JP2016156696A - Particle detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a particle detection device which achieves easy sensitivity adjustment of a photomultiplier tube.SOLUTION: A particle detection device includes: an inspection light source 10 for emitting inspection light; a photomultiplier tube 20 for detecting reaction light generated at a particle contained in a liquid irradiated with the inspection light; a correcting light source 30 for emitting calibration light which corrects an amplification voltage of the photomultiplier tube 20; and a correction section 301 for correcting the amplification voltage of the photomultiplier tube 20 on the basis of an output value of the photomultiplier tube 20 which has received the calibration light.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a detection technique, and relates to a particle detection apparatus.

  In a clean room such as a bio clean room, scattered microbial particles and non-microbial particles are detected and recorded using a particle detector (see, for example, Patent Document 1 and Non-Patent Document 1). From the particle detection result, it is possible to grasp the deterioration of the air conditioner in the clean room. In addition, a detection record of particles in the clean room may be attached to a product manufactured in the clean room as a reference material.

  The optical particle detection device, for example, sucks a gas in a clean room and irradiates the sucked gas with light. If the gas contains microbial particles or non-microbial particles, the particles irradiated with light emit fluorescence or scattered light is generated in the particles. Therefore, by detecting fluorescence or scattered light, it is possible to detect the number and size of microbial particles and non-microbial particles contained in the gas.

  In addition to a clean room, a technique for accurately detecting particles in a fluid is desired (for example, see Patent Document 2). For example, a technique for accurately detecting particles in aerosol, a technique for accurately detecting particles in plant piping, and a technique for accurately detecting particles in a fluid in a container are desired.

  The intensity of the fluorescence emitted by the particles may vary depending on the type of particles. In addition, the intensity of scattered light generated by the particles may vary depending on the type of particles. Therefore, a method for discriminating whether a particle is a biological particle or a non-biological particle based on the intensity of fluorescence and the intensity of scattered light has been proposed (see, for example, Patent Document 3).

  In the particle detector, a photomultiplier tube may be used to detect fluorescence and scattered light generated in the particle. The photomultiplier tube may require sensitivity adjustment (see, for example, Patent Documents 4 and 5).

JP 2011-83214 A JP-A-8-29331 US Patent Application Publication No. 2013/0077087 JP 2010-175415 A Japanese Patent No. 5140697

Hasegawa, M. et al., “Real-time microorganism detection technology in the air and its application”, Yamatake Corporation, azbil Technical Review December 2009, p.2-7, 2009

  Conventionally, when adjusting the sensitivity of a photomultiplier tube, a device that injects a special reagent into the flow cell or switches the flow cell, or a device that searches the optimum location by changing the amplification voltage of the photomultiplier tube However, the method of adjusting the sensitivity of the photomultiplier tube in the conventional apparatus is complicated. On the other hand, an object of the present invention is to provide a particle detection device in which the sensitivity of a photomultiplier tube can be easily adjusted.

  Aspects of the present invention include (a) an inspection light source that emits inspection light, (b) a photomultiplier tube that detects reaction light generated in particles contained in the fluid irradiated with the inspection light, and (c) A correction light source that emits calibration light for correcting the amplification voltage of the photomultiplier tube, and (d) correction for correcting the amplification voltage of the photomultiplier tube based on the output value of the photomultiplier tube that has received the calibration light. A particle detecting device.

  In the above particle detector, the wavelength band of the calibration light may overlap with the wavelength band of the reaction light.

  In the above particle detection apparatus, the correction unit is configured so that the output value of the photomultiplier tube becomes a predetermined value based on the output value of the photomultiplier tube receiving calibration light having a constant luminance. The amplified voltage may be corrected. In addition, the correction unit is based on the output value of the photomultiplier tube that has received the calibration light, and the ratio of the logarithm of the amplification voltage of the photomultiplier tube acquired in advance and the logarithm of the output of the photomultiplier tube. The amplification voltage of the multiplier may be corrected. The particle detection apparatus may further include an information storage device that stores a ratio of a logarithm of the amplification voltage of the photomultiplier tube acquired previously and a logarithm of the output of the photomultiplier tube.

