Electron counting device for micro electron beam, electron counting system and measurement method thereof

Abstract

This invention relates to an electron counting device, an electron counting system, and a measurement method for a micro-electron beam. The electron counting system includes a current measuring unit and an electron counting device, with the output end of a Faraday cylinder connected to the current measuring unit. The electron counting device includes a Faraday cylinder and an electron multiplier tube. The electron multiplier tube is housed within the Faraday cylinder, with a gap between the outer peripheral wall of the electron multiplier tube and the inner peripheral wall of the Faraday cylinder. The Faraday cylinder is connected to a second insulating tube and the electron multiplier tube via a first insulating tube. The measurement process involves: multiplying the electron beam – measuring the electron current value – calculating the number of electrons. Compared to directly collecting electrons using the Faraday cylinder inside the electron multiplier tube, the electrons amplified by the electron multiplier tube are input into the Faraday cylinder for measurement, improving the accuracy of electron measurement.

Description

Technical Field

[0001] This invention relates to the field of electronic counting devices, and in particular to an electronic counting device, electronic counting system and measurement method for a micro-electron beam. Background Technology

[0002] Currently, electron counting is generally performed by measuring electron current. However, the current generated by a small number of electrons is too small to be measured. In order to count the number of electrons, electron multiplier tubes are used to multiply the electrons, and the number of input electrons is calculated by measuring the output electron current.

[0003] Electron beam current measurement is typically performed directly using a Faraday cup. However, for small electron beams, the Faraday cup output current is low, leading to significant measurement errors. Therefore, it is considered to multiply the electrons using an electron multiplier tube before measurement.

[0004] Electron multiplier tubes (EMBs) are fabricated based on the secondary electron emission properties of materials. An EMB contains multiple dynodes, each with a secondary electron emission coefficient greater than 1. By applying a voltage to adjacent dynodes to generate an electric field, electrons incident on the first dynode are directed to the second dynode under the influence of the electric field, exciting the second dynode to produce even more secondary electrons. Electrons multiply sequentially at each dynode until the last dynode emits the multiplied electrons, completing the electron multiplication process.

[0005] A Faraday cell is a device used to collect and measure electrons. It is typically made of a conductive metal material. The metal absorbs electrons from the incident electron beam, converting them into an output current. This current is then converted into a voltage by a current measuring circuit. The voltage signal is measured, and the number of incident electrons is calculated from the current measurement result. An electron multiplier tube is used in conjunction with the Faraday cell to amplify the tiny electron beam before it is fed into the Faraday cell for measurement.

[0006] The electron collection efficiency of the electron collecting electrode inside the commonly used electron multiplier tube is unclear, and the secondary electron escape rate of the small Faraday tube is relatively high, resulting in low accuracy of electron beam current measurement and making it difficult to apply to high-precision measurement scenarios. In addition, the high-precision Faraday tube has a complex structure and cannot be integrated into the electron multiplier tube. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of this invention is to provide an electron counting device, electron counting system and measurement method for micro electron beams. Its advantage is that it can use electron multiplier tubes and high-precision Faraday cylinders together for current measurement, thereby improving the measurement accuracy of electrons.

[0008] The above-mentioned objective of this invention is achieved through the following technical solution: In one aspect, this invention provides an electron counting device for a micro-electron beam, comprising a Faraday tube and an electron multiplier tube; the electron multiplier tube is housed within the Faraday tube, a gap is left between the outer peripheral wall of the electron multiplier tube and the inner peripheral wall of the Faraday tube, the Faraday tube is connected to a second insulating tube and the electron multiplier tube via a first insulating tube, one end of a first wire passes through the first insulating tube and is inserted into the electron multiplier tube and connected to the negative electrode inside the electron multiplier tube, one end of a second wire passes through the second insulating tube and is inserted into the electron multiplier tube and connected to the positive electrode inside the electron multiplier tube; the first wire and the second wire cooperate to provide a multiplication voltage to the electron multiplier tube; the electron multiplier tube is used to amplify the incident electron beam; the Faraday tube is used to collect electrons and convert the collected electrons into an electric current.

