Mcp life test method and system for high-energy cosmic ray detection

Abstract

The application provides a MCP life test method and system for high-energy cosmic rays, and aims to solve the technical problem that the current method of evaluating MCP life by marking the output brightness gain change of an image intensifier is prone to system error. The test method comprises the following steps: sequentially placing an electron cathode, a to-be-tested MCP sample and an anode plate in a high-vacuum tube, sequentially arranging an adjustable diaphragm and the high-vacuum tube on a high-energy light source incident light path; closing the adjustable diaphragm, turning on the high-energy light source and calibrating the high-energy light source; sequentially applying a high-voltage electric field to the anode plate, the to-be-tested MCP sample and the electron cathode; adjusting the position and aperture size of the adjustable diaphragm; after electrons sequentially undergo electron multiplication and electron collection through the to-be-tested MCP sample and the anode plate, the anode plate outputs current; detecting the output current of the anode plate, taking the maximum laser intensity as a reference, and performing normalization processing on the laser intensity in the measurement interval; and obtaining the life of the to-be-tested MCP sample.

Description

TECHNICAL FIELD

[0001] The present application relates to high-energy cosmic ray detection, in particular to a MCP lifetime test method and system for high-energy cosmic ray detection. BACKGROUND

[0002] In the process of high-energy cosmic ray detection, in order to realize the discrimination of different energy protons and ions, a large dynamic range and long life image intensifier is usually used as a detection device. Among them, the micro channel plate (MCP for short) is a two-dimensional structure of photoelectric multiplier device, which has the characteristics of high gain, large dynamic range, low noise, high time resolution and high spatial resolution, and can realize the detection of electrons, ions, ultraviolet photons, alpha particles, beta particles, gamma particles, neutrons and x-rays, and obtain their characteristics in time and space. Therefore, the micro channel plate is currently used as the core device for micro light signal detection and micro light target imaging.

[0003] The successful development of the micro channel plate not only improves the gain of the image intensifier, but also reduces the volume and weight of the image intensifier, and has been widely used in high-tech fields such as cosmic exploration, earth observation and ocean monitoring. However, the micro channel plate puts forward more strict requirements on the operating environment, preparation technology and storage environment, thereby bringing about the instability of the gain and the life problem. In order to explore the engineering application of the micro channel plate in space, it is necessary to obtain various modes of the average life, gain failure and gain decline of the micro channel plate, that is, the accurate MCP life curve, so as to judge and guide the correct time region of the use of the micro channel plate. Essentially, this is a destructive test, but it has strong practical guiding significance for studying and analyzing the life change rule of the micro channel plate.

[0004] At present, the MCP life is mainly evaluated by marking the output brightness gain change of the image intensifier. However, since there are many factors affecting the gain of the image intensifier, the gain of the image intensifier is not only related to the life and reliability of the MCP, and it is impossible to determine whether it is caused by the MCP in the analysis process. Therefore, this test method is prone to systematic errors in the implementation process, mainly including position error of light incident to cathode, cosine error of device and test device optical axis angle, measurement error of brightness meter and random error of brightness meter. SUMMARY

[0005] The purpose of the present application is to solve the technical problem that the method of evaluating the MCP life by marking the output brightness gain change of the image intensifier is prone to systematic errors, and to provide a MCP lifetime test method and system for high-energy cosmic ray detection.

[0006] In order to solve the above technical problems, the technical solution of the present application is:

[0007] The application discloses a MCP (Micro Channel Plate) life test method for high-energy cosmic ray detection.

[0008] 1】Place an electron cathode, a to-be-tested MCP sample and an anode plate in a high-vacuum tube in sequence, and set a gap between the to-be-tested MCP sample and the electron cathode and between the to-be-tested MCP sample and the anode plate; and place an adjustable diaphragm and the high-vacuum tube on an incident light path of a high-energy light source in sequence, so that the adjustable diaphragm is located at a front end of the electron cathode; the high-energy light source has a pulse width of 10-100 ns and a power greater than 3 W, and the electron energy of the high-energy light source bombarding the electron cathode is 1 eV-15 eV;

[0009] 2】Close the adjustable diaphragm, turn on the high-energy light source, and calibrate the spectrum and intensity of the high-energy light source to detect whether the high-energy light source meets the requirements;

[0010] 3】Apply corresponding high-voltage electric fields to the anode plate, the to-be-tested MCP sample and the electron cathode in sequence, so that the device is in a working state;

[0011] 4】Adjust the position and aperture size of the adjustable diaphragm according to the to-be-tested position and size of the to-be-tested MCP sample, so that the electron cathode outputs electrons with a current density of 10 -9 A / cm 2 order of magnitude under the action of the electric field after receiving photons; the electrons are subjected to electron multiplication and electron collection through the to-be-tested MCP sample and the anode plate in sequence, and the anode plate outputs an electric current;

[0012] 5】Detect the output current of the anode plate, normalize the laser intensity in a measurement interval based on a maximum laser intensity, and obtain the life of the to-be-tested MCP sample by the following formula: life

[0013]

[0014] Wherein, Q n represents the total charge collected by the anode plate; S in represents the area of the electron cathode irradiated by the laser; i represents the current generated in the anode plate at an instant; Q0 represents the total charge of the anode plate in an initial state; f(I, t) represents a laser intensity normalization function; and r represents the current light transmission aperture of the adjustable diaphragm.