  Said particle | grain detection apparatus may be provided with the several photomultiplier tube which detects the reaction light from which a wavelength range differs, respectively. In addition, the particle detection apparatus may include a plurality of correction light sources that emit calibration light having different wavelength bands. In this case, the correction unit may correct the amplification voltages of the plurality of photomultiplier tubes based on the output values of the plurality of photomultiplier tubes that have received the calibration light. Further, based on the output values of the plurality of photomultiplier tubes that have received the calibration light having a constant luminance, the correction unit is configured so that the output values of the plurality of photomultiplier tubes have predetermined values. You may correct | amend each amplification voltage of a photomultiplier tube. Further, the correction unit outputs the respective output values of the plurality of photomultiplier tubes that have received the calibration light, the logarithm of the amplification voltage of the photomultiplier tube acquired in advance for each of the plurality of photomultiplier tubes, and the photomultiplier. Based on the ratio to the logarithm of the output of the tube, the amplification voltage of each of the plurality of photomultiplier tubes may be corrected. The particle detection apparatus further includes an information storage device that stores a ratio of a logarithm of the amplification voltage of the photomultiplier tube acquired in advance for each of the plurality of photomultiplier tubes and a logarithm of the output of the photomultiplier tube. It may be.

  The particle detection apparatus may further include a correction light source on / off circuit. In the above particle detector, the correction light source may include a light emitting diode. The reaction light may be fluorescence, scattered light, or both fluorescence and scattered light.

  ADVANTAGE OF THE INVENTION According to this invention, the particle | grain detection apparatus with which the sensitivity adjustment of a photomultiplier tube is easy can be provided.

It is a schematic diagram of the particle | grain detection apparatus which concerns on the 1st Embodiment of this invention. It is a typical graph which shows the relationship between the logarithm of the amplification voltage of the photomultiplier tube which concerns on the 1st Embodiment of this invention, and the logarithm of output current. It is a typical graph for demonstrating the correction method of the amplification voltage of the photomultiplier tube which concerns on the 1st Embodiment of this invention. It is a schematic diagram of the particle | grain detection apparatus which concerns on the modification of the 1st Embodiment of this invention. It is a schematic diagram of the particle | grain detection apparatus which concerns on the 2nd Embodiment of this invention. It is a graph which shows the relationship between the temperature which concerns on the 2nd Embodiment of this invention, and a correction coefficient. It is a schematic diagram of the particle | grain detection apparatus which concerns on the 3rd Embodiment of this invention. It is a schematic diagram of the particle | grain detection apparatus which concerns on the 4th Embodiment of this invention.

  Embodiments of the present invention will be described below. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic. Therefore, specific dimensions and the like should be determined in light of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(First embodiment)
As shown in FIG. 1, the particle detection apparatus according to the first embodiment of the present invention includes an inspection light source 10 that emits inspection light and reaction light generated by particles contained in the fluid irradiated with the inspection light. Based on the output value of the photomultiplier tube 20 that detects the photomultiplier tube 20, the correction light source 30 that emits calibration light for correcting the amplification voltage of the photomultiplier tube 20, and the photomultiplier tube 20 that has received the calibration light. And a correction unit 301 that corrects the amplified voltage of the multiplier tube 20. Here, the fluid is, for example, a liquid or a gas. Moreover, reaction light means at least one of fluorescence and scattered light. The fluorescence includes autofluorescence.

  The fluid irradiated with the inspection light flows, for example, in the through hole 101 of the transparent flow cell 100 as the inspection region. The flow cell 100 is made of, for example, quartz glass.

  The inspection light source 10 emits, for example, excitation light for detecting fluorescent particles flowing inside the flow cell 100 as inspection light. As the inspection light source 10, a light emitting diode (LED) and a laser can be used. The wavelength of the inspection light is, for example, 250 to 550 nm. The inspection light may be visible light or ultraviolet light. When the inspection light is visible light, the wavelength of the inspection light is, for example, in the range of 400 to 550 nm, for example, 405 nm. When the inspection light is ultraviolet light, the wavelength of the inspection light is, for example, in the range of 300 to 380 nm, for example, 340 nm. However, the wavelength of the inspection light is not limited to these.

  The particles contained in the fluid flowing through the flow cell 100 are, for example, biological substances including microorganisms, chemical substances, dust, dust, and dust such as dust. Examples of microorganisms include bacteria and fungi. Examples of bacteria include gram negative bacteria and gram positive bacteria. Examples of gram-negative bacteria include E. coli. Examples of Gram positive bacteria include Staphylococcus epidermidis, Bacillus subtilis, Micrococcus, and Corynebacterium. Examples of fungi include Aspergillus such as black mold. However, the microorganism is not limited to these.

  If the fluid contains fluorescent particles such as microorganisms, the particles emit fluorescence when irradiated with excitation light. For example, riboflavin, flavin nucleotide (FMN), flavin adenine dinucleotide (FAD), nicotinamide adenine dinucleotide phosphate (NAD (P) H), pyridoxamine, pyridoxal phosphate (pyridoxal) contained in microorganisms -5'-phosphate, pyridoxine, tryptophan, tyrosine, phenylalanine, and the like emit fluorescence. Non-biofluorescent particles also emit fluorescence when irradiated with excitation light. The wavelength and intensity of the fluorescence emitted by the particles tend to depend on the type of particles.

