A Method for Constructing an Opto-Current Model of an Inertial Sensor

Abstract

The present invention discloses a method for constructing a photocurrent model of an inertial sensor, including: establishing a photocurrent model based on the general equation of photocurrent on a metal surface and the geometric structure of the inertial sensor; respectively calibrating the parameters of the photocurrent model: obtaining the number of photoelectron emissions in each divided area of the inner surface of the inertial sensor according to the optical characteristics; regulating the potential difference between each electrode plate and the proof mass to make the state between the electrode plate and the proof mass in the saturation state and the zero state, and respectively measuring the photocurrent in these two mode combinations, and obtaining the shunt probability between all the electrode plates and the proof mass according to the photocurrent in the two mode combinations; measuring the photocurrent of the proof mass from the negative saturation state potential to the positive saturation state potential, and inversely solving the photoelectron migration probability of the inertial sensor from the photocurrent model equation. The present invention can accurately give the influence of the potential of each electrode plate in the inertial sensor on the discharge performance of the proof mass, and assist in designing the discharge strategy of the charge management system.

Description

Technical Field

[0001] The present invention belongs to the technical field of precision measurement, and more specifically, relates to a method for constructing an optoelectronic current model of an inertial sensor. Background Art

[0002] In the field of precision measurement, it is usually necessary to insulate the sensitive unit to isolate external interferences such as electrical and thermal noises. For example, in the LISA space gravitational wave detection project led by the European Space Agency, the sensitive probe of the inertial sensor consists of a test mass and surrounding electrodes. The test mass is an isolated conductor with no electrical connection to surrounding objects, and free charges in space will attach to the test mass, resulting in charge accumulation. The electrostatic force generated by the gradually accumulated charges will seriously interfere with the measurement results of the instrument. Therefore, it is necessary to control the charges on the test mass.

[0003] Taking the ultraviolet discharge technology adopted in LISA Pathfinder as an example, it irradiates the inside of the inertial sensor with ultraviolet light to excite photoelectrons on the surface of the test mass and the electrodes, thereby realizing the charge and discharge of the test mass. In actual work, many complex voltages are applied to each electrode. The energy of ultraviolet photoelectrons is at the order of eV, so the voltage of the order of volts will affect the charge and discharge rate on the surface of the test mass macroscopically by changing the movement direction of the photoelectrons. Therefore, it is necessary to study the specific influence of the voltage on each electrode on the discharge rate of the test mass. Previous work on the discharge rate only studied the influence of the DC bias voltage applied to the electrode in the same direction as the discharge axis on the performance of the ultraviolet discharge system, but there is no literature on the influence of the potential bias voltage of the electrodes in other axes of the test mass.

[0004] The electrode and the surface of the test mass may consist of regions with different surface properties (such as quantum yield, work function, light illumination ratio, etc.). Therefore, it is necessary to spatially divide the test mass and the electrodes. When it is in the space environment, solar high-energy particles and cosmic galactic rays will continuously penetrate the spacecraft to charge the test mass, and the charging rate is between dozens of e / s and 1000 e / s. In order to enable the test mass to neutralize the charging effect of particles in the universe in space, an accurate charge and discharge rate of the test mass is required. Therefore, it is necessary to establish a more accurate optoelectronic current model. Summary of the Invention

[0005] Aiming at the defects of the prior art, the purpose of the present invention is to provide a method for constructing an optoelectronic current model of an inertial sensor, which can accurately give the influence of the potential of each electrode in the inertial sensor on the discharge performance of the test mass.

[0006] To achieve the above purpose, the present invention provides a method for constructing an optoelectronic current model of an inertial sensor, including the following steps:

[0007] (1) Establish a photocurrent model based on the general equation of the photocurrent on the metal surface and the geometric structure of the inertial sensor;

[0008] (2) Calibrate the three parameters of the photocurrent model respectively. The calibration method is as follows:

[0009] (a) According to the optical characteristics of the inner surface of the inertial sensor to ultraviolet light, obtain the number of photoelectrons emitted from each divided area on the inner surface of the inertial sensor. The divided areas are divided according to the areas where each electrode plate is located, and each divided area includes an electrode plate and a proof mass corresponding to the surface of the electrode plate;