[0009] Preferably, the electron counting device for micro-electron beams provided by the present invention includes a Faraday tube comprising a first tube and a second tube. The first tube forms an incident channel, and the second tube forms a collection cavity. One end of the first tube is connected to one end of the second tube. The diameter of the incident channel is smaller than the diameter of the collection cavity. An electron multiplier tube is inserted into the incident channel. A first mounting hole and a second mounting hole are provided on the outer peripheral wall of the first tube. The first mounting hole and the second mounting hole are opposite to each other and both communicate with the incident channel. One end of a first insulating tube passes through the first mounting hole and is inserted into the incident channel and communicates with the electron multiplier tube. The other end of the first insulating tube is inserted into the first mounting hole. One end of a second insulating tube passes through the second mounting hole and is inserted into the incident channel and communicates with the electron multiplier tube. The other end of the second insulating tube is inserted into the second mounting hole.

[0010] Preferably, the electron counting device for micro-electron beams provided by the present invention further includes a grid, the grid being disposed within the incident channel and located at one end of the incident channel facing the collection cavity, the grid being spaced apart from the output end of the electron multiplier tube, and the outer peripheral wall of the grid being connected to the inner peripheral wall of the incident channel.

[0011] Preferably, in the electron counting device for micro-electron beams provided by the present invention, the grid includes a circular ring and a plurality of uprights, all of which are disposed within the circular ring, with both ends of each upright connected to the inner circumferential wall of the circular ring, and the plurality of uprights are spaced apart along the diametrical direction of the circular ring.

[0012] Preferably, the electron counting device for micro-electron beams provided by the present invention further includes a conductive baffle disposed in the incident channel, the conductive baffle being located between the grid and the electron multiplier tube, one end of the conductive baffle being connected to the output end of the electron multiplier tube, and the outer peripheral wall of the other end of the conductive baffle being connected to the inner peripheral wall of the incident channel.

[0013] Preferably, in the electron counting device for micro-electron beams provided by the present invention, the conductive baffle is frustum-shaped, the small-diameter end of the conductive baffle is connected to the output end of the electron multiplier tube, and the outer peripheral wall of the large-diameter end of the conductive baffle is connected to the inner peripheral wall of the incident channel.

[0014] Preferably, in the electron counting device for micro-electron beams provided by the present invention, the conductive baffle is made of copper.

[0015] Preferably, in the electron counting device for micro-electron beams provided by the present invention, the Faraday cylinder is covered by a magnetic shielding cover, the magnetic shielding cover is configured to form a magnetic shielding cavity, and the Faraday cylinder is housed within the magnetic shielding cavity.

[0016] Preferably, in the electron counting device for micro-electron beams provided by the present invention, the magnetic shielding cover is cylindrical.

[0017] Preferably, in the electron counting device for micro-electron beams provided by the present invention, the magnetic shielding cover is made of iron material.

[0018] On one hand, the present invention provides an electronic counting system, including a current measuring unit and the above-mentioned electronic counting device for micro electron beams, wherein the input end of the Faraday cylinder in the electronic counting device is connected to an external electron beam input device, and the output end of the Faraday cylinder is connected to the current measuring unit.

[0019] Preferably, the electronic counting system provided by the present invention is characterized in that: the current measuring unit includes a sampling resistor and a multimeter; one end of the sampling resistor is connected to the output end of the Faraday cylinder through a first shielded wire, and the other end of the sampling resistor is grounded; the sampling resistor is connected to the multimeter through a second shielded wire, and the multimeter is connected to a host computer; the multimeter is used to read the voltage value across the sampling resistor and then upload the read data to the host computer.

[0020] On the other hand, the present invention provides a measurement method for the electronic counting system as described above, comprising the following steps:

[0021] A tiny electron beam is incident onto the electron multiplier tube via the electron beam input device for multiplication.

[0022] The multiplied electron beam is converted into an electron current by the Faraday tube, and the Faraday tube outputs the electron current to the current measuring unit to measure the electron current value;

[0023] The number of incident electrons can be calculated from the current value.

