A photomultiplier tube nonlinearity comparison and calibration system

Abstract

The present invention provides a photomultiplier tube nonlinearity comparison and verification system, which relates to the field of photoelectric detection technology. The system comprises: a computer module, an electronic control module, a test device, a signal generation module, and a test recording module, which are integrated and mounted on a mounting platform. The signal generation module is used for signal acquisition and management. The electronic control module is used for system power management. The test device comprises, arranged in sequence, a temperature-controlled TEC, two LED light sources, two pinhole gratings, two first converging lenses, a reflector, a first beam splitter, a four-aperture light shield, a filter, an attenuation plate, a second beam splitter, a second converging lens, a standard photomultiplier tube, a third converging lens, a photomultiplier tube to be tested, and a darkroom. This solution ultimately achieves the analysis of the relative nonlinearity index of a photomultiplier tube using a combined direct current method and a reference tube method, making it easier to evaluate the nonlinearity of the photomultiplier tube to be tested in practical applications.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric detection technology, and in particular to a photomultiplier tube nonlinearity comparison and calibration system. Background Art

[0002] Photomultiplier tubes (PMTs), which convert received light signals into electrical signals, are a core component in the field of photoelectric detection. As highly sensitive light detectors, they are widely used in scientific research, medical diagnostics, industrial testing, and astronomy. PMTs operate based on the photoelectric effect and the electron multiplication effect. Key technical parameters include sensitivity, nonlinearity, and dark counts. While domestic and international manufacturers offer high-quality PMTs, the sensitivity and nonlinearity of individual PMTs may differ from standard values ​​depending on the user's specific needs. This can lead to inconsistent performance between pairs or batches of PMTs. To gain a deeper, more intuitive, and more relevant understanding of PMT parameters, users must compare the adaptability of PMTs produced by different domestic and international manufacturers, requiring complex and time-consuming comparative verification within their projects.

[0003] In the prior art, conventional photomultiplier tube nonlinearity comparison and calibration often directly uses optical equipment to perform direct light detection on the photomultiplier tube, and then verifies the detection data by collecting it and comparing it with relevant standard data.

[0004] When using existing optical detection equipment, the photomultiplier tube has high requirements for light intensity, environmental impact and signal stability during the detection process. Once interfered by external factors, it is likely to affect the validity of the photomultiplier tube detection data. In addition, during the detection process, a single detection data is not convenient for intuitively judging whether the nonlinearity index meets the standard.

[0005] Therefore, it is necessary to provide a photomultiplier tube nonlinearity comparison and calibration system to solve the above technical problems. Summary of the Invention

[0006] The present invention provides a photomultiplier tube nonlinearity comparison and calibration system, which solves the problem in related technologies that single detection data is not convenient for intuitively judging whether the nonlinearity index meets the standard.

[0007] To solve the above technical problems, the present invention provides a photomultiplier tube nonlinearity comparison and calibration system comprising:

[0008] A computer module, an electronic control module, a test device, a signal generating module and a test recording module are integrated and mounted on a mounting platform;

[0009] The signal generation module is used for signal acquisition and management;

[0010] The electronic control module is used for system power management;

[0011] The test device includes a temperature-controlled TEC, two LED light sources, two pinhole gratings, two first converging lenses, a reflector, a first beam splitter, a light shielding plate, a filter, an attenuation plate, a second beam splitter, a second converging lens, a standard photomultiplier tube, a third converging lens, a photomultiplier tube to be tested, and a dark box, which are arranged in sequence. The LED light source is installed on the temperature-controlled TEC, the pinhole grating is installed between the LED light source and the first converging lens, the reflector and the first beam splitter are arranged side by side, and one of the first converging lenses faces the reflector, and the other of the first converging lenses faces the first beam splitter. The four-hole light shielding plate, the filter, the attenuation plate, and the second beam splitter are arranged in sequence in the dark box, and the light output by the first beam splitter passes through the opening of the dark box and is aligned with the four-hole light shielding plate. The second converging lens and the standard photomultiplier tube are arranged in sequence on one side of the second beam splitter; the third converging lens and the photomultiplier tube to be tested are arranged in sequence on the other side of the second beam splitter.

[0012] The computer module is used for calculating and displaying the collected data;

[0013] The test record module is used to record and manage the calculated data.

[0014] Preferably, the system uses a comprehensive DC method and a reference tube method to calibrate the nonlinearity of the photomultiplier tube to be tested under test conditions. The DC method is implemented in the following manner:

[0015] Open the four apertures of the shutter in the following order: 1-2-3-4-fully open, and use the resulting output signals to calculate the ratio:

[0016]

[0017] Among them, I PMT It is the signal output by the photomultiplier tube after the shading plate is fully opened. PMT1 , I PMT2 , I PMT3 , I PMT4 It is the signal output by the photomultiplier tube when the corresponding opening is opened. This ratio represents the nonlinearity of the photomultiplier tube.

