Microchannel plate type photomultiplier pulse saturation recovery characteristic testing device and method

Abstract

The invention relates to a photomultiplier testing device and a photomultiplier testing method, in particular to a pulse saturation recovery characteristic testing device and a pulse saturation recovery characteristic testing method for a micro-channel plate type photomultiplier, and solves the problem that an existing MCP-PMT pulse saturation recovery characteristic testing device does not meet actual application requirements. And the pulse saturation recovery characteristics under different saturation depths and different recovery degrees cannot be evaluated. According to the invention, a pulse saturation recovery characteristic test is carried out on the MCP-PMT by using a laser diode and an optical attenuation sheet in a camera obscura environment, a pulse signal generator, a power divider, a combiner, a high-voltage source, a digitizer and a data processing unit, and the pulse signal generator successively generates two paths of driving pulse signals with different pulse widths. The method accords with the actual application requirement of the MCP-PMT working in a linear state, the measurement result can reflect the saturation recovery characteristic of the MCP-PMT in the actual application, and the pulse saturation recovery characteristic of the MCP-PMT under different saturation depths and different recovery degrees can be evaluated.

Description

Technical Field

[0001] The invention relates to a device and method for testing a photomultiplier tube, and in particular to a device and method for testing pulse saturation recovery characteristics of a microchannel plate type photomultiplier tube. Background Art

[0002] A photomultiplier tube is a photoelectric detection device that can convert extremely weak light signals into electrical signals and amplify them. A microchannel plate photomultiplier tube (MCP-PMT) is a type of photomultiplier tube that uses a microchannel plate (MCP) as an electron multiplication component. It has the characteristics of small size, fast time response, and high time resolution. It is mostly used for the measurement of ultrafast time processes such as sub-nanosecond to nanosecond time series.

[0003] MCP is a plate-like structure composed of millions of microchannels with diameters of several micrometers to more than ten micrometers. The inner surface of each channel is covered with secondary electron emission materials. When the photoelectrons emitted by the photocathode enter the microchannel, they will be accelerated through the microchannel under the action of the electric field and collide with the inner wall of the microchannel to produce secondary electrons. Each collision will increase the number of electrons, thereby amplifying the electronic signal. When the pulse light incident on the photocathode is strong, the number of electrons incident on the microchannel is also large, and the emission layer on the inner wall of the microchannel needs to emit more secondary electrons. On the one hand, a large number of multiplied electrons will accumulate at the end of the microchannel, forming a local electric field different from the electric field in the microchannel, which inhibits the subsequent multiplication of electrons; on the other hand, the resistance of MCP is very high, and the conductive layer on the inner wall of the microchannel cannot replenish electrons to the secondary electron emission layer in time. At this time, the electron flow output by the MCP-PMT no longer increases linearly with the increase of the input light intensity, and enters the so-called nonlinear state or saturation state.

[0004] It takes a certain amount of time for MCP-PMT to recover from a saturated state to a linear state, namely the saturation recovery time. If another pulse light is incident on the photocathode during the saturation recovery time, the output of the photomultiplier tube is still not linearly related to the incident light intensity, resulting in a large measurement error, or even an erroneous measurement result. Therefore, it is crucial to accurately measure the pulse saturation recovery characteristics of MCP-PMT. The existing MCP-PMT pulse saturation recovery characteristics test device uses two beams of pulse light of the same width and intensity to sequentially incident on the MCP-PMT. Both beams of light make the MCP-PMT work in a saturated state, but the second beam of pulse light also saturates the MCP-PMT, which is inconsistent with the actual application requirements of the MCP-PMT working in a linear state, and the measurement results cannot reflect the saturation recovery characteristics of the MCP-PMT in actual applications. In addition, the existing test device is also unable to evaluate the pulse saturation recovery characteristics of the MCP-PMT at different saturation depths and different recovery degrees. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problem that the existing MCP-PMT pulse saturation recovery characteristics testing device does not meet the actual application requirements and cannot evaluate the pulse saturation recovery characteristics under different saturation depths and different recovery degrees, and to provide a microchannel plate type photomultiplier tube pulse saturation recovery characteristics testing device and method.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A microchannel plate type photomultiplier tube pulse saturation recovery characteristic test device, which is special in that it includes a dark box, a laser diode, a light attenuation sheet and a photoelectric tube arranged in the dark box, as well as a pulse signal generator, a power divider, a combiner, a high voltage source, a digitizer and a data processing unit;

[0008] The first output channel of the pulse signal generator is connected to an input end of the combiner, the second output channel is connected to the input end of the power divider, one output end of the power divider is connected to another input end of the combiner, the other output end is connected to the trigger end of the digitizer, and the output end of the combiner is connected to the driving end of the laser diode;