[0024] In summary, the beneficial technical effects of the present invention are as follows: The electron counting device, electron counting system, and measurement method for micro-electron beams provided in this application include an electron counting system comprising a current measuring unit and an electron counting device for micro-electron beams. The input end of the Faraday cylinder in the electron counting device is connected to an external electron beam input device, and the output end of the Faraday cylinder is connected to the current measuring unit. The electron counting device for micro-electron beams includes a Faraday cylinder and an electron multiplier tube. The electron multiplier tube is housed within the Faraday cylinder, with a gap between the outer peripheral wall of the electron multiplier tube and the inner peripheral wall of the Faraday cylinder. The Faraday cylinder is connected to a second insulating tube and the electron multiplier tube via a first insulating tube. One end of a first wire passes through the first insulating tube and is inserted into the electron multiplier tube, and is connected to the electron multiplier tube. The negative electrode is connected, and one end of the second wire passes through the second insulating tube and is inserted into the electron multiplier tube, connecting to the positive electrode inside the electron multiplier tube. The first and second wires work together to provide a multiplication voltage to the electron multiplier tube. The electron multiplier tube amplifies the incident electron beam. The Faraday cylinder collects electrons and converts the collected electrons into current. The measurement process is as follows: multiply the electron beam - measure the electron current value - calculate the number of electrons. By setting a gap between the outer peripheral wall of the electron multiplier tube and the inner peripheral wall of the Faraday cylinder, an additional electric field is prevented from forming inside the Faraday cylinder, thus preventing it from affecting the collection of electrons. In addition, compared with directly using the Faraday cylinder inside the electron multiplier tube to collect electrons, the electrons amplified by the electron multiplier tube are input into the Faraday cylinder for measurement, which improves the accuracy of electron measurement. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the electron counting device for micro-electron beams provided in the first embodiment of the present invention.

[0026] Figure 2 This is a schematic diagram of the grid structure in the electron counting device for micro-electron beams provided in the first embodiment of the present invention.

[0027] Figure 3 This is a schematic diagram of the overall structure of the electronic counting system provided in the second embodiment of the present invention.

[0028] Figure 4 This is a structural block diagram of the electronic counting system provided in the second embodiment of the present invention.

[0029] Figure 5 This is a flowchart of the measurement method of the electronic counting system provided in the third embodiment of the present invention.

[0030] In the diagram, 1 is the electronic counting system; 10 is the current measuring unit; 20 is the electronic counting device; 21 is the Faraday cylinder; 211 is the first insulating tube; 2111 is the first conductor; 212 is the second insulating tube; 2121 is the second conductor; 213 is the first cylinder; 2131 is the incident channel; 214 is the second cylinder; 2141 is the collecting cavity; 22 is the electron multiplier tube; 23 is the grid; 231 is the ring; 232 is the upright; 24 is the conductive baffle; 25 is the magnetic shielding cover; and 2 is the electron beam input device. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings.

[0032] First embodiment:

[0033] Reference Figure 1 This invention discloses a micro-electron beam counting device 20, comprising a Faraday cylinder 21 and an electron multiplier tube 22. The electron multiplier tube 22 is housed within the Faraday cylinder 21, with a gap between the outer peripheral wall of the electron multiplier tube 22 and the inner peripheral wall of the Faraday cylinder 21. The Faraday cylinder 21 is connected to the electron multiplier tube 22 via a first insulating tube 211, a second insulating tube 212, and a first wire 2111. One end of the first wire 2111 passes through the first insulating tube 211 and is inserted into the electron multiplier tube 22, connecting to the negative electrode inside the electron multiplier tube 22. One end of the second wire 2121 passes through the second insulating tube 212 and is inserted into the electron multiplier tube 22, connecting to the positive electrode inside the electron multiplier tube 22. The first wire 2111 and the second wire 212... 1. It is used to provide a multiplication voltage for electron multiplier tube 22; electron multiplier tube 22 is used to amplify the incident electron beam; Faraday cylinder 21 is used to collect electrons and convert the collected electrons into current. On the one hand, by housing electron multiplier tube 22 inside Faraday cylinder 21, external interference is reduced and electron collection efficiency is improved. On the other hand, by setting a gap between the outer peripheral wall of electron multiplier tube 22 and the inner peripheral wall of Faraday cylinder 21, an additional electric field is prevented from forming inside Faraday cylinder 21 that affects electron collection. In addition, compared with directly using Faraday cylinder 21 inside electron multiplier tube 22 to collect electrons, the electrons amplified by electron multiplier tube 22 are input into Faraday cylinder 21 for measurement, which improves the accuracy of electron measurement.