  Further, scattered light due to Mie scattering, for example, is generated in the fluorescent particles and non-fluorescent particles irradiated with the excitation light. The intensity of scattered light generated in the particles tends to depend on the particle size of the particles. The particle size of the biological particles varies depending on the type of microorganism. The particle size of non-biological particles also varies from type to type. Therefore, it is possible to specify the type of particles to be measured contained in the fluid from the wavelength and intensity of fluorescence generated in the particles and the intensity of scattered light. Fluorescence and scattered light as reaction light generated in the particles irradiated with light are emitted from the particles in all directions.

  A photomultiplier tube (PMT: Photomultiplier Tube) 20 receives reaction light generated inside the through hole 101 of the flow cell 100. The wavelength band of light that can be detected by the photomultiplier tube 20 is set so as to overlap with the wavelength band of reaction light such as fluorescence or scattered light generated by particles that are detected by the particle detector. The photomultiplier tube 20 includes, for example, a cathode as a photocathode that converts received reaction light into electrons, an electron multiplier that multiplies electrons emitted from the cathode by secondary electron emission, and multiplied electrons. And an anode for outputting an output current. A current-voltage conversion circuit may be connected to the anode.

  The electron multiplier section of the photomultiplier tube 20 includes a plurality of electrodes called dynodes. When electrons enter the first dynode, the first dynode emits secondary electrons. Secondary electrons are incident on the second dynode, and the second dynode emits secondary electrons. Thereafter, up to the last dynode, incident and emission of secondary electrons are repeated, and the electron current is amplified.

The applied voltage between the cathode and the anode of the photomultiplier tube 20 is called an amplification voltage. When the photomultiplier tube 20 has n dynodes and the voltage between the dynodes is E, the amplified voltage V of the photomultiplier tube 20 is given by the following equation (1).
V = (n + 1) E (1)

  The sensitivity of the photomultiplier tube 20 is defined by the output current of the anode with respect to the light intensity of light incident on the cathode, for example. The sensitivity of the photomultiplier tube 20 may change as the photomultiplier tube 20 deteriorates with time. The deterioration with time of the photomultiplier tube 20 depends on the amplification voltage, the integrated light quantity of light incident on the cathode, and the like. The sensitivity of the photomultiplier tube 20 can be adjusted by correcting the amplified voltage V by increasing or decreasing it. In addition, the characteristics of the optical element that guides the reaction light to the photomultiplier tube 20 may also change with time.

  When the photomultiplier tube 20 is irradiated with light having a constant light intensity, the logarithm of the output current of the photomultiplier tube 20 is substantially proportional to the logarithm of the amplified voltage of the photomultiplier tube 20 as shown in FIG. . Therefore, the relationship between the logarithm of the amplification voltage of the photomultiplier tube 20 and the logarithm of the output current of the photomultiplier tube 20 when the photomultiplier tube 20 is irradiated with light having a constant light intensity is a linear function. It is possible to approximate a linear function such as

  If the sensitivity adjustment of the photomultiplier tube 20 is executed at an appropriate interval, the ratio of the logarithm of the amplified voltage of the photomultiplier tube 20 and the logarithm of the output current of the photomultiplier tube 20 is the photomultiplier. Each individual tube 20 can be considered to be substantially constant. Further, the ratio of the logarithm of the amplification voltage of the photomultiplier tube 20 and the logarithm of the output current of the photomultiplier tube 20 can be regarded as almost constant even if the sensitivity of the photomultiplier tube 20 is deteriorated. It is.

  The correction light source 30 included in the optical system of the particle detector shown in FIG. 1 emits calibration light having a constant luminance (light intensity). The wavelength band of the calibration light is set so as to overlap with the wavelength band of the reaction light such as fluorescence or scattered light generated in the particles to be detected by the particle detection device. Therefore, the wavelength band of the calibration light overlaps with the wavelength band of the light detected by the photomultiplier tube 20. For example, a light emitting diode can be used as the correction light source 30. The calibration light emitted from the correction light source 30 is guided to the photomultiplier tube 20 via, for example, the wavelength selective reflector 40. As the wavelength selective reflecting mirror 40, a dichroic mirror, an interference film filter, an optical filter, or the like can be used.

  When manufacturing the particle detection apparatus according to the first embodiment, after the correction light source 30 is incorporated, the correction light source 30 is adjusted so that calibration light having a predetermined light intensity is incident on the cathode of the photomultiplier tube 20. A power supply circuit or the like may be adjusted to eliminate individual differences in the particle detection device.

