Method and system for detecting number of free electrons of detected piece

Abstract

The embodiment of the invention discloses a method and system for detecting the number of free electrons of a detected piece. The method comprises the following steps: generating free electrons in a tested piece in a vacuum environment through a photoelectric effect; acquiring a first current value which is a stable current value when the external electric field is not applied to the measured piece; an external electric field is applied to the measured piece after the first current value is obtained, and a second current value is obtained and is a stable current value when the external electric field is applied to the measured piece; after the second current value is obtained, the external electric field applied to the measured piece is cancelled, and a third current value is obtained and is a stable current value obtained after the external electric field applied to the measured piece is cancelled; and when the second current value is verified to be valid based on the first current value and the third current value, obtaining the number of free electrons generated in the tested piece. According to the method, a tested piece can generate free electrons in a vacuum environment through a photoelectric effect, an effective current value when an external electric field is applied is determined, and the number of the free electrons generated in the tested piece is obtained based on the effective current value.

Description

Technical Field

[0001] This disclosure relates to the field of space physics technology, and in particular to a method and system for detecting the number of free electrons in a test object. Background Technology

[0002] In the fields of space physics, materials science, and the semiconductor industry, the detection of free electrons is a key technological requirement, crucial for related research and industrial development. Currently, commonly used methods for free electron detection are mainly indirect measurement techniques under non-vacuum conditions, such as conductivity measurement and thermionic emission.

[0003] While these methods are effective in certain specific applications, their applicability is limited, and they are insufficient for high-precision measurements. Furthermore, they are complex to operate, requiring multiple steps to complete the measurement, and real-time monitoring is difficult to achieve. In addition, existing methods have significant drawbacks: firstly, they cannot operate effectively in a vacuum environment, greatly affecting the accuracy of the measurement results; secondly, their complex operation and difficulty in real-time monitoring limit the flexibility and practicality of their applications. Summary of the Invention

[0004] In view of this, the present disclosure provides a method and system for detecting the number of free electrons in a test piece, which can generate free electrons in the test piece under vacuum environment through photoelectric effect, and sequentially obtain stable current values ​​(i.e., first, second, and third current values) when no external electric field is applied, an external electric field is applied, and the external electric field is removed. The validity of the second current value is verified by the first and third current values, and the number of free electrons generated inside the test piece is obtained based on the second current value after the validity is determined.

[0005] In a first aspect, embodiments of this disclosure provide a method for detecting the number of free electrons in a test piece, employing the following technical solution: The photoelectric effect generates free electrons inside the test piece in a vacuum environment. Obtain the first current value; wherein, the first current value is the steady current value of the device under test when no external electric field is applied; After obtaining the first current value, an external electric field is applied to the device under test, and a second current value is obtained based on the applied external electric field; wherein, the second current value is the stable current value of the device under test when an external electric field is applied. After obtaining the second current value, the applied electric field to the device under test is removed, and a third current value is obtained; wherein, the third current value is the stable current value of the device under test after the applied electric field is removed. Based on the first current value and the third current value, verify the validity of the second current value; When the second current value is determined to be valid, the number of free electrons generated inside the device under test is obtained based on the second current value.

[0006] Optionally, obtaining the first current value includes: Connect the emitter plate of the device under test to the negative current terminal of the microcurrent tester; Connect the receiving plate of the device under test to the positive current terminal of the microcurrent tester; Acquire a first current measurement value; wherein, the first current measurement value is the measurement value of the micro current tester on the device under test when no external electric field is applied to the device under test; Based on the first current measurement value, a first current value is obtained.

[0007] Optionally, applying an external electric field to the device under test and obtaining a second current value based on the applied external electric field includes: A negative voltage is applied to the emitter plate of the test piece; wherein the emitter plate is a metal plate capable of generating free electrons; A positive voltage is applied to the receiving plate of the test piece; wherein the receiving plate is a metal plate capable of receiving free electrons; An external electric field is formed based on the applied negative and positive voltages; Acquire a second current measurement value; wherein the second current measurement value is the measurement value of the microcurrent tester on the device under test when an external electric field is applied to the device under test; Based on the second current measurement value, a second current value is obtained.

[0008] Optionally, the step of removing the applied electric field to the device under test and obtaining the third current value when the second current value is determined to be reasonable includes: Remove the negative voltage applied to the transmitting plate and the positive voltage applied to the receiving plate; Acquire a third current measurement value; wherein the third current measurement value is the measurement value of the microcurrent tester on the device under test after the applied negative and positive voltages are removed from the device under test; Based on the third current measurement value, a third current value is obtained.

[0009] Optionally, before generating free electrons inside the test piece in a vacuum environment through the photoelectric effect, the method for detecting the number of free electrons in the test piece further includes: The test piece is measured using the lowest current range of a microcurrent tester to obtain a relative value. Subtract the relative value from the first current measurement value to obtain the first current value; Subtract the relative value from the second current measurement value to obtain the second current value; The third current value is obtained by subtracting the relative value from the third current measurement value.

[0010] Optionally, verifying the validity of the second current value based on the first current value and the third current value includes: If the second current value is greater than the product of the first current value and a preset multiple, and the difference between the third current value and the first current value is less than a preset value, then the second current value is determined to be valid. If the second current value is not greater than the product of the first current value and a preset multiple, or if the second current value is greater than the product of the first current value and a preset multiple, but the difference between the third current value and the first current value is not less than a preset value, then the second current value is determined to be invalid.

[0011] Optionally, the formula for calculating the number of free electrons is: In the formula, Indicates the number of free electrons; Indicates the second current value; It represents the electron charge.