[0034] Among them, the Faraday cylinder 21 adopts a high-precision Faraday cylinder 21 with a low electron escape rate.

[0035] Specifically, with Figure 1 Taking the orientation shown as an example, the electron multiplier tube 22 is inserted into the Faraday cylinder 21. The electron multiplier tube 22 is located at the left end of the Faraday cylinder 21. During use, the voltage required by the electron multiplier tube 22 is introduced from the first wire 2111 and the second wire 2121.

[0036] It should be noted that the inner circumferential wall of the Faraday cylinder 21 is made of a material with a low electron emission coefficient. For example, the outer wall of the Faraday cylinder 21 can be made of copper. Of course, the outer wall of the Faraday cylinder 21 can also be made of other metal materials.

[0037] Among them, the Faraday tube 21 is cylindrical.

[0038] During use, with Figure 1 Taking the orientation shown as an example, the right end of the Faraday cylinder 21 is provided with a current output interface, which is used to release the charge collected by the Faraday cylinder 21.

[0039] The first insulating tube 211 and the second insulating tube 212 are disposed opposite to each other on both sides of the Faraday cylinder 21. One end of the first insulating tube 211 is inserted into the Faraday cylinder 21 and communicates with the electron multiplier tube 22. The other end of the first insulating tube extends radially along the Faraday cylinder 21 to be flush with the outer wall of the Faraday cylinder 21. One end of the second insulating tube 212 is inserted into the Faraday cylinder 21 and communicates with the electron multiplier tube 22. The other end of the second insulating tube extends radially along the Faraday cylinder 21 to be flush with the outer wall of the Faraday cylinder 21.

[0040] The process of using the electron counting device 20 for the micro-electron beam provided in this embodiment is as follows: the micro-electron beam is incident into the electron multiplier tube 22 for multiplication to obtain an electron beam with a large number of electrons; the multiplied electron beam is collected by the Faraday tube 21, and the Faraday tube 21 converts the collected electron beam into an electron current.

[0041] Furthermore, in this embodiment, the Faraday cylinder 21 includes a first cylinder 213 and a second cylinder 214. The first cylinder 213 forms an incident channel 2131, and the second cylinder 214 forms a collection cavity 2141. One end of the first cylinder 213 is connected to one end of the second cylinder 214. The diameter of the incident channel 2131 is smaller than the diameter of the collection cavity 2141. The electron multiplier tube 22 is inserted into the incident channel 2131. A first mounting hole and a second mounting hole are provided on the outer peripheral wall of the first cylinder 213. The first mounting hole and the second mounting hole are arranged opposite to each other. Both the first mounting hole and the second mounting hole are connected to the incident channel 2131. One end of the first insulating tube 211 passes through the first mounting hole and is inserted into the incident channel 2131 and is connected to the electron multiplier tube 22. The other end of the first insulating tube 211 is inserted into the first mounting hole. One end of the second insulating tube 212 passes through the second mounting hole and is inserted into the incident channel 2131 and is connected to the electron multiplier tube 22. The other end of the second insulating tube 212 is inserted into the second mounting hole.

