Ground calibration device and method for space pressure sensor

Abstract

The invention relates to a ground calibration device and method for a space pressure sensor, and the device comprises a gas supply module which is used for providing working medium gas with stable flow; the high-speed directional flow generation module is connected with the air outlet end of the air supply module and used for outputting high-speed directional flow; the ultrahigh vacuum module comprises a calibration chamber and a first ultrahigh vacuum pump set, an air inlet of the calibration chamber is connected with the output end of the high-speed directional flow generation module, and the space pressure sensor to be calibrated is arranged in the calibration chamber and is coaxial with the air inlet of the calibration chamber and the first ultrahigh vacuum pump set. According to the high-speed directional flow pressure calibration device, the high-speed directional flow with standard pressure is generated through the high-speed directional flow generation module and serves as a standard for calibrating the space pressure sensor, the defect that the directional flow output speed of a traditional directional flow pressure calibration device is low is overcome, and the high-speed directional flow environment faced by a spacecraft during on-orbit operation can be simulated on the ground more accurately; reliability and accuracy of measured values of the space pressure sensor are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of space vacuum measurement, and in particular to a ground calibration device and method for a space pressure sensor. Background Art

[0002] The acquisition of pressure data on the outer surface of a spacecraft is of great significance for the orbital life of the spacecraft and the study of the planet's atmosphere. At present, the pressure in the space environment is generally measured by carrying a pressure sensor on the spacecraft.

[0003] Different from conventional pressure measurement, when a spacecraft is in orbit, it moves at high speed relative to the gas molecules around it, and the density of gas molecules in space is low, which is in a molecular flow state. Therefore, the pressure sensor faces a high-speed directional molecular flow, referred to as directional flow. Directional flow is a kind of steady-state non-equilibrium gas, characterized by uneven spatial distribution, but does not change with time. The physical parameters are anisotropic, and the gas laws used to study equilibrium gases are not applicable. The most important thing is that directional flow has a strong directionality, and its pressure expression is different from that of equilibrium gas. Therefore, the pressure of directional flow cannot be measured with commonly used vacuum gauges.

[0004] The most commonly used directional flow pressure measurement sensor is the converter type direction gauge, whose measurement principle is to convert the non-equilibrium directional flow into equilibrium gas, and then measure the equilibrium gas to obtain pressure data. However, this method is an indirect measurement, and the converter type direction gauge needs to be calibrated to ensure the accuracy of the measurement results. However, there is currently a lack of quantitative simulation methods for high-speed directional flow, and the pressure measurement calibration theory of high-speed directional flow is also imperfect.

[0005] For a spacecraft, its orbital speed is generally 3km / s to 43km / s, and the pressure magnitude that may affect its orbital life is about (10 -7 ~1)Pa. The calibration systems for directional flow pressure measurement sensors are generally based on molecular beam method, pressure decay method or cryogenic pumping technology, such as NASA's UHV / XHV calibration system, ESA's CASYMIR system, Lanzhou Institute of Space Technology and Physics' directional flow calibration device, etc. The speed of the standard directional flow generated based on the above principle is below 7km / s, which is far from the speed of the directional flow actually faced by most spacecraft, and cannot accurately simulate the real space environment faced by spacecraft in orbit. Therefore, the reliability and accuracy of the measurement value of the calibrated space pressure sensor in the actual orbital operation process is uncertain. Summary of the invention

[0006] In order to solve the technical problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a ground calibration device and calibration method for a space pressure sensor, which can quantitatively simulate the high-speed directional flow faced by a spacecraft in orbit on the ground, so as to accurately calibrate the space pressure sensor and ensure that its measured values ​​are accurate and reliable during actual use.

[0007] To achieve the above-mentioned object of the invention, the present invention provides a ground calibration device for a space pressure sensor, comprising:

[0008] Gas supply module, used to provide a stable flow of working gas;

[0009] A high-speed directional flow generating module, connected to the gas outlet end of the gas supply module, for outputting a high-speed directional flow;

[0010] An ultra-high vacuum module comprises a calibration chamber and a first ultra-high vacuum pump group, wherein the air inlet of the calibration chamber is connected to the output end of the high-speed directional flow generating module, and the pressure sensor of the space to be calibrated is arranged in the calibration chamber, and is coaxially arranged with the air inlet of the calibration chamber and the first ultra-high vacuum pump group;

