Sample analyzer, photometer and photometric system

Abstract

A sample analyzer, a photometer and a photometric system. The sample analyzer (2000) comprises a light source (100), a photometer (600) and a processor (500); the photometer (600) comprises a photoelectric conversion assembly (401) and a signal processing assembly (400); the photoelectric conversion assembly (401) comprises a photomultiplier tube (200) and a voltage divider circuit (300), an input end node of the voltage divider circuit (300) being connected to the cathode of the photomultiplier tube (200), and an output end node of the voltage divider circuit (300) being connected to the anode of the photomultiplier tube (200). N+1 voltage divider nodes are sequentially arranged between the input end node and the output end node, and the N+1 voltage divider nodes are respectively and sequentially connected to a photoelectron focusing electrode and N dynodes of the photomultiplier tube (200), such that voltage divider branches between two adjacent nodes form N+2 divided voltages; at least one of the divided voltage corresponding to the input end node, the divided voltage corresponding to the voltage divider node N+1, and the divided voltage corresponding to the voltage divider node N is configured to be less than the divided voltages corresponding to the other voltage divider nodes.

Description

Sample analyzer, photometer and photometric system Technical Field

[0001] This application relates to the field of photoelectric detection technology, and in particular to a sample analyzer, a photometer, and a photometric system. Background Technology

[0002] Sample analyzers are used to analyze cellular particles in biological samples, such as classifying and counting cells. Sample analyzers can be blood analyzers or flow cytometers. Low-light detection systems based on photomultiplier tubes (PMTs) in sample analyzers are a key technology in chemoimmunoassay. With the continuous development of chemoimmunoassay reagents, higher demands are placed on the measurement range of the photometric system. Currently, in existing PMT DC modes, the output current of the photomultiplier tube easily reaches saturation with increasing incident light flux, failing to improve the light intensity measurement range of the sample analyzer.

[0003] Summary of the Invention

[0004] This application provides a sample analyzer, a photometer, and a photometric system, which solves the problem in related technologies that the output current of the photomultiplier tube easily reaches saturation as the incident light flux increases, resulting in a small light intensity measurement range for the sample analyzer.

[0005] In a first aspect, this application provides a sample analyzer, comprising a light source, a photometer, and a processor. The light source generates illumination light to irradiate a reaction liquid in a reaction vessel. The photometer includes a photoelectric conversion component and a signal processing component. The photoelectric conversion component converts the light signal generated by the irradiation of the reaction liquid into an electrical signal. The signal processing component processes the electrical signal to obtain a photon count result corresponding to the light signal. The processor determines the detection result of the reaction liquid based on the photon count result. The photoelectric conversion component includes a photomultiplier tube and a voltage divider circuit. The photomultiplier tube includes a cathode, a photoelectron focusing electrode, N dynodes, and an anode arranged sequentially, where N is an integer greater than or equal to 3. The voltage divider circuit includes an input node, an output node, and N+1 voltage divider nodes arranged sequentially between the input node and the output node, along the direction from the input node to the output node. The N+1 voltage divider nodes are sequentially named voltage divider node 1, voltage divider node 2, ..., voltage divider node N, and voltage divider node N+1. The input node is connected to the cathode, and the output node is connected to the anode. The N+1 voltage divider nodes are sequentially connected to the photoelectron focusing electrode and the N multiplier electrodes. Each pair of adjacent nodes among the input node, the N+1 voltage divider nodes, and the output node forms a voltage divider branch, for a total of N+2 voltage divider branches. Along the direction from the input node to the output node, the N+2 voltage divider branches are sequentially named voltage divider branch 1, voltage divider branch 2, ..., voltage divider branch N+1, and voltage divider branch N+2. Each voltage divider node and the output node correspond to a voltage divider. In the voltage divider circuit, at least one of the voltage divider corresponding to the output node, the voltage divider corresponding to voltage divider node N+1, and the voltage divider corresponding to voltage divider node N is configured to be less than the voltage dividers corresponding to the other voltage divider nodes.

[0006] Secondly, this application also provides a photometer, which includes a photoelectric conversion component and a signal processing component. The photoelectric conversion component converts the light signal generated by the reaction liquid being irradiated by light into an electrical signal. The signal processing component processes the electrical signal to obtain the photon count result corresponding to the light signal. The photoelectric conversion component includes a photomultiplier tube and a voltage divider circuit. The photomultiplier tube includes a cathode, a photoelectron focusing electrode, N dynodes, and an anode arranged sequentially, where N is an integer greater than or equal to 3. The voltage divider circuit includes an input node, an output node, and N+1 voltage divider nodes arranged sequentially between the input node and the output node. Along the direction from the input node to the output node, the N+1 voltage divider nodes are voltage divider node 1, voltage divider node 2, ..., voltage divider node N, and voltage divider node N+1, respectively. The input node is connected to the cathode, the output node is connected to the anode, and the N+1 voltage divider nodes are sequentially connected to the photoelectron focusing electrode and the N multiplier electrodes. Each pair of adjacent nodes among the input node, the N+1 voltage divider nodes, and the output node forms a voltage divider branch, for a total of N+2 voltage divider branches. Along the direction from the input node to the output node, the N+2 voltage divider branches are sequentially voltage divider branch 1, voltage divider branch 2, ..., voltage divider branch N+1, voltage divider branch N+2. Each voltage divider node and the output node each correspond to a voltage divider. In the voltage divider circuit, at least one of the voltage divider corresponding to the output node, the voltage divider corresponding to voltage divider node N+1, and the voltage divider corresponding to voltage divider node N is configured to be less than the voltage dividers corresponding to the other voltage divider nodes.

[0007] Thirdly, this application also provides a photometric system, the photometric system comprising:

[0008] A light source, which generates illumination light to irradiate the reaction liquid in the reaction vessel;

[0009] A photomultiplier tube is used to convert the light signal generated by the reaction liquid being irradiated by light into an electrical signal;

[0010] A voltage divider circuit is used to provide a driving voltage for the photomultiplier tube;

[0011] A signal processing component is used to process the electrical signal to obtain the photon counting result corresponding to the optical signal;

[0012] A processor, the processor being configured to determine the detection result of the reaction solution based on the photon counting result;

[0013] The photomultiplier tube includes a cathode, a photoelectron focusing electrode, N dynodes, and an anode arranged sequentially, where N is an integer greater than or equal to 3. The voltage divider circuit includes an input node, an output node, and N+1 voltage divider nodes arranged sequentially between the input node and the output node. Along the direction from the input node to the output node, the N+1 voltage divider nodes are sequentially named voltage divider node 1, voltage divider node 2… voltage divider node N, and voltage divider node N+1. The input node is connected to the cathode, and the output node is connected to… The anode is described above. The N+1 voltage divider nodes are sequentially connected to the photoelectron focusing electrode and the N multiplier electrodes. Each pair of adjacent nodes among the input node, the N+1 voltage divider nodes, and the output node forms a voltage divider branch, for a total of N+2 voltage divider branches. Along the direction from the input node to the output node, the N+2 voltage divider branches are sequentially voltage divider branch 1, voltage divider branch 2, ..., voltage divider branch N+1, voltage divider branch N+2. Each voltage divider node and the output node correspond to a voltage divider.

[0014] In the voltage divider circuit, at least one of the voltage dividers corresponding to the output node, the voltage divider corresponding to voltage divider node N+1, and the voltage divider corresponding to voltage divider node N is configured to be less than the voltage dividers corresponding to the other voltage divider nodes.

[0015] The sample analyzer, photometer, and photometric system provided in the above embodiments, by configuring the voltage divider corresponding to the input terminal node in the voltage divider circuit, the voltage divider corresponding to voltage divider node N+1, and the voltage divider corresponding to voltage divider node N, at least one of which is less than the voltage divider corresponding to other voltage divider nodes, can not only achieve more voltage distribution to the cathode and reduce the total secondary electron emission coefficient of the photomultiplier tube, but also, when the light intensity increases, due to the voltage redistribution caused by the dynode current, the voltage of the subsequent electrode is smaller, resulting in less voltage distribution from the subsequent electrode to the preceding electrode, making the increase of the total secondary electron emission coefficient of the photomultiplier tube more slow. Therefore, the light intensity required for the output current of the photomultiplier tube to reach the saturation inflection point can be increased, thereby increasing the light intensity measurement range of the sample analyzer. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 is a schematic diagram of a pulse accumulation phenomenon;

[0018] Figure 2 is a system framework diagram of a dual-channel synchronous detection method;

[0019] Figure 3 is a graph showing the relationship between the output current and luminous flux of a photomultiplier tube provided by related technologies.