  The particle detection apparatus according to the first embodiment may further include a lighting / extinguishing circuit that turns on and off the correction light source 30. The correction light source 30 is turned on only when the amplification voltage of the photomultiplier tube 20 is corrected. Therefore, when the particle detection apparatus is operated, the cumulative light emission time of the correction light source 30 is very short compared to the cumulative light emission time of the inspection light source 10. Therefore, since the deterioration of the correction light source 30 is significantly slower than the deterioration of the inspection light source 10, the luminance of the calibration light emitted from the correction light source 30 can be regarded as constant.

  The correction unit 301 is included in a central processing unit (CPU) 300, for example. The correction unit 301 is based on the value of the output current of the photomultiplier tube 20 that has received calibration light having a constant luminance, so that the value of the output current of the photomultiplier tube 20 becomes a predetermined value. Correct the amplified voltage. The value of the output current of the photomultiplier tube 20 that has received calibration light having a constant luminance may be, for example, an average value for a predetermined time. The predetermined value of the output current is preferably a constant value.

  When correcting the amplification voltage of the photomultiplier tube 20, the correction unit 301 turns off the inspection light source 10 and turns on the correction light source 30, for example, by software control.

When the constant of the ratio between the logarithm logV of the amplification voltage and the logarithm logO of the output current obtained in advance for the photomultiplier tube 20 is A, the relationship between the amplification voltage V and the output O of the photomultiplier tube 20 is It is given by the following equation (2).
logO = A × logV + C (2)
Here, C is a constant.

As shown in FIG. 3, for example, at the time of the first correction, the value of the amplification voltage of the photomultiplier tube 20 when the photomultiplier tube 20 is irradiated with calibration light having a constant luminance is V ₁ , and the value of the output current. Is O ₁ , the value C ₁ of the constant C in the above equation (2) is given by the following equation (3).
_{C 1 = logO 1 -A × logV} 1 (3)

If you want the value of the output current of the photomultiplier tube 20 when the brightness is irradiated with constant calibration light photomultiplier tube 20 to a predetermined target value O _T, the correction unit 301, the amplification of the photomultiplier 20 The value of the voltage V is set to V ₂ given by the following equation (4).
V ₂ = 10 ^ {(log O _T −C ₁ ) / A}
= 10 ^ {(log O _T -log O ₁ + A × log V ₁ ) / A} (4)

For example, after the value of the amplified voltage of the photomultiplier tube 20 was period operation is a particle detector in the V _2, for example, at the time of the second correction, luminance is irradiated with constant calibration light photomultiplier tube 20 When the value of the output current of the photomultiplier tube 20 at that time becomes O ₂ , the value C ₂ of the constant C in the above equation (2) is given by the following equation (5).
_{C 2 = logO 2 -A × logV} 2 (5)

In this case, the correction unit 301, and the value of the amplified voltage V of the photomultiplier 20 to V ₃ given by the following equation (6), when the brightness is irradiated with constant calibration light photomultiplier tube 20 the value of the output current of the photomultiplier tube 20 is set to be a predetermined target value O _T.
V ₃ = 10 ^ {(log O _T -C ₂ ) / A}
= 10 ^ {(log O _T -log O ₂ + A × log V ₂ ) / A} (6)

Further, for example, after the particle detector is operated for a certain period with the amplification voltage value of the photomultiplier tube 20 set to V ₃ , for example, at the time of the third correction, the photomultiplier tube 20 is irradiated with calibration light having a constant luminance. When the value of the output current of the photomultiplier tube 20 at this time becomes O ₃ , the value C ₃ of the constant C in the above equation (2) is given by the following equation (7).
C ₃ = logO ₃ −A × log V ₃ (7)

In this case, the correction unit 301 sets the value of the amplified voltage V of the photomultiplier tube 20 to V ₄ given by the following equation (8), and irradiates the photomultiplier tube 20 with calibration light having a constant luminance. the value of the output current of the photomultiplier tube 20 is set to be a predetermined target value O _T.
V ₄ = 10 ^ {(log O _T -C ₃ ) / A}
= 10 ^ {(log O _T -log O ₃ + A × log V ₃ ) / A} (8)

As described above, the correction unit 301 shown in FIG. 1 performs photoelectrons when the photomultiplier tube 20 is irradiated with calibration light having a constant value and brightness of the amplified voltage V of the photomultiplier tube 20 when the calibration light is received. Based on the value of the output current O of the multiplier tube 20 and the constant A of the ratio of the logarithm of the output current O of the photomultiplier tube 20 to the logarithm of the amplification voltage V of the photomultiplier tube 20 obtained in advance, the luminance is the value of the output current O of the photomultiplier 20 when irradiated with predetermined calibration light photomultiplier tube 20 so that the target value O _T, corrects the value of the amplified voltage V of the photomultiplier tube 20.