[0011] The high-speed directional flow generation module includes a first chamber, a second chamber, an ion energy screening device, a charged particle stripping device and a second ultra-high vacuum pump group;

[0012] The first chamber is provided with a plasma source, an ion acceleration and extraction device, and a first ion beam collimation device which are sequentially and coaxially arranged inside, and the first ion beam collimation device is coaxially arranged with the gas outlet of the first chamber;

[0013] The second chamber is provided with a second ion beam collimator, an ion beam deceleration device, an ion beam current measuring device and an ion neutralizer in sequence, and the second ion beam collimator, the ion beam deceleration device and the ion neutralizer are coaxially arranged with the air inlet and the air outlet of the second chamber;

[0014] The air inlet and the air outlet of the ion energy screening device are connected to the air outlet of the first chamber and the air inlet of the second chamber respectively;

[0015] The charged particle stripping device is arranged on the gas outlet of the second chamber;

[0016] The second ultra-high vacuum pump group is connected to the interior of the first chamber and the second chamber, and is used to keep the interior of the first chamber and the second chamber in a vacuum state.

[0017] According to a technical solution of the present invention, the gas supply module includes a gas source, an air intake valve and a mass flow meter connected in sequence, and the output end of the mass flow meter is connected to the input end of the high-speed directional flow generating module.

[0018] According to a technical solution of the present invention, the position of the ion beam current measuring device on the axis of the second chamber is an ion beam measuring position, and the ion beam measuring position is coaxially arranged with the gas outlet of the second chamber;

[0019] The ion beam current measuring device is provided with a first transmission mechanism for driving the ion beam current measuring device to reach or leave the ion beam current measuring position;

[0020] A second transmission mechanism is arranged between the ion neutralization device and the gas outlet of the second chamber, and the second transmission mechanism is used to drive the ion neutralization device to translate along the axial direction of the second chamber to reach or leave the ion beam measurement position.

[0021] According to a technical solution of the present invention, the ultra-high vacuum module further includes:

[0022] The position and posture control device is arranged in the calibration room and is used to fix the spatial pressure sensor to be calibrated and adjust its position and azimuth.

[0023] According to a technical solution of the present invention, the posture control device has at least horizontal axial, horizontal radial, vertical radial and horizontal circumferential degrees of freedom.

[0024] According to a technical solution of the present invention, the plasma source is an ECR plasma source or a laser plasma source.

[0025] According to a technical solution of the present invention, the measurement area of ​​the ion beam current measuring device is the same as the effective neutralization area of ​​the ion neutralization device.

[0026] According to a technical solution of the present invention, the expanded uncertainty of the ground calibration device is 4.2%.

[0027] According to one aspect of the present invention, a calibration method for a ground calibration device for a space pressure sensor as described in any one of the above items is provided, comprising the following steps:

[0028] Step S1, fixing the space pressure sensor to be calibrated in the calibration chamber so that the space pressure sensor to be calibrated is coaxial with the air inlet of the calibration chamber;

[0029] Step S2, start the first ultra-high vacuum pump group and the second ultra-high vacuum pump group, evacuate the first chamber, the second chamber and the calibration chamber, and record the pressure value of the calibration chamber in the vacuum state as P2 ; Wherein, the background vacuum degree of the first chamber, the second chamber and the calibration chamber under vacuum state is less than or equal to 5×10 - 8 Pa;

[0030] Step S3, providing a stable flow of working gas to the plasma source through the gas supply module, and starting the plasma source to start discharging;

[0031] Step S4, start the ion acceleration extraction device, the first ion beam collimation device, the ion energy screening device, and the second ion beam collimation device, and adjust the experimental parameters so that the ion beam meets the initial speed v 0 , emittance is ε; the experimental parameters include the gas supply flow rate of the gas supply module, the discharge voltage of the plasma source and the voltage of the ion beam deceleration device;

[0032] Step S5, starting the ion beam deceleration device to modulate the speed of the ion beam output from the second chamber to vm / s;

[0033] Step S6, moving the ion beam current measuring device out of the beam current region, and translating the ion neutralization device to the ion beam measurement position, so that the measured ion beam current is consistent with the ion beam current entering the ion neutralization device, and using the current value on the ion neutralization device as a reference, adjusting the experimental parameters until the current indication value on the ion neutralization device is stable;

[0034] Step S7, starting the DC high voltage power supply of the charged particle stripping device, so that the charged particles in the neutralized ion beam are deflected and stripped off, forming a high-speed directional flow into the calibration chamber;

[0035] Step S8, calculating the standard pressure P of the high-speed directional flow according to the following formula:

[0036]

[0037] Wherein, α is the transparency of the ion neutralization device, I n is the current value on the ion neutralization device; m is the atomic mass; A is the measurement area of ​​the ion beam current measurement device;

[0038] Step S9, calibrating the space pressure sensor to be calibrated according to the calculated standard pressure of the high-speed directional flow and the indication of the space pressure sensor to be calibrated.