[0012] Secondly, this disclosure also provides a detection system for the number of free electrons in a test piece, the system including a laser source, a voltage source, and a microcurrent tester; The test piece is placed in a vacuum device, so that the test piece is in a vacuum environment; Connect the voltage source and the microcurrent tester to the device under test respectively, and start the microcurrent tester; When the laser source is activated, the light source emitted by the laser source illuminates the inner wall surface of the test piece along a set optical path, and free electrons are generated inside the test piece through the photoelectric effect. The microcurrent tester is used to obtain a first current value; wherein, the first current value is the stable current value of the device under test when no external electric field is applied. After acquiring the first current value, the voltage source is activated, which is used to apply an external electric field to the device under test. The microcurrent tester is used to obtain a second current value; wherein, the second current value is the stable current value of the test device when an external electric field is applied. After obtaining the second current value, the voltage source is turned off, and the external electric field applied to the device under test is removed; The microcurrent tester is used to obtain a third current value; wherein the third current value is the stable current value of the device under test after the external electric field is removed. Based on the first current value and the third current value, the validity of the second current value is verified. When the validity of the second current value is determined, the number of free electrons generated inside the device under test is obtained based on the second current value.

[0013] Optionally, the vacuum device includes a first through-chamber flange; the test piece includes a transmitting plate and a receiving plate, the receiving plate having an insulating feedthrough; the laser source includes an optical fiber; One end of the optical fiber is connected to the laser source, and the other end of the optical fiber passes through the first through-flange and the insulating feedthrough in sequence, maintaining a near-field coupling distance with the inner wall surface of the emitting plate. The light source emitted by the laser source is transmitted along the optical fiber and then irradiates the inner wall surface of the emitting plate. Through the photoelectric effect, the emitting plate generates free electrons.

[0014] Optionally, the system further includes a first test cable and a second test cable; the vacuum device further includes a second through-chamber flange; The negative terminal of the voltage source is connected to one end of the first test cable, and the other end of the first test cable passes through the second through-flange and is connected to the transmitter plate of the device under test. The positive voltage terminal of the voltage source is connected to one end of the second test cable, and the other end of the second test cable passes through the second through-flange and is connected to the receiving plate of the test piece. The negative voltage terminal of the voltage source applies a negative voltage to the transmitter plate of the device under test through the first test cable; The positive voltage terminal of the voltage source applies a positive voltage to the receiving board of the device under test through the second test cable; An external electric field is formed based on the applied negative and positive voltages.

[0015] The method for detecting the number of free electrons in a test piece provided in this disclosure places the test piece in a vacuum environment, which eliminates the effects of scattering and collisions of gas molecules in the air on free electrons, ensuring that free electrons can be generated and move in a relatively pure environment, thereby improving the accuracy and reliability of the detection. Utilizing the photoelectric effect to generate free electrons offers strong controllability, providing a stable source of free electrons for subsequent detection. A first current value can serve as a reference value for subsequent detection, reflecting the current formed by the natural movement of free electrons due to the photoelectric effect in the absence of an external electric field. Recording this reference value provides a reference for subsequent analysis of the influence of the external electric field on the current, allowing for a more accurate determination of whether the change in current under the influence of the external electric field is caused by a change in the number of free electrons. An external electric field can cause free electrons to move in a directed manner under the influence of the electric field force, resulting in a more obvious change in current. By measuring a second current value, the influence of the external electric field on the movement of free electrons can be observed, and the behavior of free electrons under the influence of the electric field can be analyzed, providing a basis for calculating the number of free electrons. The third current value is used to verify the reversibility of the system. If the current recovers to a level close to the first current value after the external electric field is removed, it indicates that the entire detection process is reversible, and the system has not undergone irreversible changes due to the external electric field, such as changes in material structure, thus ensuring the reliability of the detection results. By comparing the first, second, and third current values, it can be determined whether the second current value truly reflects the influence of the external electric field on the movement of free electrons. If the change in the second current value is caused by system errors or other interference factors, rather than the effect of the external electric field, this verification method can identify it and correct or remeasure the data, thereby improving the accuracy of the data. With an effective second current value, the number of free electrons generated inside the device under test can be calculated based on the physical relationship between current and the number of free electrons, thus achieving quantitative detection of the number of free electrons in the device under test. Accurately obtaining the number of free electrons is of great significance for studying the electrical properties and material characteristics of the device under test. In fields such as space physics, materials science, and electronic engineering, the number of free electrons is a key factor affecting the conductivity and semiconductor performance of materials. This detection method can provide important data support for research and applications in related fields.

[0016] The above description is merely an overview of the technical solution disclosed herein. In order to better understand the technical means of this disclosure and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this disclosure more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic flowchart illustrating the method for detecting the number of free electrons in a test piece provided in this embodiment of the disclosure; Figure 2 A schematic diagram of the structure of a detection system for the number of free electrons in a test piece provided in an embodiment of this disclosure; Reference numerals: 1. Test piece; 11. Transmitter plate; 12. Receiver plate; 121. Insulated feedthrough; 13. Insulating plate; 14. Insulating base; 2. Vacuum device; 21. First through-cell flange; 22. Second through-cell flange; 3. Laser source; 31. Optical fiber; 4. Voltage source; 5. Microcurrent tester; 6. First test cable; 7. Second test cable; 8. Third test cable; 9. Fourth test cable; 10. Monitoring device. Detailed Implementation

[0019] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0020] It should be understood that the following specific examples illustrate the implementation of this disclosure, and those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0021] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0022] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this disclosure. The drawings only show the components related to this disclosure and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0023] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0024] Reference Figure 1 This disclosure provides a method for detecting the number of free electrons in a test piece, comprising the following steps: S1: Free electrons are generated inside the test piece 1 in a vacuum environment through the photoelectric effect; S2: Obtain the first current value; wherein, the first current value is the stable current value of the test device 1 when no external electric field is applied; S3: After obtaining the first current value, an external electric field is applied to the device under test 1, and a second current value is obtained based on the applied external electric field; wherein, the second current value is the stable current value of the device under test 1 when an external electric field is applied. S4: After obtaining the second current value, the applied electric field to the device under test 1 is removed, and the third current value is obtained; wherein, the third current value is the stable current value of the device under test 1 after the applied electric field is removed. S5: Verify the validity of the second current value based on the first and third current values; S6: When the second current value is determined to be valid, the number of free electrons generated inside the test piece 1 is obtained based on the second current value.