[0020] Figure 4 is a schematic block diagram of a sample analyzer provided in this application;

[0021] Figure 5 is a schematic block diagram of another sample analyzer provided in this application;

[0022] Figure 6 is a schematic diagram of the structure of a sample analyzer provided in this application;

[0023] Figure 7 is a circuit diagram of a photometric system provided in an embodiment of this application;

[0024] Figure 8 is a circuit structure diagram of a voltage divider circuit and a photomultiplier tube provided in an embodiment of this application;

[0025] Figure 9 is a circuit diagram of a sample analyzer provided in an embodiment of this application;

[0026] Figure 10 is a circuit diagram of another voltage divider circuit and photomultiplier tube provided in an embodiment of this application;

[0027] Figure 11 is a circuit diagram of another voltage divider circuit and photomultiplier tube provided in an embodiment of this application;

[0028] Figure 12 is a circuit diagram of another voltage divider circuit and photomultiplier tube provided in an embodiment of this application;

[0029] Figure 13 is a circuit structure diagram of another voltage divider circuit and photomultiplier tube provided in an embodiment of this application;

[0030] Figure 14 is a circuit diagram of a photometer provided in an embodiment of this application;

[0031] Figure 15 is a circuit diagram of another voltage divider circuit and photomultiplier tube provided in an embodiment of this application;

[0032] Figure 16 is a circuit structure diagram of another voltage divider circuit and photomultiplier tube provided in an embodiment of this application;

[0033] Figure 17 is a circuit structure diagram of another voltage divider circuit and photomultiplier tube provided in an embodiment of this application;

[0034] Figure 18 shows an equal voltage division circuit in related technologies;

[0035] Figure 19 shows a tapered voltage divider circuit in the related technology;

[0036] Figure 20 is a schematic diagram of the light intensity measurement range of an inverse conical voltage divider circuit, an equal voltage divider circuit, and a conical voltage divider circuit provided in the embodiments of this application;

[0037] Figure 21 is a schematic diagram of the corresponding light intensity measurement ranges of the tapered voltage divider circuit, the equal voltage divider circuit, and the various inverse tapered voltage divider circuits provided in the embodiments of this application. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of this application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to this application are not shown or described in the specification. This is to avoid obscuring the core parts of this application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0039] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0040] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0041] With the continuous development of immunoassay reagents, higher requirements are being placed on the measurement range of photometric systems. Traditional PMT counting modes suffer from pulse accumulation at high light intensities, making them unsuitable for measuring high light intensity. As shown in Figure 1, as light intensity increases, the number of pulses per unit time increases, causing the counting system to identify two pulses as one, thus failing to measure high light intensity.

[0042] To improve the photometric range of photomultiplier tubes (PMTs), some manufacturers have used the PMT's DC channel in addition to the PMT's counting channel to further enhance the measurement range, as shown in Figure 2. By integrating the PMT counting mode and DC mode, the counting channel is used to detect weak light, while the DC channel is used to detect strong light. The counting results from the two channels are then integrated and output, thereby improving the PMT's measurement range.

[0043] Please refer to Figure 3, which is a graph showing the relationship between the output current and luminous flux of a photomultiplier tube (PMT) in related technologies. In Figure 3, the horizontal axis represents the incident light intensity, and the vertical axis represents the ratio of the output current to the voltage divider current (i.e., the voltage divider current). During PMT DC mode output, as the luminous flux incident on the cathode of the PMT increases, the output current of the PMT also increases, as shown in section A of Figure 3. Continuing to increase the incident luminous flux, the output current of the PMT deviates from the ideal linear relationship with the incident light intensity, as shown in section B of Figure 3. Further increasing the incident luminous flux eventually leads to saturation of the PMT output current, as shown in section C of Figure 3. Therefore, in the existing PMT DC mode, the output current of the PMT easily reaches saturation with increasing luminous flux, thus preventing further improvement in the luminous intensity measurement range of the PMT.

[0044] Therefore, embodiments of this application provide a sample analyzer, a photometer, and a photometric system. By configuring the voltage divider at the input node of the voltage divider circuit, and at least one of the voltage dividers at the last two voltage divider nodes being less than the voltage dividers at the other voltage divider nodes, not only can more voltage be distributed to the cathode, reducing the overall secondary electron emission coefficient of the photomultiplier tube, but also, when the light intensity increases, due to the voltage redistribution caused by the dynode current, the voltage of the subsequent electrode is smaller, resulting in less voltage being distributed from the subsequent electrode to the preceding electrode. This makes the increase in the overall secondary electron emission coefficient of the photomultiplier tube more slow, thus increasing the light intensity required for the photomultiplier tube's output current to reach the saturation inflection point, thereby increasing the light intensity measurement range of the sample analyzer. The working principle of the sample analyzer and how to increase the light intensity measurement range will be explained in detail below.

[0045] This application discloses a sample analyzer in some embodiments. Referring to FIG4, in one embodiment, the sample analyzer may include a sample component 10, a reagent component 20, a measurement component 30, and a processor 40; in some embodiments, referring to FIG5, the sample analyzer may also include a display component 50. The details are described below.

[0046] The sample component 10 carries the sample to be tested and provides it to the measurement component 30 after aspirating the sample. Referring to Figure 6, in some embodiments, the sample component 10 may include a sample carrying component 11 and a sample dispensing mechanism 12. The sample carrying component 11 carries the sample. In some examples, the sample carrying component 11 may include a sample delivery module (SDM) and a front-end track; in other examples—such as Figure 6—the sample carrying component 11 may also be a sample tray, which includes multiple sample positions for placing sample tubes. By rotating its tray structure, the sample tray can be moved to the corresponding position, such as the position for the sample dispensing mechanism 12 to aspirate the sample. The sample dispensing mechanism 12 aspirates the sample and dispenses it into the reaction cup to be added. For example, the sample dispensing mechanism 12 may include a sample needle, which moves in two or three dimensions in space via a two-dimensional or three-dimensional drive mechanism, thereby moving the sample needle to aspirate the sample carried by the sample carrying component 11, and to move to the reaction cup to be added, and dispense the sample into the reaction cup.

[0047] The reagent component 20 is used to carry reagents and, after aspirating the reagents, provides them to the measuring component 30. In some embodiments, the reagent component 20 may include a reagent carrying component 13 and a reagent dispensing mechanism 14. The reagent carrying component 13 is used to carry reagents. In one embodiment, the reagent carrying component 13 may be a reagent tray, which is arranged in a disc-shaped structure and has multiple positions for carrying reagent containers. The reagent carrying component 13 is rotatable and drives the reagent containers it carries to rotate, for rotating the reagent containers to a specific position, such as the position where the reagent dispensing mechanism 14 aspirates the reagents. The number of reagent carrying components 13 may be one or more. The reagent dispensing mechanism 14 is used to aspirate the reagents and discharge them into a reaction cup to which the reagents are to be added. In one embodiment, the reagent dispensing mechanism 14 may include a reagent needle, which is driven by a two-dimensional or three-dimensional mechanism to move in two-dimensional or three-dimensional space, so that the reagent needle can move to aspirate the reagents carried by the reagent carrying component 13, move to the reaction cup to which the reagents are to be added, and discharge the reagents into the reaction cup.

[0048] The measuring component 30 is used to perform project testing on the sample to obtain test data for the project. In some embodiments, the measuring component 30 may include a reaction component 15 and a photometric component 16. The reaction component 15 has at least one placement position for placing a reaction cup and incubating the reaction liquid in the reaction cup. For example, the reaction component 15 can be a reaction disk, which is arranged in a disk-shaped structure and has one or more placement positions for placing reaction cups. The reaction disk can rotate and drive the reaction cups in its placement positions to rotate, for distributing the reaction cups and incubating the reaction liquid in the reaction cups within the reaction disk. The photometric component 16 is used to perform photometric measurements on the incubated reaction liquid to obtain the reaction data of the sample. For example, the photometric component 16 detects the luminescence intensity of the reaction liquid to be tested and calculates the concentration of the analyte in the sample through a calibration curve. In one embodiment, the photometric component 16 is disposed outside the reaction component 15.

[0049] Please refer to Figure 7, which is a circuit diagram of a photometric system 1000 provided in an embodiment of this application. As shown in Figure 7, the photometric system 1000 may include a light source 100, a photomultiplier tube 200, a voltage divider circuit 300, a signal processing component 400, and a processor 500. The light source 100 generates illumination light to irradiate the reaction liquid in the reaction vessel. The photomultiplier tube 200 converts the light signal generated by the irradiation of the reaction liquid into an electrical signal. The voltage divider circuit 300 provides a driving voltage to the photomultiplier tube 200. The signal processing component 400 processes the electrical signal to obtain the photon count result corresponding to the light signal. The processor 500 determines the detection result of the reaction liquid based on the photon count result. The voltage divider circuit 300 is also referred to as a driving voltage divider circuit in this application.

[0050] Referring to Figure 8, in some embodiments, the photomultiplier tube 200 includes a cathode (K-electrode), a photoelectron focusing electrode (F-electrode), N dynodes, and an anode (P-electrode) arranged sequentially, where N is an integer greater than or equal to 3. The voltage divider circuit 300 includes an input node (IN node), an output node (OUT node), and N+1 voltage divider nodes arranged sequentially between the input node and the output node. Along the direction from the input node to the output node, the N+1 voltage divider nodes are voltage divider node 1, voltage divider node 2... voltage divider node N, voltage divider node N+1. The input node is connected to the cathode, and the output node is connected to the anode. The input node, N+1 voltage divider nodes, and output node are sequentially connected to the photoelectron focusing electrode and N multiplier electrodes. Each pair of adjacent nodes forms a voltage divider branch, resulting in a total of N+2 voltage divider branches. Along the direction from the input node to the output node, the N+2 voltage divider branches are sequentially named voltage divider branch 1, voltage divider branch 2… voltage divider branch N+1, voltage divider branch N+2. Each voltage divider node and output node corresponds to a voltage divider. In the voltage divider circuit 300, at least one of the voltage dividers corresponding to the output node, the voltage divider corresponding to voltage divider node N+1, and the voltage divider corresponding to voltage divider node N is configured to be lower than the voltage dividers corresponding to the other voltage divider nodes. For ease of explanation, this embodiment uses N=5 as an example.

