A method of measuring image intensifier MCP recovery time

Abstract

The present application relates to image intensifier, to solve the problem that the MCP recovery time of the image intensifier cannot be measured accurately, and proposes a method for measuring the MCP recovery time of the image intensifier, comprising: arranging a CMOS camera at the output end of a fluorescent screen; generating two same period pulse signals of M1 and M2 through a signal generator to drive the same light source; closing M1 and opening M2 to obtain the original output light intensity of the fluorescent screen through the CMOS camera; synchronously outputting the pulse signals of M1 and M2, increasing the delay time between the pulse signals of M1 and M2 at certain time intervals in turn, and obtaining the corresponding output light intensity of the fluorescent screen under different delay times through the CMOS camera; closing M2 and opening M1 to obtain the corresponding pulse afterglow of the fluorescent screen under the corresponding delay time through the CMOS camera; calculating the corresponding MCP recovery degree according to the original output light intensity, the output light intensity and the pulse afterglow of the fluorescent screen, and when the value of the MCP recovery degree is equal to 1, the corresponding delay time is the MCP recovery time.

Description

TECHNICAL FIELD

[0001] The present application relates to an image intensifier, and particularly relates to a method for measuring MCP recovery time of an image intensifier. BACKGROUND

[0002] The image intensifier is a device capable of enhancing low-brightness optical images to a sufficient brightness for observation, which is often packaged in a photomultiplier device for weak light detection. The image intensifier is generally composed of a cathode, a microchannel plate (MCP) and a fluorescent screen. The working principle is that the incident light is converted into photoelectrons by the cathode, and the photoelectrons are accelerated and multiplied by the MCP and then output to the fluorescent screen for imaging.

[0003] When the incident light is strong, the MCP will output a large current, thereby causing the channel wall at the output end of the MCP to be charged, affecting the subsequent electron multiplication and emission. However, this charging can be neutralized by the charging current of the MCP, and the time required for charging and neutralization in the entire process is the recovery time of the MCP.

[0004] For a conventional MCP device, the recovery time of the MCP can be directly measured by methods such as a pulsed electron gun and an oscilloscope. However, for a packaged image intensifier, the input end of the MCP is blocked by the cathode and cannot directly receive electron input, and the output end is affected by factors such as the fluorescent screen and the afterglow, so that the MCP recovery time in the packaged image intensifier cannot be directly tested by conventional testing methods. Moreover, during the packaging process of the image intensifier, the MCP needs to be flushed, which will change the time characteristics of the MCP, so that there will be some differences in the time characteristics of the MCP before and after packaging. When the image intensifier is used, accurate measurement of the MCP recovery time packaged in the image intensifier is a necessary means to ensure the normal operation of the image intensifier. Therefore, how to accurately measure the MCP recovery time packaged in the image intensifier is a technical problem that needs to be solved. SUMMARY

[0005] The purpose of the present application is to solve the technical problem that the MCP recovery time packaged in the image intensifier cannot be accurately measured, and a method for measuring the MCP recovery time of the image intensifier is provided.

[0006] To achieve the above purpose, the technical solution provided by the present application is as follows:

[0007] A method for measuring the MCP recovery time of an image intensifier, characterized in that it comprises the following steps:

[0008] Step 1: An external trigger CMOS camera is arranged at the output end of the fluorescent screen of the image intensifier, which is used to test the output light intensity and pulse afterglow of the image intensifier;

[0009] Step 2, generating two same period pulse signals of M1 and M2 by a signal generator to drive the same light source, so that the emitted light of the light source is incident on the cathode of the image intensifier;

[0010] Step 3, closing the M1 pulse signal, opening the M2 pulse signal, aligning the start exposure time of the CMOS camera with the rising edge of the M2 pulse signal, and obtaining the original output light intensity of the fluorescent screen by the CMOS camera;

[0011] Step 4, keeping the start exposure time of the CMOS camera aligned with the rising edge of the M2 pulse signal, synchronously outputting the M1 and M2 pulse signals, then increasing the pulse delay time of M2 relative to M1 at a certain time interval, and obtaining the corresponding output light intensity of the fluorescent screen under different delay times by the CMOS camera until the corresponding output light intensity of the fluorescent screen no longer changes with the increase of the delay time;

