A microchannel plate collection efficiency test system and test method

Abstract

The present disclosure relates to a microchannel plate collection efficiency test system and a test method. The test system includes: a pulse power supply, a light source, a photocathode, an output charge spectrum test system, a vacuum chamber, and a DC high-voltage power supply; the pulse power supply drives the light source to emit light to irradiate the photocathode; the output charge spectrum test system includes an anode and a computer, the photocathode and the anode are arranged in the vacuum chamber, and the computer is arranged outside the vacuum chamber; the DC high-voltage power supply is electrically connected to the photocathode, the anode, and the microchannel plate to be tested arranged between the photocathode and the anode to provide a working voltage; the output charge spectrum test system collects the electrons multiplied and emitted by the microchannel plate through the anode, obtains a second output pulse, and calculates the collection efficiency of the microchannel plate to be tested according to the first output pulse of the pulse power supply and the second output pulse. The present invention can test the collection efficiency of the microchannel plate through experiments.

Description

Technical Field

[0001] The present disclosure relates to the technical field of microchannel technology, and particularly relates to a microchannel plate collection efficiency testing system and a testing method. Background Art

[0002] A microchannel plate is a two-dimensional channel-type continuous dynode electron multiplier device, which simultaneously has the capabilities of detecting electrons, ions, ultraviolet photons, and soft X-rays, as well as a time resolution of sub-nanosecond level. It is composed of millions of microchannels with a diameter of several micrometers. When particles are incident on the inner wall of the microchannels, primary secondary electrons are generated. If a certain voltage is applied across the two ends of the channels, the generated primary secondary electrons are accelerated under the action of the electric field and, after multiple collisions with the channel walls and the electron multiplication process, a large number of electrons are finally generated at the output end, thus realizing the enhancement of the signal.

[0003] For a microchannel plate and a microchannel plate detector, because of its limited opening area, when electrons are incident on the surface of the microchannel plate, there is a certain probability that they will hit the electrodes on the pore walls of the microchannel plate and be absorbed, resulting in the loss of effective signals. Therefore, the collection efficiency is an important parameter for characterizing microchannel plates and microchannel plate detectors.

[0004] Currently, there is no effective experimental testing method and equipment for the collection efficiency of microchannel plates, and only the collection efficiency of microchannel plates can be obtained by relying on simulation calculations. Summary of the Invention

[0005] The purpose of the present invention is to provide a microchannel plate collection efficiency testing system and a testing method, which are used to solve the problem that only simulation calculations can be relied on to obtain the collection efficiency of microchannel plates in the prior art. The technical solutions provided by the present invention are as follows:

[0006] According to the first aspect of the embodiments of the present disclosure, a microchannel plate collection efficiency testing system is provided, including: a pulse power supply, a light source, a photocathode, an output charge spectrum testing system, a vacuum chamber, and a DC high-voltage power supply;

[0007] The power input end of the light source is connected to the pulse power supply, and the light source is used to irradiate the photocathode;

[0008] The output charge spectrum testing system includes an anode, and the photocathode and the anode are arranged in the vacuum chamber; the output charge spectrum testing system further includes a computer arranged outside the vacuum chamber;

[0009] The DC high-voltage power supply is respectively electrically connected to the photocathode, the anode, and the microchannel plate to be tested arranged between the photocathode and the anode, and the DC high-voltage power supply provides working voltages for the photocathode, the microchannel plate, and the anode respectively;

[0010] The output charge spectrum test system collects the electrons emitted after multiplication by the microchannel plate through the anode to obtain a second output pulse, and calculates the collection efficiency of the microchannel plate to be tested based on the first output pulse of the pulse power supply and the second output pulse.

[0011] In one embodiment, the microchannel plate collection efficiency test system further includes:

[0012] A silicon photodiode, disposed outside the vacuum chamber between the light source and the photocathode.

[0013] In one embodiment, the microchannel plate collection efficiency test system further includes:

[0014] A vacuum pump group, connected to the vacuum chamber, and the vacuum pump group is used to evacuate the inside of the vacuum chamber to make its vacuum degree reach a predetermined vacuum degree value.

[0015] In one embodiment, the number of microchannel plates to be tested between the photocathode and the anode is 2 or 3.

