CN202471262U - Illumination-free thermionic noise pulse discriminating single photon counter - Google Patents

Illumination-free thermionic noise pulse discriminating single photon counter Download PDF

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Publication number
CN202471262U
CN202471262U CN2011205353410U CN201120535341U CN202471262U CN 202471262 U CN202471262 U CN 202471262U CN 2011205353410 U CN2011205353410 U CN 2011205353410U CN 201120535341 U CN201120535341 U CN 201120535341U CN 202471262 U CN202471262 U CN 202471262U
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thermionic
single photon
noise pulse
pulse
discr
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CN2011205353410U
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黄笃之
李光辉
周达林
谢春香
罗朝海
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Hunan University of Science and Technology
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Hunan University of Science and Technology
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Abstract

An illumination-free thermionic noise pulse discriminating single photon counter is characterized in that: a photoelectric detector and a light shutter are arranged in a cassette, an amplifier, a discriminator, a pulse shaper, a counter, an embedded system, a stairstep signal generator, and a computer which are electrically connected with each other are arranged outside the cassette; when the single photon counter is in use, the light shutter is closed at first, thermionic noise pulse signals of the photoelectric detector pass through the stairstep signal generator and the discriminator, in order to complete scanning for a thermionic noise pulse energy spectrum, in combination with a thermionic noise pulse energy spectrum curve measured by the computer when the shutter is closed, the embedded system sets and outputs a lower threshold voltage to a reference voltage end of the discriminator, thermionic noise pulses with lower amplitudes are filtered out during measurement, and photoelectron pulses with higher amplitudes are passed and input to the counter, thereby realizing high signal-to-noise ratio and ultra-low noise measurement for light intensity; in addition, the illumination-free thermionic noise pulse discriminating single photon counter of the utility model overcomes defects of low sensitivity, high noise, poor stability for measuring the light intensity and so on of a traditional single photon counter; and the illumination-free thermionic noise pulse discriminating single photon counter is suitable for the single photon counters of various photoelectric sensors and suitable for measuring extremely weak light signals such as light scattering, etc.