[0015] Further, step 1 is specifically as follows:

[0016] Place the electron cathode, the to-be-tested MCP sample and the anode plate in a high-vacuum tube with a vacuum degree of 10 -4 Pa-10 -3 ​The high-vacuum tube is of the order of magnitude of Pa, and the to-be-tested MCP sample is arranged between the electron cathode and the anode plate; the gap between the to-be-tested MCP sample and the electron cathode and the gap between the to-be-tested MCP sample and the anode plate are 1 mm-3 mm, and the gaps are supported by resin materials to prevent high-voltage discharge, high-voltage breakdown and high-temperature structural deformation under vacuum conditions.

[0017] Further, in step 3, a corresponding high-voltage electric field is sequentially applied to the anode plate, the to-be-tested MCP sample and the electron cathode in sequence.

[0018] An adjustable voltage of 1000-1500 V is applied to the anode plate.

[0019] The input surface of the to-be-tested MCP sample is grounded, 0-1000 V adjustable voltage is applied to the output surface of the to-be-tested MCP sample if the to-be-tested MCP sample is a single MCP, and 1000-1800 V adjustable voltage is applied to the output surface of the to-be-tested MCP sample if the to-be-tested MCP sample is a double MCP.

[0020] An opening voltage of -170 V to -250 V is applied to the electron cathode.

[0021] Further, steps 1-5 are performed in a darkroom to prevent the influence of ambient light on the test results.

[0022] In order to realize the above-mentioned MCP life test method for high-energy cosmic ray detection, the application further provides an MCP life test system for high-energy cosmic ray detection, which is characterized in that:

[0023] The laser, the adjustable diaphragm, the electron cathode, the anode plate, the first ammeter, the driving line, the first ammeter data acquisition card, the spectrometer, the control system and the coaxial cable are sequentially arranged along the light emission direction of the laser.

[0024] The laser is provided with a light homogenization device and a high-vacuum tube in sequence along the light emission direction.

[0025] The electron cathode, the to-be-tested MCP sample and the anode plate are sequentially arranged in the high-vacuum tube along the light emission direction of the laser, and gaps are arranged between the to-be-tested MCP sample and the electron cathode and between the to-be-tested MCP sample and the anode plate.

[0026] The adjustable diaphragm is located between the light homogenization device and the electron cathode, and the position and aperture size of the adjustable diaphragm are adjustable.

[0027] The input end of the first ammeter is connected with the output end of the anode plate through a coaxial cable, for detecting the output current of the anode plate; the output end of the first ammeter is connected with the input end of the first ammeter data acquisition card, for collecting the detected current data; the output end of the first ammeter data acquisition card is connected with the first input end of the control system, for transmitting the collected current data to the control system;

[0028] The spectrometer is provided with a collection optical fiber; the collection optical fiber is located at the rear end of the light homogenization device, for real-time collection of the output laser intensity of the laser; the spectrometer is used for real-time monitoring of the laser intensity, and the output end of the spectrometer is connected with the second input end of the control system, for transmitting the laser intensity to the control system;

[0029] The control system is used for obtaining the lifetime of the to-be-tested MCP sample according to the input laser intensity of the laser, the output current of the anode plate and the current light aperture of the adjustable diaphragm;

[0030] One output end of the control system is connected with the input end of the adjustable diaphragm through a driving line, for adjusting the position and aperture size of the adjustable diaphragm.

[0031] Further, the light aperture of the adjustable diaphragm is less than or equal to the diameter of the to-be-tested MCP sample;

[0032] The vacuum degree of the high-vacuum tube is 10 -4 Pa-10 -3 Pa order of magnitude;

[0033] The resistance of the first ammeter is greater than or equal to 10 12 Ω, and the current accuracy reaches 1×10 -13 A;

[0034] The first ammeter is matched with the whole impedance composed of the electron cathode, the to-be-tested MCP sample and the anode plate;

[0035] The fiber core diameter of the collection optical fiber is greater than 400 um, and the wavelength is 190-1100 nm;

[0036] The lifetime MCP of the to-be-tested MCP sample is calculated by the following formula in the control system life :

[0037]

[0038] Wherein, Q n represents the total amount of charges collected by the anode plate; S in represents the area of the laser incident electron cathode; i represents the current generated in the anode plate at the moment; Q0 represents the total amount of charges of the anode plate in the initial state; f(I, t) represents a laser intensity normalization function; and r represents the current light aperture of the adjustable diaphragm.

[0039] Further, the gap between the to-be-tested MCP sample and the electron cathode, and between the to-be-tested MCP sample and the anode plate is 1mm-3mm;

[0040] The distance from the laser to the electron cathode incident surface is less than or equal to 20cm;

[0041] The length of the coaxial cable is less than or equal to 30cm;

[0042] The collection optical fiber end surface is located 10cm-40cm behind the light homogenization device, and the included angle between the fiber core axis of the collection optical fiber and the normal line of the light homogenization device is 45°-80°.