  The correction unit 301 may correct the value of the amplified voltage of the photomultiplier tube 20 based on the value of the output voltage converted from the value of the output current of the photomultiplier tube 20.

  When the correction of the amplification voltage of the photomultiplier tube 20 is completed, the correction unit 301 turns off the correction light source 30 and turns on the inspection light source 10 by software control, for example.

  When the corrected value of the amplified voltage V of the photomultiplier tube 20 exceeds the allowable range, the correction unit 301 may issue a warning that an abnormality has occurred in the photomultiplier tube 20.

  An information storage device 401 is connected to the CPU 300. The information storage device 401 stores a constant A, which is used in advance by the correction unit 301 and is a ratio A between the logarithm of the amplified voltage V of the photomultiplier tube 20 and the logarithm of the output current O of the photomultiplier tube 20. . When the correction unit 301 corrects the value of the amplified voltage of the photomultiplier tube 20 based on the value of the output voltage of the photomultiplier tube 20, the information storage device 401 stores the photomultiplier obtained in advance. The constant of the ratio between the logarithm of the amplification voltage of the tube 20 and the logarithm of the output voltage of the photomultiplier tube 20 is stored.

  As described above, the intensity of the fluorescence emitted by the particle may vary depending on the type of particle. Further, the intensity of scattered light generated by the particles depends on the diameter of the particles. Therefore, the type of particle can be specified from the intensity of reaction light such as fluorescence or scattered light generated in the particle. However, if the sensitivity of the photomultiplier tube 20 and the characteristics of the optical element that guides the reaction light to the photomultiplier tube 20 deteriorate over time, the intensity of the reaction light cannot be detected accurately, and the particles based on the intensity of the reaction light. It may be difficult to accurately identify the type of the item.

  On the other hand, according to the particle detector according to the first embodiment, it is possible to correct the sensitivity of the photomultiplier tube 20, and therefore it is possible to accurately specify the type of particle. Even when the characteristics of the optical element that guides the reaction light to the photomultiplier tube 20 deteriorate over time, the photomultiplier tube 20 can be used if the calibration light incident on the photomultiplier tube 20 is transmitted through the optical element. This sensitivity correction also compensates for deterioration with time of the optical element. The calibration light may be directly incident on the photomultiplier tube 20 to correct the sensitivity of the photomultiplier tube 20 by removing the influence of deterioration of the optical element over time.

In the conventional photomultiplier tube sensitivity adjustment method, the output of the photomultiplier tube is measured several times while changing the settings of the brightness of the calibration light and the amplification voltage of the photomultiplier tube. Looking for a new amplified voltage. On the other hand, according to the particle detector according to the first embodiment, when correcting the amplification voltage of the photomultiplier tube 20, the photoelectron when the photomultiplier tube 20 is irradiated with calibration light having a constant luminance. if the value of one measurement of the output current O of intensifier 20, by calculation, the value of the output current O of the photomultiplier tube 20 can calculate the value of the amplified voltage V such that the predetermined target value O _T It is. Therefore, it is possible to correct the amplified voltage of the photomultiplier tube 20 and adjust the sensitivity in a short time. Therefore, even during the continuous operation of the particle detector, the inspection light source 10 is turned off only for a short time, and after the correction of the amplification voltage of the photomultiplier tube 20 is completed, the inspection light source 10 is turned on immediately, Detection can be resumed.

  In the particle detection apparatus according to the first embodiment, the sensitivity of the photomultiplier tube 20 may decrease in about one day to several weeks depending on the intensity of excitation light and the type of fluid flowing through the flow cell 100, for example. obtain. On the other hand, the particle detector according to the first embodiment can easily adjust the sensitivity of the photomultiplier tube 20 and can be performed in a short time. Therefore, even when the sensitivity of the photomultiplier tube 20 is frequently adjusted, the particle detection stop time can be shortened. In addition, the particle detection device according to the first embodiment is provided with a photomultiplier every time the device is started up, every time measurement of particles is started, every time a fixed time elapses from the previous sensitivity adjustment, or every predetermined time. The sensitivity of the tube 20 may be adjusted.

(Modification of the first embodiment)
As shown in FIG. 4, the calibration light emitted from the correction light source 30 may be applied to the through-hole 101 of the flow cell 100 as the inspection region via the wavelength selective reflection mirror 40. Calibration light scattered by reflection on the outer wall and inner wall of the flow cell 100 is collected by the lens 200 and guided to the photomultiplier tube 20. According to the configuration shown in FIG. 4, the sensitivity correction of the photomultiplier tube 20 compensates for the deterioration of the flow cell 100 over time.