Description

Unglazed according to thermionic noise pulse discriminating single photon counter
Technical field
The utility model relates to a kind of unglazed according to thermionic noise pulse discriminating single photon counter.
Background technology
Along with development of modern science and technology, in fields such as physics, chemistry, biology, medical science, environment, astronomy and information science, require increasingly highly to what measure faint optical signal, demand constantly increases.Single photon counter is a kind of measuring method of measuring the atomic low light level, the photocurrent strength ratio photodetector thermonoise level (10 at room temperature of the light that it is measured itself -14W) lower, common measuring method is to come out this signal measurement that is submerged in the noise.Under atomic low light level irradiation, this method is handled light according to single photon, and photon detector is output as the discrete pulse signal of nature, adopts pulse authentication technique and digital counting technology to come out atomic low light level signal extraction.At present, the detection technique in the limit field of light has become the important means of the various more advanced phenomenons of research, and single photon counter photometry technology has been widely used in the optoelectronics all trades and professions.
Single photon counter is a kind of highly sensitive low noise Detection of Weak Signals equipment, and critical piece has photoelectric sensor, amplifier, Discr. sum counter etc.Photoelectric sensor also can be exported a series of noise spike in the individual pulse that output is produced by incident photon.The key factor that influences the photoelectric sensor single photon counting is dark-current pulse; It is generally acknowledged that dark current mainly is because the thermionic emission of photoelectric sensor; Therefore the pulse of thermoelectron pulse voltage aspect ratio photoelectron will be hanged down a bit, and getting rid of the effective method of noise is exactly to adopt the size of distinguishing each pulse, the method for height.The pulse signal that amplifies through amplifier connects Discr.; Through selecting the following discriminating voltage and the last discriminating voltage of Discr.; Realize only letting the single photoelectron pulse of emission of cathode formation pass through; And do not allow the pulse lower and higher to pass through, thereby with a large amount of thermionic noises and other noise elimination than last discriminating voltage than following discriminating voltage., select setting extremely important for the height of following discriminating voltage here, it is the most important means with a large amount of thermionic noise eliminations; If being provided with of following discriminating voltage is too high, then a large amount of useful signal pulses are also deducted, and cause sensitivity to descend; If it is low that following discriminating voltage was provided with, then a large amount of thermionic noise pulses are also passed through, and cause signal to noise ratio (S/N ratio) to descend, and weak signal is submerged in the noise.
The user of existing most of single photon counters is in the defective of considering above-mentioned existence; But can only "ball-park" estimate for threshold value, can not confirm the size of its value accurately, threshold setting is all bigger than normal; And threshold value immobilizes; Add the user mode of each components and parts of system and the influence of various factors such as difference of tenure of use, make the sensitivity of whole instrument and the parameter index of signal to noise ratio (S/N ratio) all descend comparatively fast, had a strong impact on the research and development task of the sector.
Summary of the invention
To above-mentioned situation, the purpose of the utility model provides a kind of simple in structure, compact, easy to manufacture; Need not to drop into new equipment, highly sensitive, thermionic noise is low; Measuring accuracy is high, and easy to use, commercial promise is good; Suitable penetration and promotion realizes the unglazed according to thermionic noise pulse discriminating single photon counter of hypersensitivity and ultra-low noise measurement light intensity intensity.
To achieve the above object, a non-thermal electrical noise pulse discriminator light photon counters, within the cartridge main photodetector having optical shutter and the cartridge located outside the turn amplifiers, discriminators, pulse shaper, counters, embedded system, step signal generators and computers that are electrically interconnected; said cartridge within the optical shutter and the photodetector is arranged between a light hole and diaphragm, and which in turn runs through the optical shutter aperture blades diaphragm to the photodetector, when used first light within the cartridge shutter closed, no light through the light hole, light shutter and aperture, light exposure on the photodetector, step ladder signal generator output signal to the discriminator reference voltage terminal, hot electron scanning photodetector impulse noise spectrum, the noise spectrum of the measured parameters of the system, while the computer on which the shutter is closed the light measured thermal electronic noise and pulse-height distribution curve digital threshold is set, electronic noise from the measured thermal pulse spectrum curve to determine the threshold voltage magnitude for the V next = V Abduction + V drift , embedded system control output lower threshold voltage, the lower threshold voltage is input to the discriminator reference voltage terminal, and then the amplifier processed optical pulse signal and thermal electrical noise pulses through discriminator pulse shaper filtered off below the lower threshold voltage of the thermal electron noise pulses , the photoelectron pulse signal input to the counter by the discriminator, to achieve high sensitivity and low signal to noise ratio of the high intensity light intensity noise measurements.