[0012] Step 5, closing the M2 pulse signal, opening the M1 pulse signal, aligning the start exposure time of the CMOS camera with the rising edge of the M1 pulse signal, increasing the delay time of the CMOS start exposure time relative to the M1 pulse signal at the same time interval as in step 4, and obtaining the corresponding pulse afterglow of the fluorescent screen under the corresponding delay time by the CMOS camera;

[0013] Step 6, calculating the corresponding MCP recovery degree under different delay times according to the original output light intensity of the fluorescent screen, the corresponding output light intensity under different delay times, and the corresponding pulse afterglow, and when the value of the MCP recovery degree is equal to 1, the corresponding delay time is the MCP recovery time.

[0014] Further, in step 2, the frequency, amplitude and pulse width of the two pulse signals of M1 and M2 are the same;

[0015] The pulse width of the two pulse signals is T, and T≤1μs.

[0016] Further, step 3 is specifically:

[0017] closing the M1 pulse signal, opening the M2 pulse signal, providing a synchronous external trigger signal for the CMOS camera by the signal generator, aligning the start exposure time of the CMOS camera with the rising edge of the M2 pulse signal, ending the exposure of the CMOS camera after a period of time after the fluorescent screen emits light completely decays, and then obtaining the original output light intensity of the fluorescent screen by the CMOS camera.

[0018] Further, in step 4, the time interval is t, and the delay time is T n , which satisfies the following formula:

[0019] Tn = nt, n = 0, 1, …, N, N is the number of time delays.

[0020] Further, step 5 is specifically:

[0021] Close the M2 path pulse signal, open the M1 path pulse signal, and align the start exposure time of the CMOS camera with the rising edge of the M1 path pulse signal. Then, increase the delay time of the CMOS start exposure time relative to the M1 path pulse signal in the same time interval as in step 4, so that the delay time obtained is consistent with the delay time of step 4, and the corresponding pulse afterglow of the fluorescent screen under different delay times is obtained through the CMOS camera.

[0022] Further, in step 6, the corresponding MCP recovery degree K under different delay times n satisfies the following formula:

[0023] K n = (L n -P n ) / L;

[0024] wherein, L n is the output light intensity of the fluorescent screen under different delay times T n ; P n is the corresponding pulse afterglow under different delay times T n ; and L is the original output light intensity.

[0025] When K n = 1, the corresponding delay time T n is the MCP recovery time.

[0026] Further, it further comprises:

[0027] Step 7, verify the test by connecting the fluorescent screen through the ammeter, measure the corresponding current of the fluorescent screen under different delay times, and calculate the corresponding MCP recovery degree. When the value of the MCP recovery degree is equal to 1, the corresponding delay time is the MCP recovery time. Compare whether the MCP recovery times in step 6 and step 7 are consistent; if consistent, the corresponding delay time is the MCP recovery time; if not consistent, adjust the saturation of the fluorescent screen, and return to step 1.

[0028] Further, step 7 is specifically:

[0029] Step 7.1, connect an ammeter to the output end of the image intensifier fluorescent screen, for testing the output current of the image intensifier;

[0030] Step 7.2, generate two M1 and M2 path pulse signals with the same period through a signal generator to drive the same light source, so that the emitted light of the light source is incident on the cathode of the image intensifier.

[0031] Step 7.3, turn on the M1 pulse signal, turn off the M2 pulse signal, and align the start exposure time of the CMOS camera with the rising edge of the M1 pulse signal, and obtain the M1 power current value R1 of the fluorescent screen through the ammeter, R1 is the original output current of the MCP output current;

[0032] Step 7.4, turn on the M2 pulse signal, turn off the M1 pulse signal, and align the start exposure time of the CMOS camera with the rising edge of the M2 pulse signal, and obtain the M2 current value R2 of the MCP output current through the ammeter;

[0033] Step 7.5, synchronize the output of the M1 and M2 pulse signals, and sequentially increase the pulse delay time of the M2 relative to the M1 at certain time intervals, and obtain the MCP output current I n , n=0, 1,..., N, N is the number of delays;

[0034] Step 7.6, according to the M1 power current value R1, the M2 current value R2, and the MCP output current I n , calculate the MCP recovery degree K n , when the MCP recovery degree K n is equal to 1, the corresponding delay time is the MCP recovery time.