[0018] Preferably, the reference tube method is implemented by setting a standard photomultiplier tube as a reference tube, receiving the same light signal as the photomultiplier tube to be tested, comparing the electrical signals generated by the two processing, and obtaining the deviation of the photomultiplier tube to be tested relative to the reference tube.

[0019] Preferably, the two LED light sources output a pulse signal and a continuous signal respectively.

[0020] Preferably, the filter and the attenuation plate are detachably mounted in the optical path output range of the four-hole shading plate.

[0021] Preferably, the computer module uses a correction algorithm including dark count correction, channel difference correction and non-linearity curve smoothing steps.

[0022] Preferably, the test recording module is integrated with an online comparison and verification system, and the online comparison and verification system includes a login module, a verification module, and a comparison and verification platform;

[0023] The login module is used for user account and seal login, and the verification module is used to authenticate the logged-in user. After the identity is verified to be qualified, the comparison and verification platform is opened for data management;

[0024] The comparison and verification platform includes system configuration, data analysis, chart display, alarm management, log recording, data collection, data cleaning and equipment control, and is used to add / delete / modify / check test operators and data.

[0025] Preferably, the dark box is provided with four light-transmitting holes, a first sealing tube, a second sealing tube, and a third sealing tube are fixedly installed in the dark box and are in communication with each other, the filter is detachably mounted on the first sealing tube, and the attenuation plate is detachably mounted on the connection between the first sealing tube and the second sealing tube; the test device further comprises:

[0026] A movable plate, the movable plate being slidably mounted on the dark box, the movable plate being respectively provided with two first connection holes and one second connection hole that are offset vertically, the adjustment range of the first connection hole and the second connection hole being set corresponding to the range of the light-transmitting hole;

[0027] The moving device includes a motor, a gear and a missing rack. The motor is installed on the dark box. The shaft of the motor passes through the dark box and is fixedly connected to the gear. The missing rack is fixedly connected to the movable plate. The gear is meshed with the missing rack.

[0028] Preferably, the test device further includes a switching mechanism, which includes a rotating device and a switching disk. The rotating device is installed on the dark box, and the switching disk is rotatably installed at the connection part between the first sealing tube and the second sealing tube. At least four attenuation plates are installed on the switching disk.

[0029] Preferably, an adjustment hole is also provided on the dark box, and a second brake member is fixedly provided on the shaft of the motor; the rotating device includes a rotating tube, a rotating inner ring, a first brake member, a connecting outer ring and a connecting member, one end of the rotating tube member is rotatably installed in the dark box, and the other end of the rotating tube member is fixedly connected to the switching disk, a sliding hole is provided on the rotating tube member, and the rotating inner ring is rotatably installed on the rotating tube member, and the top of the first brake member is fixedly connected to the rotating inner ring after passing through the sliding hole, and the moving range of the first brake member is aligned with the second brake member, one end of the connecting member passes through the adjusting hole and is hinged to the movable plate, and the other end of the connecting member is hinged to the bottom of the connecting outer ring, and the connecting outer ring is sleeved outside the rotating inner ring and rotatably connected.

[0030] Compared with related technologies, the photomultiplier tube nonlinearity comparison and calibration system provided by the present invention has the following beneficial effects:

[0031] The system for analyzing the comparative verification results of the nonlinearity of photomultiplier tubes is loaded onto a computer. The acquisition control panel software on the computer receives instructions and sends signals to the FPGA main control module. The accumulated raw data curve is processed in the computer using a filtering algorithm to calculate the signal ratio between the standard photomultiplier tube channel and the photomultiplier tube channel to be tested. Furthermore, the filtered data is processed using a correction algorithm to compare the standard and test photomultiplier tubes at the wavelength and light intensity of interest to obtain a verified nonlinearity index.

[0032] Finally, the relative nonlinearity index of the photomultiplier tube is analyzed by combining the DC method and the reference tube method, which can be used to more conveniently evaluate the nonlinearity of the photomultiplier tube to be tested in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0034] Figure 1 This is a system distribution diagram of the photomultiplier tube nonlinearity comparison and calibration system provided by the present invention;

[0035] Figure 2 for Figure 1 Schematic diagram of the test apparatus shown;

[0036] Figure 3 for Figure 1 A system block diagram showing the operation of the computer module shown;

[0037] Figure 4 A block diagram of the comparison and calibration platform of the photomultiplier tube nonlinearity comparison and calibration system provided by the present invention;

[0038] Figure 5 A three-dimensional diagram of an embodiment of a dark box of a photomultiplier tube nonlinearity comparison and calibration system provided by the present invention;

[0039] Figure 6 for Figure 5 A three-dimensional schematic diagram of the interior of the dark box after the cover is removed;

[0040] Figure 7 for Figure 6 The right side view of the AA section is shown;

[0041] Figure 8 for Figure 7 An enlarged schematic diagram of part B is shown;