[0051] The basic characteristics of the PMT-based voltage divider circuit will be explained in detail below with reference to Figure 8. As shown in Figure 8, the input node (IN node) of the voltage divider circuit 300 is connected to the cathode K of the photomultiplier tube 200, and the output node (OUT node) of the voltage divider circuit 300 is connected to the anode (P electrode) of the photomultiplier tube 200. N+1 voltage divider nodes are sequentially arranged between the input and output nodes, and these N+1 voltage divider nodes are sequentially connected to the photoelectron focusing electrode F and N dynodes (e.g., DY1, DY2, DY3, ...) of the photomultiplier tube 200. A resistor is provided between any two adjacent nodes in the voltage divider circuit 300. The actual current I flowing through resistor R7 is... R7 It is the voltage divider current I b And the anode current I flowing in the opposite direction through the P-Dy5-R7-P circuit p The difference is shown in equation (1); the current flowing through the other resistors is the voltage divider current I. b And the multiplier current I flowing through the resistor in the opposite direction from each multiplier electrode Dy(2,3,4,5,6) The difference is shown in equation (2). R7 =I b -I p (1) I R(2,3,4,5,6) =I b -I Dy(2,3,4,5,6) (2)

[0052] in,

[0053] As shown in Figure 8, due to the anode current I p Multiplier current I Dy(2,3,4,5,6) With voltage divider current I b They cancel each other out, therefore, with the increase of incident light intensity, the multiplier current I... Dy(2,3,4,5,6) The inter-electrode voltage of the later stages of the dynodes decreases significantly. Since the voltage supplied to the cathode-anode by the high-voltage power supply is constant, the decrease in voltage of the later stages leads to an increase in the inter-electrode voltage of the preceding stages. The decrease in inter-electrode voltage caused by the amplified electron flow of the dynodes is most significant between the final dynode (Dy5 in Figure 8) and the anode. However, the voltage between the final dynode and the anode is unrelated to the secondary electron emission coefficient of the final dynode, but it affects the voltage distribution before the final dynode, as shown in section B of Figure 3, indicating an increase in the overall electron multiplication rate. As the incident light flux further increases, the voltage between the final dynode and the anode decreases, leading to a decrease in the secondary electron collection rate of the anode, eventually reaching the saturation phenomenon shown in section C of Figure 3. Due to the above dynode current I... Dy(2,3,4,5,6) The presence of this characteristic means that the output DC of the PMT eventually saturates as the light intensity increases, thus limiting the PMT's measurement range. Based on the fundamental characteristics of PMT-based voltage divider circuits, this application proposes an inverse-cone driving voltage divider circuit. By utilizing this circuit, the DC measurement range of the PMT can be significantly improved, thereby increasing the light intensity required for the photomultiplier tube's output current to reach the saturation inflection point, i.e., raising the upper limit of the photomultiplier tube's light intensity measurement. It can be understood that the voltage of the final multiplier stage corresponds to the voltage of the last voltage divider node, i.e., voltage divider node N+1 (voltage divider node 6 in Figure 8), and the voltage of the anode corresponds to the voltage of the output node (node ​​OUT in Figure 8).

[0054] The principle of the inverse cone drive voltage divider circuit provided in the embodiments of this application to improve the light intensity measurement range will be explained in detail below.

[0055] Please refer to Figure 9, which is a circuit diagram of a sample analyzer 2000 provided in an embodiment of this application. As shown in Figure 9, the sample analyzer 2000 includes a light source 100, a photometer 600, and a processor 500. The light source 100 is used to generate illumination light to irradiate the reaction liquid in the reaction vessel. The photometer 600 includes a photoelectric conversion component 401 and a signal processing component 400. The photoelectric conversion component 401 is used to convert the light signal generated by the irradiation of the reaction liquid into an electrical signal. The signal processing component 400 is used to process the electrical signal to obtain the photon count result corresponding to the light signal. The processor 500 is used to determine the detection result of the reaction liquid based on the photon count result.

[0056] Referring to Figure 9, the photoelectric conversion component 401 includes a photomultiplier tube 200 and a voltage divider circuit 300. The photomultiplier tube 200 includes a cathode (K-electrode), a photoelectromagnetic focusing electrode (F-electrode), N dynodes, and an anode (P-electrode) arranged sequentially, where N is an integer greater than or equal to 3. The voltage divider circuit 300 includes an input node (IN node), an output node (OUT node), and N+1 voltage divider nodes arranged sequentially between the input node and the output node. Along the direction from the input node to the output node, the N+1 voltage divider nodes are voltage divider node 1, voltage divider node 2... voltage divider node N, and voltage divider node N+1. The input node of the voltage divider circuit 300 is connected to the cathode, the output node of the voltage divider circuit 300 is connected to the anode, and the N+1 voltage divider nodes are respectively connected sequentially to the photoelectromagnetic focusing electrode (F-electrode) and the N dynodes (e.g., DY1, DY2, DY3, ...) of the photomultiplier tube 200.

[0057] The F electrode is used to accelerate and focus the photoelectrons generated by the K electrode into a beam. The input node, the N+1 voltage divider nodes, and the nodes between every two adjacent nodes in the output node form a voltage divider branch, for a total of N+2 voltage divider branches. Along the direction from the input node to the output node, the N+2 voltage divider branches are sequentially named voltage divider branch 1, voltage divider branch 2… voltage divider branch N+1, voltage divider branch N+2. Each voltage divider node and the output node each correspond to a voltage divider. In the voltage divider circuit, at least one of the voltage dividers corresponding to the output node, the voltage divider corresponding to voltage divider node N+1, and the voltage divider corresponding to voltage divider node N is configured to be lower than the voltage dividers corresponding to the other voltage divider nodes.

[0058] For example, as shown in Figure 9, when the photomultiplier tube 200 has 5 dynodes, the voltage divider circuit 300 has 6 voltage divider nodes. At least one of the voltage dividers corresponding to the output node, the voltage divider corresponding to voltage divider node 6, and the voltage divider corresponding to voltage divider node 5 is configured to be lower than the voltage dividers corresponding to the other voltage divider nodes. That is, the voltage across at least one of the voltage divider branches 5, 6, and 7 is configured to be lower than the voltage across the other voltage divider branches.

[0059] As shown in Figure 9, the 4th to 6th voltage divider nodes in the voltage divider circuit are connected to ground in sequence through decoupling capacitors C1, C2, and C3. Specifically, one end of the decoupling capacitors C1, C2, and C3 is grounded, and the other end is connected to their corresponding voltage divider nodes to further reduce the influence of pulse signals on the inter-electrode voltage of the voltage divider circuit.

[0060] In the above embodiment, by configuring at least one of the voltage dividers corresponding to the input terminal node in the voltage divider circuit 300, the voltage divider corresponding to voltage divider node N+1, and the voltage divider corresponding to voltage divider node N to be less than the voltage dividers corresponding to other voltage divider nodes, it is possible not only to distribute more voltage to the cathode and reduce the total secondary electron emission coefficient of the photomultiplier tube 200, but also, when the light intensity increases, due to the voltage redistribution caused by the dynode current, the voltage of the subsequent electrode is smaller, resulting in less voltage being distributed from the subsequent electrode to the preceding electrode. This makes the increase in the total secondary electron emission coefficient of the photomultiplier tube 200 more slow. Therefore, the light intensity required for the output current of the photomultiplier tube 200 to reach the saturation inflection point can be increased, that is, the upper limit of the linear range is increased, thereby increasing the light intensity measurement range of the sample analyzer 2000.

[0061] In the embodiments of this application, the subsequent electrode refers to the anode, the Nth dynode, and the (N-1)th dynode, and the preceding electrode refers to the cathode (K electrode), the photoelectron focusing electrode (F electrode), and the first to the (N-2)th dynodes. Alternatively, the subsequent electrode refers to the anode and the Nth dynode, and the preceding electrode refers to the cathode (K electrode), the photoelectron focusing electrode (F electrode), and the first to the (N-1)th dynodes.

[0062] It should be noted that due to the special structure of the first stage (KF electrode) and the last stage (DY5-P electrode) of the photomultiplier tube 200, changing the voltage division in the voltage divider circuit 300 can significantly affect the output current of the photomultiplier tube 200. Furthermore, the inter-electrode voltage of the first stage (KF electrode) has no relation to the secondary electron emission coefficient of the first dynode (DY1); the first stage (KF electrode) is only responsible for collecting photoelectrons to the photoelectron focusing electrode (F electrode). Similarly, the electric field strength of the last stage (DY5-P electrode) has no relation to the secondary electron emission coefficient of the last dynode (DY5); the last stage (DY5-P electrode) is only responsible for collecting secondary electrons to the anode (P electrode). Therefore, without changing the negative high voltage -HV, the larger the voltage division of the first stage (KF electrode) and the last stage (DY5-P electrode), the smaller the cumulative secondary electron emission coefficient of the photomultiplier tube 200. In this embodiment, the inverse cone drive voltage divider circuit increases the voltage division of the first stage (KF pole) by changing the resistor ratio, thereby reducing the accumulation of the secondary electron reflection coefficient. Meanwhile, as shown in formula (1), the maximum output DC of the photomultiplier tube 200 is the DC current flowing through I... R7 When the current is approximately zero, that is, when the maximum output current is approximately equal to the voltage divider current I. bSince the maximum output current is essentially fixed, by reducing the cumulative secondary electron emission coefficient of the photomultiplier tube 200, a greater light intensity is required for the photomultiplier tube 200 to reach its maximum output current, thereby increasing the measurement light intensity range of the photomultiplier tube 200. As shown in Figure 9, the voltage divider of the last stage (DY5-P pole) corresponds to the voltage between voltage divider node 6 and the output node (OUT), i.e., the voltage across voltage divider branch 7. The voltage divider of the first stage (KF pole) corresponds to the voltage between the input node (IN) and voltage divider node 1, i.e., the voltage across voltage divider branch 1.

[0063] It is understood that the reason for not increasing the voltage divider of the last stage (DY5-P electrode) in this embodiment is that: when the light intensity is high, the dynode current of the last stage (DY5-P electrode) is the largest, the voltage between the electrodes of the subsequent stage of the voltage divider circuit 300 decreases, and since the total voltage of the voltage divider circuit 300 remains unchanged, the increased voltage divider of the last stage (DY5-P electrode) will be redistributed to the preceding dynodes, resulting in a significant increase in the overall multiplication factor of the photomultiplier tube when the light intensity increases. Increasing the voltage divider of the first stage (KF electrode) will not result in a significant increase in the overall multiplication factor of the photomultiplier tube 200 when the light intensity increases, since the dynode current of the first stage (KF electrode) is the smallest. Furthermore, the voltage division of the first stage (KF electrode) should not be increased too much. This is because if the electric field strength of two adjacent stages differs too much, it will weaken the anti-interference performance of the output stability of the photomultiplier tube 200. Also, if the light intensity is measured using a combination of counting and DC, and it is not desired to significantly change the luminous efficiency (count value / light intensity) of the counting mode, then the voltage division of the first stage (KF electrode) should not be increased too much.