[0035] Further, in step 7.6, the MCP recovery degree Kn at different delay times satisfies the following formula:

[0036] K n =(I n -R1) / R2.

[0037] Further, in step 7.5, the time interval is the same as in step 4, and the delay time obtained is consistent with the delay time of step 4.

[0038] Advantages of the present application:

[0039] 【1】The operation steps of the method for measuring the MCP recovery time of the image intensifier are simple and easy to implement, two pulse signals are generated by a signal generator to drive the light source, and the output light intensity and pulse afterglow of the fluorescent screen are measured and calculated by a CMOS camera, so that the recovery time of the MCP can be accurately calculated, the measurement precision and efficiency of the MCP recovery time packaged in the image intensifier are effectively improved, and the normal and stable operation of the image intensifier is ensured.

[0040] [2] By connecting an ammeter to the output end of the fluorescent screen for testing and verification, this invention can further ensure the accuracy and reliability of the measurement of the recovery time of the MCP packaged in the image intensifier, and effectively improve the test accuracy and test efficiency.

[0041] [3] By testing the difference between the recovery time of the MCP encapsulated in the image intensifier and the recovery time of the MCP before encapsulation, this invention can accurately obtain the influence of the image intensifier encapsulation process on the performance of the MCP. The result can effectively guide the manufacturing process of the image intensifier and the MCP, and help to develop an image intensifier with better performance.

[0042] [4] The present invention can accurately measure the recovery time of the MCP encapsulated in the image intensifier, and can apply image intensifiers with different recovery times to corresponding scenarios. For example, an image intensifier made of fast recovery MCP and short afterglow phosphor can effectively solve the influence between adjacent frames, thereby applying the image intensifier to higher speed imaging. The application of this testing method can expand the application field of image intensifiers and improve the imaging quality of image intensifiers. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the measurement system in an embodiment of the method for measuring the recovery time of an image intensifier MCP according to the present invention;

[0044] Figure 2 This is a schematic diagram of the driving of two pulse signals, M1 and M2, in an embodiment of the present invention;

[0045] Figure 3 This is a schematic diagram of the ammeter connection in an embodiment of the present invention. Detailed Implementation

[0046] like Figure 1 and Figure 2 As shown, a method for measuring the recovery time of an image intensifier MCP includes the following steps:

[0047] Step 1: Set up an externally triggered CMOS camera at the output end of the image intensifier's phosphor screen to test the output light intensity and pulse afterglow of the image intensifier;

[0048] Step 2: Generate two pulse signals M1 and M2 with the same period through a signal generator to drive the same light source, fix the position of the light source and the image intensifier, and make the emitted light of the light source incident on the cathode of the image intensifier.

[0049] The frequency, amplitude, and pulse width of the two pulse signals M1 and M2 are the same, and the pulse width of both pulse signals is T, and T≤1μs, which can effectively improve the test accuracy.

[0050] Step 3, turn off the M1 pulse signal and turn on the M2 pulse signal, provide a synchronous external trigger signal for the CMOS camera through the signal generator, so that the start exposure time of the CMOS camera is aligned with the rising edge of the M2 pulse signal; after a period of time when the luminescence of the screen is completely attenuated, end the exposure of the CMOS camera, and then obtain the original output light intensity L of the screen through the CMOS camera;

[0051] Step 4, keep the start exposure time of the CMOS camera aligned with the rising edge of the M2 pulse signal, first output the M1 and M2 pulse signals synchronously, set the time interval as t, and increase the pulse delay time T of the M2 relative to the M1 in the time interval t n , n = 0, 1, …, N, N is the number of delays; and obtain the corresponding output light intensity L of the screen under different delay times through the CMOS camera n , until the corresponding output light intensity of the screen no longer changes with the increase of the delay time; n

[0052] Step 5, turn off the M2 pulse signal and turn on the M1 pulse signal, first align the start exposure time of the CMOS camera with the rising edge of the M1 pulse signal, and then increase the delay time of the CMOS start exposure time relative to the M1 pulse signal in the same time interval as in step 4, and obtain the corresponding pulse afterglow P of the screen under different delay times through the CMOS camera n ;

[0053] Step 6, according to the original output light intensity L of the screen, the corresponding output light intensity L n under different delay times and the corresponding pulse afterglow P n , calculate the corresponding MCP recovery degree K n under different delay times, K n = (L n -P n ) / L;

[0054] When the value of the MCP recovery degree is equal to 1, the corresponding delay time is the MCP recovery time.