[0042] Figure 9 for Figure 6 The schematic diagram of the structure of the rotating pipe section is shown in FIG. Figure 9 (a) is a front view of the first brake member in a separated state, Figure 9 (b) is a front view of the first brake member in a synchronized state;

[0043] Figure 10 for Figure 5 The schematic diagram of the movable plate movement adjustment is shown, wherein, Figure 10 (a) is the left view of the four light-transmitting holes in the fully closed state. Figure 10 (b) is the left view of the first light hole in the open state. Figure 10 (c) is the left view of the second light-transmitting hole when it is open. Figure 10 (d) is the left view of the third light hole when it is open. Figure 10 (e) is the left view of the fourth light-transmitting hole in the open state. Figure 10 (f) is a left view of the state where the four light-transmitting holes are fully open;

[0044] Figure 11 for Figure 6 A top view of the switching disk is shown, wherein Figure 11 (a) in Figure 10 The top view of the switching disk in state (a) is shown in the figure. Figure 11 (b) in Figure 10 Top view of the switching disk in state (f); Figure 11 (c) in Figure 10 A top view of the motor continuing to drive the gear to rotate after state (f).

[0045] Description of Figure Numbers:

[0046] 100, installation platform; 200, computer module; 300, electronic control module; 400, test device; 500, signal generation module;

[0047] 11. LED light source; 12. Temperature-controlled TEC; 13. Pinhole grating; 14. First converging lens; 15. Reflector; 16. First beam splitter; 17. Light shield; 18. Filter; 19. Attenuator; 20. Second beam splitter; 21. Second converging lens; 22. Standard photomultiplier tube; 23. Third converging lens; 24. Photomultiplier tube to be tested; 25. Darkroom;

[0048] 251, first tube seal; 252, second tube seal; 253, third tube seal;

[0049] 2501, light transmission hole; 2502, adjustment hole;

[0050] 1. Movable plate; 101. First connection hole; 102. Second connection hole;

[0051] 2. Moving device; 201. Motor; 2011. Second brake member; 202. Gear; 203. Missing rack;

[0052] 3. Switching mechanism; 301. Rotating device; 3010. Sliding hole; 302. Switching disk;

[0053] 3011, rotating pipe fitting; 3012, rotating inner ring; 3013, first braking member; 3014, connecting outer ring; 3015, connecting member.

[0054] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0055] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0056] The invention provides a photomultiplier tube nonlinearity comparison and calibration system.

[0057] Please refer to Figures 1 to 3 In one embodiment of the present invention, a photomultiplier tube nonlinearity comparison and calibration system includes:

[0058] A computer module 200, an electronic control module 300, a test device 400, a signal generating module 500 and a test recording module are integrated and mounted on a mounting platform 100;

[0059] The signal generation module 500 is used for signal acquisition and management;

[0060] The electric control module 300 is used for system power management;

[0061] The test device 400 includes a temperature-controlled TEC 12, two LED light sources 11, two pinhole gratings 13, two first converging lenses 14, a reflector 15, a first beam splitter 16, a light shield 17, a filter 18, an attenuation plate 19, a second beam splitter 20, a second converging lens 21, a standard photomultiplier tube 22, a third converging lens 23, a photomultiplier tube to be tested 24, and a dark box 25, which are arranged in sequence. The LED light source 11 is installed on the temperature-controlled TEC 12, the pinhole grating 13 is installed between the LED light source 11 and the first converging lens 14, and the reflector 15 is arranged side by side with the first beam splitter 16. The first converging lens 14 faces the reflector 15, the other first converging lens 14 faces the first beam splitter 16, the four-hole light shielding plate 17, the filter 18, the attenuation plate 19 and the second beam splitter 20 are sequentially arranged in the dark box 25, and the light output by the first beam splitter 16 passes through the opening of the dark box 25 and is aligned with the four-hole light shielding plate 17, the second converging lens 21 and the standard photomultiplier tube 22 are sequentially arranged on one side of the second beam splitter 20; the third converging lens 23 and the photomultiplier tube to be measured 24 are sequentially arranged on the other side of the second beam splitter 20;

[0062] The computer module 200 is used for calculating and displaying the collected data;

[0063] The test record module is used to record and manage the calculated data.

[0064] In this embodiment, a temperature control system is composed of a temperature-controlled TEC and a heat sink to control the temperature stability of the LED light source;

[0065] In this embodiment, an electrical signal modulation system consisting of a DC power supply and a signal generator is used to control the light intensity of the LED light source;

[0066] The two LED light sources can modulate pulse signals and continuous signals respectively; the light is collimated and combined using a collimating lens, a converging lens, a beam splitter, and a reflective lens to ensure that the light beam can be normally received by the photomultiplier tube after passing through each device; the neutral density filter is selected to adjust the intensity of the light signal received by the photomultiplier tube to the required level.