[0042] Specifically, the centerline of the first cylinder 213 is parallel to the centerline of the second cylinder 214. In some feasible embodiments, the centerline of the first cylinder 213 is collinear with the centerline of the second cylinder 214. The first cylinder 213 and the second cylinder 214 together form a Faraday cylinder 21 with a narrow-mouth bottle-shaped structure. The outer diameter of the first cylinder 213 is smaller than the outer diameter of the second cylinder 214, the diameter of the incident channel 2131 is smaller than the diameter of the collecting cavity 2141, and the diameter of the incident channel 2131 is slightly larger than the diameter of the electron multiplier tube 22, so that there is a gap between the outer peripheral wall of the electron multiplier tube 22 placed in the incident channel 2131 and the inner peripheral wall of the incident channel 2131. This arrangement allows the secondary electrons generated by the impact to diverge in more directions, reducing the emission of secondary electrons towards the multiplier tube.

[0043] In this embodiment, the center line of the first insulating tube 211 and the center line of the second insulating tube 212 are both perpendicular to the center line of the first cylinder 213.

[0044] Continue to refer to Figure 1 and Figure 2 The electron counting device 20 for micro-electron beams provided in this embodiment also includes a grid 23. The grid 23 is disposed in the incident channel 2131 and is located at one end of the incident channel 2131 facing the collection cavity 2141. The grid 23 is spaced apart from the output end of the electron multiplier tube 22. The outer peripheral wall of the grid 23 is connected to the inner peripheral wall of the incident channel 2131. By setting the grid 23, the grid 23 is used to control the voltage distribution. The grid 23 forms an electric field that causes the electron multiplier tube 22 to output electrons into the collection cavity 2141.

[0045] Specifically, the grid 23 is located at the entrance of the collecting cavity 2141, which is the end of the electron multiplier tube 22 facing the collecting cavity 2141. The potential of the grid 23 is consistent with that of the Faraday cylinder 21. Thus, when electrons are output, the electric field strength formed between the grid 23 and the output end of the electron multiplier tube 22 is relatively large due to the small distance between them. This allows electrons to enter the collecting cavity 2141 along the entrance direction and pass through the grid 23 into the collecting cavity 2141 for further collection by the Faraday cylinder 21.

[0046] Furthermore, in this embodiment, the grid 23 includes a ring 231 and a plurality of uprights 232. The plurality of uprights 232 are all disposed inside the ring 231, and both ends of the uprights 232 are connected to the inner peripheral wall of the ring 231. The plurality of uprights 232 are spaced apart along the diameter direction of the ring 231.

[0047] It should be noted that the lengths of the various uprights 232 are different.

[0048] During use, the outer peripheral wall of the ring 231 is connected to the inner peripheral wall of the incident channel 2131.

[0049] Continue to refer to Figure 1 The electron counting device 20 for micro-electron beams provided in this embodiment also includes a conductive baffle 24. The conductive baffle 24 is disposed in the incident channel 2131 and is located between the grid 23 and the electron multiplier tube 22. One end of the conductive baffle 24 is connected to the output end of the electron multiplier tube 22, and the outer peripheral wall of the other end of the conductive baffle 24 is connected to the inner peripheral wall of the incident channel 2131. By setting the conductive baffle 24, the conductive baffle 24 is used to collect secondary electrons generated by the Faraday cup and electrons reflected back due to the blocking effect of the grid 23, thereby improving the accuracy of electron collection.

[0050] Furthermore, in this embodiment, the conductive baffle 24 is frustum-shaped, the small-diameter end of the conductive baffle 24 is connected to the output end of the electron multiplier tube 22, and the outer peripheral wall of the large-diameter end of the conductive baffle 24 is connected to the inner peripheral wall of the incident channel 2131.

[0051] Specifically, the center line of the conductive baffle 24 is parallel to the center line of the incident channel 2131. In some feasible embodiments, the center line of the conductive baffle 24 is collinear with the center line of the incident channel 2131.

[0052] For example, the conductive baffle 24 is made of copper; of course, the conductive baffle 24 can also be made of other metal materials, as long as it can collect the secondary electrons generated by the Faraday cup and the electrons reflected back due to the blocking effect of the grid 23.

[0053] Furthermore, in this embodiment, the Faraday tube 21 is covered by a magnetic shielding cover 25, which forms a magnetic shielding cavity, and the Faraday tube 21 is housed within the magnetic shielding cavity. By setting the magnetic shielding cover 25, the magnetic field strength of the collecting cavity 2141 and the incident channel 2131 is almost zero. Placing the electron multiplier tube 22 inside the incident channel 2131 of the Faraday tube 21 ensures that the electron multiplier tube 22 will not be affected by the magnetic field.