[0009] There is a continuously adjustable output delay between the first output channel and the second output channel of the pulse signal generator, and the pulse width of the driving pulse output by the first output channel is greater than that of the second output channel; the pulse signal generator is used to drive the laser diode to generate a pulse light signal and trigger the digitizer; the combiner is used to combine the driving pulse output by the first output channel of the pulse signal generator and the driving pulse output by one output end of the power divider into one channel, thereby driving the laser diode to generate two pulse light signals in succession within one output cycle;

[0010] The photoelectric tube is arranged at the rear end of the laser diode, the MCP-PMT to be tested is arranged on one side thereof, and the light attenuation sheet is arranged at the front end of the MCP-PMT to be tested; the photoelectric tube is used to monitor the light intensity change of the laser diode, and the light attenuation sheet is used to attenuate the light intensity incident to the MCP-PMT to be tested;

[0011] The photocathode incident windows of the MCP-PMT and phototube to be tested are both within the illumination range of the laser diode, the high voltage input ends are respectively connected to the output ends of the high voltage source, the anode output ends are respectively connected to the two input channels of the digitizer, and the output end of the digitizer is connected to the data processing unit.

[0012] Furthermore, the distance between the laser diode and the MCP-PMT and photoelectric tube to be tested is 20 cm.

[0013] Furthermore, the light attenuation sheet is a reflective neutral density dimming sheet;

[0014] The digitizer adopts an oscilloscope or a plug-in type digital processor.

[0015] Furthermore, the dark box is an iron cabinet body with matte black paint sprayed on the inside.

[0016] The present invention also provides a method for testing pulse saturation recovery characteristics of a microchannel plate type photomultiplier tube, using the above-mentioned microchannel plate type photomultiplier tube pulse saturation recovery characteristics testing device, which is special in that it includes the following steps:

[0017] Step 1, turn on the digitizer and the high voltage source, set the amplitude, frequency and pulse width of the output drive pulse of the first output channel of the pulse signal generator, the time interval and range of the amplitude, frequency and pulse width of the output drive pulse of the second output channel, and the range and time interval of the output delay between the first output channel and the second output channel of the pulse signal generator;

[0018] Step 2, turn on the pulse signal generator, so that the second output channel outputs the driving pulse according to the set amplitude, frequency, pulse width change time interval and change range, and the power divider divides the driving pulse output by the second output channel into two paths, one of which is sent to the laser diode through the combiner to drive the laser diode to generate a pulse light signal, and the other is sent to the digitizer to trigger the digitizer to start working;

[0019] Step 3, the pulse light signal is attenuated by the light attenuation sheet and then incident on the MCP-PMT to be tested. At the same time, the pulse light signal is directly incident on the phototube. After receiving the pulse light signal, the MCP-PMT to be tested and the phototube generate a light response signal and send it to the digitizer. The digitizer converts the light response signal into a digital signal and sends it to the data processing unit to obtain the output signal of the MCP-PMT to be tested and the phototube;

[0020] Step 4, the data processing unit processes the output signals of the MCP-PMT and the phototube to be tested, calculates the output charge of the MCP-PMT and the phototube to be tested under different pulse width driving pulses, and then obtains the working curve of the MCP-PMT to be tested;

[0021] Step 5, setting the pulse width of the drive pulse output by the second output channel of the pulse signal generator to a fixed pulse width and smaller than the pulse width of the drive pulse output by the first output channel, and then making the first output channel and the second output channel output the drive pulse according to the set amplitude, frequency and pulse width, as well as the range and time interval of the output delay variation;

[0022] Step 6, the power divider divides the driving pulse output by the second output channel into two paths, one of which is combined with the driving pulse output by the first output channel into one path in the combiner, and then sent to the laser diode to drive the laser diode to generate two pulse light signals in one output cycle, and the other is sent to the digitizer to trigger the digitizer to start working, and then according to the method of step 3, the output signal of the MCP-PMT to be tested under different output delays is obtained;

[0023] Step 7: The data processing unit normalizes the output signal of the MCP-PMT to be tested under different output delays according to the working curve of the MCP-PMT to be tested obtained in step 4, thereby obtaining a pulse saturation recovery characteristic curve of the MCP-PMT to be tested.