[0043] Further, the distance from the laser to the electron cathode incident surface is 3cm-5cm, which is used to better improve the electron excitation effect;

[0044] The length of the coaxial cable is 10cm, which can effectively reduce the interference of the surrounding electromagnetic environment;

[0045] The collection optical fiber end surface is located 20cm behind the light homogenization device, and the included angle between the fiber core axis of the collection optical fiber and the normal line of the light homogenization device is 50°.

[0046] Further, the to-be-tested MCP sample and the electron cathode, and the to-be-tested MCP sample and the anode plate are both provided with a resin support structure, which is used to prevent high-voltage discharge, high-voltage breakdown and high-temperature structural deformation under vacuum conditions.

[0047] Further, a second current meter and a second current meter data acquisition card are further included;

[0048] The input end of the second current meter is connected to the output end of the electron cathode, which is used to detect the output current of the electron cathode, the output end thereof is connected to the input end of the second current meter data acquisition card, which is used to collect the output current of the electron cathode in real time, and the output end of the second current meter data acquisition card is connected to the third input end of the control system.

[0049] Further, the light transmission aperture of the adjustable diaphragm is 2mm-10mm;

[0050] The vacuum degree of the high-vacuum tube is 10 -4 Pa-10 -3 Pa order of magnitude;

[0051] The gap between the to-be-tested MCP sample and the electron cathode, and between the to-be-tested MCP sample and the anode plate is 1mm-3mm;

[0052] The distance from the laser to the electron cathode incident surface is less than or equal to 20cm;

[0053] The length of the coaxial cable is less than or equal to 30 cm.

[0054] The end face of the collection optical fiber is located at 10-40 cm behind the light homogenization device, and the included angle between the core axis of the collection optical fiber and the normal line of the light homogenization device is 45-80 degrees.

[0055] Further, the light aperture of the adjustable diaphragm is 2-4 mm.

[0056] The distance from the laser to the incident surface of the electron cathode is 3-5 cm, so as to better improve the electron excitation effect.

[0057] The length of the coaxial cable is 10 cm, which can effectively reduce the interference of the surrounding electromagnetic environment.

[0058] The end face of the collection optical fiber is located at 20 cm behind the light homogenization device, and the included angle between the core axis of the collection optical fiber and the normal line of the light homogenization device is 50 degrees.

[0059] Further, the resin support structure is arranged between the to-be-measured MCP sample and the electron cathode and between the to-be-measured MCP sample and the anode plate, so as to prevent high-voltage discharge, high-voltage breakdown and high-temperature structural deformation under vacuum conditions.

[0060] Further, the second current meter and the second current meter data acquisition card are further included.

[0061] The input end of the second current meter is connected to the output end of the electron cathode, so as to detect the output current of the electron cathode, the output end of the second current meter is connected to the input end of the second current meter data acquisition card, so as to acquire the output current of the electron cathode in real time, and the output end of the second current meter data acquisition card is connected to the third input end of the control system.

[0062] The resistance of the second current meter is greater than or equal to 10 12 Ω, and the current accuracy reaches 1x10 -13 A.

[0063] The second current meter is matched with the whole impedance composed of the electron cathode, the to-be-measured MCP sample and the anode plate.

[0064] The beneficial effects of the present application are as follows:

[0065] 1. The MCP lifetime test method for high-energy cosmic ray detection provided by the application places the electron cathode, microchannel plate MCP and anode plate as a whole in a closed high-vacuum tube, controls the position and number of photons reaching the MCP cathode surface by adjusting the position and aperture size of the adjustable diaphragm, so as to realize the position and intensity adjustment of the injected electrons of the MCP, and then the MCP lifetime can be accurately obtained by the input laser intensity, anode plate output current and the current light transmission aperture of the adjustable diaphragm. The method can effectively reduce system error, realize scientific and effective evaluation of the MCP lifetime, provide detailed data support and technical guidance for the development of high-performance micro-light detection devices, and can be widely applied in the development and engineering production of MCP and image intensifiers.

[0066] 2. The MCP lifetime test system for high-energy cosmic ray detection provided by the application is provided with a laser for generating incident photons, the position and number of photons reaching the electron cathode surface are adjusted by adjusting the position and aperture size of the adjustable diaphragm, so as to further realize the position and intensity adjustment of the injected electrons of the MCP, the real-time output laser intensity of the laser is detected by the spectrometer in real time while the diaphragm is adjusted, and the real-time output current of the anode plate is detected by the first ammeter. The system can accurately and effectively obtain the change process of the MCP output micro-current with irradiation time, and provides a very important basis for studying and analyzing the MCP lifetime characteristics.