[0067] By setting up a sealed dark box structure, stray light signals are prevented from entering; by sequentially opening and closing the holes of the four-hole light shielding plate to obtain the light signal data received by the photomultiplier tube, and then fully opening the four holes to obtain the light signal data received by the photomultiplier tube, the nonlinearity of the photomultiplier tube under this light intensity can be obtained.

[0068] The computer module integrates an FPGA main control module to process feedback signals from the acquisition card and electric control box, signal modulation system, temperature control system, photomultiplier tube and related indicator lights, acquisition card cooling fan and other non-core electronic components in the signal generation module, and perform real-time control.

[0069] In this embodiment, the signal collected by the photomultiplier tube is transmitted via a cable to the signal input module; then the signal is amplified, filtered, and converted to analog-to-digital by the analog signal acquisition module; then the signal is input to the FPGA main control module for accumulation; and then the signal is imported into the computer via the network port communication module.

[0070] The system for analyzing the comparative verification results of the nonlinearity of photomultiplier tubes is loaded onto a computer. The acquisition control panel software on the computer receives instructions and sends signals to the FPGA main control module. The accumulated raw data curve is processed in the computer using a filtering algorithm to calculate the signal ratio between the standard photomultiplier tube channel and the photomultiplier tube channel to be tested. Furthermore, the filtered data is processed using a correction algorithm to compare the standard and test photomultiplier tubes at the wavelength and light intensity of interest to obtain a verified nonlinearity index.

[0071] Finally, the relative nonlinearity index of the photomultiplier tube is analyzed by combining the DC method and the reference tube method, which can be used to more conveniently evaluate the nonlinearity of the photomultiplier tube to be tested in practical applications.

[0072] In this embodiment, the system uses a comprehensive DC method and a reference tube method to calibrate the nonlinearity of the photomultiplier tube under test conditions. The DC method is implemented as follows:

[0073] Open the four holes of the four-hole shutter in the following order: 1-2-3-4-fully open, and use the obtained output signals to calculate the ratio:

[0074]

[0075] Among them, I PMT It is the signal output by the photomultiplier tube after the shading plate is fully opened. PMT1 , I PMT2 , I PMT3 , I PMT4 It is the signal output by the photomultiplier tube when the corresponding opening is opened. This ratio represents the nonlinearity of the photomultiplier tube.

[0076] The four small holes are all within the range of the light spot, realizing the separation and superposition of different light fields.

[0077] In this embodiment, the reference tube method is implemented as follows: a standard photomultiplier tube is set as a reference tube, which receives the same light signal as the photomultiplier tube to be tested, and the electrical signals generated by the two are compared to obtain the deviation of the photomultiplier tube to be tested relative to the reference tube.

[0078] In this embodiment, the two LED light sources output a pulse signal and a continuous signal respectively. The signal generated by the combined beam is similar to a pulse signal with background noise, which can better simulate the use scenario of a photomultiplier tube.

[0079] In this embodiment, the filter 18 and the attenuation plate 19 are detachably mounted within the light path output range of the light shielding plate.

[0080] The attenuation sheet includes a mechanical design that is convenient for insertion and removal. The attenuation sheet is mounted on a removable fixture, and the attenuation sheet can be selected and replaced according to light intensity requirements.

[0081] In this embodiment, the computer module 200 uses a correction algorithm including dark count correction, channel difference correction, and nonlinearity curve smoothing steps.

[0082] The output signal formula of the photomultiplier tube is:

[0083] I PMT (I RS )=SRS PMT · I RS +D(I RS ).

[0084] SRS PMT is the photomultiplier tube sensitivity, I RS is the input signal intensity, D(I RS ) is the nonlinear deviation of the output value. Open the shutters in the following order: 1-2-3-4-full open; the input signal entering from the four shutter openings will be divided into four parts:

[0085] I RS =I RS1 +I RS2 +I RS3 +I RS4

[0086] For ease of processing, it is simplified to:

[0087]

[0088] When we use the above formula to analyze the nonlinearity of the output signal,

[0089]

[0090] Therefore, the nonlinearity can be obtained experimentally as follows:

[0091]

[0092] It is experimentally reasonable to infer the time when the light intensity is strong from the time when the light intensity is weak, because when the light intensity is high, the nonlinearity of the photomultiplier tube increases significantly, while when the light intensity is low, the linearity is better.

[0093] The dark signal of the photomultiplier tube is recorded as I PMT,0 There are many sources for such dark signals, but the most important characteristic is that they do not change with changes in the input signal. After measuring the dark signal of a standard photomultiplier tube or a photomultiplier tube to be tested, the nonlinearity experimental calculation formula needs to be modified as follows:

[0094]

[0095] Using the reference method to eliminate systematic errors, we perform the same acquisition on the data of the standard photomultiplier tube and obtain I StPMT And the data corresponding to each opening are compared with the photomultiplier tube to be tested. It is believed that the standard photomultiplier tube has good linearity under this condition. A second correction is made to obtain a nonlinearity comparison index:

[0096]

[0097] This indicator is used to test the nonlinearity of the photomultiplier tube to be tested.