[0010] (b) Apply the same DC bias voltage to the electrode plate to be measured and other electrode plates, so that the potential difference between the electrode plate to be measured and the proof mass is greater than the maximum kinetic energy of the photoelectrons emitted, so that the electrode plate to be measured and the proof mass are in the saturation state, and measure the photocurrent of the proof mass in the saturation state; change the DC bias voltage of the electrode plate to be measured to be the same as that of the proof mass, so that the electrode plate to be measured and the proof mass are in the zero state, and measure the photocurrent of the proof mass in the zero state; finally, calculate the shunt probability between the electrode plate to be measured and the proof mass according to the photocurrents in these two modes;

[0011] (c) Take other electrode plates as the electrode plates to be measured in turn, and repeat step (b) to obtain the shunt probability between each electrode plate and the proof mass;

[0012] (d) Regulate the potential difference between each electrode plate and the proof mass to change from the negative saturation state potential to the positive saturation state potential with the same step size, and measure the photocurrent from the proof mass at each potential difference point. Finally, according to the number of photoelectrons emitted from each divided area on the inner surface of the inertial sensor and the shunt probability between each electrode plate and the proof mass, inversely solve the photoelectron migration probability of the inertial sensor from the photocurrent model equation.

[0013] The construction method of the photocurrent model of the inertial sensor provided by the present invention has the following effects: (1) It can calibrate the influence of the potential of each electrode plate in the inertial sensor on the discharge performance of the proof mass. Since there is a complex modulation electric field on the electrode plate, and the influence of these electric fields on the discharge performance of the proof mass has not been further given, therefore, studying the influence of the potential on each electrode plate on the discharge performance of the proof mass can assist in the design of the charge management system; (2) This method takes into account the influence of the cosine distribution of the photoelectron emission angle, and the description of the model is more accurate.

[0014] In one embodiment, the equation of the photocurrent model is:

[0015]

[0016] In the formula, i and j represent the labels of the divided areas on the inner surface of the inertial sensor; The photocurrent from any i surface inside the inertial sensor to any opposite j surface; b i Represents the total number of photoelectrons emitted from any i surface inside the inertial sensor per unit time; a i→j Represents the shunt probability that the total photoelectrons generated from any i surface inside the inertial sensor migrate to the opposite j surface; f i→j (V) Represents the probability that the photoelectrons generated from any i surface inside the inertial sensor overcome the potential difference between the i surface and the opposite j surface and migrate to the j surface.

[0017] In one embodiment, in step (a), the optical properties include the absorption rate and reflectivity of ultraviolet light by each divided region of the inner surface of the inertial sensor, and the ratio of diffuse reflection and specular reflection of the reflected ultraviolet light.

[0018] In one embodiment, in step (a), the number of photoelectrons emitted from each divided region of the inner surface of the inertial sensor:

[0019]

[0020] In the formula, i represents the label of the divided region of the inner surface of the inertial sensor; b i Represents the number of photoelectrons emitted from region i of the inner surface of the inertial sensor; P represents the incident light power of the ultraviolet LED lamp irradiating the inside of the inertial sensor; ρ(θ) represents the ultraviolet light illumination absorption ratio of the inner surface of the inertial sensor; QY int Represents the quantum yield, defined as the number of photoelectrons that can be generated by a single incident ultraviolet photon.

[0021] In one embodiment, in step (b), under ultraviolet light irradiation, the maximum kinetic energy of the emitted photoelectrons is on the order of eV.

[0022] In one embodiment, the total photocurrent of the proof mass is equal to the photocurrent flowing from the plate to the proof mass minus the photocurrent flowing from the proof mass to the plate, and the calculation formula is:

[0023]

[0024] In the formula, n represents the total number of plates in the inertial sensor; b i TM Represents the total number of photoelectrons emitted from the i surface of the proof mass per unit time, b i EH Represents the total number of photoelectrons emitted from the i surface of the plate per unit time; Represents the probability that the total number of photoelectrons emitted from the i surface of the proof mass per unit time is shunted to the opposite plate j surface, Represents the probability that the total number of photoelectrons emitted from the i surface of the plate per unit time is shunted to the opposite proof mass j surface; fTM (V i ) indicates that the photoelectrons generated from the surface of the test mass i can overcome the potential difference V between the surface of the test mass i and the surface of the opposite plate j i The probability of migration to surface j, f EH (V i ) indicates that the photoelectrons generated from the surface of plate i can overcome the potential difference V between the surface of plate i and the surface of the opposite test mass j i The probability of migrating to surface j.