[0067] 3. The MCP lifetime test system for high-energy cosmic ray detection provided by the application is connected with a second ammeter at the output end of the electron cathode, so as to reflect whether the light source is stable by detecting the output current of the electron cathode, and to realize real-time monitoring of the performance of the electron cathode; meanwhile, the gain of the MCP can be obtained by calculating the ratio of the anode plate and the electron cathode. BRIEF DESCRIPTION OF DRAWINGS

[0068] Figure 1 It is a structural schematic view of the MCP lifetime test system for high-energy cosmic ray detection.

[0069] Specific reference signs are as follows:

[0070] 1-laser; 2-light homogenization device; 3-adjustable diaphragm; 4-electron cathode; 5-MCP sample to be detected; 6-anode plate; 7-first ammeter; 8-driving line; 9-first ammeter data acquisition card; 10-acquisition optical fiber; 11-driving power supply; 12-spectrometer; 13-control system; 14-coaxial cable. DETAILED DESCRIPTION

[0071] In order to make the advantages and characteristics of the application clearer, the application is further described in detail below in combination with the drawings and specific embodiments.

[0072] A MCP lifetime testing method for high-energy cosmic ray detection, specifically comprising the following steps:

[0073] 1】Place the electron cathode 4, the MCP sample 5 to be tested, and the anode plate 6 in a whole-closed high vacuum tube with a vacuum degree of 10 -4 Pa-10 - 3 10-4Pa order of magnitude, and set a gap of 1mm-3mm between the MCP sample 5 to be tested and the electron cathode 4, and between the MCP sample 5 to be tested and the anode plate 6; the gaps are supported by resin materials to prevent high-voltage discharge, high-voltage breakdown, and high-temperature structural deformation under vacuum conditions; sequentially arrange the adjustable diaphragm 3 and the high vacuum tube on the incident light path, so that the adjustable diaphragm 3 is located at the front end of the electron cathode 4; wherein the high-energy light source has a pulse width of 10-100ns and a power greater than 3W, and the electron energy of the electron cathode 4 is 1eV-15eV;

[0074] 2】Close the adjustable diaphragm 3, turn on the high-energy light source, and calibrate the spectrum and intensity of the high-energy photons to detect whether the test requirements are met;

[0075] 3】Apply corresponding high-voltage electric fields to the anode plate 6, the MCP sample 5 to be tested, and the electron cathode 4 in sequence to make the device in an optimal working state; wherein an adjustable voltage of 1000-1500V is applied to the anode plate 6; the input surface of the MCP sample 5 to be tested is grounded, if the MCP sample 5 to be tested is a single MCP, an adjustable voltage of 0-1000V is applied to the output surface thereof, if the MCP sample 5 to be tested is a double MCP, an adjustable voltage of 1000-1800V is applied to the output surface thereof; an opening voltage of -170V--250V is applied to the electron cathode 4. In this embodiment, the MCP sample 5 to be tested is a single MCP, the input surface thereof is grounded, and the voltage applied to the output surface thereof is positively correlated with the distance between the anode plate 6 and the MCP sample 5 to be tested, since the distance between the anode plate 6 and the MCP sample 5 to be tested is set to 2mm in this embodiment, the voltage applied to the output surface thereof is 300V; 1200V is applied to the anode plate 6; -200V is applied to the electron cathode 4 as the opening voltage; it is worth noting that after the test is completed, 40-75V should be applied to the electron cathode 4 as the closing voltage to protect it.

[0076] 4】Adjust the position and aperture size of the adjustable diaphragm 3 according to the position and size of the MCP sample 5 to be tested, so that the surface of the electron cathode 4 receives as many photons as possible, and the electron cathode 4 excites electrons with an output current density of 10 -9 A / cm 2 order of magnitude under the action of the electric field; after the electrons are multiplied by the MCP sample 5 to be tested, the anode plate 6 collects the multiplied electrons and outputs current;

[0077] 5】Detect the output current of the anode plate 6, and normalize the laser intensity in the measurement interval based on the maximum laser intensity; the lifetime MCP of the to-be-tested MCP sample 5 is obtained through the following formula: life :

[0078]

[0079] wherein Q n represents the total amount of charge collected by the anode plate 6; the unit is C (coulomb); S in represents the area of the laser-incident electron cathode 4; the unit is cm (centimeter); i represents the current generated at the anode plate 6 at the moment; the unit is A (ampere), Q0 represents the total amount of charge of the anode plate 6 under the initial state condition, which is usually 0; the unit is C (coulomb); f(I, t) represents the laser intensity normalization function; and r represents the current light aperture of the adjustable diaphragm 3, the unit is cm (centimeter).

[0080] In order to prevent the influence of ambient light on the test result, the test needs to be carried out in a darkroom.