[0055] As shown in Figure 3 , step 7, verify the test by connecting the screen with an ammeter, measure the corresponding current of the screen under different delay times, and calculate the corresponding MCP recovery degree, when the value of the MCP recovery degree is equal to 1, the corresponding delay time is the MCP recovery time, compare whether the MCP recovery times in step 6 and step 7 are consistent; if consistent, the corresponding delay time is the MCP recovery time; if not consistent, adjust the saturation of the screen, and return to step 1.

[0056] Step 7 specifically comprises:​

[0057] Step 7.1, connect ammeter at the output of the image intensifier fluorescent screen for testing the output current of the image intensifier;

[0058] Step 7.2, generate two same period pulse signals of M1 and M2 through the signal generator to drive the same light source, so that the emitted light of the light source is incident on the cathode of the image intensifier;

[0059] Step 7.3, turn on the M1 pulse signal, turn off the M2 pulse signal, and align the start exposure time of the CMOS camera with the rising edge of the M1 pulse signal, and obtain the M1 power current value R1 of the fluorescent screen through the ammeter, R1 is the original output current of the MCP output current;

[0060] Step 7.4, turn on the M2 pulse signal, turn off the M1 pulse signal, and align the start exposure time of the CMOS camera with the rising edge of the M2 pulse signal, and obtain the M2 current value R2 of the MCP output current through the ammeter;

[0061] Step 7.5, synchronize the output of the M1 and M2 pulse signals, and increase the pulse delay time of M2 relative to M1 at a certain time interval, and obtain the MCP output current I n , n = 0, 1,..., N, N is the number of times of delay;

[0062] Step 7.6, according to the M1 power current value R1, the M2 current value R2, and the MCP output current I n at different delay times, calculate the MCP recovery degree K n at different delay times, wherein the MCP recovery degree Kn at different delay times satisfies: K n = (I n -R1) / R2, when the value of the MCP recovery degree K n is equal to 1, the corresponding delay time is the MCP recovery time.

Claims

1. A method for measuring the recovery time of an image intensifier MCP, characterized in that, Includes the following steps: Step 1: Set up an externally triggered CMOS camera at the output end of the image intensifier's phosphor screen to test the output light intensity and pulse afterglow of the image intensifier; Step 2: Generate two pulse signals, M1 and M2, with the same period through a signal generator to drive the same light source, so that the emitted light from the light source is incident on the cathode of the image intensifier. Step 3: Turn off the M1 pulse signal, turn on the M2 pulse signal, and align the start exposure time of the CMOS camera with the rising edge of the M2 pulse signal to obtain the original output light intensity of the fluorescent screen through the CMOS camera. Step 4: Keep the start exposure time of the CMOS camera aligned with the rising edge of the M2 pulse signal. First, output the M1 and M2 pulse signals synchronously. Then, increase the pulse delay time of the M2 channel relative to the M1 channel at certain time intervals. Obtain the output light intensity of the fluorescent screen at different delay times through the CMOS camera until the output light intensity of the fluorescent screen no longer changes with the increase of the delay time. Step 5: Turn off the M2 pulse signal and turn on the M1 pulse signal. First, align the start exposure time of the CMOS camera with the rising edge of the M1 pulse signal. Then, increase the delay time of the CMOS start exposure time relative to the M1 pulse signal at the same time interval as in Step 4. Finally, obtain the pulse afterglow of the fluorescent screen corresponding to the delay time through the CMOS camera. Step 6: Based on the original output light intensity of the fluorescent screen, the corresponding output light intensity and pulse afterglow at different delay times, calculate the MCP recovery degree at different delay times. When the value of the MCP recovery degree is equal to 1, the corresponding delay time is the MCP recovery time.

2. The method for measuring the recovery time of an image intensifier MCP according to claim 1, characterized in that: In step 2, the frequency, amplitude, and pulse width of the two pulse signals M1 and M2 are the same; The pulse width of both pulse signals is T, and T≤1μs.