[0025] In one embodiment, in step (b), when the inertial sensor is in a positive saturation state, f TM (V i ) are all 1, f EH (V i ) are all 0; when the inertial sensor is in the zero state, f TM (V i ) are all 1, the photoelectron migration probability f of the electrode i to be tested EH (V i ) is 1, and the photoelectron migration probability of other plates is 0. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart of a method for constructing an inertial sensor photocurrent model provided by an embodiment of the present invention;

[0027] Figure 2 It is a schematic diagram of the principle of calibration of photocurrent model parameters of an inertial sensor provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] Figure 1 FIG. 1 is a flow chart of a method for constructing an inertial sensor photocurrent model provided by an embodiment of the present invention. Figure 1 As shown, the method for constructing a photocurrent model provided by the present invention includes a step of establishing a photocurrent model of an inertial sensor and a step of calibrating parameters of the photocurrent model.

[0030] Among them, the inertial sensor photocurrent model is based on the spatial segmentation of the electrode plate and the proof mass. The reason is that the surfaces of the electrode plate and the proof mass may consist of regions with different surface properties (such as quantum yield, work function, light illumination ratio, etc.), so fine segmentation of specific electrodes is required. Since the photoelectrons generated on the metal surface have a cosine emission angle, the photoelectrons emitted from the same electrode plate (or proof mass) will not only flow to the opposite proof mass (or electrode plate), but a part of them will also flow to the proof mass in the adjacent region.

[0031] The general photocurrent equation for the metal surface is:

[0032]

[0033] In the formula, represents the photocurrent of the metal surface; P represents the incident light power of the LED irradiating the metal; ρ(θ) represents the ultraviolet light illumination absorption ratio of the metal surface; QY int represents the quantum yield, which is defined as the number of photoelectrons that can be generated by a single incident photon; f(V) represents the photoelectron migration probability, which is defined as the ratio of the number of photoelectrons that flow from the surface of one conductor to and reach the surface of another conductor under certain conditions to the total number of emitted electrons between the metal conductors.

[0034] Therefore, the photocurrent from any i surface in the inertial sensor reaching any j surface opposite to it per unit time

[0035]

[0036] In the formula, b i represents the total number of photoelectrons emitted from any i surface in the inertial sensor per unit time, a i→j represents the shunt probability that the total photoelectrons generated from any i surface in the inertial sensor migrate to the j surface; f i→j (V) represents the probability that the photoelectrons generated from any i surface in the inertial sensor can overcome the potential difference between the i surface and the opposite j surface and migrate to the j surface.

[0037] It can be seen from this that the important influencing parameters of the photocurrent model based on the inertial sensor are divided into three: the first factor is the number of photoelectrons b i in region i. The light illumination absorption rate of each surface after ultraviolet light is reflected and absorbed by each surface determines the distribution of the number of photoelectrons generated in each region of the electrode plate and the proof mass; the second factor is the shunt probability a i→j, since the emission angle of photoelectrons generated on the metal surface follows a cosine distribution, the photoelectrons emitted from the electrode plate (or proof mass) will not only flow towards the opposite proof mass (or electrode plate), but also a part of them will flow towards the proof mass (or electrode plate) in the adjacent area; the third factor is the photoelectron migration probability f i→j (V), after the photoelectrons are emitted from the surface of the electrode plate or proof mass, they will be affected by the potential difference between the electrode plate and the proof mass. When the potential difference hinders the movement of electrons, only part of the electrons can reach the opposite surface, and the ratio of the electrons contributing to charging to the total number of electrons emitted from the emission surface is the photoelectron migration probability.

[0038] Therefore, the position where the photoelectrons can finally reach is jointly affected by the shunt probability and the photoelectron migration probability, and the position where the photoelectrons finally stay determines whether the proof mass is in a charging state or a discharging state macroscopically.

[0039] Since the photoelectron migration probability f i→j (V i ) only depends on the potential difference V i , that is, when the potential differences between the i surface and the j surface and the k (k≠j) surface are the same respectively, the photoelectron migration probability from the i surface to the j surface is the same as that from the i surface to the k surface, f i→j (V i ) = f i→k (V i ), so f i→j (V i ) can be simplified to f(V i ).