(Second Embodiment)
The particle | grain detection apparatus which concerns on 2nd Embodiment is further provided with the temperature measuring device 50 which measures the atmospheric temperature of the light source 30 for correction | amendment, as shown in FIG. When the correction light source 30 is a light emitting diode, the light intensity of the calibration light emitted from the correction light source 30 tends to decrease as the ambient temperature of the correction light source 30 in FIG. 6 increases.

The relationship between the output current O _A of the photomultiplier tube 20 at the ambient temperature T of the correction light source 30 and the output current O _C of the photomultiplier tube 20 corrected for the influence of the ambient temperature T of the correction light source 30 is It is given by the following equation (9).
O _C = O _A / M (9)
Here, M is a correction coefficient and is given by the following equation (10).
M = −B × T + D (10)
Here, B and D are constants, and can be acquired in advance based on the characteristics of the correction light source 30 and the photomultiplier tube 20. An example showing the relationship between the temperature T and the correction coefficient M is shown in FIG.

In the second embodiment, the correction unit 301 shown in FIG. 5 outputs the output current O _{A of the} photomultiplier tube 20 based on the measured value T _D of the ambient temperature of the correction light source 30 measured by the temperature measuring instrument 50. And the value of the amplified voltage V of the photomultiplier tube 20 is corrected based on the corrected value of the output current O _C of the photomultiplier tube 20.

For example, the correction unit 301 substitutes the measured value T _D of the ambient temperature of the correction light source 30 measured by the temperature measuring instrument 50 into the equation (10), and calculates the correction coefficient M _D at the temperature. Further, the correction unit 301, by dividing the value of the output current O _A photomultiplier tube 20 by the correction factor M _D, corrects the value of the output current O _A photomultiplier tube 20. The correction unit 301 corrects the value of the amplification voltage V of the photomultiplier tube 20 using the corrected value of the output current O _C of the photomultiplier tube 20.

For example, in the first correction, the above equation (4) is replaced by the following equation (11).
V ₂
= 10 ^ {(log O _T -log (O ₁ / M _D ) + A × log V ₁ ) / A} (11)
For example, in the second correction, the above equation (6) is replaced with the following equation (12).
V ₃
= 10 ^ {(log O _T -log (O ₂ / M _D ) + A × log V ₂ ) / A} (12)
For example, in the third correction, the above equation (8) is replaced by the following equation (13).
V ₄
= 10 ^ {(log O _T -log (O ₃ / M _D ) + A × log V ₃ ) / A} (13)

  In the second embodiment, the information storage device 401 further stores the relationship between the atmospheric temperature T of the correction light source 30 and the correction coefficient M as in the above equation (10). Other components of the particle detection apparatus according to the second embodiment are the same as those of the first embodiment. According to the particle detector according to the second embodiment, it is possible to accurately correct the amplified voltage V of the photomultiplier tube 20 even if the ambient temperature of the correction light source 30 fluctuates.

(Third embodiment)
As shown in FIG. 7, the particle detection apparatus according to the third embodiment includes a half mirror 60 that reflects a part of calibration light emitted from the correction light source 30, and calibration light reflected by the half mirror 60. The photo detector 70 that receives light, and a feedback circuit 80 that performs feedback control so that the light intensity of the calibration light is constant by adjusting the current supply to the correction light source 30 based on the light intensity of the calibration light received by the photo detector 70. Is provided. Instead of the half mirror 60, a glass window capable of reflecting a part of the calibration light may be used. Alternatively, without using the half mirror 60 or the like, the photodetector 70 may be arranged at a position where the calibration light reflected and scattered by the wall surface around the optical system travels, and the light intensity of the calibration light may be measured.

Other components of the particle detection apparatus according to the third embodiment are the same as those in the first or second embodiment. According to the particle detector according to the third embodiment, even if the light intensity of the calibration light emitted from the correction light source 30 fluctuates, the feedback circuit 80 immediately causes the light intensity of the calibration light to be constant. It is corrected. Therefore, the amplified voltage V of the photomultiplier tube 20 can be accurately corrected also by the particle detector according to the third embodiment. Further, the correction of the calibration light by the feedback circuit 80 and the correction of the value of the output current O of the photomultiplier tube 20 based on the measured value T _D of the ambient temperature of the light source 30 for correction described in the second embodiment. , The amplified voltage V of the photomultiplier tube 20 can be corrected with higher accuracy.

  Further, the temperature of the output of the photodetector 70 can be corrected to correct the amplified voltage V of the photomultiplier tube 20 with higher accuracy.