[0054] The electron multiplier tube 22 is placed inside the incident channel 2131 of the Faraday cylinder 21. Since the magnetic field has a significant impact on the electron multiplication process, it is necessary to ensure that the magnetic field around the electron multiplier tube 22 is on a very small scale. Due to the large magnetic field interference around the electron emission equipment, a magnetic field shield is added around the collection cavity 2141 and the incident channel 2131. The magnetic field shield is made of magnetically conductive material, which allows the magnetic field lines to flow along the magnetically conductive material and not enter the interior of the Faraday cylinder 21, ensuring that the magnetic field strength of the collection cavity 2141 and the incident channel 2131 is almost zero. Placing the electron multiplier tube 22 inside the incident channel 2131 of the Faraday cylinder 21 ensures that the electron multiplier tube 22 is not affected by the magnetic field.

[0055] For example, the magnetic shielding cover 25 is cylindrical. Of course, the magnetic shielding cover 25 may also be frustum-shaped.

[0056] For example, the magnetic shield 25 is made of iron to prevent external magnetic fields from affecting the internal electron multiplication process.

[0057] In the feasible embodiment where the magnetic shielding cover 25 is cylindrical, the inner diameter of the magnetic shielding cover 25 is larger than the outer diameter of the second cylinder 214. During use, the magnetic shielding cover 25 is wrapped around the outside of the Faraday cylinder 21, and the inside of the Faraday cylinder 21 is a vacuum environment.

[0058] Second embodiment:

[0059] Continue to refer to Figure 3 and Figure 4 The present invention discloses an electronic counting system 1, including a current measuring unit 10 and an electronic counting device 20 for a micro electron beam provided in the first embodiment above. The input end of the Faraday cylinder 21 in the electronic counting device 20 is connected to an external electron beam input device 2, and the output end of the Faraday cylinder 21 is connected to the current measuring unit 10.

[0060] During the measurement process, the Faraday cylinder 21 sends the output electron current to the current measuring unit 10 to measure the current magnitude; the number of incident electrons is calculated from the magnitude of the output current, and the number of electrons is counted.

[0061] Furthermore, in this embodiment, the current measurement unit 10 includes a sampling resistor and a multimeter. One end of the sampling resistor is connected to the output terminal of the Faraday cylinder 21 through a first shielded wire, and the other end of the sampling resistor is grounded. The sampling resistor is connected to the multimeter through a second shielded wire, and the multimeter is connected to the host computer. The multimeter is used to read the voltage value across the sampling resistor and then upload the read data to the host computer.

[0062] Specifically, the two sides of the sampling resistor are connected to the multimeter via a second shielded wire.

[0063] During the measurement process, the sampling resistor converts the current into voltage. The voltage value across the sampling resistor is measured and read using a multimeter to obtain the electron current value. For direct current, the charge q measured by the Faraday tube 21 within the time range t is obtained by measuring the current value I per unit time according to the formula I = q / t. For pulse current, the total charge is obtained by measuring the integral value of the pulse current over a period of time according to the formula q = ∫Idt. The charge of the incident electron is then obtained by the amplification factor of the electron multiplier tube 22 and divided by the charge of a single electron, 1.6 × 10⁻⁶. -19 The number of electrons obtained.

[0064] The current measurement unit 10 can also use a capacitor charge integration circuit. By integrating the input current across the capacitor and measuring the integrated voltage value across the capacitor, the amount of charge on the capacitor over a period of time can be obtained, thereby calculating the number of electrons.

[0065] Third embodiment:

[0066] Continue to refer to Figure 5 The present invention discloses a measurement method for an electronic counting system 1 as described in the second embodiment above, comprising the following steps:

[0067] S101. A tiny electron beam is incident onto an electron multiplier tube 22 via an electron beam input device 2 for multiplication.