[0064] In this embodiment, the principle of reducing the voltage division of the last stage (DY5-P pole) in the voltage divider circuit 300 is as follows: As the light intensity gradually increases, the current of the subsequent electrode increases, causing the inter-electrode voltage of the subsequent electrode to decrease. At the same time, since the total voltage of the voltage divider circuit 300 remains constant at -HV, the voltage of the voltage divider circuit 300 will be redistributed when the light intensity increases, with the first few stages having a larger voltage division and the last few stages having a smaller voltage division. Furthermore, since the last stage (DY5-P pole) has no relation to the secondary electron emission coefficient of the final stage dynode, the voltage of the last stage (DY5-P pole) is redistributed to the previous stages when the light intensity increases, which will significantly increase the total secondary electron emission coefficient of the photomultiplier tube 200. Therefore, by reducing the voltage division of the last stage (DY5-P pole), less voltage is redistributed to the previous stages when the light intensity increases, making the increase in the total secondary electron emission coefficient of the photomultiplier tube slower, thereby delaying the DC saturation inflection point of the photomultiplier tube 200. At the same time, the partial voltage of the last stage (DY5-P electrode) should not be too small. It should be appropriately reduced without affecting the secondary electron collection rate of the last doubling electrode.

[0065] The principle behind reducing the voltage division of the penultimate stage in the voltage divider circuit 300 is as follows: First, more voltage is distributed to the first stage (KF electrode), reducing the overall secondary electron emission coefficient of the photomultiplier tube 200. Second, as light intensity increases, the voltage of the subsequent stage is distributed to the preceding stage. The less voltage the subsequent stage receives, the smaller the voltage distribution due to the voltage redistribution caused by the multiplier stage current when light intensity increases. This results in less voltage being distributed from the subsequent stage electrode to the preceding stage electrode, making the increase in the overall secondary electron emission coefficient of the photomultiplier tube 200 more slow. Therefore, the light intensity required for the output current of the photomultiplier tube 200 to reach the saturation inflection point can be increased, thereby increasing the light intensity measurement range of the sample analyzer 2000. It should be noted that the penultimate stage refers to the multiplier N, and the voltage division of the penultimate stage refers to the voltage between the multiplier N-1 and the multiplier N, also known as the voltage between voltage divider node N and voltage divider node N+1, or the voltage across voltage divider branch N+1. As shown in Figure 9, the voltage divider in the penultimate stage refers to the voltage between voltage divider nodes 5 and 6. The preceding stage can be understood as the multiplier electrode before the penultimate stage, for example, multiplier 1 to multiplier N-2, and the following stage can be understood as the electrode after the penultimate stage, such as the anode.

[0066] In some embodiments, each voltage divider branch includes at least one voltage divider resistor.

[0067] For example, referring to Figure 9, each voltage divider branch includes a voltage divider resistor. For instance, voltage divider branch 1 includes resistor R1, voltage divider branch 2 includes resistor R2, voltage divider branch 3 includes resistor R3, voltage divider branch 4 includes resistor R4, voltage divider branch 5 includes resistor R5, voltage divider branch 6 includes resistor R6, and voltage divider branch 7 includes resistor R7.

[0068] It should be noted that by configuring at least one voltage divider resistor in each voltage divider branch, since the resistance value is positively correlated with the voltage, it is possible to set the voltage across each voltage divider branch using the voltage divider resistor.

[0069] In some embodiments, the resistance value corresponding to voltage divider branch N+2 is configured to be less than the resistance values ​​corresponding to voltage divider branches 2 to N+1 respectively.

[0070] For example, as shown in Figure 9, when N is 5, the resistance value corresponding to voltage divider branch 7 is configured to be less than the resistance values ​​corresponding to voltage divider branches 2 to 6. Specifically, when the resistance value corresponding to voltage divider branch 7 is configured to be less than the resistance values ​​corresponding to voltage divider branches 2 to 6, the voltage across the output node is less than the voltage across the other voltage divider nodes; that is, the voltage across voltage divider branch 7 is less than the voltage across the other voltage divider branches.

[0071] It should be noted that since voltage divider branch 7 is the last stage (DY5-P pole) voltage divider branch in voltage divider circuit 300, the last stage (DY5-P pole) voltage divider branch has no relation to the secondary electron emission coefficient of the final stage dynode. Therefore, by reducing the resistance of voltage divider branch 7, the voltage redistributed to the previous stage can be reduced when the light intensity increases, so that the total secondary electron emission coefficient of photomultiplier tube 200 increases more slowly, thereby delaying the DC saturation inflection point of photomultiplier tube 200.

[0072] In some embodiments, the resistance values ​​corresponding to voltage divider branches 2 to N+1 are configured to be the same.

[0073] For example, as shown in Figure 9, when N is 5, the resistance values ​​of voltage divider branches 2 to 6 are configured to be the same, that is, the resistance values ​​of resistors R2, R3, R4, R5, and R6 are the same.

[0074] In the above embodiment, by configuring the voltage divider branches 2 to N+1 to have the same resistance value, the voltage on the voltage divider branch N+2 can be evenly distributed to the voltage divider branches 2 to N+1 when the light intensity increases, so that the total secondary electron emission coefficient of the photomultiplier tube 200 increases more slowly, thereby delaying the DC saturation inflection point of the photomultiplier tube.

[0075] In some embodiments, the resistance value corresponding to voltage divider branch N+2 is configured to be greater than the resistance value corresponding to voltage divider branch N+1, and less than the resistance values ​​corresponding to voltage divider branches 2 to N respectively.

[0076] For example, when N is 5, the resistance value corresponding to voltage divider branch 7 is greater than the resistance value corresponding to voltage divider branch 6, but the resistance values ​​corresponding to voltage divider branch 7 and voltage divider branch 6 are both less than the resistance values ​​corresponding to voltage divider branches 2 to 5 respectively.

[0077] In the above embodiment, by configuring the resistance value corresponding to voltage divider branch N+2 to be greater than the resistance value corresponding to voltage divider branch N+1, and less than the resistance values ​​corresponding to voltage divider branches 2 to N respectively, more voltage can be distributed to the first stage (KF electrode) on voltage divider branch N+1, reducing the overall secondary electron emission coefficient of photomultiplier tube 2000. Moreover, when the light intensity increases, the voltage distributed to the front electrode is less due to the smaller voltage of voltage divider branch N+1, making the increase of the overall secondary electron emission coefficient of photomultiplier tube 2000 more slow. Therefore, the light intensity required for the output current of photomultiplier tube 200 to reach the saturation inflection point can be increased, thereby increasing the light intensity measurement range of sample analyzer 2000.

[0078] In some embodiments, the resistance value corresponding to voltage divider branch N+1 is equal to the resistance value corresponding to voltage divider branch N+2, and the resistance values ​​corresponding to voltage divider branch N+1 and voltage divider branch N+2 are both less than the resistance values ​​corresponding to voltage divider branches 2 to N respectively.

[0079] For example, when N is 5, the resistance value corresponding to voltage divider branch 7 is equal to the resistance value corresponding to voltage divider branch 6, but the resistance values ​​corresponding to voltage divider branch 7 and voltage divider branch 6 are both less than the resistance values ​​corresponding to voltage divider branches 2 to 5 respectively.

[0080] In the above embodiment, by configuring the resistance value corresponding to voltage divider branch N+1 to be equal to the resistance value corresponding to voltage divider branch N+2, and the resistance values ​​corresponding to voltage divider branches N+1 and N+2 are both less than the resistance values ​​corresponding to voltage divider branches 2 to N respectively, it can be achieved that when the light intensity increases, the voltage on voltage divider branches N+1 and N+2 is small, resulting in less voltage being distributed to the front electrode. This makes the increase in the total secondary electron emission coefficient of photomultiplier tube 200 more slow. Therefore, the light intensity required for the output current of photomultiplier tube 200 to reach the saturation inflection point can be increased, thereby increasing the light intensity measurement range of sample analyzer 2000.

[0081] In some embodiments, the resistance values ​​of the N+2 voltage divider branches decrease along the direction from the input node to the output node.

[0082] Please refer to Table 1. In the voltage divider circuit 300, the cathode corresponds to stage 0, the first dynode corresponds to stage 1, and so on. The nth dynode corresponds to stage n, where n is the total number of dynodes. The anode corresponds to stage n+1. That is, voltage divider branch 1 corresponds to stage 0, voltage divider branch 2 corresponds to stage 1, voltage divider branch 3 corresponds to stage 2, and voltage divider branch N+2 corresponds to stage n+1.

[0083] Table 1

[0084] For example, as shown in Table 1, when the resistance values ​​of voltage divider branch 1, voltage divider branch 2, ... voltage divider branch N+1, voltage divider branch N+2 are 3R, 1R, 1R, 1R...0.5R, 0.7R respectively, the slope corresponding to each voltage divider branch can be calculated according to the least multiplicative linear slope formula. If the slope corresponding to each voltage divider branch is less than the preset slope value, it can be determined that the resistance values ​​of the N+2 voltage divider branches decrease along the direction from the input node to the output node.

[0085] The formula for the least-multiplication linear slope is:

[0086] In the formula, K represents the slope, i represents the i-th voltage-dividing branch, and x iLet y represent the number of stages corresponding to the i-th voltage divider branch. i This represents the resistance value corresponding to the i-th voltage divider branch. The preset slope value can be set according to the actual situation, and the specific value is not limited here. In some implementations, the preset slope value can be 0. If the slope K corresponding to each voltage divider branch is less than 0, it can be determined that the resistance values ​​corresponding to the N+2 voltage divider branches decrease along the direction from the input node to the output node.