[0024] Furthermore, it also includes:

[0025] Step 8, adjusting the pulse width of the driving pulse output by the first output channel of the pulse signal generator, and keeping the pulse width of the driving pulse output by the second output channel unchanged, and obtaining the pulse saturation recovery characteristic curve of the MCP-PMT to be tested at different saturation depths according to the method of steps 5 to 7;

[0026] The saturation depth is calculated as follows:

[0027] A linear fit is performed on the linear region of the working curve of the MCP-PMT to be tested obtained in step 4 to obtain the linear fitting value of the working curve of the MCP-PMT to be tested, and then the saturation depth D of the MCP-PMT to be tested under different pulse widths is calculated according to the following formula:

[0028]

[0029] Among them, Q 饱和 Q is the output charge in the saturation region of the MCP-PMT working curve to be tested. 拟合 It is the linear fitting value corresponding to the output charge in the saturation region of the MCP-PMT working curve to be tested.

[0030] Furthermore, it also includes:

[0031] Step 9: Keep the pulse width of the output drive pulse of the first output channel of the pulse signal generator unchanged, adjust the pulse width of the output drive pulse of the second output channel to make it smaller than that of the first output channel, and then follow the method of steps 5 to 7 to obtain the pulse saturation recovery characteristic curve of the MCP-PMT to be tested under different recovery degrees.

[0032] Furthermore, step 4 is specifically as follows:

[0033] 4.1. Calculate the output charge Q of the MCP-PMT and phototube to be tested respectively according to the following formula:

[0034]

[0035] Among them, V i is the amplitude of the output signal of the MCP-PMT or photoelectric tube to be tested at the i-th sampling point;

[0036] R is the input impedance of the digitizer, and f is the sampling frequency of the digitizer;

[0037] 4.2. Draw a graph with the output charge of the phototube as the horizontal axis and the output charge of the MCP-PMT to be tested as the vertical axis to obtain the working curve of the MCP-PMT to be tested.

[0038] Furthermore, step 7 is specifically as follows:

[0039] 7.1. Calculate the output charge Q of the output drive pulse of the second output channel of the pulse signal generator corresponding to the output signal of the MCP-PMT to be measured according to the method in step 4.1. 1 ;

[0040] 7.2. According to the working curve of the MCP-PMT to be tested obtained in step 4, the output charge Q of the MCP-PMT to be tested under the driving pulse with the set pulse width of the second output channel of the pulse signal generator is obtained. 设定 ;

[0041] 7.3, Q 设定 Q 1 Perform normalization to obtain the normalized output of the MCP-PMT to be tested;

[0042] 7.4. Draw a graph with the output delay between the first output channel and the second output channel of the pulse signal generator as the horizontal axis and the normalized output of the MCP-PMT to be tested as the vertical axis to obtain the pulse saturation recovery characteristic curve of the MCP-PMT to be tested.

[0043] Furthermore, in step 5, the amplitude of the drive pulse output by the first output channel of the pulse signal generator is 2V, the frequency is 1Hz, and the pulse width is 2μs; the amplitude of the drive pulse output by the second output channel is 4V, the frequency is 1Hz, and the pulse width is 100ns; the output delay variation range between the first output channel and the second output channel is 100ns to 900ms.

[0044] Compared with the prior art, the present invention has the following beneficial technical effects:

[0045] The present invention provides a device for testing pulse saturation recovery characteristics of a microchannel plate photomultiplier tube. The device utilizes a laser diode and an optical attenuation sheet in a dark box environment, as well as a pulse signal generator, a power divider, a combiner, a high-voltage source, a digitizer, and a data processing unit to test the pulse saturation recovery characteristics of an MCP-PMT. The pulse signal generator successively generates two driving pulse signals with different pulse widths, which are consistent with the actual application requirements of the MCP-PMT working in a linear state. The measurement results can reflect the saturation recovery characteristics of the MCP-PMT in actual applications, and can also evaluate the pulse saturation recovery characteristics of the MCP-PMT at different saturation depths and different recovery degrees. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a structural schematic diagram of a testing device in an embodiment of the present invention;

[0047] Figure 2 The output signal waveform diagram of the MCP-PMT and the photoelectric tube to be tested when the driving pulse width is 85ns obtained in step 3 of the test method in the embodiment of the present invention;

[0048] Figure 3 The working curve of the MCP-PMT to be tested and its linear fitting curve diagram obtained in step 4 of the test method in the embodiment of the present invention;

[0049] Figure 4 The output signal waveform diagram of the MCP-PMT and the photoelectric tube to be tested when the pulse signal generator output delay is 1 μs obtained in step 6 of the test method in the embodiment of the present invention;

[0050] Figure 5 The pulse saturation recovery characteristic curve of the MCP-PMT to be tested obtained in step 7 of the test method in the embodiment of the present invention;

[0051] Figure 6 The pulse saturation recovery characteristic curve of the MCP-PMT to be tested at different saturation depths obtained in step 8 of the test method in the embodiment of the present invention;

[0052] Figure 7 The pulse saturation recovery characteristic curve diagram of the MCP-PMT to be tested at different recovery degrees obtained in step 9 of the test method in the embodiment of the present invention;