[0098] After obtaining the nonlinearity of the photomultiplier tube to be tested under a certain light intensity, the incident signal intensity of the photomultiplier tube can be changed by replacing the attenuation plate and adjusting the LED light intensity, and then the signal and indicators are plotted to explore the changes in gain and nonlinearity of the photomultiplier tube to be tested under different incident signal intensities.

[0099] The choice of attenuation film affects the incident signal intensity of the photomultiplier tube used for testing. In research and detection, it is necessary to use different transmittances to conduct multiple detection experiments. Different attenuation combinations can be preset to meet the needs.

[0100] Considering the total optical transmittance of each component in the optical system, the scattering in the optical system, and the receiving angle of the photomultiplier tube to the light signal, a series of factors can be combined into a coefficient τ C0 The influence of the light intensity is combined and finally formed before the light intensity reaches the photoelectric signal conversion device such as the photomultiplier tube. RS or the number of photons n Pho,RSThe design and selection of the photomultiplier tube should ensure that it can normally receive such a signal light intensity I RS or the number of photons n Pho,RS .

[0101] If the transmittance of each attenuator is τ CA,i , then the transmittance of the attenuation group is required to be T CA ,satisfy:

[0102] I LS τ C0 Τ CA ≈I RS or

[0103] Among them I LS is the light intensity of the LED light source; the efficiency of all the light emitted by the LED light source after collimation modulation and entering the black box through the shading plate, the total optical transmittance of each component of the test system except the attenuator and variable attenuator, the obstruction and scattering in the test system, and the receiving angle of the photomultiplier tube to the light signal are combined into a coefficient recorded as τ C0 Before starting the experimental test, you should first LS τ C0 Calibrate to select the appropriate attenuator or attenuator group; where T CA It is the adjustable efficiency of the entire optical path.

[0104] In order to test the performance of the photomultiplier tube within the light intensity range of interest, an attenuator is used to coarsely adjust the light intensity level, and then the LED light source current and voltage are adjusted to fine-tune the light intensity.

[0105] The significance of the nonlinearity comparison index is to compare the nonlinearity of the response of a standard PMT and the PMT under test. It is more intuitive in two scenarios: first, when there is a standard PMT, which can eliminate some errors caused by light source instability and environmental factors; second, when the ratio between the readings of a pair of PMTs is important, it can better determine which PMT has the highest similarity.

[0106] In a preferred embodiment of the present invention, the test recording module is integrated with an online comparison and verification system, and the online comparison and verification system includes a login module, a verification module, and a comparison and verification platform;

[0107] The login module is used for user account and seal login, and the verification module is used to authenticate the logged-in user. After the identity is verified to be qualified, the comparison and verification platform is opened for data management;

[0108] The comparison and verification platform includes system configuration, data analysis, chart display, alarm management, log recording, data collection, data cleaning and equipment control, and is used to add / delete / modify / check test operators and data.

[0109] The system configuration is used to implement the addition / deletion / modification / check of name, description, numerical options, whether to enable, date and time;

[0110] The data analysis is used to add / delete / modify / check the sample number, test date, photomultiplier tube model, gain adjustment value, calibration results, and calibration personnel;

[0111] The chart display is used to add / delete / modify / check data name, type, value, date, and color;

[0112] The alarm management is used to add / delete / modify / check the alarm name, alarm type, alarm level, alarm time, and processing personnel;

[0113] The log records are used to add / delete / modify / check the operator, operation time, operation type, operation description, and operation results;

[0114] The data collection is used for adding / deleting / modifying / checking the photomultiplier tube data, collection time, experimenter, voltage, and temperature;

[0115] The data cleaning is used for the addition / deletion / modification / check functions of data name, date, content, source, and classification;

[0116] The device control is used to add / delete / modify / check the device name, remote control, configuration parameters, operator, and operation time.

[0117] By setting up an online comparison and verification system, it is convenient to record, compare and centrally manage test personnel, test items, test objectives and test-related data.

[0118] Please refer to Figure 5 and Figure 6 The dark box 25 is provided with four light-transmitting holes 2501. A first sealing tube 251, a second sealing tube 252, and a third sealing tube 253 are fixedly installed in the dark box 25. The filter 18 is detachably mounted on the first sealing tube 251. The attenuation plate 19 is detachably mounted on the connection between the first sealing tube 251 and the second sealing tube 252. The test device 400 further includes:

[0119] A movable plate 1 is slidably mounted on the dark box 25. The movable plate 1 is provided with two first connection holes 101 and a second connection hole 102 that are offset vertically. The adjustment ranges of the first connection holes 101 and the second connection holes 102 correspond to the ranges of the light-transmitting holes 2501.