[0087] In the above embodiment, by configuring the resistance values ​​of the N+2 voltage divider branches to decrease along the direction from the input node to the output node, it is possible to achieve a slower increase in the total secondary electron emission coefficient of the photomultiplier tube 200 when the light intensity increases, because the voltage of the subsequent electrode is smaller, resulting in less voltage being distributed to the preceding electrode. This allows the light intensity required for the output current of the photomultiplier tube 200 to reach the saturation inflection point to be increased, thereby increasing the light intensity measurement range of the sample analyzer 2000.

[0088] In some embodiments, the resistance values ​​of the last M voltage divider branches in the N+2 voltage divider branches each decrease along the direction from the input node to the output node, wherein M is less than or equal to (N+1) / 2.

[0089] For example, when N is 5, the resistance values ​​of voltage divider branches 5, 6, and 7 decrease along the direction from the input node to the output node, and the resistance values ​​of voltage divider branches 2, 3, and 4 can be the same or different.

[0090] In the above embodiment, by configuring the resistance values ​​of the last M voltage divider branches in the N+2 voltage divider branches to decrease along the direction from the input node to the output node, the voltage across the last M voltage divider branches can be gradually reduced. This results in a smaller voltage distribution to the front electrode when the light intensity increases, due to the smaller voltage on the rear electrode. Consequently, the overall secondary electron emission coefficient of the photomultiplier tube 200 increases more slowly. Therefore, the light intensity required for the output current of the photomultiplier tube 200 to reach the saturation inflection point can be increased, thereby increasing the light intensity measurement range of the sample analyzer 2000.

[0091] In some embodiments, the resistance values ​​corresponding to voltage divider branch N+1 and N+2 are both less than the resistance values ​​corresponding to voltage divider branches 2 to N respectively, and the minimum resistance value corresponding to voltage divider branch N+1 and / or the minimum resistance value corresponding to voltage divider branch N+2 is 0.2 times the minimum resistance value corresponding to voltage divider branches 2 to N respectively.

[0092] For example, when the minimum resistance value corresponding to each of voltage divider branches 2 to N is represented as R, the minimum resistance value corresponding to voltage divider branch N+1 and / or the minimum resistance value corresponding to voltage divider branch N+2 can be 0.2R. For example, the minimum resistance value corresponding to voltage divider branch N+1 is 0.5R, and the minimum resistance value corresponding to voltage divider branch N+2 is 0.5R. As another example, the minimum resistance value corresponding to voltage divider branch N+1 is 0.7R, and the minimum resistance value corresponding to voltage divider branch N+2 is 0.7R.

[0093] In the above embodiment, by configuring the resistance values ​​corresponding to voltage divider branch N+1 and N+2 to be smaller than the resistance values ​​corresponding to voltage divider branches 2 to N respectively, and the minimum resistance value corresponding to voltage divider branch N+1 and / or the minimum resistance value corresponding to voltage divider branch N+2 to N respectively to be 0.2 times the minimum resistance value corresponding to voltage divider branches 2 to N respectively, the voltage across voltage divider branches N+1 and N+2 can be much smaller than the voltage across each voltage divider branch from 2 to N. This ensures that when the light intensity increases, the voltage across voltage divider branches N+1 and N+2 is smaller, resulting in less voltage being distributed to the front electrode. Consequently, the overall secondary electron emission coefficient of photomultiplier tube 200 increases more slowly. Therefore, the light intensity required for the output current of photomultiplier tube 200 to reach the saturation inflection point can be increased, thereby increasing the light intensity measurement range of sample analyzer 2000.

[0094] In some embodiments, at least one of the voltage divider branches N to N+2 includes at least one diode, and each of the voltage divider branches 1 to N-1 includes at least one voltage divider resistor.

[0095] For example, when N is 5, at least one of the voltage divider branches 5, 6, and 7 includes at least one diode, and each of the voltage divider branches 1 to 4 includes at least one voltage divider resistor. Referring to Figure 10, voltage divider branch 6 includes diode Z6, and voltage divider branch 7 includes diode Z7.

[0096] It should be noted that in the embodiments of this application, a diode can be used instead of a voltage divider resistor, which can also make the total secondary electron emission coefficient of the photomultiplier tube 200 increase more slowly, thus increasing the light intensity required for the output current of the photomultiplier tube 200 to reach the saturation inflection point.

[0097] In some embodiments, the voltage divider branch N+2 includes at least one diode, and the voltages of the N+1 voltage divider nodes and the output node decrease along the direction from the input node to the output node.

[0098] For example, please refer to Figure 11. When N is 5, voltage divider branch 7 includes diode Z7, voltage divider branches 1 to 6 all include voltage divider resistors, and the voltages corresponding to the 6 voltage divider nodes and the output node decrease along the direction from the input node to the output node. That is, the voltage corresponding to the output node is less than the voltages corresponding to the 6 voltage divider nodes.

[0099] For example, the slope of the voltage corresponding to each of the N+1 voltage divider nodes and the output node can be calculated using the least multiplication linear slope formula. If the slope of the voltage corresponding to each of the N+1 voltage divider nodes and the output node is less than 0, it can be determined that the voltage of each of the N+1 voltage divider nodes and the output node decreases along the direction from the input node to the output node.

[0100] In the above embodiment, by configuring the voltage divider branch N+2 to include at least one diode, it can be ensured that the voltage on the voltage divider branch N+2 remains at a certain value. By configuring the voltage dividers corresponding to the N+1 voltage divider nodes and the output terminal nodes to decrease along the direction from the input terminal node to the output terminal node, when the light intensity increases, the voltage on the voltage divider branch N+2 is small, resulting in less voltage being distributed to the front electrode. This makes the increase in the total secondary electron emission coefficient of the photomultiplier tube 200 more slow. Therefore, the light intensity required for the output current of the photomultiplier tube 200 to reach the saturation inflection point can be increased, thereby increasing the light intensity measurement range of the sample analyzer 2000.

[0101] In some embodiments, voltage divider branch N+2 includes at least one diode, and at least one of voltage divider branch N+1 and voltage divider branch N includes at least one diode, wherein the reverse voltage of the diode in voltage divider branch N+2 is greater than the reverse voltage of the other diodes.

[0102] As shown in Figure 10, voltage divider branch 6 includes diode Z6, voltage divider branch 7 includes diode Z7, and the reverse voltage of diode Z7 in voltage divider branch 7 is greater than the reverse voltage of diode Z6.

[0103] Please refer to Figure 12. Voltage divider branch 5 includes diode Z5, voltage divider branch 6 includes diode Z6, and voltage divider branch 7 includes diode Z7. The reverse voltage of diode Z7 in voltage divider branch 7 is greater than the reverse voltage of diodes Z5 and Z6.

[0104] For example, when the maximum reverse voltage of other diodes is 1U, the maximum reverse voltage of diode Z7 in voltage divider branch 7 is 5U.

[0105] In the above embodiment, by configuring the reverse voltage of the diode in the voltage divider branch N+2 to be greater than the reverse voltage of the other diodes, when the light intensity increases, since the reverse voltage of the diode in the voltage divider branch N+2 and the reverse voltage of the other diodes are all less than the voltage of the front electrode, the smaller reverse voltage of the diode in the voltage divider branch N+2 and the reverse voltage of the other diodes results in less voltage being distributed to the front electrode, making the increase of the total secondary electron emission coefficient of the photomultiplier tube 200 more slow. Therefore, the light intensity required for the output current of the photomultiplier tube 200 to reach the saturation inflection point can be increased, thereby increasing the light intensity measurement range of the sample analyzer 2000.

[0106] In some embodiments, the last M voltage divider branches in the direction from the input node to the output node of the N+2 voltage divider branches each include at least one diode, and the other voltage divider branches in the N+2 voltage divider branches each include at least one voltage divider resistor, wherein M is less than or equal to (N+1) / 2.

[0107] For example, when N is 5 and M is 3, voltage divider branch 5 includes diode Z5, voltage divider branch 6 includes diode Z6, voltage divider branch 7 includes diode Z7, and each of voltage divider branches 1 to 4 includes at least one voltage divider resistor.

[0108] In some embodiments, the voltage division corresponding to each of the N+1 voltage divider nodes and the output node decreases along the direction from the input node to the output node.

[0109] For example, the slope of the voltage corresponding to each of the N+1 voltage divider nodes and the output node can be calculated using the least multiplication linear slope formula. If the slope of the voltage corresponding to each of the N+1 voltage divider nodes and the output node is less than 0, it can be determined that the voltage of each of the N+1 voltage divider nodes and the output node decreases along the direction from the input node to the output node.

[0110] In the above embodiment, by configuring N+1 voltage divider nodes and the voltage divider corresponding to each output node to decrease along the direction from the input node to the output node, when the light intensity increases, the voltage distributed to the front electrode is less due to the smaller voltage on the rear electrode, which makes the increase of the total secondary electron emission coefficient of the photomultiplier tube 200 more slow. Therefore, the light intensity required for the output current of the photomultiplier tube 200 to reach the saturation inflection point can be increased, thereby increasing the light intensity measurement range of the sample analyzer 2000.

[0111] In some embodiments, the reverse voltage of the diode in the (N+2)th voltage divider branch is greater than the reverse voltage of the other diodes.

[0112] For example, when N is 5 and M is 3, voltage divider branch 5 includes diode Z5, voltage divider branch 6 includes diode Z6, and voltage divider branch 7 includes diode Z7. The reverse voltage of diode Z7 in voltage divider branch 7 is greater than the reverse voltage of diode Z5 and diode Z6.