[0081] In order to realize the above-mentioned MCP lifetime test method for high-energy cosmic ray detection, the application further provides an MCP lifetime test structure for high-energy cosmic ray detection, as shown in the figure, comprising a high-vacuum tube, a laser 1, a light homogenization device 2, an adjustable diaphragm 3, an electron cathode 4, an anode plate 6, a first ammeter 7, a driving line 8, a first ammeter data acquisition card 9, a driving power supply 11, a spectrometer 12, an acquisition optical fiber 10, a control system 13 and a coaxial cable 14. Figure 1

[0082] The light source in the application is provided by the laser 1, according to the characteristics and test requirements of the to-be-tested MCP sample 5, an ultraviolet laser is adopted in the embodiment, specifically an ultraviolet LED, the output center wavelength is ≤280 nm, the wavelength drift is ≤±3 nm at room temperature (25℃), the stable output power is ≥3.0 W, and the service life is ≥2000 hours; in other embodiments of the application, the laser 1 can also adopt an LD light source. The laser 1 is driven to emit light by the driving power supply 11 in the embodiment, and a signal source can also be used to drive light emission when the laser 1 is small power. The light homogenization device 2 and the high-vacuum tube are sequentially located on the exit light path of the laser 1. The light homogenization device 2 is used to make the incident laser energy uniformly distributed, which can usually adopt a homogenization device such as ground glass, an integrating sphere, etc., since the volume of the ground glass is small, and the structure is simple and convenient to operate, the ground glass is preferred in the embodiment, and the ground glass is placed close to the laser 1, so that an energy-uniform light spot can be obtained within an effective divergence angle. The vacuum degree of the high-vacuum tube is 10 -4 Pa-10 -3 ​The electron cathode 4, the MCP sample 5 to be tested, and the anode plate 6 are sequentially arranged inside the high-vacuum tube along the emission direction of the laser 1, with gaps of 1mm-3mm between the MCP sample 5 and the electron cathode 4, and between the MCP sample 5 and the anode plate 6. To prevent high-voltage discharge, high-voltage breakdown, and high-temperature structural deformation under vacuum conditions, resin support structures are provided between the MCP sample 5 and the electron cathode 4, and between the MCP sample 5 and the anode plate 6. It is worth noting that to prevent ion contamination and air oxidation, the high-vacuum tube needs to be nitrogen-filled for storage when the system is not in operation, and then set to a high-vacuum state for the next operation. The position and aperture of the adjustable aperture 3 are adjustable. By adjusting the position and aperture of the adjustable aperture 3, the position and number of photons incident on the surface of the electron cathode 4 can be adjusted, so that the corresponding position on the surface of the electron cathode 4 receives as many photons as possible. The adjustable aperture 3 is located between the light homogenization device 2 and the electron cathode 4. It can be placed close to the outer surface of the high vacuum tube's optical window or close to the front surface of the electron cathode 4. In this embodiment, the adjustable aperture 3 is placed close to the outer surface of the high vacuum tube's optical window. This arrangement is beneficial for the structural design of the high vacuum tube and the adjustment of the size of the adjustable aperture 3. The aperture of the adjustable aperture 3 can be set in different shapes, such as circular, square, triangular, star-shaped, etc. In this embodiment, a circular shape is used. The aperture of the adjustable aperture 3 is less than or equal to the diameter of the MCP sample 5 under test. Since the performance degradation and damage of some areas of the MCP sample 5 under test can cause damage to the MCP sample 5, the adjustable aperture 3 should be selected as small as possible during the MCP lifetime test. One output terminal of the control system 13 is connected to the input terminal of the adjustable aperture 3 through the drive line 8, and is used to drive and adjust the position and aperture size of the adjustable aperture 3 according to the characteristics and test requirements. To select a suitable luminous flux during testing, the adjustable aperture 3 in this embodiment employs pulse code modulation to drive the aperture of the adjustable aperture 3 to a suitable angle via a small servo motor rotating the transmission shaft. The electron cathode 4 is used to convert incident photons into electrons. It is typically made of materials such as dual-alkali, multi-alkali, Cs, Au, Cs, B, and Gd. Since the light source in this embodiment is an ultraviolet light source, the electron cathode 4 is a gold-plated electron cathode with a plating thickness of 50μm-200μm. To obtain better excitation effect, the distance between the laser 1 and the incident surface of the electron cathode 4 should not be too long, typically less than or equal to 20cm, preferably 3cm-5cm. The smaller the distance, the more photons irradiate the surface of the electron cathode 4, and the more electrons are excited by the electron cathode 4. In this invention, the MCP sample 5 under test is used to multiply the electrons input from the electron cathode 4. It can use a single MCP or a dual MCP. When using a dual MCP, the voltage applied to the output surface of the MCP sample 5 under test is twice that of a single MCP, typically 1000-1800V.In order to ensure that the MCP sample 5 to be tested can obtain sufficient electron injection, the current excited on the surface of the electron cathode 4 by the incident light in the embodiment needs to be greater than or equal to 5 nA. The anode plate 6 is used for collecting the electrons excited by the MCP sample 5 to be tested, and can adopt a material such as a PCB plate or a graphite anode, and the MCP sample 5 needs to be stored in a high-vacuum cavity filled with nitrogen. In order to collect all the electrons excited by the MCP sample 5 to be tested, the anode plate 6 is usually consistent in shape with the adjustable diaphragm 3, and the diameter of the anode plate 6 is greater than the size of the maximum light aperture of the adjustable diaphragm 3, that is, the diameter of the anode plate 6 is greater than the diameter of the MCP sample 5 to be tested.