[0068] Specifically, a tiny electron beam is incident into an electron multiplier tube 22 for multiplication to obtain an electron beam with a larger number of electrons.

[0069] S102, the multiplied electron beam is converted into an electron current by the Faraday tube 21, and the Faraday tube 21 outputs the electron current to the current measuring unit 10 to measure the electron current value.

[0070] Specifically, the multiplied electron beam is collected by the Faraday tube 21, and the collected electron beam is converted into an electron current. The Faraday tube 21 outputs the electron current to the current measurement unit 10. The sampling resistor converts the electron current into a voltage, which is then input into a multimeter. The multimeter reads the voltage value across the sampling resistor to obtain the electron current value.

[0071] S103. The number of incident electrons is calculated from the current value.

[0072] Specifically, for direct current, the charge q measured by the Faraday tube 21 within the time range t is obtained by measuring the current value I per unit time, according to the formula I = q / t. For pulsed current, the total charge is obtained by measuring the integral value of the pulsed current over a period of time, according to the formula q = ∫Idt. The charge of the incident electron is then obtained by using the magnification factor of the electron multiplier tube 22, and divided by the charge of a single electron, 1.6 × 10⁻⁶. -19 The number of electrons obtained.

[0073] The measurement method of the electronic counting system 1 provided in this application includes a current measuring unit 10 and a micro-electron beam counting device 20. The input end of the Faraday cylinder 21 in the electronic counting device 20 is connected to an external electron beam input device 2, and the output end of the Faraday cylinder 21 is connected to the current measuring unit 10. The micro-electron beam counting device 20 includes a Faraday cylinder 21 and an electron multiplier tube 22. The electron multiplier tube 22 is housed within the Faraday cylinder 21, with a gap between the outer peripheral wall of the electron multiplier tube 22 and the inner peripheral wall of the Faraday cylinder 21. The Faraday cylinder 21 is connected to a second insulating tube 212 and the electron multiplier tube 22 via a first insulating tube 211. One end of a first wire 2111 passes through the first insulating tube 211 and is inserted into the electron multiplier tube 22, and is connected to the negative electrode inside the electron multiplier tube 22. A second wire... One end of 2121 passes through the second insulating tube 212 and is inserted into the electron multiplier tube 22, and is connected to the positive electrode inside the electron multiplier tube 22; the first wire 2111 and the second wire 2121 cooperate to provide a multiplication voltage to the electron multiplier tube 22; the electron multiplier tube 22 is used to amplify the incident electron beam; the Faraday cylinder 21 is used to collect electrons and convert the collected electrons into current; the measurement process is: multiply the electron beam - measure the electron current value - calculate the number of electrons; by setting a gap between the outer peripheral wall of the electron multiplier tube 22 and the inner peripheral wall of the Faraday cylinder 21, an additional electric field is prevented from forming inside the Faraday cylinder 21 from affecting the collection of electrons; in addition, compared with directly using the Faraday cylinder 21 inside the electron multiplier tube 22 to collect electrons, the electrons amplified by the electron multiplier tube 22 are input into the Faraday cylinder 21 for measurement, which improves the accuracy of electron measurement.

[0074] The electron counting device 20 for micro-electron beams provided by the present invention has the following advantages: the device has a simple structure, is easy to manufacture, and is easy to operate.

[0075] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0076] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An electron counting device for a micro-electron beam, characterized in that: Including Faraday cylinders and electron multiplier tubes; The electron multiplier tube is housed within the Faraday cylinder, with a gap between the outer peripheral wall of the electron multiplier tube and the inner peripheral wall of the Faraday cylinder. The Faraday cylinder is connected to the electron multiplier tube via a first insulating tube, a second insulating tube, and the electron multiplier tube. One end of a first wire passes through the first insulating tube and is inserted into the electron multiplier tube, and is connected to the negative electrode inside the electron multiplier tube. One end of a second wire passes through the second insulating tube and is inserted into the electron multiplier tube, and is connected to the positive electrode inside the electron multiplier tube. The first wire and the second wire work together to provide a multiplication voltage to the electron multiplier tube; The electron multiplier tube is used to amplify the incident electron beam; The Faraday cylinder is used to collect electrons and convert the collected electrons into an electric current.