For the effect that realizes reducing noise He significantly improve sensitivity, its further step also has:
Optical shutter is a mechanical type manual control optical shutter.
Optical shutter is that mechanical type controls optical shutter automatically.
When optical shutter is closed, do not have any smooth incident, autoscan thermionic noise pulse height distributes.
When optical shutter is opened, realize the high s/n ratio luminous intensity measurement.
Step generator comprises the square-wave generator of being made up of operational amplifier IC1, capacitor C 1, resistance R 1, R2, R3 and R4; Form signaling switch by Sheffer stroke gate IC2, diode D3 and D4; And input embedded system trigger sweep signal; The ramp generator of forming by operational amplifier IC3 and IC4; Wherein be that the differential amplifier that core is formed is regulated output voltage through its output terminal sampling with IC4, the gate-control signal stack of the output voltage of IC4 and IC2 output forms step signal output at operational amplifier IC3 output terminal and supplies with the Discr. reference voltage terminal.
The Discr. threshold voltages be set to manual setting.
The Discr. threshold voltages be set to automatic setting.
Produce stepped rising scanning voltage during step generator work, ascending gradually changing adds aforementioned stepped rising scanning voltage at the Discr. reference voltage terminal, and scanning calorimeter electronic noise pulse height distributes, and realizes the discriminating of thermionic noise pulse.
Before the optical shutter surveying work begins,, make it be in optimum Working according to thermionic noise pulse height distributed and arranged Discr. threshold voltages.
The utility model is employed in and establishes photodetector, optical shutter in the magazine, magazine peripheral hardware amplifier, Discr., pulse shaper, counter, embedded system, step generator and computing machine, and they are electrically connected each other; Optical shutter during use in the closed magazine of elder generation; Photodetector thermionic noise pulse signal is through step generator and Discr. scanning calorimeter electronic noise pulse power spectrum; The thermionic noise pulse spectrum curve that records when closing shutter in conjunction with computing machine; By embedded system output threshold voltages to Discr. reference voltage terminal is set; Elimination through the photoelectron pulse and the enter counter of higher amplitude, realizes the technical scheme of high s/n ratio and ultra-low noise measurement light intensity intensity than the thermionic noise pulse of amplitude during measurement; The sensitivity that has overcome traditional single photon counter is low, noise is high, defectives such as luminous intensity measurement poor stability.
The utility model is compared the beneficial effect that prior art produces:
(1) the utility model only will be installed an optical shutter on traditional single photon counter; Through the control optical shutter; Record the pure thermionic noise burst spectrum of single photon counter in real time, systematic parameter is set, eliminate the performance difference and the difference of user mode and tenure of use of system's components and parts according in good time state; The sensitivity of system is significantly improved, and thermionic noise reduces greatly.
(2) the utility model adds a ladder signal generator at traditional single photon counter Discr. reference voltage terminal, and the control step generator produces stepped rising scanning voltage, and scanning records the pure thermionic noise burst spectrum of single photon counter.
(3) parts of the utility model increase, it is simple in structure, compact, and is easy to manufacture, need not to drop into new equipment, and cost free increases.
(4) the utility model use, easy to maintenance, highly sensitive, thermionic noise is low, and measuring accuracy is high.
(5) the utility model system architecture is simple, reliable, low cost of manufacture, and processing ease has greatly improved the sensitivity of single photon counter and the stability of luminous intensity measurement, and commercial promise is good, suitable penetration and promotion.
The utility model is suitable for the measurement of the single photon counter and the atomic low light level signals such as light scattering, astronomical photometry, military affairs, chemistry, material, biomedicine and low light level optical fiber communication of various photoelectric sensors.
Below in conjunction with accompanying drawing and embodiment the utility model is further described.
Description of drawings
Fig. 1 is the unglazed structural representation of differentiating the single photon counter system according to the thermionic noise pulse of the utility model.
Fig. 2 is magazine, optical shutter, diaphragm and the photodetector horizontal sectional drawing of the utility model.
Fig. 3 is the stepped in time rising scanning voltage curve map of the utility model.
Fig. 4 is the utility model step generator circuit diagram.
Fig. 5 is the utility model thermionic noise pulse spectrogram.
Among the figure: 1, magazine; 1-1, light hole, 1-2, diaphragm, 2, optical shutter; 3, photodetector; 4, amplifier; 5, Discr.; 6, step generator; 7, pulse shaper; 8, counter; 9, embedded system; 10, computing machine.
Embodiment