[0053] The following are the descriptions of the reference numerals:

[0054] 1- pulse signal generator, 2- power divider, 3- combiner, 4- dark box, 5- laser diode, 6- light attenuation plate, 7- MCP-PMT to be tested, 8- photoelectric tube, 9- high voltage source, 10- digitizer, 11- data processing unit. DETAILED DESCRIPTION

[0055] The following is a further detailed description of the device and method for testing pulse saturation recovery characteristics of a microchannel plate photomultiplier tube proposed in the present invention in conjunction with the accompanying drawings and specific embodiments. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0056] A device for testing pulse saturation recovery characteristics of a microchannel plate type photomultiplier tube, such as Figure 1 As shown, it includes a dark box 4, a laser diode 5, a light attenuation sheet 6 and a photoelectric tube 8 arranged in the dark box 4, as well as a pulse signal generator 1, a power divider 2, a combiner 3, a high-voltage source 9, a digitizer 10 and a data processing unit 11. The dark box 4 is a closed experimental space with a black inner side and a cable through hole in the side wall. In this embodiment, the dark box 4 is an iron cabinet box with a matte black paint sprayed on the inner side.

[0057] The first output channel of the pulse signal generator 1 is connected to an input end of the combiner 3, the second output channel is connected to the input end of the power divider 2, an output end of the power divider 2 is connected to another input end of the combiner 3, the other output end is connected to the trigger end of the digitizer 10, and the output end of the combiner 3 is connected to the driving end of the laser diode 5.

[0058] The output delay between the first output channel and the second output channel of the pulse signal generator 1 is continuously adjustable from nanoseconds to seconds, and the pulse width of the driving pulse output by the first output channel is greater than that of the second output channel. The pulse signal generator 1 is used to drive the laser diode 5 to generate a pulsed light signal and trigger the digitizer 10. During the test, the driving pulse output by the first output channel can make the MCP-PMT 7 to be tested work in a saturated state, and the driving pulse output by the second output channel can make the MCP-PMT 7 to be tested work in a linear state.

[0059] In this embodiment, the amplitude of the driving pulse output by the first output channel of the pulse signal generator 1 is 2V, the pulse width is 2μs, and the frequency is 1Hz, and the amplitude of the driving pulse output by the second output channel is 4V, the pulse width is 100ns, and the frequency is 1Hz. During the test, the output delay between the first output channel and the second output channel is adjusted from 100ns to 900ms in sequence, and the driving pulse output by the second output channel is output after the driving pulse output by the first output channel.

[0060] The combiner 3 is used to combine the driving pulse output from the first output channel of the pulse signal generator 1 and the driving pulse output from one output end of the power divider 2 into one channel, thereby driving the laser diode 5 to generate two pulse light signals in succession within one output cycle. The time width and time interval of the pulse light signal are determined by the output settings of the first output channel and the second output channel of the pulse signal generator 1.

[0061] The laser diode 5 is used as a test pulse light source to make the photocathode of the MCP-PMT 7 and the phototube 8 to be tested generate photoelectrons. The wavelength of the laser diode is selected according to the spectral range to be tested. In this embodiment, the central wavelength of the laser diode is 405nm. The width of the output pulse light signal is determined by the width of the driving pulse. The intensity of the output pulse light signal can be adjusted and set by the control software.

[0062] The phototube 8 is arranged at the rear end of the laser diode 5, and the MCP-PMT 7 to be tested is arranged on one side thereof, and the light attenuation plate 6 is arranged at the front end of the MCP-PMT 7 to be tested. The phototube 8 is used to monitor the light intensity change of the laser diode 5 and obtain the working curve of the MCP-PMT 7 to be tested. The light attenuation plate 6 adopts a reflective neutral density dimmer plate to attenuate the light intensity incident to the MCP-PMT 7 to be tested. The photocathode incident windows of the MCP-PMT 7 to be tested and the phototube 8 are both located within the illumination range of the laser diode 5, and ensure that the light emitted by the laser diode 5 is uniformly irradiated on the photocathode incident windows of the MCP-PMT 7 to be tested and the phototube 8. In this embodiment, the distance between the laser diode 5 and the MCP-PMT 7 to be tested and the phototube 8 is 20 cm.

[0063] The high voltage input ends of the phototube 8 and the MCP-PMT 7 to be tested are respectively connected to the output ends of the high voltage source 9, and the anode output ends are respectively connected to the two input channels of the digitizer 10, and the output end of the digitizer 10 is connected to the data processing unit 11. The high voltage source 9 is used to provide DC high voltage to the MCP-PMT 7 to be tested and the phototube 8, and the gain of the MCP-PMT 7 to be tested can be adjusted by adjusting the output voltage value of the high voltage source 9. The digitizer 10 uses an oscilloscope or a plug-in digital processor to convert the analog electrical signals output by the MCP-PMT 7 to be tested and the phototube 6 into digital signals.

