electrical signal of nonlinear response corrector is as the electrical signal of photodetector: nonlinear response update equation used when said nonlinear response corrector is revised the signal of telecommunication that receives does

I wherein _InBe the intensity of the signal of telecommunication that is input to the nonlinear response corrector, I _OutBe the intensity of the signal of telecommunication of nonlinear response corrector output, A, B and C are respectively real parameter, and A ∈ (0.8,1), B ∈ (0.9,2), C ∈ (0.05,0.15).

Implement the spectrophotometer of this method, it is made up of light source, monochromator, sample cell, photodetector and calculating and display unit, and said photodetector is made up of photomultiplier and nonlinear response corrector; The output of light source connects the light signal input of monochromator; The light signal output end of monochromator connects the light signal input of sample cell; The electrical signal of monochromator connects the wavelength signals input of nonlinear response corrector and the wavelength signals input of calculating and display unit; The light signal output end of sample cell connects the light signal input of photomultiplier; The electrical signal of photomultiplier connects the electric signal input end of nonlinear response corrector, and the electrical signal of nonlinear response corrector connects the input of calculating and display unit.

The another kind of spectrophotometer of implementing this method, it is made up of light source, sample cell, monochromator, photodetector and calculating and display unit, and said photodetector is made up of photomultiplier and nonlinear response corrector; The output of light source connects the light signal input of sample cell; The light signal output end of sample cell connects the light signal input of monochromator; The light signal output end of monochromator connects the light signal input of photomultiplier; The electrical signal of monochromator connects the wavelength signals input of nonlinear response corrector; The electrical signal of photomultiplier connects the electric signal input end of nonlinear response corrector, and the electrical signal of nonlinear response corrector connects the input of calculating and display unit.

The method that the nonlinear response of photomultiplier is revised of the present invention can be revised the nonlinear response education linearity of photomultiplier effectively; Photodetector of the present invention can be good at converting the light signal of varying strength into the signal of telecommunication by linear scale, suppresses response non-linear of photomultiplier; Spectrophotometric transmittance accuracy of the present invention is high, can reach 10 ^-4Level.

Description of drawings

Fig. 1 is the structural representation of the photodetector of embodiment two; Fig. 2 is the structural representation of the photodetector of embodiment five; Fig. 3 is the spectrophotometric structural representation of embodiment seven.

Embodiment

Embodiment one: the method that the nonlinear response to photomultiplier of this embodiment is revised, its process is following:

One, the light signal of wide spectrum to input carries out length scanning, and in scanning process, exports the light signal of the single wavelength of a series of differences successively, in real time, and G is a positive integer;

Each light signal in the light signal of G different single wavelength that two, one by one step 1 obtained is handled as follows, obtains the non-linear update equation of G different single wavelength:

21, the light signal to pending single wavelength carries out intensity modulation, obtains the light signal of K different light intensity;

The light signal of K the different light intensity that two or two, step 2 one is obtained is input in the photomultiplier successively; Make photomultiplier export K the signal of telecommunication successively, write down the pairing light intensity value that is input to the light signal in the photomultiplier of each signal of telecommunication in intensity level and this K the signal of telecommunication of a said K signal of telecommunication;

Two or three, the pairing light intensity value that is input to the optical signal in the photomultiplier of each signal of telecommunication in the intensity level of K the signal of telecommunication that obtains based on step 2 two and this K the signal of telecommunication; Draw light-electroresponse curve; Said light-electroresponse curve ordinate is the intensity that incides the optical signal of photomultiplier, and abscissa is the electrical signal intensity of photomultiplier output;

Two or four, the light-electroresponse curve that step 2 three is obtained carries out linearity correction, obtains the non-linear fair curve that is used to revise, utilizes least square method to carry out match to non-linear fair curve again, obtains the non-linear update equation of this list wavelength;

Three, the light signal with specific single wavelength is input in the photomultiplier; In the non-linear update equation of G different single wavelength that step 2 obtains, select the equation that is complementary with this specific single wavelength; And utilize the equation of selecting that the signal of telecommunication of photomultiplier output is revised, then with revised signal of telecommunication output.