3. The method for measuring the recovery time of an image intensifier MCP according to claim 2, characterized in that, Step 3 specifically involves: Turn off the M1 pulse signal and turn on the M2 pulse signal. Use the signal generator to provide a synchronous external trigger signal to the CMOS camera, so that the start exposure time of the CMOS camera is aligned with the rising edge of the M2 pulse signal. After the phosphor screen has completely decayed for a period of time, end the exposure of the CMOS camera and then obtain the original output light intensity of the phosphor screen through the CMOS camera.

4. The method for measuring the recovery time of an image intensifier MCP according to claim 3, characterized in that: In step 4, the time interval is t, and the delay time is T. n The two satisfy the following equation: T n =nt, n = 0, 1, ..., N, where N is the number of delays.

5. The method for measuring the recovery time of an image intensifier MCP according to claim 4, characterized in that, Step 5 specifically involves: Turn off the M2 pulse signal, turn on the M1 pulse signal, and align the start exposure time of the CMOS camera with the rising edge of the M1 pulse signal. Then, increase the delay time of the CMOS start exposure time relative to the M1 pulse signal at the same time intervals to make the obtained delay time consistent with the delay time in step 4. Then, obtain the pulse afterglow of the fluorescent screen corresponding to different delay times through the CMOS camera.

6. The method for measuring the recovery time of an image intensifier MCP according to claim 5, characterized in that: In step 6, the degree of MCP recovery K corresponding to different delay times. n Satisfy the following formula: K n =(L n -P n ) / L; Among them, L n For different delay times T n The output light intensity corresponding to the lower phosphor screen; P n For different delay times T n The following corresponds to the pulse afterglow; L is the original output light intensity; K n When = 1, the corresponding delay time T n This is the MCP recovery time.

7. The method for measuring the recovery time of an image intensifier MCP according to claim 1, characterized in that, Also includes: Step 7: Connect an ammeter to the fluorescent screen for verification testing. Measure the current corresponding to the fluorescent screen under different delay times and calculate the corresponding MCP recovery degree. When the value of the MCP recovery degree is equal to 1, the corresponding delay time is the MCP recovery time. Compare whether the MCP recovery time in Step 6 and Step 7 is consistent. If they are consistent, the corresponding delay time is the MCP recovery time. If they are inconsistent, adjust the saturation of the fluorescent screen and return to Step 1.

8. The method for measuring the recovery time of an image intensifier MCP according to claim 7, characterized in that, Step 7 specifically includes: Step 7.1: Connect an ammeter to the output terminal of the image intensifier's phosphor screen to test the output current of the image intensifier; Step 7.2: Generate two pulse signals M1 and M2 with the same period through the signal generator to drive the same light source, so that the emitted light from the light source is incident on the cathode of the image intensifier. Step 7.3: Turn on the M1 pulse signal, turn off the M2 pulse signal, and align the start exposure time of the CMOS camera with the rising edge of the M1 pulse signal. Obtain the M1 power supply current value R1 of the fluorescent screen through the ammeter. R1 is the original output current of the MCP output current. Step 7.4: Turn on the M2 pulse signal, turn off the M1 pulse signal, and align the start exposure time of the CMOS camera with the rising edge of the M2 pulse signal. Obtain the M2 current value R2 of the MCP output current through the ammeter. Step 7.5: Synchronously output pulse signals M1 and M2, and sequentially increase the pulse delay time of M2 relative to M1 at certain time intervals. Obtain the MCP output current I at different delay times using a CMOS camera. n n = 0, 1, ..., N, where N is the number of delays; Step 7.6: Based on the supply current value R1 of M1, the current value R2 of M2, and the output current I of MCP under different delay times... n Calculate the degree of MCP recovery K under different delay times. n When MCP recovery level K n When the value is equal to 1, the corresponding delay time is the MCP recovery time.

9. The method for measuring the recovery time of an image intensifier MCP according to claim 8, characterized in that: In step 7.6, the degree of MCP recovery Kn under different delay times satisfies the following formula: K n =(I n -R1) / R2。 10. The method for measuring the recovery time of an image intensifier MCP according to claim 9, characterized in that: In step 7.5, the time interval is the same as in step 4, and the delay time obtained is consistent with the delay time in step 4.

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