[0039] According to a technical solution of the present invention, in step S9, it specifically includes:

[0040] By adjusting the experimental parameters, the current value on the ion neutralization device is gradually increased to obtain a high-speed directional flow with a speed of vm / s and different standard pressures. Several pressure calibration points are uniformly selected in each order of magnitude within the pressure range of the high-speed directional flow to carry out the experiment, and the reading of the pressure sensor of the space to be calibrated at each pressure calibration point is recorded as P 4 , and calculate the calibration factor K according to the following formula:

[0041]

[0042] Among them, P 2 is the pressure value of the calibration chamber under vacuum state, P 3 is the reading of the pressure sensor of the space to be calibrated corresponding to the pressure value of the calibration chamber in the vacuum state; P is the standard pressure of the high-speed directional flow; P 4 is the reading of the space pressure sensor to be calibrated at the calibration point;

[0043] The calibration coefficients corresponding to all the pressure calibration points are averaged to obtain a final calibration coefficient.

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

[0045] The present invention proposes a ground calibration device and method for space pressure sensors. The calibration device is based on the principle of plasma discharge and surface grazing Auger neutralization. By ionizing the working gas, accelerating, aligning, screening, aligning, decelerating, measuring, neutralizing, and deflecting and stripping, the velocity range is (3-43) km / s and the pressure range is (5×10 -7 Compared with the traditional directional flow pressure ground calibration device, the present invention can obtain a standard directional flow with a wider speed range, more accurately simulate the high-speed directional flow environment faced by spacecraft during in-orbit operation on the ground, effectively improve the reliability and accuracy of the space pressure sensor measurement value, and has the advantages of flexible operation and high calibration efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 A schematic diagram of the structure of a ground calibration device for a space pressure sensor provided in an embodiment of the present invention is shown;

[0048] Figure 2 Schematically showing a structural diagram of an air supply module provided in an embodiment of the present invention;

[0049] Figure 3 Schematically showing a structural diagram of a high-speed directional flow generating module provided in an embodiment of the present invention;

[0050] Figure 4 The schematic diagram shows the structure of an ultra-high vacuum module provided in an embodiment of the present invention.

[0051] The corresponding relationship between the component names and the reference numerals is as follows:

[0052] 1 Gas supply module; 2 High-speed directional flow generation module; 3 Ultra-high vacuum module;

[0053] 1-1 air source; 1-2 air inlet valve; 1-3 mass flow meter;

[0054] 2-1 plasma source; 2-2 ion acceleration and extraction device; 2-3 first ion beam collimation device; 2-4 first flange; 2-5 ion energy screening device; 2-6 second flange; 2-7 second ion beam collimation device; 2-8 ion beam deceleration device; 2-9 ion beam flow measurement device; 2-10 ion neutralization device; 2-11 bellows; 2-12 third flange; 2-13 charged particle stripping device; 2-14 fourth flange; 2-15 first chamber; 2-16 second chamber; 2-17 first ultra-high vacuum pump group;

[0055] 3-1 calibration room; 3-2 posture control device; 3-3 fifth flange; 3-4 second ultra-high vacuum pump group. DETAILED DESCRIPTION

[0056] The description of the embodiments of this specification should be combined with the corresponding drawings, which should be considered as part of the complete specification. In the drawings, the shape or thickness of the embodiments may be enlarged and indicated for simplification or convenience. Furthermore, the parts of each structure in the drawings will be described separately. It is worth noting that the elements not shown in the drawings or not described in words are in a form known to ordinary technicians in the relevant technical field.

[0057] The description of the embodiments herein and any reference to directions and orientations are only for the convenience of description and are not to be construed as any limitation on the scope of protection of the present invention. The following description of the preferred embodiments may involve combinations of features, which may exist independently or in combination, and the present invention is not particularly limited to the preferred embodiments. The scope of the present invention is defined by the claims.