[0064] The present embodiment provides a microchannel plate type photomultiplier tube pulse saturation recovery characteristic test device, which uses a laser diode 5, a light attenuation plate 6 and a phototube 8 in a dark box environment to perform a pulse saturation recovery characteristic test on the MCP-PMT7 to be tested. The pulse signal generator 1 generates two drive pulse signals with a certain time interval and different pulse widths, thereby driving the laser diode 5 to generate two pulse light signals with a certain time interval and different pulse widths. The time width of the pulse light signal generated first is wider, causing the MCP-PMT7 to be tested to be saturated; the time width of the pulse light signal generated later is narrower. Under normal circumstances, the MCP-PMT7 to be tested will work in a linear state under the excitation of the narrower pulse light signal. Using a narrower pulse light signal to evaluate the saturation recovery characteristics of the MCP-PMT7 to be tested is consistent with the actual application requirements of the MCP-PMT. In addition, by further adjusting the time width of the pulse light signal generated first, the saturation recovery characteristics of the MCP-PMT7 to be tested at different saturation depths can be obtained; by further adjusting the time width of the pulse light signal generated later, the saturation recovery characteristics of the MCP-PMT7 to be tested at different recovery degrees can be obtained.

[0065] This embodiment also provides a method for testing the pulse saturation recovery characteristics of a microchannel plate type photomultiplier tube, using the above-mentioned microchannel plate type photomultiplier tube pulse saturation recovery characteristics testing device, comprising the following steps:

[0066] Step 1, turn on the digitizer 10 and the high-voltage source 9, set the amplitude of the output drive pulse of the first output channel of the pulse signal generator 1 to 2V, the frequency to 1Hz, and the pulse width to 2μs, the amplitude of the output drive pulse of the second output channel to 4V, the frequency to 1Hz, and the pulse width to increase from 10ns to 4μs, and the output delay between the first output channel and the second output channel of the pulse signal generator 1 to a range of 100ns to 900ms.

[0067] Step 2, turn on the pulse signal generator 1, so that the second output channel outputs a driving pulse according to the set amplitude, frequency, pulse width change time interval and change range. The power divider 2 divides the driving pulse output by the second output channel into two paths, one of which is sent to the laser diode 5 through the combiner 3 to drive the laser diode 5 to generate a pulse light signal, and the other is sent to the digitizer 10 to trigger the digitizer 10 to start working.

[0068] Step 3, the pulse light signal is attenuated by the light attenuation sheet 6 and then incident on the MCP-PMT 7 to be tested. At the same time, the pulse light signal is directly incident on the phototube 8. After receiving the pulse light signal, the MCP-PMT 7 to be tested and the phototube 8 generate a light response signal and send it to the digitizer 10. The digitizer 10 converts the light response signal into a digital signal and sends it to the data processing unit 11 to obtain the output signal of the MCP-PMT 7 to be tested and the phototube 8. Figure 2 As shown, it is the output signal waveform diagram of the MCP-PMT7 and the photoelectric tube 8 to be tested when the pulse width of the driving pulse output by the second output channel of the pulse signal generator 1 is 85ns.

[0069] Step 4: The data processing unit 11 processes the output signals of the MCP-PMT 7 and the phototube 8 to be tested, calculates the output charge of the MCP-PMT 7 and the phototube 8 under different pulse width driving pulses, and then obtains the working curve of the MCP-PMT 7 to be tested. Specifically:

[0070] 4.1. Calculate the output charge Q of the MCP-PMT7 and photoelectric tube 8 to be tested respectively according to the following formula, in nC:

[0071]

[0072] Among them, V i is the amplitude of the output signal of the MCP-PMT7 or photoelectric tube 8 to be tested at the i-th sampling point, in V; R is the input impedance of the digitizer 10, in Ω; f is the sampling frequency of the digitizer 10, in GHz;

[0073] 4.2, such as Figure 3 As shown, a curve is drawn with the output charge of the phototube 8 as the horizontal axis and the output charge of the MCP-PMT 7 to be tested as the vertical axis to obtain a working curve of the MCP-PMT 7 to be tested.

[0074] Step 5, set the pulse width of the output pulse of the second output channel to 100ns, and then make the first output channel and the second output channel of the pulse signal generator 1 output the driving pulse according to the set amplitude, frequency and pulse width, as well as the time interval and variation range of the output delay variation, and the first output channel outputs before the second output channel.