[0083] The resistance of the first ammeter 7 is greater than or equal to 10 12 Ω, and the current accuracy reaches 1×10 -13 A, and the input end of the first ammeter 7 is connected to the output end of the anode plate 6 through the coaxial cable 14, and is used for detecting the output current of the anode plate 6. The coaxial cable 14 is used as a main signal transmission channel to lead out the current signal from the anode plate 6. In order to reduce the interference of the surrounding electromagnetic environment, the length of the coaxial cable 14 needs to be ≤30 cm, and in the embodiment, the length is 10 cm. At the same time, in order to ensure the accuracy of the test results, it needs to be noted that the impedance of the first ammeter 7 needs to be matched with the overall impedance of the electron cathode 4, the MCP sample 5 to be tested and the anode plate 6, otherwise, the output current of the anode plate 6 is easy to be shunted, and the service life test result of the MCP sample 5 to be tested deviates from the true value. In the measurement process, the signal cable of the first ammeter 7 needs to be fixed to reduce the current jump phenomenon caused by vibration. The output end of the first ammeter 7 is connected to the input end of the first ammeter data acquisition card 9, which is used for collecting the detected current data. The output end of the first ammeter data acquisition card 9 is connected to the first input end of the control system 13, which is used for transmitting the collected current data to the control system 13. Preferably, the output end of the electron cathode 4 is connected to a second ammeter and a second ammeter data acquisition card. The second ammeter is used for detecting the output current of the electron cathode 4, and the requirements of the second ammeter and the first ammeter are consistent. The output end of the second ammeter is connected to the input end of the second ammeter data acquisition card, which is used for collecting the output current of the electron cathode 4 in real time. The output end of the second ammeter data acquisition card is connected to the third input end of the control system 13. In this way, whether the light source is stable can be reflected by detecting the output current of the electron cathode, and the performance of the electron cathode 4 can be monitored in real time. At the same time, the gain of the MCP can be obtained by calculating the ratio of the anode plate and the electron cathode.

[0084] During the test, the output power of the laser 1 increases with time, which is constantly reduced until it reaches a steady state, so it is necessary to monitor the intensity of the output laser. The collection optical fiber 10 is located at the rear end of the light homogenization device 2, which is used to collect the output laser intensity of the laser 1. In the present application, the fiber core diameter of the collection optical fiber 10 is greater than 400 um, which passes through the wavelength of 190-1100 nm, and the outer layer is provided with a protective sleeve. The end face of the collection optical fiber 10 is located at the rear 10 cm-40 cm of the light homogenization device 2, and the fiber core axis and the normal line of the light homogenization device 2 are at an angle of 45°-80°. Preferably, in the present embodiment, an adjusting frame is arranged below the fiber light of the collection optical fiber 10, which is used to adjust the angle and position thereof; the end face of the collection optical fiber 10 is adjusted to be located at the rear 20 cm of the ground glass, and the fiber core axis and the normal line of the ground glass are adjusted to be at an angle of 50°, which can better collect the output laser intensity of the laser 1. The spectrometer 12 is used to monitor the laser center wavelength and the laser intensity change in real time, and the output end thereof is connected to the second input end of the control system 13 through USB, which is used to transmit the laser intensity change to the control system 13. The control system 13 transmits the laser intensity change to the MCP life The calculation is as follows:

[0085]

[0086] Wherein, Q n represents the total amount of charge collected by the anode plate 6; the unit is C (coulomb); S in represents the area of the laser incident electron cathode 4; the unit is cm (centimeter); i represents the instantaneous current generated at the anode plate 6; the unit is A (ampere), Q0 represents the total amount of charge of the anode plate 6 under the initial state condition, which is usually 0; the unit is C (coulomb); f(I,t) represents the laser intensity normalization function; r represents the current light aperture of the adjustable diaphragm 3, the unit is cm (centimeter).

[0087] The working principle of the system is specifically as follows: the laser 1 generates incident photons, which directly bombard the electron cathode 4 through the light homogenization device 2 and the adjustable diaphragm 3, and electrons are excited under the action of a suitable electric field. By adjusting the position and aperture size of the diaphragm 3, the position and the number of photons reaching the surface of the electron cathode 4 can be controlled, and the position and intensity of the injected electrons of the MCP sample 5 to be tested can be further adjusted. In the working process, a corresponding high voltage is applied between the two ends of the MCP. In the testing process, on the one hand, the real-time output laser intensity of the laser 1 in a period of time is detected in real time through the optical fiber 10 and the spectrometer 12, and is sent to the control system 13; on the other hand, the corresponding real-time output current of the anode plate 6 is detected through the first ammeter 7, and is sent to the control system 13. According to the input real-time output laser intensity, the real-time output current and the current light transmission aperture of the adjustable diaphragm 3, the control system 13 can accurately obtain the MCP lifetime after processing. The testing method and system can effectively reduce the system error and realize scientific and effective evaluation of the MCP lifetime. The testing method and system provide detailed data support and technical guidance for the development of high-performance micro-light detection devices.