[0016] According to a second aspect of the embodiments of the present disclosure, there is provided a method for testing the collection efficiency of a microchannel plate, which is used for the microchannel plate collection efficiency test system described in any of the above embodiments, and includes the following steps:

[0017] Load a predetermined number of microchannel plates to be tested between the photocathode and the anode in the vacuum chamber;

[0018] Apply working voltages to the photocathode, the microchannel plate, and the anode through a DC high-voltage power supply;

[0019] Turn on the pulse power supply to drive the light source, and adjust the parameters of the pulse power supply to change the light emission intensity of the light source so that the photoelectrons generated by the photocathode under the irradiation of the light source meet the measurement conditions;

[0020] Control the first output pulse frequency of the pulse power supply within a preset frequency range, collect the electrons emitted after multiplication by the microchannel plate through the anode to obtain a second output pulse, and obtain the first output pulse frequency R in and the second output pulse frequency R out ;

[0021] Calculate the ratio of the first output pulse frequency R in and the second output pulse frequency R out and use the ratio as the collection efficiency of the microchannel plate.

[0022] In one embodiment, the adjusting the parameters of the pulse power supply to change the light emission intensity of the light source so that the photoelectrons generated by the photocathode under the irradiation of the light source meet the measurement conditions includes:

[0023] Adjust the parameters of the pulsed power supply, and detect the ground conduction current of the photocathode in real time;

[0024] Determine whether the ground conduction current of the photocathode meets a preset first condition;

[0025] If the ground conduction current of the photocathode does not meet the preset first condition, return to execute the step of adjusting the parameters of the pulsed power supply;

[0026] When the ground conduction current of the photocathode meets the preset first condition, measure the initial photocurrent I at this time through a silicon photodiode s , calculate the coefficient k = I in / I s ; where, I in is the ground conduction current value of the photocathode when the preset first condition is met;

[0027] Lower the light source intensity, and determine whether the real-time photocurrent measured by the silicon photodiode meets a preset second condition;

[0028] If the real-time photocurrent meets the preset second condition, it is determined that the photoelectrons generated by the photocathode meet the measurement conditions; otherwise, return to execute the step of lowering the light source intensity.

[0029] In one embodiment, the first condition is that the ground conduction current of the photocathode is on the order of 100 pA.

[0030] In one embodiment, determining whether the real-time photocurrent meets a preset second condition includes:

[0031] Calculate the product of the real-time photocurrent measured by the silicon photodiode and the coefficient;

[0032] Determine whether the currently calculated product reaches the femtoampere level. If so, it is determined that the real-time photocurrent meets the preset second condition.

[0033] In one embodiment, the preset frequency range is 50 - 100 kHz, and the preset number is 2 or 3.

[0034] In one embodiment, before applying the working voltage to the photocathode, microchannel plate, and anode through the DC high-voltage power supply, it further includes:

[0035] Evacuate the inside of the vacuum chamber through a vacuum pump group to make its vacuum degree reach a predetermined vacuum degree value.

[0036] The technical solutions provided by the embodiments of the present disclosure may include the following beneficial effects:

[0037] The present invention provides a microchannel plate collection efficiency test system and a test method. The test system is built to make the microchannel plate work, and output pulses are obtained through the output charge spectrum test system. Since the pulse height distribution indicates the relationship between the signals and the energies of various noise electrons contained in the output pulses of an optoelectronic imaging system and the proportion they account for in the total number of output electrons, the collection efficiency of the microchannel plate is characterized by the ratio of the output signal pulse counting rate to the input signal pulse counting rate. The collection efficiency of the microchannel plate can be tested through experiments, solving the problem in the prior art that only simulation calculations can be relied on to calculate the collection efficiency of the microchannel plate, and playing an important role in testing the performance of the microchannel plate and the detector.

[0038] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure.

[0040] Figure 1 is a schematic structural diagram of a microchannel plate collection efficiency test system provided by the present invention;

[0041] Figure 2 is a flowchart of a microchannel plate collection efficiency test method provided by the present invention;

[0042] Figure 3 is Figure 2 a flowchart of the implementation method of step S3 in DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] Here, the exemplary embodiments will be described in detail, and the examples are shown in the accompanying drawings. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. On the contrary, they are only examples of systems and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0044] Figure 1 As shown is a schematic structural diagram of a microchannel plate collection efficiency test system provided by the present invention, as Figure 1As shown in the figure, the system includes: a pulse power supply 1, a light source 2, a photocathode 3, an output charge spectrum test system, a vacuum chamber 6, and a DC high-voltage power supply 9. Among them, the power input terminal of the light source 2 is connected to the pulse power supply 1, and the light source 2 is used to irradiate the photocathode 3. The output charge spectrum test system includes an anode 5. The photocathode 3 and the anode 5 are arranged in the vacuum chamber 6. The output charge spectrum test system further includes a computer 7 arranged outside the vacuum chamber 6. The DC high-voltage power supply 9 is electrically connected to the photocathode 3, the anode 5, and a microchannel plate 4 to be tested arranged between the photocathode 3 and the anode 5 respectively. The DC high-voltage power supply 9 provides working voltages for the photocathode 3, the microchannel plate 4, and the anode 5 respectively. The output charge spectrum test system collects the electrons emitted after being multiplied by the microchannel plate 4 through the anode 5, obtains a second output pulse through the computer 7, and the computer 7 also calculates the collection efficiency of the microchannel plate 4 to be tested according to the first output pulse of the pulse power supply 1 and the second output pulse.