[0040] Based on the above parameters, the total discharge rate (total photocurrent) of the proof mass surface is equal to the photocurrent flowing from the electrode plate to the proof mass minus the photocurrent flowing from the proof mass to the electrode plate, and the expression is as follows:

[0041]

[0042] In the formula, n represents the total number of electrode plates in the inertial sensor, and the surface of the proof mass is divided into n pieces of surfaces corresponding to the electrode plates one by one; b i TM represents the total number of photoelectrons emitted from the i surface of the proof mass per unit time, and b i EH represents the total number of photoelectrons emitted from the i surface of the electrode plate per unit time; represents the probability that the total number of photoelectrons emitted from the i surface of the proof mass per unit time is shunted to the opposite electrode plate j surface, represents the probability that the total number of photoelectrons emitted from the i surface of the electrode plate per unit time is shunted to the opposite proof mass j surface; f TM (Vi ) indicates that the photoelectrons generated from the surface of the test mass i can overcome the potential difference V between the surface of the test mass i and the surface of the opposite plate j i The probability of migration to surface j, f EH (V i ) indicates that the photoelectrons generated from the surface of plate i can overcome the potential difference V between the surface of plate i and the surface of the opposite test mass j i The probability of migrating to surface j.

[0043] The parameters of the inspection quality photocurrent model are calibrated by combining the characteristic state equations.

[0044] This method specifically includes the following steps:

[0045] Step 1: First, the optical properties of each plate and the test mass surface in the inertial sensor to ultraviolet light can be set through the ray optics interface of the finite element simulation software, and the number of photoelectrons emitted from each area i in the inertial sensor can be obtained by simulation. i .

[0046] In step 1, the optical properties refer to the absorption rate and reflectivity of the internal inspection mass division area and each plate to ultraviolet light when ultraviolet light irradiates the inside of the inertial sensor, as well as the ratio of diffuse reflection and specular reflection of the reflected ultraviolet light part.

[0047] Step 2: Use a DC bias voltage regulator to apply the same DC bias voltage to the plate to be tested and other plates, and make the DC bias voltage of the plate to be tested and the test mass greater than the maximum emission kinetic energy of the photoelectrons. At this time, the electric field between the plate to be tested and the test mass hinders the photoelectrons emitted from the surface of the plate or the test mass, resulting in f i→j (V) = 0 or 1, at this time, the charging or discharging photocurrent is zero, and the charging and discharging state between the plate to be tested and the test mass is defined as a saturated state. The positive saturation state indicates that there is only photocurrent flowing from the plate to the test mass, and the negative saturation state is the opposite. Adjust the potential of the plate to be tested to be the same as the potential of the test mass, and the potentials of other plates remain unchanged. At this time, a beam of photocurrent in the opposite direction to the previous one is added between the plate to be tested and the test mass, and the potential difference between the test mass and the plate to be tested is zero. At this time, the charging and discharging state between the plate to be tested and the test mass is defined as a zero-point state.

[0048] In step 2, according to literature research, the maximum kinetic energy of photoelectrons emitted from the gold surface under ultraviolet light irradiation is in the eV level, or the kinetic energy of the emitted photoelectrons is determined experimentally, e.g. when ultraviolet light is incident, a bias voltage source is set to set the potential difference between the plate and the test mass, and an electrometer is used to measure the absolute value of the current between the two. The maximum current is measured, indicating that the photoelectrons flowing from the plate to the test mass or from the test mass to the plate are completely suppressed and cannot be emitted. The potential energy applied by the plate and the test mass at this time is the maximum emission kinetic energy of the photoelectrons.

[0049] Step 3: Measure the saturated photocurrent for the inspection mass after stabilization and the zero-state photocurrent separately using an electrometer. and the zero-state photocurrent

[0050] Step 4: The zero-state photocurrent contains one more item of photocurrent flowing in the opposite direction than the saturated photocurrent. Therefore, the shunt probability a between the plate under test and the inspection mass can be obtained from these two states. i→j , and all the shunt probabilities a between all the plates and the inspection mass are obtained by this method. i→j parameters.

[0051] Step 5: Determine the sampling interval ΔV, then measure the photocurrent when the inspection mass moves from the negative saturation potential to the positive saturation potential, and finally solve the photoelectron migration probability f i→j (V0) inversely from the photocurrent model equation.

[0052] The following is a detailed description in combination with specific embodiments:

[0053] As Figure 2 shown, eight parallel plates are placed around the inspection mass. The eight plates and the inspection mass are kept parallel, and the eight plates are numbered 1,..., 8 clockwise starting from the Z-axis direction.