Embodiment two: combine Fig. 1 that this execution mode is described; The photodetector based on embodiment one said method acquisition of this embodiment; It comprises photomultiplier 1 and nonlinear response corrector 2; The light signal input of photomultiplier 1 is as the light signal input of photodetector; The electrical signal of photomultiplier 1 connects the electric signal input end of nonlinear response corrector 2, and the electrical signal of nonlinear response corrector 2 is as the electrical signal of photodetector; Used nonlinear response update equation did when 2 pairs of signals of telecommunication that receive of said nonlinear response corrector were revised $I_{\mathrm{Out}}=A-{\mathrm{BI}}_{\mathrm{In}}+{\mathrm{CI}}_{\mathrm{In}}^2,$ I wherein _InBe the intensity of the signal of telecommunication that is input to nonlinear response corrector 2, I _OutBe the intensity of the signal of telecommunication of nonlinear response corrector 2 output, A, B and C are respectively real parameter, and A ∈ (0.8,1), B ∈ (0.9,2), C ∈ (0.05,0.15).

In this embodiment; The light signal that photomultiplier 1 receives from light source; This light signal converts the signal of telecommunication into behind photomultiplier; This signal of telecommunication is input in the nonlinear response corrector 2, and nonlinear response corrector 2 utilizes non-linear update equation that this signal of telecommunication is revised, then with revised signal of telecommunication output.

Embodiment three: what this embodiment and embodiment two were different is that said nonlinear response update equation does $I_{\mathrm{Out}}=0.9375-1.038I_{\mathrm{In}}+0.102I_{\mathrm{In}}^2.$

This embodiment is that the correction effect of light signal of 400nm～500nm is best to wave-length coverage.

Embodiment four: what this embodiment and embodiment two were different is that said nonlinear response update equation does $I_{\mathrm{Out}}=0.8917-1.9621I_{\mathrm{In}}+{0.071I}_{\mathrm{In}}^2.$

This embodiment is that the correction effect of light signal of 400nm～500nm is best to wave-length coverage.

Embodiment five: what this embodiment and embodiment two were different is that said nonlinear response update equation does $I_{\mathrm{Out}}=0.8656-0.917I_{\mathrm{In}}+{0.051I}_{\mathrm{In}}^2.$

This embodiment is that the correction effect of light signal of 400nm～500nm is best to wave-length coverage.

Embodiment six: combine Fig. 2 that this execution mode is described; What this embodiment and embodiment two were different is; It also comprises a monochromator 3; The light signal input of monochromator 3 is as the light signal input of photodetector, and the light signal output end of monochromator 3 connects the light signal input of photomultiplier 1, and the electrical signal of monochromator 3 connects the wavelength signals input of nonlinear response corrector 2; The output of photomultiplier 1 connects the electric signal input end of nonlinear response corrector 2, and the electrical signal of nonlinear response corrector 2 is as the electrical signal of photodetector; Said nonlinear response update equation is:

$I_{\mathrm{out}}=\left\{\begin{array}{c}0.9375-1.038I_{\mathrm{in}}+0.102I_{\mathrm{in}}^2,400\mathrm{nm}\&le;\mathrm{\&lambda;}<500\mathrm{nm}\\ 0.8917-1.962I_{\mathrm{in}}+0.071I_{\mathrm{in}}^2,500\mathrm{nm}\&le;\mathrm{\&lambda;}<600\mathrm{nm}\\ 0.8656-0.917I_{\mathrm{in}}+0.051I_{\mathrm{in}}^{2}600\mathrm{nm}\&le;\mathrm{\&lambda;}<700\mathrm{nm}\end{array}\right..$

In this embodiment; The wide spectrum light signal of 3 pairs of light source outputs of monochromator carries out length scanning; And the light signal of in scanning process, exporting a series of single wavelength successively, is in real time given photomultiplier 1; When monochromator 3 is exported the light signal of each wavelength; The wavelength information of the light signal of this wavelength is sent in the nonlinear response corrector 2, exports after each light signal that photomultiplier 1 will receive converts the signal of telecommunication into, the signal of telecommunication of output is received by nonlinear response corrector 2; Nonlinear response corrector 2 is selected the nonlinear response update equation of corresponding wavelength scope according to the wavelength information that receives, and then the signal of telecommunication that receives is revised.