[0045] In this embodiment, under the action of the pulse power supply 1, the light source 2 generates photons with a certain illuminance. The photons interact with the photocathode 3 to generate photoelectrons. The photoelectrons are multiplied by the microchannel plate 4 to be tested and then emitted onto the anode 5. In addition to the anode 5, the output charge spectrum test system further includes a computer 7 with corresponding statistical analysis software. The computer 7 statistically analyzes the magnitude and distribution of the electron energy collected by the anode 5 when the test conditions are met, obtains pulse height distribution data, and obtains the pulse frequency of the second output pulse signal output from the pulse height distribution. Subsequently, according to the first output pulse of the pulse power supply 1 and the second output pulse under the test conditions, the collection efficiency of the microchannel plate 4 to be tested is calculated. Finally, the pulse height distribution data and / or graph of the second output pulse, as well as signal parameters such as the frequency of the second output pulse, can be output to the user, and at the same time, the test result of the collection efficiency of the microchannel plate 4 is output.

[0046] Preferably, as Figure 1 shown in the figure, the microchannel plate collection efficiency test system provided by the present invention further includes: a silicon photodiode 10, arranged outside the vacuum chamber 6 between the light source 2 and the photocathode 3. The silicon photodiode 10 is used to detect the light intensity of the light source 2 so as to timely adjust the pulse power supply 1 to adjust the light intensity of the light source 2 to meet the test conditions. Obviously, in this embodiment, the silicon photodiode 10 needs to be externally connected to a circuit to form an induced current detection circuit, which will not be elaborated here.

[0047] Preferably, as Figure 1 shown in the figure, the microchannel plate collection efficiency test system provided by the present invention further includes: a vacuum pump group 8, connected to the vacuum chamber 6. The vacuum pump group 8 is used to evacuate the inside of the vacuum chamber 6 to make its vacuum degree reach a predetermined vacuum degree value. A one-way valve that only allows outflow and no inflow can be arranged at the connection position between the vacuum pump group 8 and the vacuum chamber to ensure the vacuum degree of the vacuum chamber 6.

[0048] Preferably, when using Figure 1 the system shown in the figure for testing, when testing, the number of microchannel plates 4 to be tested placed between the photocathode 3 and the anode 5 is 2 or 3, which can achieve the optimal signal amplification effect of the system, and enable the output charge spectrum test system to obtain more reliable analysis and test results.

[0049] Corresponding to the microchannel plate collection efficiency test system provided by the embodiments of the present invention, the embodiments of the present invention also provide a Figure 1 method for testing the microchannel plate collection efficiency of the microchannel plate collection efficiency test system shown in the figure, as Figure 2 shown in the figure, the method includes the following steps S1 - S5:

[0050] S1: Install a predetermined number of microchannel plates 4 to be tested between the photocathode 3 and the anode 5 in the vacuum chamber 6;

[0051] Preferably, the preset number is 2 or 3.

[0052] S2: Apply operating voltages to the photocathode 3, the microchannel plate 4, and the anode 5 through the DC high - voltage power supply 9;

[0053] Preferably, Figure 2 in the method shown in the figure, before step S2, the step of evacuating the inside of the vacuum chamber 6 by the vacuum pump group 8 to make its vacuum degree reach a predetermined vacuum degree value may further be included.

[0054] In this embodiment, when the positions of the components of the test system are adjusted and the vacuum degree of the vacuum chamber 6 meets the test requirements, appropriate operating voltages are respectively applied to the photocathode 3, the microchannel plate 4, and the anode 5 through the DC high - voltage power supply 9.

[0055] S3: Turn on the pulse power supply 1 to drive the light source 2, and adjust the parameters of the pulse power supply 1 to change the light emission intensity of the light source 2 so that the photoelectrons generated by the photocathode 3 irradiated by the light source 2 meet the measurement conditions.

[0056] In this embodiment, it is necessary to adjust the light source 2 so that the photoelectrons generated by the photocathode 3 meet the measurement conditions. For example, if there are too few photoelectrons, the microchannel plate 4 cannot generate or cannot reach the required number of multiplied electrons for testing.