[0113] In the above embodiment, by configuring the reverse voltage of the diode in the voltage divider branch N+2 to be greater than the reverse voltage of the other diodes, when the light intensity increases, since the reverse voltage of the diode in the voltage divider branch N+2 and the reverse voltage of the other diodes are all less than the voltage of the front electrode, the smaller reverse voltage of the diode in the voltage divider branch N+2 and the reverse voltage of the other diodes results in less voltage being distributed to the front electrode, making the increase of the total secondary electron emission coefficient of the photomultiplier tube 200 more slow. Therefore, the light intensity required for the output current of the photomultiplier tube 200 to reach the saturation inflection point can be increased, thereby increasing the light intensity measurement range of the sample analyzer 2000.

[0114] In some embodiments, each of the N+2 voltage divider branches includes at least one diode, and the reverse voltage of the diode in the N+2 voltage divider branch is greater than the reverse voltage of the other diodes in the last M voltage divider branches along the direction from the input node to the output node in the N+2 voltage divider branches, where M is less than or equal to (N+1) / 2.

[0115] It should be noted that each voltage divider branch in the voltage divider circuit 300 of this application embodiment can be replaced by a diode instead of a voltage divider resistor.

[0116] As shown in Figure 13, when N is 5 and M is 3, voltage divider branch 1 includes diode Z1, voltage divider branch 2 includes diode Z2, voltage divider branch 3 includes diode Z3, voltage divider branch 4 includes diode Z4, voltage divider branch 5 includes diode Z5, voltage divider branch 6 includes diode Z6, and voltage divider branch 7 includes diode Z7. The reverse voltage of diode Z7 in voltage divider branch 7 is greater than the reverse voltage of diodes Z5 and Z6.

[0117] In the above embodiment, by configuring the reverse voltage of the diode in the voltage divider branch N+2 to be greater than the reverse voltage of other diodes, when the light intensity increases, since the reverse voltage of the diodes in the last M voltage divider branches is less than the reverse voltage of other diodes, the voltage supplied to the front electrode is less, which makes the increase of the total secondary electron emission coefficient of the photomultiplier tube 200 more slow. Therefore, the light intensity required for the output current of the photomultiplier tube 200 to reach the saturation inflection point can be increased, thereby increasing the light intensity measurement range of the sample analyzer 2000.

[0118] Please refer to Figure 14, which is a circuit structure diagram of a photometer 600 provided in an embodiment of this application. As shown in Figure 14, the photometer 600 includes a photoelectric conversion component 401 and a signal processing component 400. The photoelectric conversion component 401 converts the light signal generated by the reaction liquid being irradiated by irradiation light into an electrical signal. The signal processing component 400 processes the electrical signal to obtain the photon count result corresponding to the light signal.

[0119] The processor 500 determines the detection result of the reaction solution based on the photon counting result.

[0120] Referring to Figure 14, the photoelectric conversion component 401 includes a photomultiplier tube 200 and a voltage divider circuit 300. The photomultiplier tube 200 includes a cathode (K-electrode), a photoelectromagnetic focusing electrode (F-electrode), N dynodes, and an anode (P-electrode) arranged sequentially, where N is an integer greater than or equal to 3. The voltage divider circuit 300 includes an input node (IN node), an output node (OUT node), and N+1 voltage divider nodes arranged sequentially between the input node and the output node. Along the direction from the input node to the output node, the N+1 voltage divider nodes are voltage divider node 1, voltage divider node 2... voltage divider node N, and voltage divider node N+1. The input node of the voltage divider circuit 300 is connected to the cathode, the output node of the voltage divider circuit 300 is connected to the anode, and the N+1 voltage divider nodes are respectively connected sequentially to the photoelectromagnetic focusing electrode (F-electrode) and the N dynodes (e.g., DY1, DY2, DY3,... DYN) of the photomultiplier tube 200.

[0121] The F electrode is used to accelerate and focus the photoelectrons generated by the K electrode into a beam. The input node, the N+1 voltage divider nodes, and the nodes between every two adjacent nodes in the output node form a voltage divider branch, for a total of N+2 voltage divider branches. Along the direction from the input node to the output node, the N+2 voltage divider branches are sequentially named voltage divider branch 1, voltage divider branch 2… voltage divider branch N+1, voltage divider branch N+2. Each voltage divider node and the output node each correspond to a voltage divider. In the voltage divider circuit 300, at least one of the voltage dividers corresponding to the output node, the voltage divider corresponding to voltage divider node N+1, and the voltage divider corresponding to voltage divider node N is configured to be lower than the voltage dividers corresponding to the other voltage divider nodes.

[0122] In the above embodiment, by configuring at least one of the voltage dividers corresponding to the input terminal node in the voltage divider circuit 300, the voltage divider corresponding to voltage divider node N+1, and the voltage divider corresponding to voltage divider node N to be less than the voltage dividers corresponding to other voltage divider nodes, it is possible not only to distribute more voltage to the cathode and reduce the total secondary electron emission coefficient of the photomultiplier tube 200, but also, when the light intensity increases, due to the voltage redistribution caused by the dynode current, the voltage of the subsequent electrode is smaller, resulting in less voltage being distributed from the subsequent electrode to the preceding electrode. This makes the increase in the total secondary electron emission coefficient of the photomultiplier tube 200 more slow. Therefore, it is possible to increase the light intensity required for the output current of the photomultiplier tube 200 to reach the saturation inflection point, thereby increasing the light intensity measurement range of the sample analyzer 2000.

[0123] In some embodiments, each voltage divider branch includes at least one voltage divider resistor.

[0124] For example, referring to Figure 9, each voltage divider branch includes a voltage divider resistor. For instance, voltage divider branch 1 includes resistor R1, voltage divider branch 2 includes resistor R2, voltage divider branch 3 includes resistor R3, voltage divider branch 4 includes resistor R4, voltage divider branch 5 includes resistor R5, voltage divider branch 6 includes resistor R6, and voltage divider branch 7 includes resistor R7.

[0125] In some embodiments, the resistance value corresponding to voltage divider branch N+2 is configured to be less than the resistance values ​​corresponding to voltage divider branches 2 to N+1 respectively.

[0126] For example, as shown in Figure 15, when N is 5, if the resistance of each voltage divider branch 2 to voltage divider branch 6 is 1R, the resistance of voltage divider branch 7 is configured to be less than the resistance of each voltage divider branch 2 to voltage divider branch 6, for example, the resistance of voltage divider branch 7 is 0.5R. The resistance of R1 is 3R.

[0127] In the above embodiment, by reducing the resistance of the voltage divider branch 7, the voltage redistributed to the front electrode can be reduced when the light intensity increases, so that the total secondary electron emission coefficient of the photomultiplier tube 200 increases more slowly, thereby delaying the DC saturation inflection point of the photomultiplier tube 200.

[0128] In some embodiments, the resistance value corresponding to voltage divider branch N+2 is configured to be greater than the resistance value corresponding to voltage divider branch N+1, and both are less than the resistance values ​​corresponding to voltage divider branches 2 to N respectively.

[0129] For example, as shown in Figure 16, when N is 5, if the resistance of voltage divider branch 2 to voltage divider branch 5 is 1R, the resistance of voltage divider branch 7 can be 0.7R, and the resistance of voltage divider branch 6 can be 0.5R.

[0130] In the above embodiment, by configuring the resistance value corresponding to voltage divider branch N+2 to be greater than the resistance value corresponding to voltage divider branch N+1, and less than the resistance values ​​corresponding to voltage divider branches 2 to N respectively, more voltage on voltage divider branch N+1 can be distributed to the first stage (KF electrode), reducing the total secondary electron emission coefficient of photomultiplier tube 200. Moreover, when the light intensity increases, the voltage of voltage divider branch N+1 is relatively small, resulting in less voltage being distributed to the front electrode, which makes the increase in the total secondary electron emission coefficient of photomultiplier tube 200 more slow. Therefore, the light intensity required for the output current of photomultiplier tube 200 to reach the saturation inflection point can be increased, thereby increasing the light intensity measurement range of sample analyzer 2000.

[0131] In some embodiments, the resistance values ​​corresponding to voltage divider branches 2 to N+1 are configured to be the same, and the resistance value corresponding to voltage divider branch N+2 is configured to be less than the respective resistance values ​​corresponding to voltage divider branches 2 to N+1.

[0132] For example, as shown in Figure 15, when N is 5, if the resistance of each voltage divider branch 2 to voltage divider branch 6 is 1R, the resistance of voltage divider branch 7 is configured to be less than the resistance of each voltage divider branch 2 to voltage divider branch 6, for example, the resistance of voltage divider branch 7 is 0.5R.

[0133] In some embodiments, the resistance value corresponding to voltage divider branch N+1 is equal to the resistance value corresponding to voltage divider branch N+2, and the resistance values ​​corresponding to voltage divider branch N+1 and voltage divider branch N+2 are both less than the resistance values ​​corresponding to voltage divider branches 2 to N respectively.

[0134] For example, when N is 5, the resistance value corresponding to voltage divider branch 7 is equal to the resistance value corresponding to voltage divider branch 6, but the resistance values ​​corresponding to voltage divider branch 7 and voltage divider branch 6 are both less than the resistance values ​​corresponding to voltage divider branches 2 to 5 respectively.

[0135] In some embodiments, the resistance values ​​of the last M voltage divider branches in the N+2 voltage divider branches decrease along the direction from the input node to the output node, where M is less than or equal to (N+1) / 2.

[0136] For example, when N is 5, the resistance values ​​of voltage divider branches 5, 6, and 7 decrease along the direction from the input node to the output node, while the resistance values ​​of voltage divider branches 2, 3, and 4 can be the same.

[0137] As shown in Figure 17, the resistance of voltage divider branch 2, voltage divider branch 3, and voltage divider branch 4 is 1R, the resistance of voltage divider branch 5 can be 0.9R, the resistance of voltage divider branch 6 can be 0.7R, and the resistance of voltage divider branch 7 can be 0.4R.