[0088] In the measurement process, the isolation shielding of the first ammeter 7 is necessary, especially when the test voltage is relatively high and the current is very small, the influence is great. When measuring the micro-current, the isolation materials such as clamps, terminal blocks and shielding wires of parts should be carefully selected. According to experience and actual data, the isolation performance of polytetrafluoroethylene, glass and ceramic materials is relatively ideal, but since glass and ceramic are difficult to process and are easy to damage, polytetrafluoroethylene is preferred in the embodiment. In the use process, the clamps, joints and the like should be kept clean, so that the isolation shielding performance of the first ammeter 7 remains good and the measurement accuracy is improved. In addition, the shielding of the coaxial cable 14 is also very important, and shielded cable should be used, and core coaxial shielded cable is preferred. The wiring of the coaxial cable 14 should be away from interference sources such as alternating current and high-voltage power supply.

[0089] The above description is only used to illustrate the technical solutions of the present application, but not to limit it. For ordinary skilled persons in the art, the specific technical solutions described in the above embodiments can be modified, or some technical features can be replaced by equivalents, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions protected by the present application.

Claims

1. A method for testing the lifetime of an MCP for high-energy cosmic rays, characterized by, It comprises the following steps: 1】Place the electron cathode (4), the MCP sample to be tested (5) and the anode plate (6) in the high vacuum tube in turn, and set a gap between the MCP sample to be tested (5) and the electron cathode (4) and between the MCP sample to be tested (5) and the anode plate (6); and place the adjustable diaphragm (3) and the high vacuum tube in the incident light path of the high-energy light source in turn; the high-energy light source has a pulse width of 10-100 ns and a power greater than 3 W, and the electron energy of the electron cathode (4) is 1 eV-15 eV; 2】Close the adjustable diaphragm (3), turn on the high-energy light source, and calibrate the spectrum and intensity of the high-energy light source; 3】Apply a corresponding high-voltage electric field to the anode plate (6), the MCP sample to be tested (5) and the electron cathode (4) in turn to make the device work; 4】According to the position and size of the to-be-tested MCP sample (5), the position and aperture size of the adjustable diaphragm (3) are adjusted, so that the electron cathode (4) receives photons and outputs an electron current density of 10 -9 A / cm 2 order of magnitude under the action of an electric field; and the electrons are sequentially subjected to electron multiplication and electron collection by the to-be-tested MCP sample (5) and the anode plate (6), and the anode plate (6) outputs an electric current. 5】The output current of the anode plate (6) is detected, and the laser intensity in the measurement interval is normalized based on the maximum laser intensity. The lifetime MCP of the MCP sample (5) to be measured is obtained by the following formula life : where Q n represents the total amount of charge collected by the anode plate (6); S in represents the area of the laser-incident electron cathode (4); i represents the instantaneous current generated at the anode plate (6); Q0represents the total amount of charge of the anode plate (6) in the initial state; f(I, t) represents a laser intensity normalization function; and r represents the current aperture of the adjustable diaphragm (3).

2. The MCP life test method for high-energy cosmic ray detection according to claim 1, characterized in that: Step 1 is specifically: The electron cathode (4), the MCP sample (5) to be tested and the anode plate (6) are placed in a high vacuum tube with a vacuum degree of 10 -4 Pa-10 -3 The electron cathode (4), the MCP sample (5) to be tested and the anode plate (6) are placed in a high vacuum tube with a vacuum degree of 10 -4 Pa-10 -3 The electron cathode (4), the MCP sample (5) to be tested and the anode plate (6) are placed in a high vacuum tube with a vacuum degree of 10 -4 Pa-10 -3 The electron cathode (4), the MCP sample (5) to be tested and the anode plate (6) are placed in a high vacuum tube with a vacuum degree of 10 -4 Pa-10 -3 The electron cathode (4), the MCP sample (5) to be tested and the anode plate (6) are placed in a high vacuum tube with a vacuum degree of 10 -4 Pa-10 -3 The electron cathode (4), the MCP sample (5) to be tested and the anode plate 3. The MCP life test method for high-energy cosmic ray detection according to claim 1 or 2, characterized in that: In step 3, applying a corresponding high-voltage electric field to the anode plate (6), the MCP sample to be tested (5) and the electron cathode (4) in turn is specifically: Applying a 1000-1500 V adjustable voltage to the anode plate (6); Grounding the input surface of the MCP sample to be tested (5), and applying a 0-1000 V adjustable voltage to the output surface of the MCP sample to be tested (5) if the MCP sample to be tested (5) is a single MCP, or applying a 1000-1800 V adjustable voltage to the output surface of the MCP sample to be tested (5) if the MCP sample to be tested (5) is a double MCP; Applying an opening voltage of -170 V to -250 V to the electron cathode (4).

4. The MCP life test method for high-energy cosmic ray detection according to claim 3, characterized in that: Steps 1-5 are performed in a darkroom.