[0025] The method for detecting the number of free electrons in the test piece 1 disclosed herein places the test piece 1 in a vacuum environment, which can eliminate the influence of scattering and collision of free electrons by gas molecules in the air, ensuring that free electrons can be generated and move in a relatively pure environment, thereby improving the accuracy and reliability of the detection. Utilizing the photoelectric effect to generate free electrons offers strong controllability, providing a stable source of free electrons for subsequent detection.

[0026] The first current value serves as a benchmark for subsequent detections. It reflects the current generated by the natural movement of free electrons due to the photoelectric effect in the absence of an external electric field. Recording this benchmark value provides a reference for subsequent analysis of the impact of the external electric field on the current, allowing for a more accurate determination of whether the current change under the external electric field is caused by a change in the number of free electrons. An external electric field can cause free electrons to move in a directional manner under the influence of the electric field force, resulting in a more pronounced current change. Measuring the second current value allows observation of the impact of the external electric field on the movement of free electrons, enabling analysis of the behavior of free electrons under the electric field and providing a basis for calculating the number of free electrons. The third current value is used to verify the reversibility of the system. If the current recovers to a level close to the first current value after the external electric field is removed, it indicates that the entire detection process is reversible, and the system has not undergone irreversible changes due to the external electric field, such as changes in material structure, thus ensuring the reliability of the detection results.

[0027] By comparing the first, second, and third current values, it can be determined whether the second current value truly reflects the influence of the applied electric field on the motion of free electrons. If the change in the second current value is caused by system errors or other interference factors, rather than the effect of the applied electric field, this verification method can identify it, allowing the data to be corrected or remeasured, thereby improving the accuracy of the data.

[0028] By using an effective second current value, the number of free electrons generated inside the device under test (DUT) 1 can be calculated based on the physical relationship between current and the number of free electrons, thus achieving quantitative detection of the number of free electrons in DUT 1. Accurately obtaining the number of free electrons is of great significance for studying the electrical properties and material characteristics of DUT 1. In fields such as space physics, materials science, and electronic engineering, the number of free electrons is a key factor affecting the conductivity and semiconductor performance of materials. This detection method can provide important data support for research and applications in related fields.

[0029] In S1, refer to Figure 2The schematic diagram of the detection system for the number of free electrons in the test piece is shown. The test piece 1 is placed in a vacuum device 2 (e.g., a vacuum chamber) so that the test piece 1 is in a vacuum environment. In order for the test piece 1 to generate the photoelectric effect, a laser source 3 is required, such as an ultraviolet laser source (UV) laser source 3, which can generate ultraviolet light. This light source is irradiated onto the inner wall surface of the test piece 1 so that it can generate free electrons.

[0030] The test piece 1 includes two parallel plates, typically about 2 cm apart. The plates are usually made of metal, such as gold-plated, silver-plated, copper, or aluminum, which are highly conductive. The plate directly receiving light is the emitting plate 11, and the parallel plate is the receiving plate 12. To ensure the relative position of the emitting plate 11 and the receiving plate 12 is stable, a support plate is fixedly connected between them. This support plate is usually also an insulating plate 13, providing insulation. If the support plate lacks insulation, insulating material is laid on its inner surface to transform it into an insulating plate 13. A closed space is typically formed between the emitting plate 11, the receiving plate 12, and the insulating plate 13. The number of insulating plates 13 depends on the shape and size of the emitting plate 11 and the receiving plate 12. For example, if the emitting plate 11 and the receiving plate 12 are circular (e.g., 10 cm in diameter), there is usually one insulating plate 13; if they are square, there are usually four insulating plates 13. However, since the device under test 1 is in a vacuum environment, the content of residual gas and impurities is very low. Even if a closed space is not formed between the emitting plate 11, the receiving plate 12, and the insulating plate 13, a photoelectric effect can still be generated, meeting the necessary conditions for supporting the detection of the number of free electrons. To prevent the vacuum device 2 from affecting the electrical performance of the device under test 1, an insulating base 14 is provided below the device under test 1. The insulating base 14 isolates the current conduction between the device under test 1 and the vacuum device 2, thereby improving the accuracy of subsequent free electron detection.

[0031] According to the photoelectric effect theory, electrons can only be emitted when the wavelength of light is less than a certain critical value (i.e., the limiting wavelength). For the materials used in the test piece 1, such as gold plating, silver plating, copper, and aluminum plating, the minimum limiting wavelength is 258 nm (for gold). Therefore, a laser source 3 with a wavelength of 254 nm can be used. The UV lamp of the laser source 3 has a power emission spectrum curve at 254 nm that is greater than 10 mW / m² / nm, which fully meets the requirements.