[0057] S4: Control the first output pulse frequency of the pulse power supply 1 within a preset frequency range, collect the electrons multiplied and emitted by the microchannel plate 4 through the anode 5 to obtain a second output pulse, and acquire the first output pulse frequency R in and the second output pulse frequency R out .

[0058] Preferably, the preset frequency range is 50 to 100 kHz.

[0059] S5: Calculate the ratio of the first output pulse frequency R in and the second output pulse frequency R out as the collection efficiency of the microchannel plate 4.

[0060] In this embodiment, under the action of the pulse power supply 1, the light source 2 generates photons with a certain illuminance. The photons interact with the photocathode 3 to generate photoelectrons. The photoelectrons are multiplied by the microchannel plate 4 to be tested and then emitted onto the anode 5. The output charge spectrum test system tests and analyzes the magnitude and distribution of the electron energy collected by the anode 5 to obtain the pulse height distribution data. From the pulse height distribution, the pulse counting rate of the output second output pulse signal is obtained. Since the pulse height distribution indicates the relationship between the signals and the magnitudes of various noise electron energies contained in the output pulse of an optoelectronic imaging system and their proportions in the total number of output electrons, the ratio of the second output pulse counting rate to the input first output pulse counting rate can characterize the collection efficiency of the microchannel plate to be tested.

[0061] In an alternative embodiment, as Figure 3 shown, step S3 may include the following steps S31 - S35:

[0062] S31: Adjust the parameters of the pulse power supply 1 and detect the ground conduction current I in of the photocathode 3 in real time;

[0063] S32: Determine whether the ground conduction current I in of the photocathode 3 satisfies a preset first condition; if so, continue to execute S33, otherwise, return to execute step S31;

[0064] Preferably, the first condition is that the ground conduction current of the photocathode 3 is on the order of 100 pA.

[0065] S33: Measure the initial photocurrent I s at this time through the silicon photosensitive diode 10, and calculate the coefficient k = I in / I s ;

[0066] S34: Lower the light source intensity, and according to the real - time photocurrent I s ' measured by the silicon photosensitive diode 10,

[0067] S35: Determine whether the real - time photocurrent satisfies a preset second condition; if so, execute S36, otherwise return to execute S34;

[0068] Preferably, the second condition is that the product of the real-time photocurrent measured by the silicon photodiode 10 and the coefficient reaches the femtoampere level. That is, step S34 may include:

[0069] S341: Calculate the product I = I s ’×k of the real-time photocurrent measured by the silicon photodiode 10 and the coefficient;

[0070] S342: Determine whether the currently calculated product I reaches the femtoampere level. If so, execute S343; otherwise, execute S344;

[0071] S343: Determine that the real-time photocurrent satisfies the preset second condition.

[0072] S344: Determine that the real-time photocurrent does not satisfy the preset second condition.

[0073] S36: Determine that the photoelectrons generated by the photocathode 3 satisfy the measurement conditions.

[0074] The microchannel plate collection efficiency test system and test method provided by the embodiments of the present invention build a test system to make the microchannel plate work, obtain output pulses through the output charge spectrum test system, and characterize the collection efficiency of the microchannel plate by the ratio of the output signal pulse counting rate to the input signal pulse counting rate. It can experimentally test the collection efficiency of the microchannel plate, solves the problem in the prior art that only simulation calculations can be relied on to calculate the collection efficiency of the microchannel plate, and plays an important role in testing the performance of the microchannel plate and the detector.

[0075] Those skilled in the art will readily think of other embodiments of the present disclosure after considering the specification and the practice disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common general knowledge or conventional technical means in the technical field not disclosed in the present disclosure. The specification and the embodiments are only regarded as exemplary, and the true scope and spirit of the present disclosure are pointed out by the following claims.

[0076] It should be understood that the present disclosure is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present disclosure is only limited by the appended claims.

Claims

1. A microchannel plate collection efficiency test system, characterized in that, Including: A pulse power supply (1), a light source (2), a photocathode (3), an output charge spectrum test system, a vacuum chamber (6), and a DC high-voltage power supply (9); The power input terminal of the light source (2) is connected to the pulse power supply (1), and the light source (2) is used to irradiate the photocathode (3); The output charge spectrum test system includes an anode (5), and the photocathode (3) and the anode (5) are arranged in the vacuum chamber (6); the output charge spectrum test system further includes a computer (7) arranged outside the vacuum chamber (6); The DC high-voltage power supply (9) is electrically connected to the photocathode (3), the anode (5), and a microchannel plate (4) to be tested arranged between the photocathode (3) and the anode (5) respectively, and the DC high-voltage power supply (9) provides working voltages for the photocathode (3), the microchannel plate (4), and the anode (5) respectively; The output charge spectrum test system collects the electrons multiplied and emitted by the microchannel plate (4) through the anode (5) to obtain a second output pulse, and calculates the collection efficiency of the microchannel plate (4) to be tested according to the first output pulse of the pulse power supply (1) and the second output pulse.