(Fourth embodiment)
As shown in FIG. 8, the particle detection apparatus according to the fourth embodiment includes a plurality of photomultiplier tubes 20A, 20B, and 20C that detect reaction light having different wavelength bands, and calibration light having different wavelength bands. A plurality of correction light sources 30A, 30B, and 30C. The particle detection apparatus according to the fourth embodiment further includes wavelength selective reflectors 90A and 90B arranged in the traveling direction of the reaction light generated in the flow cell 100.

  For example, the wavelength-selective reflecting mirror 90A reflects scattered light having the same wavelength as the inspection light and transmits fluorescence having a wavelength longer than that of the inspection light. A photomultiplier tube 20A for detecting scattered light is disposed at the focal point of the scattered light reflected by the wavelength selective reflecting mirror 90A. For example, the wavelength selective reflecting mirror 90B reflects the fluorescence in the first wavelength band and transmits the fluorescence in the second wavelength band in a wavelength selective manner. A photomultiplier tube 20B for detecting the fluorescence in the first wavelength band is disposed at the focal point of the fluorescence in the first wavelength band reflected by the wavelength selective reflection mirror 90B. A photomultiplier tube 20C for detecting the fluorescence in the second wavelength band is disposed at the focal point of the fluorescence in the second wavelength band transmitted through the wavelength selective reflection mirror 90B.

  As the wavelength selective reflecting mirrors 90A and 90B, a dichroic mirror, an interference film filter, an optical filter, and the like can be used. The wavelength selective reflecting mirrors 90A and 90B constitute at least a part of the spectroscopic optical system.

  For example, the wavelength band of calibration light emitted from the correction light source 30A overlaps with the wavelength band of scattered light detected by the photomultiplier tube 20A. The wavelength band of the calibration light emitted from the correction light source 30B overlaps the fluorescence wavelength band of the first wavelength band detected by the photomultiplier tube 20B. The wavelength band of calibration light emitted from the correction light source 30C overlaps with the fluorescence wavelength band of the second wavelength band detected by the photomultiplier tube 20C.

  The calibration light emitted from the correction light source 30A passes through the wavelength selective reflector 40A, is reflected by the wavelength selective reflector 90A, and reaches the photomultiplier tube 20A. The calibration light emitted from the correction light source 30B passes through the wavelength selective reflectors 40B and 40A, is reflected by the wavelength selective reflector 90B, and reaches the photomultiplier tube 20B. The calibration light emitted from the correction light source 30C passes through the wavelength selective reflectors 40C and 40A, passes through the wavelength selective reflector 90B, and reaches the photomultiplier tube 20C.

  When correcting the amplification voltage of the photomultiplier tube 20A, the correction unit 301 turns off the inspection light source 10 and the correction light sources 30B and 30C and turns on the correction light source 30A, for example, by software control. When correcting the amplification voltage of the photomultiplier tube 20B, the correction unit 301 turns off the inspection light source 10 and the correction light sources 30A and 30C and turns on the correction light source 30B by software control, for example. When correcting the amplification voltage of the photomultiplier tube 20C, the correction unit 301 turns off the inspection light source 10 and the correction light sources 30A and 30B and turns on the correction light source 30C by software control, for example.

  In 4th Embodiment, the correction | amendment part 301 receives each output value of several photomultiplier tubes 20A, 20B, 20C which received the calibration light with constant brightness | luminance, and several photomultiplier tubes 20A, 20B, Based on the ratio of the logarithm of the amplification voltage of the photomultiplier tube acquired in advance for each of 20C and the logarithm of the output of the photomultiplier tube, the output values of the photomultiplier tubes 20A, 20B, and 20C are The amplification voltages of the plurality of photomultiplier tubes 20A, 20B, and 20C are corrected so as to have a predetermined value.

  A specific method for correcting the amplified voltages of the plurality of photomultiplier tubes 20A, 20B, and 20C is the same as that in the first embodiment.

  In the fourth embodiment, the information storage device 401 uses the ratio of the logarithm of the amplification voltage acquired in advance for the photomultiplier tube 20A and the logarithm of the output, and the amplification voltage acquired in advance for the photomultiplier tube 20B. The ratio of the logarithm and the logarithm of the output and the ratio of the logarithm of the amplification voltage and the logarithm of the output acquired in advance for the photomultiplier tube 20C are stored.

  Other components of the particle detection device according to the fourth embodiment are the same as those of the particle detection device according to any of the first to third embodiments. In some cases, the sensitivity fluctuations of the plurality of photomultiplier tubes 20A, 20B, and 20C may be different, but according to the particle detection device according to the fourth embodiment, the plurality of photomultiplier tubes 20A, 20B, and 20C. It is possible to accurately adjust the sensitivity of each. Note that the number of photomultiplier tubes is not limited to three.