[0032] To ensure that the light emitted by the laser source 3 can illuminate the interior of the test piece 1, an insulated feedthrough 121 needs to be created on the receiving plate 12. Since the test piece 1 already has an exhaust port, it can be converted into an insulated feedthrough 121 simply by adding insulating material at the exhaust port. The insulating material is usually epoxy resin, acrylic, or other high-temperature resistant insulating materials with a volume resistivity of 10¹⁴ Ω∙cm. The vacuum device 2 itself has multiple through-chamber flanges, including the first through-chamber flange 21. The laser source 3 is usually equipped with an optical fiber 31. If not, an additional optical fiber 31 needs to be added. Since the exhaust port of the test piece 1 is small, the outer layer of the optical fiber 31 needs to be stripped, leaving only the core. The core length is usually 1~2cm. The diameter of the modified insulated feedthrough 121 usually needs to be slightly larger than the diameter of the optical fiber core to facilitate the entry of the optical fiber 31 into the interior of the test piece 1. Generally, the core diameter of the optical fiber 31 is about 0.5mm, and the diameter of the insulated feedthrough 121 is 0.6mm~0.7mm. One end of the optical fiber 31 is optically coupled to the laser source 3, and the other end of the optical fiber 31 is sequentially connected to the first through-flange 21 and the insulating feedthrough 121, maintaining a near-field coupling distance with the inner wall surface of the emitting plate 11 (meaning that the end of the optical fiber 31 and the inner wall surface of the emitting plate 11 are kept at a relatively close and appropriate distance, so that the laser can efficiently and stably transfer energy from the optical fiber 31 to the emitting plate 11 in the near field). The beam (light source) generated by the laser source 3 is propagated along the optical fiber 31 with low loss according to the principle of total internal reflection, and finally accurately irradiates the inner wall surface of the emitting plate 11. The energy of the photons is absorbed by the electrons in the emitting plate 11, so that the electrons gain enough energy to overflow the surface of the emitting plate 11 and become free electrons.

[0033] In S2, free electrons overflowing from the surface of the emitting plate 11 undergo random thermal motion, causing some free electrons to move towards the receiving plate 12. These moving free electrons form a current. Since this current is usually quite weak, a microcurrent meter 5 is needed for accurate measurement to determine its value. A vacuum environment is a necessary condition for ensuring the accuracy of free electron quantity measurement. Therefore, in a non-vacuum environment, gas molecules can cause many interferences to the measurement. For example, free electrons are prone to collision and scattering with gas molecules, changing their direction and energy. They may also cause gas molecules to ionize, generating additional charged particles that affect the measurement results. At the same time, the polarization of gas molecules in the electric field can lead to electric field distortion, affecting the trajectory and speed of free electrons. In addition, oxygen, water vapor, and other substances in a non-vacuum environment can react chemically with the materials of the emitting plate 11 and the receiving plate 12, changing the surface properties of the materials and affecting the emission and reception efficiency of free electrons. The working pressure of a vacuum environment is usually maintained below 1.3×10-3 Pa, with very few residual gas molecules, which avoids the above-mentioned problems, ensures the stable movement of free electrons, the stability of the electric field, and the unchanged surface properties of materials, thereby ensuring measurement accuracy. At the same time, the ionization of residual gas molecules will generate a background current, the value of which is the first current value, which can be regarded as the background noise. The background noise can be reduced by differential pumping system and cold trap technology.

[0034] Before activating the laser source 3, the emitting plate 11 of the device under test 1 is connected to the negative current terminal of the microcurrent meter 5, and the receiving plate 12 of the device under test 1 is connected to the positive current terminal of the microcurrent meter 5, so that a circuit can be formed between the device under test 1 and the microcurrent meter 5, allowing the microcurrent meter 5 to measure the current magnitude normally. The current measurement resolution of the microcurrent meter 5 is at least in the 10 fA (femtoampere) range to accurately measure minute currents.

[0035] Ideally, the reading of the microcurrent tester 5 should be zero when the input terminal is open. However, in reality, the microcurrent tester 5 does exhibit a small current when the input terminal is open. This current is called the input bias current, caused by the bias current of the active device and the leakage current flowing through the insulator inside the instrument. The input bias current is superimposed on the measured current, so the current value displayed by the microcurrent tester 5 is the sum of the input bias current and the actual current value. To eliminate the input bias current, before starting the laser source 3, the test piece 1 should be measured using the lowest current range of the microcurrent tester 5 to allow the reading to stabilize (approximately 5 minutes). Then, the REL (Relative) function of the microcurrent tester 5 should be activated. The REL function sets the current reading of the microcurrent tester 5 to a reference value (i.e., the REL value), which is the current relative value. When the test piece 1 is replaced, the relative value can be re-acquired due to environmental changes, thus ensuring the accuracy of the current acquisition.

[0036] After the laser source 3 is turned on, no external electric field is applied to the test device 1. The current of the test device 1 is measured by the micro current tester 5. After the measured value stabilizes, the measured value is the first current measurement value. The first current value can be obtained by subtracting the relative value from the first current measurement value.

[0037] In step S3, voltage source 4 is set up. After acquiring the first current value, voltage source 4 is activated, applying a negative voltage to the transmitting plate 11 of the device under test 1 and a positive voltage to the receiving plate 12. According to the basic principle of electric fields, the application of positive and negative voltages will create an external electric field between the transmitting plate 11 and the receiving plate 12, with the direction of the electric field pointing from the positive voltage receiving plate 12 to the negative voltage transmitting plate 11. Under the action of the external electric field, the free electrons overflowing from the transmitting plate 11 will be driven by the electric field force and almost all of them will be attracted to the receiving plate 12. This directional flow of free electrons can form a current larger than the first current value.

[0038] To facilitate the application of external voltage from voltage source 4 to device under test 1, a first test cable 6 and a second test cable 7 are configured, and a through-chamber flange of vacuum device 2 is selected as the second through-chamber flange 22. The negative terminal of voltage source 4 is connected to one end of the first test cable 6, and the other end of the first test cable 6 passes through the second through-chamber flange 22 and is connected to the transmitter plate 11 of device under test 1; the positive terminal of voltage source 4 is connected to one end of the second test cable 7, and the other end of the second test cable 7 passes through the second through-chamber flange 22 and is connected to the receiver plate 12 of device under test 1; the negative terminal of voltage source 4 applies a negative voltage to the transmitter plate 11 of device under test 1 through the first test cable 6; the positive terminal of voltage source 4 applies a positive voltage to the receiver plate 12 of device under test 1 through the second test cable 7.