[0138] In the above embodiment, by configuring the resistance of the last M voltage divider branches in the N+2 voltage divider branches to decrease along the direction from the input node to the output node, the voltage across the last M voltage divider branches can be gradually reduced. This results in a smaller voltage distribution to the front electrode when the light intensity increases, due to the smaller voltage on the rear electrode. Consequently, the overall secondary electron emission coefficient of the photomultiplier tube 200 increases more slowly. Therefore, the light intensity required for the output current of the photomultiplier tube 200 to reach the saturation inflection point can be increased, thereby increasing the light intensity measurement range of the sample analyzer 2000.

[0139] In some embodiments, the resistance values ​​corresponding to voltage divider branch N+1 and N+2 are both less than the resistance values ​​corresponding to voltage divider branches 2 to N respectively, and the minimum resistance value corresponding to voltage divider branch N+1 and / or the minimum resistance value corresponding to voltage divider branch N+2 is 0.2 times the minimum resistance value corresponding to voltage divider branches 2 to N respectively.

[0140] For example, when the minimum resistance value corresponding to each of voltage divider branches 2 to N is represented as R, the minimum resistance value corresponding to voltage divider branch N+1 and / or the minimum resistance value corresponding to voltage divider branch N+2 can be 0.2R. For example, the minimum resistance value corresponding to voltage divider branch N+1 is 0.5R, and the minimum resistance value corresponding to voltage divider branch N+2 is 0.5R. As another example, the minimum resistance value corresponding to voltage divider branch N+1 is 0.7R, and the minimum resistance value corresponding to voltage divider branch N+2 is 0.7R.

[0141] In the above embodiment, by configuring the resistance values ​​corresponding to voltage divider branch N+1 and N+2 to be smaller than the resistance values ​​corresponding to voltage divider branches 2 to N respectively, and the minimum resistance value corresponding to voltage divider branch N+1 and / or the minimum resistance value corresponding to voltage divider branch N+2 to N respectively to be 0.2 times the minimum resistance value corresponding to voltage divider branches 2 to N respectively, the voltage across voltage divider branches N+1 and N+2 can be much smaller than the voltage across each voltage divider branch from 2 to N. This ensures that when the light intensity increases, the voltage across voltage divider branches N+1 and N+2 is smaller, resulting in less voltage being distributed to the front electrode. Consequently, the overall secondary electron emission coefficient of photomultiplier tube 200 increases more slowly. Therefore, the light intensity required for the output current of photomultiplier tube 200 to reach the saturation inflection point can be increased, thereby increasing the light intensity measurement range of sample analyzer 2000.

[0142] In some embodiments, at least one of the voltage divider branches N to N+2 includes a diode, and each of the voltage divider branches 1 to N-1 includes a voltage divider resistor.

[0143] For example, when N is 5, at least one of the voltage divider branches 5, 6, and 7 includes at least one diode, and each of the voltage divider branches 1 to 4 includes at least one voltage divider resistor. Referring to Figure 10, voltage divider branch 6 includes diode Z6, and voltage divider branch 7 includes diode Z7.

[0144] In some embodiments, voltage divider branch N+2 includes at least one diode, and at least one of voltage divider branch N+1 and voltage divider branch N includes a diode, wherein the reverse voltage of the diode in voltage divider branch N+2 is greater than the reverse voltage of the other diodes.

[0145] Please refer to Figure 12. Voltage divider branch 5 includes diode Z5, voltage divider branch 6 includes diode Z6, and voltage divider branch 7 includes diode Z7. The reverse voltage of diode Z7 in voltage divider branch 7 is greater than the reverse voltage of diodes Z5 and Z6.

[0146] In the above embodiment, by configuring the reverse voltage of the diode in the voltage divider branch N+2 to be greater than the reverse voltage of the other diodes, when the light intensity increases, since the reverse voltage of the diode in the voltage divider branch N+2 and the reverse voltage of the other diodes are all less than the voltage of the front electrode, the smaller reverse voltage of the diode in the voltage divider branch N+2 and the reverse voltage of the other diodes results in less voltage being distributed to the front electrode, making the increase of the total secondary electron emission coefficient of the photomultiplier tube 200 more slow. Therefore, the light intensity required for the output current of the photomultiplier tube 200 to reach the saturation inflection point can be increased, thereby increasing the light intensity measurement range of the sample analyzer 2000.

[0147] Please refer to Figures 15 to 17, and Figures 18, 19, and 20. Figures 15 to 17 show the inverse conical voltage divider circuit provided in the embodiments of this application. Figure 18 shows an equal voltage divider circuit in the related art, in which the resistance values ​​of voltage divider branches 2 to 7 are all the same. Figure 19 shows a conical voltage divider circuit in the related art, in which the resistance values ​​of voltage divider branches 5 to 7 are all greater than the resistance values ​​of voltage divider branches 2 to 4. Figure 20 is a schematic diagram of the light intensity measurement range corresponding to the inverse conical voltage divider circuit, the equal voltage divider circuit, and the conical voltage divider circuit. As shown in Figure 20, the light intensity measurement range of the conical voltage divider circuit is 0-3.5 units of indicated light intensity, the light intensity measurement range of the equal voltage divider circuit is 0-4.5 units of indicated light intensity, while the light intensity measurement range of the inverse conical voltage divider circuit in this embodiment is increased to 0-6 units of indicated light intensity. Therefore, it can be seen that by utilizing the characteristic of the inverse conical voltage divider circuit to delay the DC saturation inflection point, this embodiment can effectively expand the light intensity measurement range of the sample analyzer 2000.

[0148] In some embodiments, the linear range of the sample analyzer 2000 is improved by 1.2-5 times compared to an equal voltage divider circuit. The inverse-cone drive voltage divider circuit in this embodiment configures at least one of the voltage dividers corresponding to the output node, the voltage divider corresponding to voltage divider node N+1, and the voltage divider corresponding to voltage divider node N to be smaller than the voltage dividers corresponding to other voltage divider nodes. Compared to an equal voltage divider circuit, this improves the linear range of the sample analyzer 2000, thereby making it suitable for testing scenarios with higher light intensity.

[0149] Please refer to Figure 21. Figure 21 is a schematic diagram showing the corresponding light intensity measurement ranges of the conical voltage divider circuit, the equal voltage divider circuit, and various inverse conical voltage divider circuits provided in the embodiments of this application. As shown in Figure 21, the horizontal axis represents light intensity, and the vertical axis represents the DC component, i.e., the output current (Ip). Curve 1 represents the DC component output by the conical circuit, where the resistance value corresponding to voltage divider branch 1 is 3R, the resistance values ​​corresponding to voltage divider branches 2 to N-1 are all the same, which is 1R, and the resistance values ​​corresponding to voltage divider branches N, N+1, and N+2 are 2R, 3R, and 2.5R, respectively. Curve 2 represents the DC component output by the equal voltage divider circuit, where the resistance value corresponding to voltage divider branch 1 is 3R, and the resistance values ​​corresponding to voltage divider branches 2 to N+2 are all the same, which is 1R. Curve 3 represents the DC component output of the first type of inverted cone voltage divider circuit provided in this application embodiment, wherein the resistance value corresponding to voltage divider branch 1 is 3R, the resistance values ​​corresponding to voltage divider branches 2 to N are all the same, 1R, and the resistance values ​​corresponding to voltage divider branches N+1 and N+2 are 0.7R and 0.5R, respectively. Curve 4 represents the DC component output of the second type of inverted cone voltage divider circuit provided in this application embodiment, wherein the resistance value corresponding to voltage divider branch 1 is 3R, the resistance values ​​corresponding to voltage divider branches 2 to N are all the same, 1R, and the resistance values ​​corresponding to voltage divider branches N+1 and N+2 are both 0.7R. Curve 5 represents the DC component output of the fourth type of inverted cone voltage divider circuit provided in this application embodiment, wherein the resistance value corresponding to voltage divider branch 1 is 3R, the resistance values ​​corresponding to voltage divider branches 2 to N are all the same, 1R, and the resistance values ​​corresponding to voltage divider branches N+1 and N+2 are both 0.5R. Therefore, compared with the tapered voltage divider circuit and the equal-ratio voltage divider circuit, the various reverse tapered voltage divider circuits provided in this application embodiment can effectively delay the DC saturation inflection point, thereby effectively expanding the light intensity measurement range of the sample analyzer 2000. Furthermore, in the various reverse tapered voltage divider circuits, as the DC component segment gradually decreases with the gradual reduction of the resistance of the last two stages (the resistance values ​​corresponding to the voltage divider branches N+1 and N+2), the DC saturation inflection point is gradually delayed. That is, when the resistance value is not less than 0.2R, the smaller the resistance values ​​corresponding to the voltage divider branches N+1 and N+2, the better the effect of expanding the light intensity measurement range of the sample analyzer 2000.