[0075] Step 6, the power divider 2 divides the driving pulse output from the second output channel into two paths, one of which is combined with the driving pulse output from the first output channel in the combiner 3, and then sent to the laser diode 5, driving the laser diode 5 to generate two pulse light signals in one output cycle, and the other is sent to the digitizer 10, triggering the digitizer 10 to start working, and then according to the method of step 3, the output signal of the MCP-PMT7 to be tested under different output delays is obtained. Figure 4 As shown, it is the output signal waveform diagram of the MCP-PMT 7 and the photoelectric tube 8 to be tested when the output delay of the pulse signal generator is 1μs.

[0076] Step 7: The data processing unit 11 normalizes the output signal of the MCP-PMT 7 under different output delays according to the working curve of the MCP-PMT 7 under test obtained in step 4, and then obtains the pulse saturation recovery characteristic curve of the MCP-PMT 7 under test. Specifically:

[0077] 7.1. Calculate the output charge Q of the output signal of the MCP-PMT7 and the photoelectric tube 8 to be tested corresponding to the output pulse of the second output channel of the pulse signal generator 1 according to the method in step 4.1. 1 ;

[0078] 7.2. According to the working curve of the MCP-PMT 7 to be tested obtained in step 4, the output charge Q of the MCP-PMT 7 to be tested under the driving pulse with the set pulse width of the second output channel of the pulse signal generator 1 is obtained. 设定 ;

[0079] 7.3, Q 设定 Q 1 Perform normalization to obtain the normalized output of the MCP-PMT7 to be tested;

[0080] 7.4. Draw a curve with the output delay between the first output channel and the second output channel of the pulse signal generator 1 as the horizontal axis and the normalized output of the MCP-PMT7 to be tested as the vertical axis. Figure 5 The pulse saturation recovery characteristic curve of the MCP-PMT7 to be tested is shown. Among them, the pulse width of the saturation of the MCP-PMT7 to be tested (i.e., the driving pulse output by the first output channel of the pulse signal generator 1) is 2μs, the saturation depth is 53.6%, and the pulse width for monitoring the recovery degree of the MCP-PMT7 to be tested (i.e., the driving pulse output by the second output channel of the pulse signal generator 1) is 100ns.

[0081] Step 8: Adjust the pulse width of the drive pulse output from the first output channel of the pulse signal generator 1, and keep the pulse width of the drive pulse output from the second output channel unchanged. According to the method of steps 5 to 7, the following is obtained: Figure 6 The pulse saturation recovery characteristic curve of the MCP-PMT7 under test at different saturation depths is shown. The saturation depth is calculated by the following method:

[0082] like Figure 3 As shown, a linear fitting is performed on the linear region of the working curve of the MCP-PMT 7 to be tested to obtain the linear fitting value of the working curve of the MCP-PMT 7 to be tested, and then the saturation depth D of the MCP-PMT 7 to be tested under different pulse width driving pulses is calculated according to the following formula:

[0083]

[0084] Among them, Q 饱和 is the output charge in the saturation region of the working curve of the MCP-PMT 7 to be tested, Q 拟合 It is the linear fitting value corresponding to the output charge in the saturation region of the working curve of the MCP-PMT7 to be tested.

[0085] According to the above method, it is calculated that when the pulse width is 1 μs, the saturation depth is 26.4%; when the pulse width is 2 μs, the saturation depth is 53.6%; when the pulse width is 3 μs, the saturation depth is 66.9%.

[0086] Step 9: Keep the pulse width of the output drive pulse of the first output channel of the pulse signal generator 1 unchanged, adjust the pulse width of the output drive pulse of the second output channel to make it smaller than the first output channel, and then follow the method of steps 5 to 7 to obtain the following: Figure 7 The pulse saturation recovery characteristic curve of the MCP-PMT7 to be tested under different recovery degrees is shown. The recovery degree is defined as the amount of charge output when the MCP-PMT7 to be tested recovers from a saturated state to a linear working state. In this embodiment, the pulse width of the driving pulse of the second output channel of the pulse signal generator 1 is used to represent it. The larger the pulse width, the greater the recovery degree, and the smaller the pulse width, the smaller the recovery degree.

[0087] It should be noted that Figure 6 and Figure 7 In the figure, channel 1 refers to the pulse width of the drive pulse output by the first output channel of the pulse signal generator 1, and channel 2 refers to the pulse width of the drive pulse output by the second output channel of the pulse signal generator 1.

[0088] This embodiment uses a constructed microchannel plate type photomultiplier tube pulse saturation recovery characteristic test device to provide a microchannel plate type photomultiplier tube pulse saturation recovery characteristic test method, which can obtain a pulse saturation recovery characteristic curve of the MCP-PMT to be tested that is consistent with actual applications, and can also obtain saturation recovery characteristic curves at different saturation depths and saturation recovery characteristic curves at different recovery degrees.