2. The microchannel plate collection efficiency test system according to claim 1, wherein It further includes: A silicon photodiode (10), arranged outside the vacuum chamber (6) between the light source (2) and the photocathode (3).

3. The microchannel plate collection efficiency test system according to claim 1, wherein It further includes: A vacuum pump group (8), connected to the vacuum chamber (6), and the vacuum pump group (8) is used to evacuate the inside of the vacuum chamber (6) to make its vacuum degree reach a predetermined vacuum degree value.

4. The microchannel plate collection efficiency test system according to claim 1, wherein The number of microchannel plates (4) to be tested between the photocathode (3) and the anode (5) is 2 or 3 pieces.

5. A method for testing the collection efficiency of a microchannel plate, characterized in that, For the microchannel plate collection efficiency test system according to any one of claims 1-3, it includes the following steps: Load a predetermined number of microchannel plates (4) to be tested between the photocathode (3) and the anode (5) in the vacuum chamber (6); Apply working voltages to the photocathode (3), the microchannel plate (4), and the anode (5) through the DC high-voltage power supply (9); Turn on the pulse power supply (1) to drive the light source (2), and adjust the parameters of the pulse power supply (1) to change the light emission intensity of the light source (2) so that the photoelectrons generated by the photocathode (3) irradiated by the light source (2) meet the measurement conditions; The first output pulse frequency of the pulse power supply (1) is controlled within a preset frequency range, and the electrons multiplied and emitted by the microchannel plate (4) are collected through the anode (5) to obtain a second output pulse, thereby obtaining the first output pulse frequency R in and the second output pulse frequency R out ; Calculate the ratio of the first output pulse frequency R in and the second output pulse frequency R out and use the ratio as the collection efficiency of the microchannel plate (4).

6. The microchannel plate collection efficiency testing method according to claim 5, wherein The adjusting the parameters of the pulse power supply (1) to change the light emission intensity of the light source (2) so that the photoelectrons generated by the photocathode (3) irradiated by the light source (2) meet the measurement conditions includes: Adjust the parameters of the pulse power supply (1) and detect the ground conduction current of the photocathode (3) in real time; Judge whether the ground conduction current of the photocathode (3) meets a preset first condition; If the ground conduction current of the photocathode (3) does not meet the preset first condition, return to execute the step of adjusting the parameters of the pulse power supply (1); When the ground conduction current of the photocathode (3) satisfies a preset first condition, the initial photocurrent I at this time is measured by a silicon photodiode (10) disposed outside the vacuum chamber (6) between the light source (2) and the photocathode (3). s , calculate the coefficient k = I in / I s ; where I in is the value of the ground conduction current of the photocathode (3) when the preset first condition is satisfied. Lower the light source intensity, and judge whether the real-time photocurrent measured by the silicon photodiode (10) meets a preset second condition; If the real-time photocurrent satisfies a preset second condition, it is determined that the photoelectrons generated by the photocathode (3) satisfy the measurement conditions; otherwise, return to execute the step of reducing the light source intensity.

7. The method for testing the collection efficiency of a microchannel plate according to claim 6, characterized in that The first condition is that the conduction current of the photocathode (3) to the ground is on the order of 100 pA.

8. The microchannel plate collection efficiency testing method according to claim 6, wherein The determination of whether the real-time photocurrent satisfies a preset second condition includes: Calculating the product of the real-time photocurrent measured by the silicon photodiode (10) and the coefficient; Judging whether the currently calculated product reaches the femtoampere level. If so, it is determined that the real-time photocurrent satisfies the preset second condition.

9. The method for testing the collection efficiency of a microchannel plate according to claim 5, characterized in that, The preset frequency range is 50 - 100 kHz, and the predetermined number of sheets is 2 or 3.

10. The method for testing the collection efficiency of a microchannel plate according to any one of claims 5-9, characterized in that, Before applying operating voltages to the photocathode (3), the microchannel plate (4), and the anode (5) through the DC high-voltage power supply (9), it further includes: Evacuating the interior of the vacuum chamber (6) through the vacuum pump group (8) to make its vacuum degree reach a predetermined vacuum degree value.

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