[0120] The mobile device 2 includes a motor 201, a gear 202 and a missing rack 203. The motor 201 is installed on the dark box 25. The shaft of the motor 201 passes through the dark box 25 and is fixedly connected to the gear 202. The missing rack 203 is fixedly connected to the movable plate 1, and the gear 202 is meshed with the missing rack 203.

[0121] In this embodiment, a flip cover that can be opened and closed is provided on the top of the dark box 25 to facilitate opening for equipment adjustment or maintenance.

[0122] In this embodiment, the light shielding plate 17 is integrated on the dark box 25, and the four light-transmitting holes 2501 are four corresponding small hole structures;

[0123] The second beam splitter 20, the third converging lens 23 and the photomultiplier tube 24 to be tested are all mounted on the second sealing tube 252, and the photomultiplier tube 24 to be tested is detachably mounted between the dark box 25 and the second sealing tube 252;

[0124] The third sealing tube 253 is connected to the second sealing tube 252 and is aligned with the range of the second beam splitter 20 . The second converging lens 21 and the standard photomultiplier tube 22 are both mounted on the third sealing tube 253 .

[0125] The movement adjustment principle of the movable plate 1 is:

[0126] like Figure 10 As shown in (a), the movable plate 1 blocks the four light-transmitting holes 2501, and the device is in a fully closed state;

[0127] When it is necessary to adjust the opening of each light-transmitting hole 2501 in sequence, the motor 201 is started, the motor 201 drives the gear 202 to rotate, the gear 202 drives the missing rack 203 to move, and the missing rack 203 drives the movable plate 1 to move;

[0128] like Figure 10 As shown in (b), the first connecting hole 101 on the movable plate 1 is connected to the first light-transmitting hole 2501;

[0129] like Figure 10As shown in (c), another first connection hole 101 on the movable plate 1 is connected to the second light-transmitting hole 2501;

[0130] like Figure 10 As shown in (d), the first connecting hole 101 on the movable plate 1 is connected to the third light-transmitting hole 2501;

[0131] like Figure 10 As shown in (e), another first connection hole 101 on the movable plate 1 is connected to the fourth light-transmitting hole 2501;

[0132] like Figure 10 As shown in (f) , the second connection hole 102 on the movable plate 1 is connected to the four light-transmitting holes 2501 .

[0133] In this embodiment, a track structure for moving and adjusting the movable panel 1 is provided on the dark box 25 , and a sliding seal is formed between the movable panel 1 and the dark box 25 to ensure the stability of the connection between the movable panel 1 and the dark box 25 .

[0134] The standard photomultiplier tube 22 passes through the dark box 25 and is inserted on the third sealing tube 253 ; the photomultiplier tube to be tested 24 passes through the dark box 25 and is inserted on the second sealing tube 252 .

[0135] By driving the movable plate 1 to move through the motor 201, the automatic opening and closing adjustment of the four light-transmitting holes 2501 is facilitated, so as to perform automatic control of 1-2-3-4-full opening in sequence, reduce the need for manual adjustment, and improve the convenience and intelligence of equipment operation.

[0136] Please refer again Figure 6 The test device 400 also includes a switching mechanism 3, which includes a rotating device 301 and a switching disk 302. The rotating device 301 is installed on the dark box 25, and the switching disk 302 is rotatably installed at the connection between the first sealing tube 251 and the second sealing tube 252. At least four attenuation plates 19 are installed on the switching disk 302.

[0137] In this embodiment, the attenuation plate 19 is fixedly installed on the switching disk 302 in a detachable installation manner, and at least four of the attenuation plates 19 are evenly distributed within the rotation range of the switching disk 302. When the attenuation plate 19 is adjusted to the working state, the attenuation plate 19 is aligned with the range through which the light beam passes, and is aligned with the connection between the first sealing tube 251 and the second sealing tube 252, so as to maintain the normal use state of the attenuation plate 19.

[0138] In order to facilitate the switching of the attenuation plate 19 during the test without turning off the light, manual operation is reduced, and the test is carried out continuously.

[0139] In an optional implementation of this embodiment, the rotating device 301 can be an independent motor structure, and the rotating device 301 is installed in the dark box 25. The rotating axis of the rotating device 301 is fixed to the switching disk 302, and is used to directly drive the switching disk 302 for rotation adjustment, so as to select different attenuation plates 19 for use on the switching disk 302.