5. An MCP life test system for high-energy cosmic ray detection for implementing the MCP life test method for high-energy cosmic ray detection according to any one of claims 1-4, characterized in that: It comprises a laser (1), an adjustable diaphragm (3), an electron cathode (4), an anode plate (6), a first current meter (7), a driving line (8), a first current meter data acquisition card (9), a spectrometer (12), a control system (13) and a coaxial cable (14); The laser (1) is provided with a light homogenization device (2) and a high vacuum tube in turn; The electron cathode (4), the MCP sample to be tested (5) and the anode plate (6) are arranged in the high vacuum tube in turn along the emission direction of the laser (1), and a gap is arranged between the MCP sample to be tested (5) and the electron cathode (4) and between the MCP sample to be tested (5) and the anode plate (6); The adjustable diaphragm (3) is located between the light homogenization device (2) and the electron cathode (4), and the position and aperture size of the adjustable diaphragm (3) are adjustable. The input end of the first ammeter (7) is connected to the output end of the anode plate (6) through a coaxial cable (14) for detecting the output current of the anode plate (6); the output end of the first ammeter (7) is connected to the input end of the first ammeter data acquisition card (9) for collecting the detected current data, and the output end of the first ammeter data acquisition card (9) is connected to the first input end of the control system (13) for transmitting the collected current data to the control system (13); The spectrometer (12) is provided with a collection optical fiber (10); the collection optical fiber (10) is located at the rear end of the light homogenization device (2) for real-time collection of the output laser intensity of the laser (1); the spectrometer (12) is used for real-time monitoring of the laser intensity, and the output end thereof is connected to the second input end of the control system (13) for transmitting the laser intensity to the control system (13); The control system (13) is used for obtaining the lifetime of the MCP sample (5) to be detected according to the input laser intensity of the laser (1), the output current of the anode plate (6) and the current light aperture of the adjustable diaphragm (3); One output end of the control system (13) is connected to the input end of the adjustable diaphragm (3) through a driving line (8) for adjusting the position and aperture size of the adjustable diaphragm (3).

6. The MCP lifetime test system for high-energy cosmic ray detection according to claim 5, characterized in that: The light aperture of the adjustable diaphragm (3) is less than or equal to the diameter of the MCP sample (5) to be detected; The high vacuum tube has a vacuum degree of 10 -4 Pa-10 -3 Pa order of magnitude; The resistance of the first galvanometer (7) is greater than or equal to 10 12 Ω, with a current accuracy of 1 x 10 -13 A; The first ammeter (7) is impedance matched with the whole composed of the electron cathode (4), the MCP sample (5) to be detected and the anode plate (6); The fiber core diameter of the collection optical fiber (10) is greater than 400 um, and the wavelength thereof is 190-1100 nm; The lifetime MCP of the MCP sample (5) under test is calculated in the control system (13) by the formula life : where Q n represents the total amount of charge collected by the anode plate (6); S in represents the area of the laser-incident electron cathode (4); i represents the instantaneous current generated at the anode plate (6); Q0represents the total amount of charge of the anode plate (6) in the initial state; f(I, t) represents a laser intensity normalization function; and r represents the current aperture of the adjustable aperture (3).

7. The MCP lifetime test system for high-energy cosmic ray detection according to claim 6, characterized in that: The gap between the MCP sample (5) to be detected and the electron cathode (4) and the gap between the MCP sample (5) to be detected and the anode plate (6) are 1 mm-3 mm; The distance from the laser (1) to the incident surface of the electron cathode (4) is less than or equal to 20 cm; The length of the coaxial cable (14) is less than or equal to 30 cm; The end surface of the collection optical fiber (10) is located at 10 cm-40 cm behind the light homogenization device (2), and the included angle between the fiber core axis of the collection optical fiber (10) and the normal line of the light homogenization device (2) is 45°-80°.

8. The MCP lifetime test system for high-energy cosmic ray detection according to claim 7, characterized in that: The distance from the laser (1) to the incident surface of the electron cathode (4) is 3 cm-5 cm; The length of the coaxial cable (14) is 10 cm; The end surface of the collection optical fiber (10) is located at 20 cm behind the light homogenization device (2), and the included angle between the fiber core axis of the collection optical fiber (10) and the normal line of the light homogenization device (2) is 50°.

9. The MCP lifetime test system for high-energy cosmic ray detection according to any one of claims 5-8, characterized in that: Resin support structures are arranged between the to-be-tested MCP sample (5) and the electron cathode (4) and between the to-be-tested MCP sample (5) and the anode plate (6).

10. The MCP life test system for high-energy cosmic ray detection according to claim 9, characterized in that: a second ammeter and a second ammeter data acquisition card are further included; an input end of the second ammeter is connected to an output end of the electron cathode (4) to detect the output current of the electron cathode (4), an output end of the second ammeter is connected to an input end of the second ammeter data acquisition card to collect the output current of the electron cathode (4) in real time, and an output end of the second ammeter data acquisition card is connected to a third input end of the control system (13); The resistance of the second current meter is greater than or equal to 10 12 Ω, and the current accuracy reaches 1 x 10 -13 A; the second ammeter is impedance-matched with the whole of the electron cathode (4), the to-be-tested MCP sample (5) and the anode plate (6).

Images