Claims

1. A device for testing pulse saturation recovery characteristics of a microchannel plate type photomultiplier tube, characterized in that: It comprises a dark box (4), a laser diode (5) arranged in the dark box (4), a light attenuation sheet (6) and a photoelectric tube (8), as well as a pulse signal generator (1), a power divider (2), a combiner (3), a high voltage source (9), a digitizer (10) and a data processing unit (11); The first output channel of the pulse signal generator (1) is connected to an input end of a combiner (3), the second output channel is connected to an input end of a power divider (2), an output end of the power divider (2) is connected to another input end of the combiner (3), another output end is connected to a trigger end of a digitizer (10), and the output end of the combiner (3) is connected to a driving end of a laser diode (5); The first output channel and the second output channel of the pulse signal generator (1) have a continuously adjustable output delay, and the pulse width of the driving pulse output by the first output channel is greater than that of the second output channel; the pulse signal generator (1) is used to drive the laser diode (5) to generate a pulse light signal and trigger the digitizer (10); the combiner (3) is used to combine the driving pulse output by the first output channel of the pulse signal generator (1) and the driving pulse output by one output end of the power divider (2) into one channel, thereby driving the laser diode (5) to successively generate two pulse light signals within one output cycle; The photoelectric tube (8) is arranged at the rear end of the laser diode (5), the MCP-PMT (7) to be tested is arranged on one side thereof, and the light attenuation sheet (6) is arranged at the front end of the MCP-PMT (7) to be tested; the photoelectric tube (8) is used to monitor the light intensity change of the laser diode (5), and the light attenuation sheet (6) is used to attenuate the light intensity incident on the MCP-PMT (7) to be tested; The photocathode incident windows of the MCP-PMT (7) and the phototube (8) to be tested are both located within the illumination range of the laser diode (5); the high voltage input ends are respectively connected to the output ends of the high voltage source (9); the anode output ends are respectively connected to two input channels of a digitizer (10); and the output end of the digitizer (10) is connected to a data processing unit (11).

2. The device for testing pulse saturation recovery characteristics of a microchannel plate type photomultiplier tube according to claim 1, characterized in that: The distance between the laser diode (5) and the MCP-PMT (7) to be tested and the photoelectric tube (8) is 20 cm.

3. The device for testing pulse saturation recovery characteristics of a microchannel plate type photomultiplier tube according to claim 1 or 2, characterized in that: The light attenuation film (6) is a reflective neutral density light reduction film; The digitizer (10) adopts an oscilloscope or a plug-in type digital processor.

4. The device for testing pulse saturation recovery characteristics of a microchannel plate type photomultiplier tube according to claim 3, characterized in that: The dark box (4) is an iron cabinet body with matte black paint sprayed on the inner side.

5. A method for testing pulse saturation recovery characteristics of a microchannel plate type photomultiplier tube, using a device for testing pulse saturation recovery characteristics of a microchannel plate type photomultiplier tube according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1, turning on the digitizer (10) and the high voltage source (9), setting the amplitude, frequency and pulse width of the drive pulse output by the first output channel of the pulse signal generator (1), the time interval and range of the amplitude, frequency and pulse width of the drive pulse output by the second output channel, and the range and time interval of the output delay change between the first output channel and the second output channel of the pulse signal generator (1); Step 2, turning on the pulse signal generator (1) to enable the second output channel to output a driving pulse according to the set amplitude, frequency, pulse width change time interval and change range, the power divider (2) divides the driving pulse output by the second output channel into two paths, one of which is sent to the laser diode (5) through the combiner (3) to drive the laser diode (5) to generate a pulse light signal, and the other is sent to the digitizer (10) to trigger the digitizer (10) to start working; Step 3, the pulse light signal is attenuated by the light attenuation sheet (6) and then incident on the MCP-PMT (7) to be tested. At the same time, the pulse light signal is directly incident on the phototube (8). After receiving the pulse light signal, the MCP-PMT (7) to be tested and the phototube (8) generate a light response signal and send it to the digitizer (10). The digitizer (10) converts the light response signal into a digital signal and sends it to the data processing unit (11), thereby obtaining the output signals of the MCP-PMT (7) to be tested and the phototube (8); Step 4, the data processing unit (11) processes the output signals of the MCP-PMT (7) and the phototube (8) to be tested, calculates the output charge amounts of the MCP-PMT (7) and the phototube (8) to be tested under different pulse width driving pulses, and then obtains the working curve of the MCP-PMT (7) to be tested; Step 5, setting the pulse width of the drive pulse output by the second output channel of the pulse signal generator (1) to a fixed pulse width and smaller than the pulse width of the drive pulse output by the first output channel, and then making the first output channel and the second output channel output the drive pulse according to the set amplitude, frequency and pulse width, as well as the range and time interval of output delay variation; Step 6, the power divider (2) divides the driving pulse output from the second output channel of the pulse signal generator (1) into two paths, one of which is combined with the driving pulse output from the first output channel into one path in the combiner (3), and then sent to the laser diode (5), driving the laser diode (5) to generate two pulse light signals in one output cycle, and the other is sent to the digitizer (10), triggering the digitizer (10) to start working, and then according to the method of step 3, the output signal of the MCP-PMT (7) to be tested under different output delays is obtained; Step 7, the data processing unit (11) normalizes the output signal of the MCP-PMT (7) to be tested under different output delays according to the working curve of the MCP-PMT (7) to be tested obtained in step 4, thereby obtaining a pulse saturation recovery characteristic curve of the MCP-PMT (7) to be tested.