[0054] Apply the same DC bias voltage V EH,1 to the plate under test 1 and the other plates, and apply a DC bias voltage V TM to the inspection mass, so that the potential difference V1 = V EH,1 -V TM between the plate under test 1 and the inspection mass is greater than the maximum photoelectron emission kinetic energy E k = 1 eV. At this time, the inertial sensor is in the positive saturation state, and the photocurrent of the inspection mass is measured using an electrometer.

[0055] When the charging and discharging states of the plate under test and the inspection mass are in the positive saturation state, all the photoelectrons emitted from the surface of the inspection mass i can overcome the electric field between the inspection mass and the plate and reach the surface of the plate j. The corresponding photoelectron migration probability f TM (V i ) is all 1. And all the photoelectrons emitted from the surface of the plate j cannot overcome the electric field between the plate and the inspection mass and reach the surface of the inspection mass i. The corresponding photoelectron migration probability f EH (V i ) is all 0. Therefore, according to equation (3), the expression for the photocurrent of the inspection mass in the positive saturation state is:

[0056]

[0057] Change the voltage of the plate 1 to be tested and the voltage of the inspection mass V TM The DC bias voltage on the plate to be tested 1 is the same as the potential difference with the test mass, and the DC bias voltage on the other plates is still V EH,1 At this time, the charge and discharge state of the electrode plate to be tested and the test mass are at zero point, and the photocurrent of the test mass is measured by an electrometer.

[0058] When the charge and discharge states of the electrode to be tested and the test mass are at zero, all the photoelectrons emitted from the surface of the test mass i can overcome the electric field between the test mass and the electrode and reach the surface of the electrode j, corresponding to the photoelectron migration probability f TM (V i ) are all 1. For the plate, only all the photoelectrons emitted from the surface of plate 1 can overcome the electric field between the plate and the test mass and reach the surface of test mass 1, corresponding to the photoelectron migration probability f EH (V i ) is 1 when i=1 and 0 when i≠1. Therefore, the quality photocurrent under zero state is The expression is:

[0059]

[0060] According to the expressions of the test quality photocurrent in the saturated state and the zero-point state, the zero-point state photocurrent contains more information than the saturated state photocurrent, which is a photocurrent flowing in the opposite direction. Therefore, by combining the above formulas (4) and (5), the shunt probability parameter between the plate to be tested and the inspection mass can be obtained:

[0061] Then change the electrode to be tested to i, measure the zero-state and saturation-state photocurrents between all electrodes and the test mass in turn, and obtain the shunt probability a between all electrodes and the test mass. i→j .

[0062] For solving the third parameter, the photoelectron migration probability f i→j (V), first set all the plate voltages to be the same, measure the quality photocurrent when the plate voltage changes from the negative saturation potential point to the positive saturation potential point, with a sampling interval of ΔV, and set the known parameter a i→j and b i Substituting into equation (5), the photoelectron migration probability f is obtained by inverse solution: i→j (V).

[0063]

[0064] The method for constructing the photocurrent model of the inertial sensor provided by this embodiment has the following effects: (1) It can calibrate the influence of the potential of each plate in the inertial sensor on the discharge performance of the proof mass. Since there is a complex modulation electric field on the plate, and no further information is given about the influence of these electric fields on the discharge performance of the proof mass, studying the influence of the potential on each plate on the discharge performance of the proof mass can assist in the design of the charge management system; (2) This method takes into account the influence of the cosine distribution of the photoelectron emission angle, and the description of the model is more accurate.