2. The electron counting device for micro-electron beams according to claim 1, characterized in that: The Faraday cylinder includes a first cylinder and a second cylinder. The first cylinder forms an incident channel, and the second cylinder forms a collection cavity. One end of the first cylinder is connected to one end of the second cylinder, and the diameter of the incident channel is smaller than the diameter of the collection cavity. The electron multiplier tube is inserted into the incident channel. A first mounting hole and a second mounting hole are provided on the outer peripheral wall of the first cylinder. The first mounting hole and the second mounting hole are arranged opposite to each other and are both connected to the incident channel. One end of the first insulating tube passes through the first mounting hole and is inserted into the incident channel and is connected to the electron multiplier tube. The other end of the first insulating tube is inserted into the first mounting hole. One end of the second insulating tube passes through the second mounting hole and is inserted into the incident channel and is connected to the electron multiplier tube. The other end of the second insulating tube is inserted into the second mounting hole.

3. The electron counting device for micro-electron beams according to claim 2, characterized in that: It also includes a grid, which is disposed in the incident channel and located at one end of the incident channel facing the collection cavity. The grid is spaced apart from the output end of the electron multiplier tube, and the outer peripheral wall of the grid is connected to the inner peripheral wall of the incident channel.

4. The electron counting device for micro-electron beams according to claim 3, characterized in that: The grid includes a circular ring and multiple uprights. The multiple uprights are all disposed inside the circular ring, and both ends of the uprights are connected to the inner circumferential wall of the circular ring. The multiple uprights are spaced apart along the diameter of the circular ring.

5. The electron counting device for micro-electron beams according to claim 3, characterized in that: It also includes a conductive baffle, which is disposed in the incident channel and located between the grid and the electron multiplier tube. One end of the conductive baffle is connected to the output end of the electron multiplier tube, and the outer peripheral wall of the other end of the conductive baffle is connected to the inner peripheral wall of the incident channel.

6. The electron counting device for micro-electron beams according to claim 5, characterized in that: The conductive baffle is frustum-shaped, with its small-diameter end connected to the output end of the electron multiplier tube, and its large-diameter end's outer peripheral wall connected to the inner peripheral wall of the incident channel.

7. The electron counting device for micro-electron beams according to any one of claims 5-6, characterized in that: The conductive baffle is made of copper.

8. The electron counting device for micro-electron beams according to claim 1, characterized in that: The Faraday cylinder is covered by a magnetic shielding cover, which forms a magnetic shielding cavity, and the Faraday cylinder is housed within the magnetic shielding cavity.

9. The electron counting device for micro-electron beams according to claim 8, characterized in that: The magnetic shielding cover is cylindrical.

10. The electron counting device for micro-electron beams according to claim 9, characterized in that: The magnetic shielding cover is made of iron.

11. An electronic counting system, characterized in that: The device includes a current measuring unit and an electron counting device for a micro-electron beam as described in any one of claims 1 to 10, wherein the input end of the Faraday cylinder in the electron counting device is connected to an external electron beam input device, and the output end of the Faraday cylinder is connected to the current measuring unit.

12. The electronic counting system according to claim 11, characterized in that: The current measurement unit includes a sampling resistor and a multimeter. One end of the sampling resistor is connected to the output terminal of the Faraday cylinder through a first shielded wire, and the other end of the sampling resistor is grounded. The sampling resistor is connected to the multimeter via a second shielded wire, and the multimeter is connected to a host computer. The multimeter is used to read the voltage value across the sampling resistor and then upload the read data to the host computer.

13. A measurement method for an electronic counting system as described in any one of claims 11-12, characterized in that: Includes the following steps: A tiny electron beam is incident onto the electron multiplier tube via the electron beam input device for multiplication. The multiplied electron beam is converted into an electron current by the Faraday tube, and the Faraday tube outputs the electron current to the current measuring unit to measure the electron current value; The number of incident electrons can be calculated from the current value.

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