6. The method for testing pulse saturation recovery characteristics of a microchannel plate photomultiplier tube according to claim 5, characterized in that: Also includes: Step 8, adjusting the pulse width of the driving pulse output by the first output channel of the pulse signal generator (1), and keeping the pulse width of the driving pulse output by the second output channel unchanged, and obtaining the pulse saturation recovery characteristic curve of the MCP-PMT (7) to be tested at different saturation depths according to the method of steps 5 to 7; The saturation depth is calculated as follows: A linear fit is performed on the linear region of the working curve of the MCP-PMT (7) to be tested obtained in step 4 to obtain the linear fitting value of the working curve of the MCP-PMT (7) to be tested, and then the saturation depth D of the MCP-PMT (7) to be tested under different pulse widths is calculated according to the following formula: Among them, Q 饱和 is the output charge in the saturation region of the working curve of the MCP-PMT (7) to be tested, Q 拟合 is the linear fitting value corresponding to the output charge in the saturation region of the working curve of the MCP-PMT (7) to be tested.

7. The method for testing pulse saturation recovery characteristics of a microchannel plate photomultiplier tube according to claim 6, characterized in that: Also includes: Step 9, keep the pulse width of the drive pulse output by the first output channel of the pulse signal generator (1) unchanged, adjust the pulse width of the drive pulse output by the second output channel to be smaller than that of the first output channel, and then follow the method of steps 5 to 7 to obtain the pulse saturation recovery characteristic curve of the MCP-PMT (7) to be tested under different recovery degrees.

8. The method for testing pulse saturation recovery characteristics of a microchannel plate photomultiplier tube according to any one of claims 5 to 7, characterized in that: Step 4 is as follows: 4.

1. Calculate the output charge Q of the MCP-PMT (7) and the photoelectric tube (8) to be tested respectively according to the following formula: Wherein, R is the input impedance of the digitizer (10), f is the sampling frequency of the digitizer (10); V i is the amplitude of the output signal of the MCP-PMT (7) or photoelectric tube (8) to be tested at the i-th sampling point; 4.

2. A curve is drawn with the output charge of the phototube (8) as the horizontal axis and the output charge of the MCP-PMT (7) to be tested as the vertical axis to obtain a working curve of the MCP-PMT (7) to be tested.

9. The method for testing pulse saturation recovery characteristics of a microchannel plate photomultiplier tube according to claim 8, characterized in that: Step 7 is as follows: 7.

1. Calculate the output charge Q1 of the output signal of the MCP-PMT (7) to be tested corresponding to the output pulse of the second output channel of the pulse signal generator (1) according to the method of step 4.1; 7.

2. According to the working curve of the MCP-PMT (7) to be tested obtained in step 4, the output charge Q of the MCP-PMT (7) to be tested under the driving pulse with the set pulse width of the second output channel of the pulse signal generator (1) is obtained. 设定 ; 7.

3. Q 设定 Normalize Q1 to obtain the normalized output of the MCP-PMT (7) to be tested; 7.

4. A curve is drawn with the output delay between the first output channel and the second output channel of the pulse signal generator (1) as the horizontal axis and the normalized output of the MCP-PMT (7) to be tested as the vertical axis to obtain a pulse saturation recovery characteristic curve of the MCP-PMT (7) to be tested.

10. The method for testing pulse saturation recovery characteristics of a microchannel plate photomultiplier tube according to claim 9, characterized in that: In step 5, the amplitude of the driving pulse output by the first output channel of the pulse signal generator (1) is 2V, the frequency is 1Hz, and the pulse width is 2μs, the amplitude of the driving pulse output by the second output channel is 4V, the frequency is 1Hz, and the pulse width is 100ns, and the output delay between the first output channel and the second output channel varies in the range of 100ns to 900ms.

Images