[0150] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

A sample analyzer, characterized in that, The sample analyzer includes a light source, a photometer, and a processor. The light source generates illumination light to irradiate the reaction liquid in the reaction vessel. The photometer includes a photoelectric conversion component and a signal processing component. The photoelectric conversion component converts the light signal generated by the reaction liquid being irradiated by the illumination light into an electrical signal. The signal processing component processes the electrical signal to obtain a photon count result corresponding to the light signal. The processor determines the detection result of the reaction liquid based on the photon count result. The photoelectric conversion component includes a photomultiplier tube and a voltage divider circuit. The photomultiplier tube includes a cathode, a photoelectron focusing electrode, N dynodes, and an anode arranged sequentially, where N is an integer greater than or equal to 3. The voltage divider circuit includes an input node, an output node, and N+1 voltage divider nodes arranged sequentially between the input node and the output node. Along the direction from the input node to the output node, the N+1 voltage divider nodes are sequentially voltage divider node 1, voltage divider node 2... voltage divider node N, voltage divider node N+1. The input node is connected to the cathode. The output node is connected to the anode, and the N+1 voltage divider nodes are sequentially connected to the photoelectron focusing electrode and the N multiplier electrodes. Each pair of adjacent nodes among the input node, the N+1 voltage divider nodes, and the output node forms a voltage divider branch, for a total of N+2 voltage divider branches. Along the direction from the input node to the output node, the N+2 voltage divider branches are sequentially voltage divider branch 1, voltage divider branch 2, ..., voltage divider branch N+1, voltage divider branch N+2. Each voltage divider node and the output node correspond to a voltage divider. In the voltage divider circuit, at least one of the voltage dividers corresponding to the output node, the voltage divider corresponding to voltage divider node N+1, and the voltage divider corresponding to voltage divider node N is configured to be less than the voltage dividers corresponding to the other voltage divider nodes. The sample analyzer according to claim 1 is characterized in that, Each of the voltage divider branches includes at least one voltage divider resistor. The sample analyzer according to claim 2 is characterized in that, The resistance value corresponding to voltage divider branch N+2 is configured to be less than the resistance values ​​corresponding to voltage divider branches 2 to N+1 respectively. The sample analyzer according to claim 3 is characterized in that, The resistance values ​​of each voltage divider branch from 2 to N+1 are configured to be the same. The sample analyzer according to claim 2 is characterized in that, The resistance value corresponding to voltage divider branch N+2 is configured to be greater than the resistance value corresponding to voltage divider branch N+1, and less than the resistance values ​​corresponding to voltage divider branches 2 to N respectively. The sample analyzer according to claim 2 is characterized in that, The resistance value corresponding to voltage divider branch N+1 is equal to the resistance value corresponding to voltage divider branch N+2, and the resistance values ​​corresponding to voltage divider branch N+1 and voltage divider branch N+2 are both less than the resistance values ​​corresponding to voltage divider branches 2 to N respectively. The sample analyzer according to claim 2 is characterized in that, The resistance values ​​of the N+2 voltage divider branches decrease along the direction from the input node to the output node. The sample analyzer according to claim 2 is characterized in that, The resistance values ​​of the last M voltage divider branches in the N+2 voltage divider branches decrease along the direction from the input node to the output node, where M is less than or equal to (N+1) / 2. The sample analyzer according to claim 2 is characterized in that, The resistance values ​​corresponding to voltage divider branch N+1 and N+2 are both less than the resistance values ​​corresponding to voltage divider branches 2 to N respectively. The minimum resistance value corresponding to voltage divider branch N+1 and / or the minimum resistance value corresponding to voltage divider branch N+2 is 0.2 times the minimum resistance value corresponding to voltage divider branches 2 to N respectively. The sample analyzer according to claim 1 is characterized in that, At least one of the voltage divider branches N to N+2 includes at least one diode, and each of the voltage divider branches 1 to N-1 includes at least one voltage divider resistor. The sample analyzer according to claim 10 is characterized in that, The voltage divider branch N+2 includes at least one diode, and the voltages corresponding to the N+1 voltage divider nodes and the output node decrease along the direction from the input node to the output node. The sample analyzer according to claim 10 is characterized in that, The voltage divider branch N+2 includes at least one diode, and at least one of the voltage divider branches N+1 and N includes at least one diode. The reverse voltage of the diode in the voltage divider branch N+2 is greater than the reverse voltage of the other diodes. The sample analyzer according to claim 1 is characterized in that, The last M voltage divider branches in the N+2 voltage divider branches along the direction from the input terminal node to the output terminal node each include at least one diode, and the other voltage divider branches in the N+2 voltage divider branches each include at least one voltage divider resistor, wherein M is less than or equal to (N+1) / 2. The sample analyzer according to claim 13 is characterized in that, The voltage division corresponding to each of the N+1 voltage dividing nodes and the output node decreases along the direction from the input node to the output node. The sample analyzer according to claim 13 is characterized in that, The reverse voltage of the diode in the (N+2)th voltage divider branch is greater than the reverse voltage of the other diodes. The sample analyzer according to claim 1 is characterized in that, Each of the N+2 voltage divider branches includes at least one diode, and the reverse voltage of the diode in the N+2 voltage divider branches is greater than the reverse voltage of the other diodes in the last M voltage divider branches along the direction from the input terminal node to the output terminal node, where M is less than or equal to (N+1) / 2. A photometer, characterized in that, The photometer includes a photoelectric conversion component and a signal processing component. The photoelectric conversion component is used to convert the light signal generated by the reaction liquid being irradiated by irradiation light into an electrical signal. The signal processing component is used to process the electrical signal to obtain the photon count result corresponding to the light signal. The photoelectric conversion component includes a photomultiplier tube and a voltage divider circuit. The photomultiplier tube includes a cathode, a photoelectron focusing electrode, N dynodes, and an anode arranged sequentially, where N is an integer greater than or equal to 3. The voltage divider circuit includes an input node, an output node, and N+1 voltage divider nodes arranged sequentially between the input node and the output node. Along the direction from the input node to the output node, the N+1 voltage divider nodes are sequentially voltage divider node 1, voltage divider node 2... voltage divider node N, voltage divider node N+1. The input node is connected to the cathode. The output node is connected to the anode, and the N+1 voltage divider nodes are sequentially connected to the photoelectron focusing electrode and the N multiplier electrodes. Each pair of adjacent nodes among the input node, the N+1 voltage divider nodes, and the output node forms a voltage divider branch, for a total of N+2 voltage divider branches. Along the direction from the input node to the output node, the N+2 voltage divider branches are sequentially voltage divider branch 1, voltage divider branch 2, ..., voltage divider branch N+1, voltage divider branch N+2. Each voltage divider node and the output node correspond to a voltage divider. In the voltage divider circuit, at least one of the voltage dividers corresponding to the output node, the voltage divider corresponding to voltage divider node N+1, and the voltage divider corresponding to voltage divider node N is configured to be less than the voltage dividers corresponding to the other voltage divider nodes. The photometer according to claim 17 is characterized in that, Each of the voltage divider branches includes at least one voltage divider resistor. The photometer according to claim 18 is characterized in that, The resistance value corresponding to voltage divider branch N+2 is configured to be less than the resistance values ​​corresponding to voltage divider branches 2 to N+1 respectively. The photometer according to claim 19 is characterized in that, The resistance values ​​corresponding to voltage divider branches 2 to N+1 are configured to be the same. The photometer according to claim 18 is characterized in that, The resistance value corresponding to voltage divider branch N+2 is configured to be greater than the resistance value corresponding to voltage divider branch N+1, and both are less than the resistance values ​​corresponding to voltage divider branches 2 to N respectively. The photometer according to claim 18 is characterized in that, The resistance value corresponding to voltage divider branch N+1 is equal to the resistance value corresponding to voltage divider branch N+2, and the resistance values ​​corresponding to voltage divider branch N+1 and voltage divider branch N+2 are both less than the resistance values ​​corresponding to voltage divider branches 2 to N respectively. The photometer according to claim 18 is characterized in that, The resistance values ​​of the last M voltage divider branches in the N+2 voltage divider branches each decrease along the direction from the input terminal node to the output terminal node, wherein M is less than or equal to (N+1) / 2. The photometer according to claim 18 is characterized in that, The resistance values ​​corresponding to voltage divider branch N+1 and N+2 are both less than the resistance values ​​corresponding to voltage divider branches 2 to N respectively. The minimum resistance value corresponding to voltage divider branch N+1 and / or the minimum resistance value corresponding to voltage divider branch N+2 is 0.2 times the minimum resistance value corresponding to voltage divider branches 2 to N respectively. The photometer according to claim 19 is characterized in that, At least one of the voltage divider branches N to N+2 includes a diode, and each of the voltage divider branches 1 to N-1 includes a voltage divider resistor. The photometer according to claim 25 is characterized in that, The voltage divider branch N+2 includes at least one diode, and at least one of the voltage divider branches N+1 and N includes a diode. The reverse voltage of the diode in the voltage divider branch N+2 is greater than the reverse voltage of the other diodes. A photometric system, characterized in that, The photometric system includes: A light source, which generates illumination light to irradiate the reaction liquid in the reaction vessel; A photomultiplier tube is used to convert the light signal generated by the reaction liquid being irradiated by light into an electrical signal; A voltage divider circuit is used to provide a driving voltage for the photomultiplier tube; A signal processing component is used to process the electrical signal to obtain the photon counting result corresponding to the optical signal; A processor, the processor being configured to determine the detection result of the reaction solution based on the photon counting result; The photomultiplier tube includes a cathode, a photoelectron focusing electrode, N dynodes, and an anode arranged sequentially, where N is an integer greater than or equal to 3. The voltage divider circuit includes an input node, an output node, and N+1 voltage divider nodes arranged sequentially between the input node and the output node. Along the direction from the input node to the output node, the N+1 voltage divider nodes are sequentially named voltage divider node 1, voltage divider node 2… voltage divider node N, and voltage divider node N+1. The input node is connected to the cathode, and the output node is connected to… The anode is described above. The N+1 voltage divider nodes are sequentially connected to the photoelectron focusing electrode and the N multiplier electrodes. Each pair of adjacent nodes among the input node, the N+1 voltage divider nodes, and the output node forms a voltage divider branch, for a total of N+2 voltage divider branches. Along the direction from the input node to the output node, the N+2 voltage divider branches are sequentially voltage divider branch 1, voltage divider branch 2, ..., voltage divider branch N+1, voltage divider branch N+2. Each voltage divider node and the output node correspond to a voltage divider. In the voltage divider circuit, at least one of the voltage dividers corresponding to the output node, the voltage divider corresponding to voltage divider node N+1, and the voltage divider corresponding to voltage divider node N is configured to be less than the voltage dividers corresponding to the other voltage divider nodes.

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