[0140] In another optional implementation of this embodiment, please refer to FIG. Figure 6 、 Figure 7 、 Figure 8 and Figure 9 In (a), the dark box 25 is further provided with an adjustment hole 2502, and the shaft of the motor 201 is fixed with a second brake 2011; the rotating device 301 includes a rotating tube 3011, a rotating inner ring 3012, a first brake 3013, a connecting outer ring 3014 and a connecting member 3015, one end of the rotating tube 3011 is rotatably mounted in the dark box 25, and the other end of the rotating tube 3011 is fixedly connected to the switching disk 302, a sliding hole 3010 is provided on the rotating tube 3011, and the rotating inner ring 3 012 is rotatably installed on the rotating tube 3011, the top of the first brake member 3013 passes through the sliding hole 3010 and is fixedly connected to the rotating inner ring 3012, the moving range of the first brake member 3013 is aligned with the second brake member 2011, one end of the connecting member 3015 passes through the adjusting hole 2502 and is hinged to the movable plate 1, the other end of the connecting member 3015 is hinged to the bottom of the connecting outer ring 3014, and the connecting outer ring 3014 is sleeved outside the rotating inner ring 3012 and rotatably connected.

[0141] In this embodiment, a damping structure is provided at the connection between the rotating tube 3011 and the dark box 25, so that the rotating tube 3011 and the switching disk 302 will not rotate freely to maintain the stability of the device when in use (but rotation can be achieved by hand pushing or other driving power; for example: the damping part on a notebook).

[0142] In this embodiment, the shaft of the motor 201 passes through the middle of the rotating tube 3011 , and the two are distributed on the same axis.

[0143] In this embodiment, the connecting member 3015 is a spring telescopic tube, which provides elastic buffering for the continued movement of the movable plate 1 after the first braking member 3013 abuts against the second braking member 2011 .

[0144] In this embodiment, the first brake member 3013 and the second brake member 2011 include two usage states:

[0145] like Figure 9 (a) in the separation state, the first brake member 3013 is separated from the second brake member 2011 and there is no contact, and the motor 201 is used to independently control the rotation of the gear 202, thereby providing power for the movement of the movable plate 1;

[0146] like Figure 9 (b) in the synchronous state, the first brake member 3013 abuts against the second brake member 2011, and the motor 201 drives the gear 202 to rotate while also driving the second brake member 2011 to rotate. The second brake member 2011 drives the first brake member 3013 in the abutting state to rotate, and the first brake member 3013 drives the rotating tube member 3011 to rotate through the rotating inner ring 3012, and the rotating tube member 3011 drives the switching disk 302 to rotate, thereby providing power for the rotation of the switching disk 302.

[0147] In the synchronous state, the missing rack 203 is cyclically separated and engaged during the rotation of the gear 202 , so that the gear 202 can continue to rotate, providing support for the rotation adjustment of the switching disk 302 .

[0148] In this embodiment, the motor 201 can be used for the movement adjustment of the movable plate 1 during the detection process; after the movable plate 1 is adjusted to the fully open state, it can also be used for the rotation adjustment of the switching disk 302, making the testing and switching process more convenient and smooth, simplifying the adjustment steps and processes, and facilitating the automatic adjustment of the equipment usage mode.

[0149] Please refer to Figure 11 (a) to Figure 11 (b) and Figure 9 (a) to Figure 9 In (b), while the movable plate 1 is moving and adjusting, the movable plate 1 synchronously pushes the connecting outer ring 3014 to extend through the connecting member 3015. While the connecting outer ring 3014 is extending, the first brake member 3013 is driven to move toward the second brake member 2011 through the rotating inner ring 3012.

[0150] Please refer to Figure 11 (b) to Figure 11In (c), when the movable plate 1 is adjusted to the fully open state, the motor 201 can continue to drive the gear 202 to rotate, and the missing rack 203 is pushed by the gear 202 and the elastic reset effect of the connecting member 3015, repeatedly engaging and disengaging, providing support for the motor 201 to drive the switching disk 302 alone.

[0151] Ultimately, under the driving action of the motor 201, the working state of the movable plate 1 is switched, and the first brake member 3013 can be switched from the separation state to the synchronization state simultaneously; after the state is switched, the motor 201 can be used alone to adjust the rotation of the switching disk 302, so that after completing a round of testing, it is convenient to switch to the next group of attenuation plates 19, reducing the manual adjustment steps during the test process and facilitating continuous testing.

[0152] Similarly, after the attenuation plate 19 is switched, the motor 201 is used to control the gear 202 to rotate in the opposite direction, so that the gear 202 drives the missing rack 203 and the movable plate 1 to reset. When the movable plate 1 is reset, the first brake member 3013 is pulled to contract through the connecting member 3015, so that the first brake member 3013 is separated from the second brake member 2011, so as to provide reset for the next group of attenuation plates 19 tests.