Shown in accompanying drawing; A kind of unglazed according to thermionic noise pulse discriminating single photon counter; Mainly be provided with optical shutter 2 and photodetector 3 in its magazine 1; Between optical shutter 2 and the photodetector 3 a light hole 1-1 and diaphragm 1-2 are set also in this magazine 1; And light hole 1-1 runs through optical shutter 2 blades, diaphragm 1-2 successively to photodetector 3, establishes amplifier 4, Discr. 5, pulse shaper 7, counter 8, embedded system 9, step generator 6 and computing machine 10 successively outside the magazine 1, and they are electrically connected each other; Optical shutter 2 is provided with mechanical type manual control optical shutter, mechanical type controls optical shutter automatically; When optical shutter 2 is closed, there is not any smooth incident, autoscan thermionic noise pulse height distributes; When optical shutter 2 is opened, realize the high s/n ratio luminous intensity measurement; Before optical shutter 2 surveying works begin, should make it be in optimum Working according to thermionic noise pulse height distributed and arranged Discr. 5 threshold voltages; Step generator 6 is like Fig. 4; It comprises the square-wave generator of being made up of operational amplifier IC1, capacitor C 1, resistance R 1, R2, R3 and R4; Form signaling switch by Sheffer stroke gate IC2, diode D3 and D4; And input embedded system 9 trigger sweep signals, by the ramp generator that operational amplifier IC3 and IC4 form, wherein be that the differential amplifier that core is formed is regulated output voltage through its output terminal sampling with IC4; The gate-control signal stack of the output voltage of IC4 and IC2 output is exported supply Discr. 5 reference voltage terminals at operational amplifier IC3 output terminal formation step signal such as Fig. 3; Produce stepped rising scanning voltage during step generator 6 work; Ascending gradually changing; Add aforementioned stepped rising scanning voltage at Discr. 5 reference voltage terminals, scanning calorimeter electronic noise pulse height distributes, and realizes the discriminating of thermionic noise pulse; During use; Optical shutter 2 in the earlier closed magazine 1, unglazed through light hole 1-1, optical shutter 2 and diaphragm 1-2, unglazed being radiated on the photodetector 3; Step generator 6 output stairstep signal to Discr.s 5 reference voltage terminals; Scan light electric explorer 3 thermionic noise pulse power spectrums, actual measurement system noise spectrum parameter, simultaneously; The thermionic noise pulse height distribution curve that computing machine 10 records when it the closes optical shutter 2 line of numbers threshold value setting of going forward side by side confirms that by the thermionic noise pulse spectrum curve of actual measurement the threshold voltage size is V Down=V Turn+ V FloatEmbedded system 9 control output threshold voltages; This threshold voltages is input to Discr. 5 reference voltage terminals; Photoelectric pulse signal and the thermionic noise pulse handled by amplifier 4 are lower than the thermionic noise pulse in the threshold voltages through Discr. 5, pulse shaper 7 eliminations again, and the photoelectron pulse signal is input to counter 8 through Discr. 5, realizes the hypersensitivity and the ultra-low noise measurement light intensity intensity of high s/n ratio.
In conjunction with accompanying drawing, a kind of unglazed principle of work of differentiating single photon counter according to the thermionic noise pulse.
Unglazed according to thermionic noise pulse discriminating single photon counter system; It comprises that photodetector 3 is installed in the magazine 1; Light is radiated on the photodetector 3 by the light hole 1-1 of magazine 1, on the light hole 1-1 optical shutter 2 is installed in the magazine 1, and the single photon counter system does not have the light signal input when optical shutter 2 is closed; Photodetector 3 self produces thermionic noise; Obtain the different thermionic noise pulse electrical signal of big low height through amplifier 4 amplifications, trigger step generators 6 by computing machine 10 control embedded systems 9 and produce ladder rising scanning voltage as shown in Figure 3, thermionic noise pulse electrical signal input Discr. 5; Add stepped rising scanning voltage at Discr. 5 reference voltage terminals; The scanning of triggering Discr. 5 reference voltages realizes the scanning of thermionic noise pulse voltage height by Discr. 5, and scanning is passed through the thermionic noise pulse signal of Discr. 5 again through 7 shapings of pulse reshaper; Enter counter 8 is measured then, and it is as shown in Figure 5 to obtain noise spike height profile curve through computing machine 10 data acquisition and processing (DAP); Through Computer Analysis noise spike height profile curve, obtain noise spike height profile point of inflexion on a curve, begin from flex point; Rising along with scanning voltage; Thereafter, the pulse height distribution curve is a curve that count value is very little and constant basically, reaches optimal state; This has been enough to explain when flex point the overwhelming majority's noise filtering; But this is desirable state, and when carrying out the pulse discriminating, small drift can take place discriminating voltage usually; Therefore, for reaching highest signal to noise ratio and sensitivity, after obtaining knee voltage, should on the knee voltage basis, add V Float=20mV~30mV is worth with this and is set at threshold voltages; Most thermionic noises that so fully guaranteed filtering, and also very little to the sensitivity influence have guaranteed the high stability of surveying instrument simultaneously.
With reference to Figures 1 and 2, the measuring very weak optical signal, the optical shutter on the cartridge 1 2, the feeble light through the through-aperture diaphragm 1-1 and 1-2 irradiated on the photodetector 3, light shutters previously closed by the computer 2:00 measured pulse height distribution curve, the discriminator 5 to accurately determine the threshold voltage, in fact, the measured magnitude of the voltage threshold value V the = V Abduction + V drift , under the control by the embedded system 9 threshold voltage is set, this lower threshold voltage input to the discriminator 5 reference voltage terminal, processed by the amplifier 4 optical pulse signal by the discriminator 5 lower than the threshold voltage of a large number of hot electrons noise pulses filtered so that only photoelectron pulse signals input to the counter 8 and the measurement, thereby greatly improving the signal to noise ratio measurement.