[0039] Similarly, to facilitate current measurement of the device under test (DUT) 1 by the microcurrent tester 5, a third test cable 8 and a fourth test cable 9 are configured. The negative terminal of the microcurrent tester 5 is connected to one end of the third test cable 8, and the other end of the third test cable 8 passes through the second through-flange flange 22 and is connected to the transmitting plate 11 of the DUT 1. The positive terminal of the microcurrent tester 5 is connected to one end of the fourth test cable 9, and the other end of the fourth test cable 9 passes through the second through-flange flange 22 and is connected to the receiving plate 12 of the DUT 1. Based on the third test cable 8 and the fourth test cable 9, the microcurrent tester 5 and the DUT 1 are electrically connected, enabling the microcurrent tester 5 to perform current measurement of the DUT 1. Since the current generated by the DUT 1 is usually very weak, shielded cables are required to increase anti-interference capabilities, and shielding measures must be taken at both ends of the test cables.

[0040] During the process of applying an external electric field to the test device 1, the micro current tester 5 measures the test device 1. After the measured value stabilizes, the measured value is the second current measured value. Subtracting the relative value from the second current measured value yields the second current value.

[0041] In step S4, after acquiring the second current value, the voltage source 4 is turned off, thereby removing the negative voltage applied to the transmitting plate 11 and the positive voltage applied to the receiving plate 12, thus achieving the effect of removing the external electric field. After the external electric field is removed, the micro-current tester 5 measures the device under test 1. After the measured value stabilizes, this measured value is the third current measured value. Subtracting the relative value from the third current measured value yields the third current value.

[0042] In step S5, it is determined whether the second current value is greater than the product of the first current value and a preset multiple, and whether the difference between the third current value and the first current value is less than a preset value. If the second current value is greater than the product of the first current value and the preset multiple, and the difference between the third current value and the first current value is less than the preset value, then the second current value is deemed valid. If the second current value is not greater than the product of the first current value and the preset multiple, or if the second current value is greater than the product of the first current value and the preset multiple, but the difference between the third current value and the first current value is not less than the preset value, then the second current value is deemed invalid. This is because when an external electric field is applied, free electrons are subjected to the electric field force, resulting in directional movement based on random thermal motion. Free electrons that originally could not reach the receiving plate 12 due to insufficient kinetic energy have more opportunities to reach the receiving plate 12 under the acceleration of the electric field force. At the same time, the electric field also encourages more free electrons to participate in directional movement, which greatly increases the number of free electrons reaching the receiving plate 12 from the transmitting plate 11, thereby leading to a significant increase in current. Therefore, under reasonable conditions, the second current value will be greater than the first current value. The preset multiple is a value determined based on theoretical calculations and extensive experimental experience. It represents the theoretically expected increase in current after applying an external electric field. This multiple considers various factors such as the strength of the external electric field, the material properties of the measured component 1, and the mobility of free electrons. If the second current value is greater than the product of the first current value and the preset multiple, it indicates that the external electric field has indeed had the expected effect on the movement of free electrons, resulting in a significant increase in current that meets theoretical expectations. Therefore, the second current value can be considered reasonable. In actual measurement, various errors and interference factors may exist, such as the accuracy error of the measuring instrument and environmental noise interference. Setting the preset multiple can, to some extent, eliminate the influence of these errors and interference. If the second current value is only slightly greater than the first current value, it may be a false increase caused by measurement error or interference, rather than the result of the external electric field actually working. Only when the second current value is greater than the product of the first current value and the preset multiple can it be more reliably proven that the external electric field caused a real and significant change in current. Only then is the second current value more likely to accurately reflect the reasonable result of the physical phenomenon.

[0043] The reliability of the second current value can be further verified by the third current value. This is because when the external electric field is removed, the free electrons should return to a state of random thermal motion similar to that before the external electric field was applied. In theory, the third current value should be close to or equal to the first current value. If the third current value is close to the first current value, it indicates that the system is stable during the entire measurement process and has not been affected by other continuous interference factors, thus indirectly proving that the second current value is reliable.

[0044] Verifying the second current value using the first and third current values ​​ensures that the second current value is not an anomaly caused by temporary interference or measurement error, thus guaranteeing its validity. When an invalid second current value is detected, an alarm is issued, and various measures are taken, such as inspecting the detection instruments, wiring connections, and light sources in the detection system, and checking whether the vacuum environment meets standards. After eliminating the causes affecting the detection, the detection is repeated.

[0045] In step S6, upon confirming the validity of the second current value, this value is incorporated into the formula for calculating the number of free electrons to obtain the number of free electrons generated inside the device under test 1. The formula for calculating the number of free electrons is as follows: In the formula, Indicates the number of free electrons; Indicates the second current value; Represents electron charge, The unit is coulomb, and 1 coulomb equals 1 ampere-second.

[0046] The number of free electrons can be calculated manually or intelligently. After obtaining the number of free electrons generated inside the device under test (DUT) 1, the laser source 3 and the microcurrent tester 5 are turned off. The optical fiber 31 is extracted from the DUT 1 and the vacuum device 2. The first test cable 6, the second test cable 7, the third test cable 8, and the fourth test cable 9 are disconnected from the DUT 1. If the insulating feedthrough 121 and the insulating plate 13 have been modified, they are restored to their original state.

[0047] In the case of intelligent computing, a monitoring device 10 is set up, which includes a memory, a processor, and a computer program stored in the memory and executable by the processor. The computer program calculates the number of free electrons according to a pre-set mathematical model by detecting and analyzing the current signal from the microcurrent tester 5.

[0048] The microcurrent tester 5 is connected to the monitoring device 10. Based on this connection structure, the monitoring device 10 can automatically calculate the number of free electrons. There are two implementation methods. In the first specific implementation, the microcurrent tester 5 can store relative values. After acquiring the first, second, and third current measurement values, the tester directly subtracts the stored relative values ​​from these measurement values ​​to obtain the first, second, and third current values. Since these measurement values ​​are not acquired simultaneously but sequentially, the tester can send a current value to the monitoring device 10 after acquiring one, or send them to the monitoring device 10 simultaneously after acquiring all of them. Based on the received first and third current values, the monitoring device 10 verifies the validity of the second current value. When the second current value is determined to be valid, it calculates the number of free electrons generated inside the device under test 1 based on the second current value.