(Other embodiments)
Although the present invention has been described by the embodiments as described above, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques should be apparent to those skilled in the art. For example, the particle detection device may use only the fluorescence emitted by the particles as the detection target, or may use only the scattered light generated by the particles as the detection target. Further, for example, in the above formulas (2) to (8) of the first embodiment, the amplification voltage V of the photomultiplier tube 20 when the photomultiplier tube 20 is irradiated with calibration light having a constant luminance is set. An example is shown in which the value is a value set at the time of the previous correction, but the value of the amplification voltage V of the photomultiplier tube 20 when the photomultiplier tube 20 is irradiated with calibration light having a constant luminance is: It may be a predetermined constant value. However, if the value of the amplification voltage V of the photomultiplier tube 20 when the photomultiplier tube 20 is irradiated with calibration light having a constant luminance is the value set at the time of the previous correction, the photoelectrons before and after the correction The difference in the value of the amplified voltage V of the multiplier 20 tends to be small. Thus, it should be understood that the present invention includes various embodiments and the like not described herein.

10 Inspection light source 20, 20A, 20B, 20C Photomultiplier tube 30, 30A, 30B, 30C Correction light source 40, 40A, 40B, 40C, 90A, 90B Wavelength selective reflecting mirror 50 Temperature measuring device 60 Half mirror 70 Photo detector 80 Feedback Circuit 100 Flow Cell 101 Through-hole 300 Central Processing Unit 301 Correction Unit 401 Information Storage Device

Claims (16)

An inspection light source that emits inspection light; and
A photomultiplier tube for detecting reaction light generated by particles contained in the fluid irradiated with the inspection light;
A correction light source that emits calibration light for correcting the amplification voltage of the photomultiplier;
Based on the output value of the photomultiplier tube that has received the calibration light, a correction unit that corrects the amplified voltage of the photomultiplier tube;
A particle detector.   The particle detection apparatus according to claim 1, wherein a wavelength band of the calibration light overlaps with a wavelength band of the reaction light.   Based on the output value of the photomultiplier tube that has received the calibration light having a constant brightness, the correction unit amplifies the amplified voltage of the photomultiplier tube so that the output value of the photomultiplier tube becomes a predetermined value. The particle | grain detection apparatus of Claim 1 or 2 which correct | amends.   The correction unit, the output value of the photomultiplier tube that has received the calibration light, the ratio of the logarithm of the amplification voltage of the photomultiplier tube acquired in advance and the logarithm of the output of the photomultiplier tube, The particle detector according to any one of claims 1 to 3, wherein an amplification voltage of the photomultiplier tube is corrected on the basis thereof.   The particle detection device according to claim 4, further comprising an information storage device that stores the ratio between a logarithm of the amplification voltage of the photomultiplier tube acquired in advance and a logarithm of the output of the photomultiplier tube.   The particle | grain detection apparatus of Claim 1 or 2 provided with the said several photomultiplier tube which detects the said reaction light from which a wavelength range differs, respectively.   The particle | grain detection apparatus of Claim 6 provided with the said some light source for correction | amendment which emits the said calibration light from which a wavelength range differs, respectively.   8. The correction unit according to claim 6, wherein the correction unit corrects amplification voltages of the plurality of photomultiplier tubes based on output values of the plurality of photomultiplier tubes that have received the calibration light. Particle detector.   Based on the output values of the plurality of photomultiplier tubes that have received the calibration light having a constant luminance, the correction unit, so that the output values of the plurality of photomultiplier tubes become a predetermined value, The particle detection apparatus according to claim 6, wherein the amplification voltage of each of the plurality of photomultiplier tubes is corrected.   The correction unit outputs the output value of each of the plurality of photomultiplier tubes that have received the calibration light, and the logarithm of the amplification voltage of the photomultiplier tube acquired in advance for each of the plurality of photomultiplier tubes. 10. The particle detector according to claim 6, wherein the amplification voltage of each of the plurality of photomultiplier tubes is corrected based on a ratio to a logarithm of the output of the photomultiplier tube.   The information storage device further stores the ratio of the logarithm of the amplification voltage of the photomultiplier tube acquired in advance for each of the plurality of photomultiplier tubes and the logarithm of the output of the photomultiplier tube. 10. The particle detection apparatus according to 10.   The particle detection apparatus according to claim 1, further comprising a light-on / off circuit for the correction light source.   The particle | grain detection apparatus of any one of Claim 1 thru | or 12 in which the said light source for a correction | amendment contains a light emitting diode.   The particle | grain detection apparatus of any one of Claim 1 thru | or 13 whose said reaction light is fluorescence.   The particle detection apparatus according to claim 1, wherein the reaction light is scattered light.   The particle | grain detection apparatus of any one of Claim 1 thru | or 13 whose said reaction light is fluorescence and scattered light.

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