[0065] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for constructing an opto-current model of an inertial sensor, characterized in that, The steps are as follows: (1) Establish a photocurrent model based on the general equation of the metal surface photocurrent and the geometric structure of the inertial sensor; (2) Calibrate the three parameters of the photocurrent model respectively. The calibration method is as follows: (a) According to the optical properties of the inner surface of the inertial sensor to ultraviolet light, obtain the number of photoelectrons emitted from each divided area on the inner surface of the inertial sensor. The divided areas are divided according to the areas where each electrode plate is located, and each divided area includes an electrode plate and a proof mass corresponding to the surface of the electrode plate; (b) Apply the same DC bias voltage to the electrode plate to be measured and other electrode plates, so that the potential difference between the electrode plate to be measured and the proof mass is greater than the maximum photoelectron emission kinetic energy, so that the electrode plate to be measured and the proof mass are in a saturated state, and measure the photocurrent of the proof mass in the saturated state; change the DC bias voltage of the electrode plate to be measured to be the same as the DC bias voltage of the proof mass, so that the electrode plate to be measured and the proof mass are in a zero state, and measure the photocurrent of the proof mass in the zero state; Finally, calculate the shunt probability between the electrode plate to be measured and the proof mass according to the photocurrents in these two modes; (c) Successively use other electrode plates as the electrode plate to be measured, and repeat step (b) to obtain the shunt probability between each electrode plate and the proof mass; (d) Regulate the potential difference between each electrode plate and the proof mass to change from the negative saturation state potential to the positive saturation state potential with the same step size, and measure the photocurrent from the proof mass at each potential difference point. Finally, according to the number of photoelectrons emitted from each divided area on the inner surface of the inertial sensor and the shunt probability between each electrode plate and the proof mass, inversely solve the photoelectron migration probability of the inertial sensor from the photocurrent model equation.

2. The method for constructing the photocurrent model of the inertial sensor according to claim 1, wherein The equation of the photocurrent model is: In the formula, i and j represent the labels of the divided regions on the inner surface of the inertial sensor; The photocurrent from any i surface inside the inertial sensor to any opposite j surface; b i Represents the total number of photoelectrons emitted from any i surface inside the inertial sensor per unit time; a i→j Represents the shunt probability that the total photoelectrons generated from any i surface inside the inertial sensor migrate to the opposite j surface; f i→j (V) represents the probability that the photoelectrons generated from any i surface inside the inertial sensor overcome the potential difference between the i surface and the opposite j surface and migrate to the j surface.

3. The method for constructing an inertial sensor photocurrent model according to claim 2, wherein, In step (a), the optical properties include the absorption rate and reflection rate of each divided area on the inner surface of the inertial sensor to ultraviolet light, and the ratio of diffuse reflection and specular reflection of the reflected ultraviolet light part.

4. The method for constructing the photocurrent model of the inertial sensor according to claim 2, wherein In step (a), the number of photoelectrons emitted from each divided area on the inner surface of the inertial sensor: In the formula, i represents the label of the divided area on the inner surface of the inertial sensor; b i represents the number of photoelectrons emitted from area i on the inner surface of the inertial sensor; P represents the incident light power of the ultraviolet LED lamp irradiating the inside of the inertial sensor; ρ(θ) represents the ultraviolet light absorption ratio on the inner surface of the inertial sensor; QY int represents the quantum yield, which is defined as the number of photoelectrons that can be generated by a single incident ultraviolet photon.

5. The method for constructing the photocurrent model of the inertial sensor according to claim 2, wherein In step (b), under ultraviolet light irradiation, the maximum photoelectron emission kinetic energy is on the order of eV.

6. The method for constructing the photocurrent model of the inertial sensor according to claim 2, wherein The total photocurrent of the proof mass is equal to the photocurrent flowing from the electrode plate to the proof mass minus the photocurrent flowing from the proof mass to the electrode plate. The calculation formula is: Where n represents the total number of plates in the inertial sensor; b i TM represents the total number of photoelectrons emitted from the surface of the test mass i per unit time, b i EH represents the total number of photoelectrons emitted from the surface of plate i per unit time; represents the probability that the total number of photoelectrons emitted from the surface of the test mass i per unit time is shunted to the surface of the opposite plate j, represents the probability that the total number of photoelectrons emitted from the surface of plate i per unit time is shunted to the surface of the opposite test mass j; f TM (V i ) represents the probability that the photoelectrons generated from the surface of the test mass i can overcome the potential difference V between the surface of the test mass i and the surface of the opposite plate j i and migrate to the surface of j, f EH (V i ) represents the probability that the photoelectrons generated from the surface of plate i can overcome the potential difference V between the surface of plate i and the surface of the opposite test mass j i and migrate to the surface of j.

7. The method for constructing the photocurrent model of the inertial sensor according to claim 5, wherein In step (b), when the inertial sensor is in the positive saturation state, f TM (V i ) are all 1, and f EH (V i ) are all 0; when the inertial sensor is in the zero state, f TM (V i ) are all 1, the photoelectron migration probability f EH (V i ) of the plate i to be measured is 1, and the photoelectron migration probabilities of other plates are 0.

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