Embodiment seven: combine Fig. 3 that this execution mode is described; The spectrophotometer based on embodiment one said method acquisition of this embodiment; It is made up of light source 4, monochromator 3, sample cell 5, photodetector 7 and calculating and display unit 6, and said photodetector 7 is made up of photomultiplier 1 and nonlinear response corrector 2; The output of light source 4 connects the light signal input of monochromator 3; The light signal output end of monochromator 3 connects the light signal input of sample cell 5; The electrical signal of monochromator 3 connects the wavelength signals input of nonlinear response corrector 2 and the wavelength signals input of calculating and display unit 6; The light signal output end of sample cell 5 connects the light signal input of photomultiplier 1; The electrical signal of photomultiplier 1 connects the electric signal input end of nonlinear response corrector 2, and the electrical signal of nonlinear response corrector 2 connects the input of calculating and display unit 6.

Embodiment eight: what this embodiment and embodiment seven were different is that the nonlinear response update equation that said nonlinear response corrector 2 is embedded with is:

$I_{\mathrm{out}}=\left\{\begin{array}{c}0.9375-1.038I_{\mathrm{in}}+0.102I_{\mathrm{in}}^2,400\mathrm{nm}\&le;\mathrm{\&lambda;}<500\mathrm{nm}\\ 0.8917-1.962I_{\mathrm{in}}+0.071I_{\mathrm{in}}^2,500\mathrm{nm}\&le;\mathrm{\&lambda;}<600\mathrm{nm}\\ 0.8656-0.917I_{\mathrm{in}}+0.051I_{\mathrm{in}}^{2}600\mathrm{nm}\&le;\mathrm{\&lambda;}<700\mathrm{nm}\end{array}\right..$

In this embodiment, at first take out the sample in the sample cell 5, the wide spectrum light signal of 3 pairs of light sources of monochromator, 4 outputs carries out length scanning then, and in scanning process, exports the light signal of a series of single wavelength successively, in real time; In the light signal of the single wavelength of this series; Select the light signal of required specific wavelength; It is directly incident in the photomultiplier 1, and simultaneously, monochromator 3 is sent to the wavelength information of the light signal of this specific wavelength in nonlinear response corrector 2 and calculating and the display unit 6; The light signal of this specific wavelength that photomultiplier 1 will receive converts the signal of telecommunication into, and this signal of telecommunication is exported to nonlinear response corrector 2; Nonlinear response corrector 2 is according to the wavelength information that receives; Select the nonlinear response update equation of corresponding wavelength; And utilize this nonlinear response update equation that the signal of telecommunication that receives is revised, the revised signal of telecommunication is exported to calculated and display unit 6 then; Calculating and display unit 6 are preserved this signal of telecommunication that receives as initial value i0.

Then, put back to the sample in the sample cell 5, the light signal of the specific wavelength of make selecting is through behind the sample cell 5, reenters to be mapped in the photomultiplier 1, and monochromator 3 is given nonlinear response corrector 2 with the wavelength information of the light signal of this specific wavelength; After photomultiplier 1 will pass through light signal behind the sample cell 5 and convert the signal of telecommunication into, export to nonlinear response corrector 2 again; Nonlinear response corrector 2 is selected the nonlinear response update equation of corresponding wavelength once more according to received wavelength information; And utilize this equation that the signal of telecommunication that this receives is revised, this revised signal of telecommunication is exported to calculated and display unit 6 then; Calculate and display unit 6 with the signal of telecommunication of this reception as test value i _tPreserve.

Utilize the spectrophotometer of this embodiment, selecting the wavelength of monochromator output is the light signal of λ, according to i ₀And i _t, can calculate absorbance (or transmittance) or the sample purity of testing sample to the light signal of this wavelength.Through calculating the absorbance (or transmittance) of testing sample to a plurality of wavelength; To calculate and the wavelength of the light signal that display unit 6 receives is that abscissa, the testing sample that calculates gained are ordinate to the absorbance (or transmittance) of each wavelength, can draw the curve of the transmittance of testing sample again with wavelength variations.The spectrophotometer of this embodiment, owing to adopted the photomultiplier that comprises the nonlinear response corrector, accurately measuring samples is to have high-precision spectrophotometer to the absorbance (or transmittance) of specific wavelength light signal.Absorbance is defined as the negative logarithm of transmittance.