[0153] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A photomultiplier tube nonlinearity comparison and calibration system, characterized in that: include: A computer module, an electronic control module, a test device, a signal generating module and a test recording module are integrated and mounted on a mounting platform; The signal generation module is used for signal acquisition and management; The electronic control module is used for system power management; The test device includes a temperature-controlled TEC, two LED light sources, two pinhole gratings, two first converging lenses, a reflector, a first beam splitter, a light shielding plate, a filter, an attenuation plate, a second beam splitter, a second converging lens, a standard photomultiplier tube, a third converging lens, a photomultiplier tube to be tested, and a dark box, which are arranged in sequence. The LED light source is installed on the temperature-controlled TEC, the pinhole grating is installed between the LED light source and the first converging lens, the reflector and the first beam splitter are arranged side by side, and one of the first converging lenses faces the reflector, and the other of the first converging lenses faces the first beam splitter. The four-hole light shielding plate, the filter, the attenuation plate, and the second beam splitter are arranged in sequence in the dark box, and the light output by the first beam splitter passes through the opening of the dark box and is aligned with the four-hole light shielding plate. The second converging lens and the standard photomultiplier tube are arranged in sequence on one side of the second beam splitter; the third converging lens and the photomultiplier tube to be tested are arranged in sequence on the other side of the second beam splitter. The computer module is used for calculating and displaying the collected data; The test record module is used to record and manage the calculated data; The dark box is provided with four light-transmitting holes. A first sealing tube, a second sealing tube, and a third sealing tube are fixedly installed in the dark box. The filter is detachably mounted on the first sealing tube. The attenuation plate is detachably mounted on the connection between the first sealing tube and the second sealing tube. The test device further comprises: A movable plate, the movable plate being slidably mounted on the dark box, the movable plate being respectively provided with two first connection holes and one second connection hole that are offset vertically, the adjustment range of the first connection hole and the second connection hole being set corresponding to the range of the light-transmitting hole; The moving device includes a motor, a gear and a missing rack. The motor is installed on the dark box. The shaft of the motor passes through the dark box and is fixedly connected to the gear. The missing rack is fixedly connected to the movable plate. The gear is meshed with the missing rack.

2. The photomultiplier tube nonlinearity comparison and calibration system according to claim 1, characterized in that: The system uses a comprehensive DC method and a reference tube method to calibrate the nonlinearity of the photomultiplier tube under test conditions. The DC method is implemented as follows: Open the four apertures of the shutter in the following order: 1-2-3-4-fully open, and use the resulting output signals to calculate the ratio: Among them, I PMT It is the signal output by the photomultiplier tube after the shading plate is fully opened. PMT1 , I PMT2 , I PMT3 , I PMT4 It is the signal output by the photomultiplier tube when the corresponding opening is opened. This ratio represents the nonlinearity of the photomultiplier tube.

3. The photomultiplier tube nonlinearity comparison and calibration system according to claim 2, characterized in that: The reference tube method is implemented by setting a standard photomultiplier tube as a reference tube, which receives the same light signal as the photomultiplier tube to be tested. The electrical signals generated by the two are compared to obtain the deviation of the photomultiplier tube to be tested relative to the reference tube.

4. The photomultiplier tube nonlinearity comparison and calibration system according to claim 3, characterized in that: The two LED light sources output a pulse signal and a continuous signal respectively.

5. The photomultiplier tube nonlinearity comparison and calibration system according to claim 4, characterized in that: The filter and the attenuation plate are respectively detachably mounted in the light path output range of the four-hole shading plate.

6. The photomultiplier tube nonlinearity comparison and calibration system according to claim 5, characterized in that: The computer module uses a correction algorithm that includes dark count correction, channel difference correction, and nonlinearity curve smoothing steps.

7. The photomultiplier tube nonlinearity comparison and calibration system according to claim 6, characterized in that: The test record module is integrated with an online comparison and verification system, which includes a login module, a verification module, and a comparison and verification platform; The login module is used for user account and seal login, and the verification module is used to authenticate the logged-in user. After the identity is verified to be qualified, the comparison and verification platform is opened for data management; The comparison and verification platform includes system configuration, data analysis, chart display, alarm management, log recording, data collection, data cleaning and equipment control, and is used to add / delete / modify / check test operators and data.

8. The photomultiplier tube nonlinearity comparison and calibration system according to claim 7, characterized in that: The test device also includes a switching mechanism, which includes a rotating device and a switching disk. The rotating device is installed on the dark box. The switching disk is rotatably installed at the connection between the first sealing tube and the second sealing tube. At least four attenuation plates are installed on the switching disk.

9. The photomultiplier tube nonlinearity comparison and calibration system according to claim 8, characterized in that: The dark box is also provided with an adjusting hole, and the shaft of the motor is fixedly provided with a second brake member; the rotating device comprises a rotating tube, a rotating inner ring, a first brake member, a connecting outer ring and a connecting member, one end of the rotating tube member is rotatably installed in the dark box, and the other end of the rotating tube member is fixedly connected to the switching disk. A sliding hole is provided on the rotating tube member, and the rotating inner ring is rotatably installed on the rotating tube member, and the top of the first brake member is fixedly connected to the rotating inner ring after passing through the sliding hole. The moving range of the first brake member is aligned with the second brake member, one end of the connecting member passes through the adjusting hole and is hinged to the movable plate, and the other end of the connecting member is hinged to the bottom of the connecting outer ring, and the connecting outer ring is sleeved outside the rotating inner ring and rotatably connected.

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