[0049] In the second specific implementation scheme, the microcurrent meter 5 sends the relative value to the monitoring device 10, which stores the relative value. The microcurrent meter 5 acquires and sends the first current measurement value, the second current measurement value, and the third current measurement value to the monitoring device 10. It can send the measurement value to the monitoring device 10 after acquiring one value, or it can send all values ​​simultaneously after acquiring them. The monitoring device 10 subtracts the relative value from the received first, second, and third current measurement values ​​to obtain the first, second, and third current values. The monitoring device 10 then performs validity verification and calculates the number of free electrons.

[0050] When measuring the device under test 1, the microcurrent tester 5 needs to wait until the measured value stabilizes before it can be used. If manual observation is used, the tester needs to constantly check the readings of the microcurrent tester 5, which increases the tester's workload. Therefore, the monitoring device 10 can be further improved to allow the monitoring device 10 to cooperate with the microcurrent tester 5 to automatically acquire the first current value, the second current value, and the third current value.

[0051] The specific method for the monitoring device 10 to automatically acquire the first current value is as follows: the voltage source 4 and the laser source 3 are respectively connected to the monitoring device 10. The monitoring device 10 controls the start and stop of the laser source 3, the voltage source 4, and the micro-current tester 5, and receives the parameters and parameter acquisition time sent by the micro-current tester 5 in real time. The parameters are the current measurement value (referring to the original data measured without subtracting the relative value) or the actual current value (referring to the actual current data obtained after subtracting the relative value from the current measurement value). After the laser source 3 is started, the monitoring device 10 constructs a first curve based on the real-time received parameters and parameter acquisition time. This curve can be used to intuitively present the stable state of the parameters. Therefore, when it is determined from the first curve that the fluctuation amplitude of the parameters within the preset time range is always less than the preset threshold, it is determined that the parameters have reached a stable state. The stable time period in the first curve is determined, and the first current value is obtained based on the average value of all parameters within the stable time period. If the parameter is a current measurement value, the first current value is obtained by subtracting the relative value from the average value of all parameters within the stable time period in the first curve graph; if the parameter is a real current value, the first current value is obtained by averaging all parameters within the stable time period in the first curve graph.

[0052] The specific implementation method of the monitoring device 10 automatically acquiring the second current value is as follows: After starting the voltage source 4, the monitoring device 10 constructs a second curve based on the parameters received after the voltage source 4 is started and the parameter acquisition time. When it is determined from the second curve that the fluctuation amplitude of the parameter within a preset time range is always less than a preset threshold, it is determined that the parameter has reached a stable state during the process of applying an external electric field to the device under test 1. The stable time period in the second curve is determined, and the second current value is acquired based on the average value of all parameters within this stable time period. If the parameter is a current measurement value, the second current value is obtained by subtracting the relative value from the average value of all parameters within the stable time period in the second curve; if the parameter is a real current value, the second current value is the average value of all parameters within the stable time period in the second curve.

[0053] The specific implementation method of the monitoring device 10 automatically acquiring the third current value is as follows: After the voltage source 4 is turned off, the monitoring device 10 constructs a third curve based on the parameters received after the voltage source 4 is turned off and the parameter acquisition time. When it is determined from the third curve that the fluctuation amplitude of the parameter within a preset time range is always less than a preset threshold, it is determined that the parameter has reached a stable state again after the external electric field of the measured device 1 is removed. The stable time period in the third curve is determined, and the third current value is obtained based on the average value of all parameters within this stable time period. If the parameter is a current measurement value, the third current value is obtained by subtracting the relative value from the average value of all parameters within the stable time period in the third curve; if the parameter is a real current value, the average value of all parameters within the stable time period in the third curve is the third current value.

[0054] Traditional measurement methods in non-vacuum environments typically rely on air or other media, which are absent in a vacuum environment. Therefore, traditional methods cannot be directly applied to vacuum conditions. Furthermore, traditional methods are complex to operate and struggle to achieve real-time monitoring of free electrons, limiting their flexibility and practicality in real-world applications, especially in scenarios requiring rapid response and continuous monitoring. This disclosure provides a simple and efficient method for measuring the number of free electrons in a vacuum environment. Based on the law of charge conservation, it introduces charged particles into a specifically structured metal cavity to address the measurement of the number of spatial free electrons induced by various factors in a vacuum. The method is simple to operate and provides accurate and reliable results. This method is suitable not only for laboratory research but also for real-time monitoring of free electron numbers in industrial production, providing strong support for scientific research and technological applications in related fields. In addition, the power of the UV laser source 3 can be adjusted according to actual needs to optimize the generation efficiency of free electrons. Furthermore, the movement speed of free electrons can be adjusted by changing the voltage value of the voltage source 4, further improving detection accuracy. These optional technical features enhance the flexibility and adaptability of the experiment.

[0055] Reference Figure 2 This disclosure provides a detection system for the number of free electrons in a test piece 1, the system comprising a laser source 3, a voltage source 4, and a microcurrent tester 5; The test piece 1 is placed in the vacuum device 2, so that the test piece 1 is in a vacuum environment; Connect the voltage source 4 and the micro current tester 5 to the device under test 1 respectively, and start the micro current tester 5; When the laser source 3 is activated, the light source emitted by the laser source 3 shines on the inner wall surface of the test piece 1 along the set optical path, and free electrons are generated inside the test piece 1 through the photoelectric effect. The first current value is obtained using a microcurrent tester 5; wherein, the first current value is the stable current value of the test piece 1 when no external electric field is applied. After obtaining the first current value, the voltage source 4 is activated. The voltage source 4 is used to apply an external electric field to the device under test 1. The second current value is obtained using a microcurrent tester 5; wherein, the second current value is the stable current value when an external electric field is applied to the test piece 1. After obtaining the second current value, the voltage source 4 is turned off, and the external electric field applied to the device under test 1 is removed; The third current value is obtained using a microcurrent tester 5; where the third current value is the stable current value of the test piece 1 after the external electric field is removed. Based on the first and third current values, the validity of the second current value is verified. When the validity of the second current value is determined, the number of free electrons generated inside the test piece 1 is obtained based on the second current value.