With the upper type is standing wave farm labourer operation mode; This embodiment also can adopt length scanning formula mode of operation; Promptly the light signal of each wavelength of monochromator 3 output press said process respectively and operate, can obtain testing sample the absorbance (or transmittance) of each wavelength light signal and testing sample purity etc.

In this embodiment, testing sample is the filter of a cover U.S. NBS, belong to respectively to be applicable to 5 kinds of wavelength, and the filter of every kind of wavelength has 3,15 altogether.The result that the spectrophotometer that utilizes this embodiment is measured this cover filter is shown in table one:

Table one:

And the standard value that U.S.'s certificate shows is shown in table two:

Table two:

This shows that the spectrophotometer of this embodiment has very high transmittance accuracy, can reach 10 ^-4Level..

Embodiment nine: combine Fig. 4 that this execution mode is described; The spectrophotometer based on execution mode one said method acquisition of this execution mode; It is made up of light source 4, sample cell 5, monochromator 3, photodetector 7 and calculating and display unit 6, and said photodetector 7 is made up of photomultiplier 1 and nonlinear response corrector 2; The output of light source 4 connects the light signal input of sample cell 5; The light signal output end of sample cell 5 connects the light signal input of monochromator 3; The light signal output end of monochromator 3 connects the light signal input of photomultiplier 1; The electrical signal of monochromator 3 connects the wavelength signals input of nonlinear response corrector 2; The electrical signal of photomultiplier 1 connects the electric signal input end of nonlinear response corrector 2, and the electrical signal of nonlinear response corrector 2 connects the input of calculating and display unit 6.

Claims (9)

1. the method for the nonlinear response of photomultiplier being revised is characterized in that its process is following:

One, the light signal of 400nm～500nm to input carries out length scanning, and in scanning process, exports the light signal of G different single wavelength successively, in real time, and G is a positive integer;

Each light signal in the light signal of G different single wavelength that two, one by one step 1 obtained is handled as follows, obtains the nonlinear response update equation of G different single wavelength:

21, the light signal to pending single wavelength carries out intensity modulation, obtains the light signal of K different light intensity;

The light signal of K the different light intensity that two or two, step 2 one is obtained is input in the photomultiplier successively; Make photomultiplier export K the signal of telecommunication successively, write down the pairing light intensity value that is input to the light signal in the photomultiplier of each signal of telecommunication in intensity level and this K the signal of telecommunication of a said K signal of telecommunication;

Two or three, the pairing light intensity value that is input to the optical signal in the photomultiplier of each signal of telecommunication in the intensity level of K the signal of telecommunication that obtains based on step 2 two and this K the signal of telecommunication; Draw light-electroresponse curve; Said light-electroresponse curve ordinate is the intensity that incides the optical signal of photomultiplier, and abscissa is the electrical signal intensity of photomultiplier output;

Two or four, the light-electroresponse curve that step 2 three is obtained carries out linearity correction, obtains the non-linear fair curve that is used to revise, utilizes least square method to carry out match to non-linear fair curve again, obtains the nonlinear response update equation of this list wavelength;

Three, the light signal with specific single wavelength is input in the photomultiplier; In the nonlinear response update equation of G different single wavelength that step 2 obtains, select the equation that is complementary with this specific single wavelength; And utilize the equation of selecting that the signal of telecommunication of photomultiplier output is revised, then with revised signal of telecommunication output.

2. implement the photodetector of the said method of claim 1; It is characterized in that it comprises photomultiplier (1) and nonlinear response corrector (2); The light signal input of photomultiplier (1) is as the light signal input of photodetector; The electrical signal of photomultiplier (1) connects the electric signal input end of nonlinear response corrector (2), and the electrical signal of nonlinear response corrector (2) is as the electrical signal of photodetector; Nonlinear response update equation used when said nonlinear response corrector (2) is revised the signal of telecommunication that receives does

I wherein _InBe the intensity of the signal of telecommunication that is input to nonlinear response corrector (2), I _OutBe the intensity of the signal of telecommunication of nonlinear response corrector (2) output, A, B and C are respectively real parameter, and A ∈ (0.8,1), B ∈ (0.9,2), C ∈ (0.05,0.15).