Claims (7)

1. single photon counter is differentiated in unglazed photograph thermionic noise pulse; It is characterized in that mainly being provided with in the magazine (1) optical shutter (2) and photodetector (3); Magazine (1) is outer establishes amplifier (4), Discr. (5), pulse shaper (7), counter (8), embedded system (9), step generator (6) and computing machine (10) successively, and they are electrically connected each other; One light hole (1-1) and diaphragm (1-2) also are set between interior optical shutter of said magazine (1) (2) and the photodetector (3); And light hole (1-1) runs through optical shutter (2) blade, diaphragm (1-2) successively to photodetector (3), during use, and the optical shutter (2) in the closed magazine of elder generation (1); Unglazed through light hole (1-1), optical shutter (2) and diaphragm (1-2); Unglazed being radiated on the photodetector (3), step generator (6) output stairstep signal to Discr. (5) reference voltage terminal, scan light electric explorer (3) thermionic noise pulse power spectrum; Actual measurement system noise spectrum parameter; Simultaneously, the thermionic noise pulse height distribution curve that computing machine (10) records when it closes optical shutter (2) the line of numbers threshold value setting of going forward side by side confirms that by the thermionic noise pulse spectrum curve of actual measurement the threshold voltage size is V Down=V Turn+ V FloatEmbedded system (9) control output threshold voltages; This threshold voltages is input to Discr. (5) reference voltage terminal; Photoelectric pulse signal and the thermionic noise pulse handled by amplifier (4) are lower than the thermionic noise pulse in the threshold voltages through Discr. (5), pulse shaper (7) elimination again, and the photoelectron pulse signal is input to counter (8) through Discr. (5), realize the hypersensitivity and the ultra-low noise measurement light intensity intensity of high s/n ratio.
2. according to claim 1 unglazed according to thermionic noise pulse discriminating single photon counter, it is characterized in that optical shutter (2) is a mechanical type manual control optical shutter.
3. according to claim 1ly unglazedly differentiate single photon counter, it is characterized in that optical shutter (2) controls optical shutter automatically for mechanical type according to the thermionic noise pulse.
4. according to claim 1 unglazed according to thermionic noise pulse discriminating single photon counter; It is characterized in that step generator (6) comprises the square-wave generator of being made up of operational amplifier IC1, capacitor C 1, resistance R 1, R2, R3 and R4; Form signaling switch by Sheffer stroke gate IC2, diode D3 and D4; And input embedded system (9) trigger sweep signal; The ramp generator of forming by operational amplifier IC3 and IC4; Wherein be that the differential amplifier that core is formed is regulated output voltage through its output terminal sampling with IC4, the gate-control signal stack of the output voltage of IC4 and IC2 output forms step signal output at operational amplifier IC3 output terminal and supplies with Discr. (5) reference voltage terminal.
5. according to claim 1 unglazed according to thermionic noise pulse discriminating single photon counter, it is characterized in that the manual setting that is set to of Discr. (5) threshold voltages.
6. according to claim 1 unglazed according to thermionic noise pulse discriminating single photon counter, it is characterized in that the automatic setting that is set to of Discr. (5) threshold voltages.
7. according to claim 1 unglazed according to thermionic noise pulse discriminating single photon counter; Produce stepped rising scanning voltage when it is characterized in that step generator (6) work; Ascending gradually changing; Add aforementioned stepped rising scanning voltage at Discr. (5) reference voltage terminal, scanning calorimeter electronic noise pulse height distributes, and realizes the discriminating of thermionic noise pulse.
CN2011205353410U 2011-12-20 2011-12-20 Illumination-free thermionic noise pulse discriminating single photon counter Withdrawn - After Issue CN202471262U (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102435325A (en) * 2011-12-20 2012-05-02 湖南科技大学 Single-photon counter for identifying empty-illumination thermo-electron noise pulse
CN112449680A (en) * 2018-06-19 2021-03-05 贝克顿·迪金森公司 Variable multiplexing switch for detector array, system and method of use thereof

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102435325A (en) * 2011-12-20 2012-05-02 湖南科技大学 Single-photon counter for identifying empty-illumination thermo-electron noise pulse
CN102435325B (en) * 2011-12-20 2014-09-03 湖南科技大学 Single-photon counter for identifying empty-illumination thermo-electron noise pulse
CN112449680A (en) * 2018-06-19 2021-03-05 贝克顿·迪金森公司 Variable multiplexing switch for detector array, system and method of use thereof

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