[0056] Furthermore, the vacuum device 2 includes a first through-chamber flange 21; the test piece 1 includes a transmitting plate 11 and a receiving plate 12, the receiving plate 12 having an insulating feedthrough 121; the laser source 3 includes an optical fiber 31. One end of the optical fiber 31 is connected to the laser source 3, and the other end of the optical fiber 31 passes through the first through-flange 21 and the insulating feeder 121 in sequence, maintaining a near-field coupling distance with the inner wall surface of the emitting plate 11. The light source emitted by the laser source 3 is conducted along the optical fiber 31 and then irradiates the inner wall surface of the emitting plate 11. Through the photoelectric effect, the emitting plate 11 generates free electrons.

[0057] Furthermore, the system also includes a first test cable 6 and a second test cable 7; the vacuum device 2 also includes a second through-chamber flange 22; The negative terminal of the voltage source 4 is connected to one end of the first test cable 6, and the other end of the first test cable 6 passes through the second through-flange 22 and is connected to the transmitter plate 11 of the test piece 1. The positive voltage terminal of voltage source 4 is connected to one end of the second test cable 7, and the other end of the second test cable 7 passes through the second through-flange 22 and is connected to the receiving plate 12 of the test piece 1. The negative voltage of voltage source 4 is applied to the transmitter plate 11 of device under test 1 through the first test cable 6; The positive voltage of voltage source 4 is applied to the receiving plate 12 of the device under test 1 through the second test cable 7; An external electric field is formed based on the applied negative and positive voltages.

[0058] Furthermore, the system also includes a monitoring device 10, which is connected to a microcurrent tester 5. The monitoring device 10 is used to verify the validity of a second current value based on a first current value and a third current value. When the second current value is determined to be valid, the number of free electrons generated inside the test piece 1 is obtained based on the second current value.

[0059] Furthermore, the voltage source 4 and the laser source 3 are respectively connected to the monitoring device 10. The monitoring device 10 controls the start and stop of the laser source 3, the voltage source 4 and the micro current tester 5, and is also used to cooperate with the micro current tester 5 to automatically acquire the first current value, the second current value and the third current value.

[0060] Furthermore, the voltage source and the laser source are respectively connected to the monitoring device. The monitoring device controls the start and stop of the laser source, the voltage source and the micro current tester. It is also used to cooperate with the micro current tester to automatically acquire the first current value, the second current value and the third current value.

[0061] The various variations and specific examples of the above-described method for detecting the number of free electrons in a test piece are also applicable to the detection system for the number of free electrons in a test piece provided in this disclosure. Through the foregoing detailed description of the method for detecting the number of free electrons in a test piece, those skilled in the art can clearly understand the implementation method of the detection system for the number of free electrons in a test piece. For the sake of brevity, it will not be described in detail here.

[0062] The basic principles of this disclosure have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this disclosure are merely examples and not limitations, and should not be considered as essential features of each embodiment of this disclosure. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the scope of this disclosure to the necessity of employing the aforementioned specific details for implementation.

[0063] In this disclosure, 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. The block diagrams of devices, apparatuses, devices, and systems involved in this disclosure are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as "comprising," "including," "having," etc., are open-ended terms meaning "including but not limited to," and are used interchangeably with them. The terms "or" and "and" as used herein refer to the terms "and / or," and are used interchangeably with them unless the context clearly indicates otherwise. The term "such as" as used herein refers to the phrase "such as but not limited to," and is used interchangeably with it.

[0064] Additionally, as used herein, the "or" used in a list of items beginning with "at least one" indicates a separate list, such that a list of, for example, "at least one of A, B, or C" means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Furthermore, the word "exemplary" does not imply that the described example is preferred or better than other examples.

[0065] It should also be noted that in the systems and methods of this disclosure, the components or steps can be decomposed and / or recombined. These decompositions and / or recombinations should be considered as equivalent solutions to this disclosure.

[0066] Various changes, substitutions, and modifications can be made to the technology described herein without departing from the teachings defined by the appended claims. Furthermore, the scope of the claims of this disclosure is not limited to the specific aspects of the processes, machines, manufactures, events, means, methods, and actions described above. Currently existing or later-developed processes, machines, manufactures, events, means, methods, or actions that perform substantially the same function or achieve substantially the same result as the corresponding aspects described herein can be utilized. Therefore, the appended claims include such processes, machines, manufactures, events, means, methods, or actions within their scope.

[0067] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0068] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this disclosure to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. A method for detecting the number of free electrons in a test piece, characterized in that, include: Through the photoelectric effect, free electrons are generated inside the test piece (1) in a vacuum environment; Obtain the first current value; wherein, the first current value is the stable current value of the device under test (1) when no external electric field is applied; After obtaining the first current value, an external electric field is applied to the test device (1), and a second current value is obtained based on the applied external electric field; wherein, the second current value is the stable current value of the test device (1) when an external electric field is applied. After obtaining the second current value, the applied electric field to the test device (1) is removed, and the third current value is obtained; wherein, the third current value is the stable current value of the test device (1) after the applied electric field is removed. Based on the first current value and the third current value, verify the validity of the second current value; When the second current value is determined to be valid, the number of free electrons generated inside the test piece (1) is obtained based on the second current value.