3. photodetector according to claim 2 is characterized in that said nonlinear response update equation does $I_{\mathrm{Out}}=0.9375-1.038I_{\mathrm{In}}+{0.102I}_{\mathrm{In}}^2.$

4. photodetector according to claim 2 is characterized in that said nonlinear response update equation does $I_{\mathrm{Out}}=0.8917-1.962I_{\mathrm{In}}+{0.071I}_{\mathrm{In}}^2.$

5. photodetector according to claim 2 is characterized in that said nonlinear response update equation does $I_{\mathrm{Out}}=0.8656-0.917I_{\mathrm{In}}+{0.051I}_{\mathrm{In}}^2.$

6. photodetector according to claim 2; It is characterized in that it also comprises a monochromator (3); The light signal input of monochromator (3) is as the light signal input of photodetector; The light signal output end of monochromator (3) connects the light signal input of photomultiplier (1); The electrical signal of monochromator (3) connects the wavelength signals input of nonlinear response corrector (2), and the output of photomultiplier (1) connects the electric signal input end of nonlinear response corrector (2), and the electrical signal of nonlinear response corrector (2) is as the electrical signal of photodetector; Said nonlinear response update equation is:

$I_{\mathrm{out}}=\left\{\begin{array}{c}0.9375-1.038I_{\mathrm{in}}+0.102I_{\mathrm{in}}^2,400\mathrm{nm}\&le;\mathrm{\&lambda;}<500\mathrm{nm}\\ 0.8917-1.962I_{\mathrm{in}}+0.071I_{\mathrm{in}}^2,500\mathrm{nm}\&le;\mathrm{\&lambda;}<600\mathrm{nm}\\ 0.8656-0.917I_{\mathrm{in}}+0.051I_{\mathrm{in}}^2,600\mathrm{nm}\&le;\mathrm{\&lambda;}<700\mathrm{nm}\end{array}\right..$

7. implement the spectrophotometer of the said method of claim 1; It is characterized in that it is made up of light source (4), monochromator (3), sample cell (5), photodetector (7) and calculating and display unit (6), said photodetector (7) is made up of photomultiplier (1) and nonlinear response corrector (2); The output of light source (4) connects the light signal input of monochromator (3); The light signal output end of monochromator (3) connects the light signal input of sample cell (5); The electrical signal of monochromator (3) connects the wavelength signals input of nonlinear response corrector (2) and the wavelength signals input of calculating and display unit (6); The light signal output end of sample cell (5) connects the light signal input of photomultiplier (1); The electrical signal of photomultiplier (1) connects the electric signal input end of nonlinear response corrector (2), and the electrical signal of nonlinear response corrector (2) connects the input of calculating and display unit (6).

8. spectrophotometer according to claim 7 is characterized in that the nonlinear response update equation that said nonlinear response corrector (2) is embedded with is:

$I_{\mathrm{out}}=\left\{\begin{array}{c}0.9375-1.038I_{\mathrm{in}}+0.102I_{\mathrm{in}}^2,400\mathrm{nm}\&le;\mathrm{\&lambda;}<500\mathrm{nm}\\ 0.8917-1.962I_{\mathrm{in}}+0.071I_{\mathrm{in}}^2,500\mathrm{nm}\&le;\mathrm{\&lambda;}<600\mathrm{nm}\\ 0.8656-0.917I_{\mathrm{in}}+0.051I_{\mathrm{in}}^2,600\mathrm{nm}\&le;\mathrm{\&lambda;}<700\mathrm{nm}\end{array}\right..$

9. implement the spectrophotometer of the said method of claim 1; It is characterized in that it is made up of light source (4), sample cell (5), monochromator (3), photodetector (7) and calculating and display unit (6), said photodetector (7) is made up of photomultiplier (1) and nonlinear response corrector (2); The output of light source (4) connects the light signal input of sample cell (5); The light signal output end of sample cell (5) connects the light signal input of monochromator (3); The light signal output end of monochromator (3) connects the light signal input of photomultiplier (1); The electrical signal of monochromator (3) connects the wavelength signals input of nonlinear response corrector (2); The electrical signal of photomultiplier (1) connects the electric signal input end of nonlinear response corrector (2), and the electrical signal of nonlinear response corrector (2) connects the input of calculating and display unit (6).

Images