2. The method for detecting the number of free electrons in a test piece according to claim 1, characterized in that, The process of obtaining the first current value includes: Connect the emitter plate (11) of the test piece (1) to the negative current terminal of the microcurrent tester (5); The receiving plate (12) of the test piece (1) is connected to the positive current terminal of the microcurrent tester (5); Obtain the first current measurement value; wherein, the first current measurement value is the measurement value of the micro current tester (5) on the test piece (1) when no external electric field is applied to the test piece (1); Based on the first current measurement value, a first current value is obtained.

3. The method for detecting the number of free electrons in a test piece according to claim 2, characterized in that, The process of applying an external electric field to the device under test (1) and obtaining a second current value based on the applied external electric field includes: A negative voltage is applied to the emitter plate (11) of the test piece (1); wherein the emitter plate (11) is a metal plate capable of generating free electrons; A positive voltage is applied to the receiving plate (12) of the test piece (1); wherein the receiving plate (12) is a metal plate capable of receiving free electrons; An external electric field is formed based on the applied negative and positive voltages; Obtain a second current measurement value; wherein, the second current measurement value is the measurement value of the micro current tester (5) on the test piece (1) when an external electric field is applied to the test piece (1); Based on the second current measurement value, a second current value is obtained.

4. The method for detecting the number of free electrons in a test piece according to claim 3, characterized in that, When the second current value is determined to be reasonable, the external electric field applied to the device under test (1) is removed, and the third current value is obtained, including: Remove the negative voltage applied to the transmitting plate (11) and the positive voltage applied to the receiving plate (12); Obtain a third current measurement value; wherein the third current measurement value is the measurement value of the micro current tester (5) on the test piece (1) after the negative and positive voltages applied to the test piece (1) are removed; Based on the third current measurement value, a third current value is obtained.

5. The method for detecting the number of free electrons in a test piece according to claim 4, characterized in that, Before generating free electrons inside the test piece (1) in a vacuum environment through the photoelectric effect, the method further includes: The test piece (1) is measured using the lowest current range of the microcurrent tester (5) to obtain a relative value; Subtract the relative value from the first current measurement value to obtain the first current value; Subtract the relative value from the second current measurement value to obtain the second current value; The third current value is obtained by subtracting the relative value from the third current measurement value.

6. The method for detecting the number of free electrons in a test piece according to claim 1, characterized in that, The step of verifying the validity of the second current value based on the first current value and the third current value includes: If the second current value is greater than the product of the first current value and a preset multiple, and the difference between the third current value and the first current value is less than a preset value, then the second current value is determined to be valid. If the second current value is not greater than the product of the first current value and a preset multiple, or if the second current value is greater than the product of the first current value and a preset multiple, but the difference between the third current value and the first current value is not less than a preset value, then the second current value is determined to be invalid.

7. The method for detecting the number of free electrons in a test piece according to claim 1, characterized in that, The formula for calculating the number of free electrons is: In the formula, Indicates the number of free electrons; Indicates the second current value; It represents the electron charge.

8. A system for detecting the number of free electrons in a test piece, characterized in that, The system includes a laser source (3), a voltage source (4), and a microcurrent tester (5). The test piece (1) is placed in a vacuum device (2) so that the test piece (1) is in a vacuum environment; Connect the voltage source (4) and the micro current tester (5) to the device under test (1) respectively, and start the micro current tester (5). When the laser source (3) is activated, the light source emitted by the laser source (3) illuminates the inner wall surface of the test piece (1) along the set optical path, and free electrons are generated inside the test piece (1) through the photoelectric effect. The microcurrent tester (5) is used to obtain a first current value; wherein the first current value is the stable current value of the test piece (1) when no external electric field is applied. After obtaining the first current value, the voltage source (4) is activated. The voltage source (4) is used to apply an external electric field to the device under test (1). The second current value is obtained using the microcurrent tester (5); wherein the second current value is the stable current value of the test piece (1) when an external electric field is applied. After obtaining the second current value, the voltage source (4) is turned off, and the external electric field applied to the device under test (1) is removed; The third current value is obtained using the microcurrent tester (5); wherein the third current value is the stable current value of the test piece (1) after the external electric field is removed. Based on the first current value and the third current value, the validity of the second current value is verified. When the validity of the second current value is determined, the number of free electrons generated inside the test piece (1) is obtained based on the second current value.

9. The detection system for the number of free electrons in a test piece according to claim 8, characterized in that, The vacuum device (2) includes a first through-chamber flange (21); the test piece (1) includes a transmitting plate (11) and a receiving plate (12), the receiving plate (12) having an insulating feedthrough (121); the laser source (3) includes an optical fiber (31); One end of the optical fiber (31) is connected to the laser source (3), and the other end of the optical fiber (31) passes through the first through-flange (21) and the insulating feedthrough (121) in sequence, maintaining a near-field coupling distance with the inner wall surface of the emitting plate (11). The light source emitted by the laser source (3) is irradiated on the inner wall surface of the emitting plate (11) after being conducted along the optical fiber (31). Through the photoelectric effect, the emitting plate (11) generates free electrons.

10. The detection system for the number of free electrons in the test piece according to claim 9, the system further comprising a first test cable (6) and a second test cable (7); the vacuum device (2) further comprising a second through-cell flange (22); The negative voltage terminal of the voltage source (4) is connected to one end of the first test cable (6), and the other end of the first test cable (6) passes through the second through-flange (22) and is connected to the transmitter plate (11) of the test piece (1). The positive voltage terminal of the voltage source (4) is connected to one end of the second test cable (7), and the other end of the second test cable (7) passes through the second through-flange (22) and is connected to the receiving plate (12) of the test piece (1); The negative voltage of the voltage source (4) is applied to the transmitter plate (11) of the device under test (1) through the first test cable (6); The positive voltage of the voltage source (4) is applied to the receiving plate (12) of the device under test (1) through the second test cable (7); An external electric field is formed based on the applied negative and positive voltages.

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