[0058] like Figure 1As shown, the present invention provides a ground calibration device for a space pressure sensor, comprising a gas supply module 1, a high-speed directional flow generation module 2 and an ultra-high vacuum module 3. The gas supply module 1 is used to provide a working gas with a stable flow rate; the high-speed directional flow generation module 2 is connected to the gas outlet of the gas supply module 1, and is used to generate a high-speed directional flow with a standard pressure, and used as a standard for the calibration of the space sensor; the ultra-high vacuum module 3, including a calibration chamber 3-1, a first ultra-high vacuum pump group 3-4 and a posture control device 3-2, is used to provide the required background vacuum environment for the calibration of the space pressure sensor to be calibrated.

[0059] like Figure 2 As shown, the gas supply module 1 includes a gas source 1-1, an air intake valve 1-2 and a mass flow meter 1-3 connected in sequence, and the output end of the mass flow meter 1-3 is connected to the input end of the high-speed directional flow generating module 2. The various components of the gas supply module 1 are connected in sequence, and the output gas flow rate is controlled by the mass flow meter 1-3.

[0060] like Figure 3 As shown, the high-speed directional flow generating module 2 includes a first chamber 2-15, a second chamber 2-16, an ion energy screening device 2-5, a charged particle stripping device 2-13 and a second ultra-high vacuum pump group 2-17. The interior of the first chamber 2-15 is provided with a plasma source 2-1, an ion acceleration extraction device 2-2 and a first ion beam collimation device 2-3 which are arranged in sequence and coaxially, and the first ion beam collimation device 2-3 is arranged coaxially with the gas outlet of the first chamber 2-15. The interior of the second chamber 2-16 is provided with a second ion beam collimation device 2-7, an ion beam deceleration device 2-8, an ion beam flow measurement device 2-9 and an ion neutralization device 2-10 which are arranged in sequence, and the second ion beam collimation device 2-7, the ion beam deceleration device 2-8 and the ion neutralization device 2-10 are arranged coaxially with the gas inlet and gas outlet of the second chamber 2-16. The air inlet and the air outlet of the ion energy screening device 2-5 are connected to the air outlet of the first chamber 2-15 and the air inlet of the second chamber 2-16 through the first flange 2-4 and the second flange 2-6 respectively. The charged particle stripping device 2-13 is arranged on the air outlet of the second chamber 2-16 and is connected to the second cavity 2-16 through the third flange 2-12. The charged particle stripping device 2-13 is connected to the calibration chamber 3-1 through the fourth flange 2-14. The second ultra-high vacuum pump group 2-17 is connected to the interior of the first chamber 2-15 and the second chamber 2-16, and is used to keep the interior of the first chamber 2-15 and the second chamber 2-16 in a vacuum state.

[0061] like Figure 4As shown, the ultra-high vacuum module 3 includes a calibration chamber 3-1 and a first ultra-high vacuum pump group 3-4. The air inlet of the calibration chamber 3-1 is connected to the output end of the high-speed directional flow generating module 2. The pressure sensor of the space to be calibrated is arranged in the calibration chamber 3-1, and is coaxially arranged with the air inlet of the calibration chamber 3-1 and the first ultra-high vacuum pump group 3-4 to ensure that the flow field in the calibration chamber 3-1 is axially distributed, thereby reducing the impact on the high-speed directional flow field. The posture control device 3-2 is arranged in the calibration chamber 3-1, and is used to fix the pressure sensor of the space to be calibrated and adjust its position and azimuth.

[0062] The working principle of the present invention is as follows:

[0063] First, a background vacuum is established in the first chamber 2-15, the second chamber 2-16 and the calibration chamber 3-1, and then the gas supply module 1 supplies gas to the plasma source 2-1 at a constant flow rate. The working gas is ionized into plasma in the plasma source 2-1, and the ions in the plasma are extracted and accelerated to 2.2×10 5 m / s~3.8×10 5 m / s, and then the first ion beam collimator 2-3 collimates the ion beam to reduce the emittance. After the ion beam enters the ion energy screening device 2-5, the ions with specific energy in the ion beam are extracted and passed through the second ion beam collimator 2-7 to obtain a monoenergetic and collimated ion beam. The speed of the monoenergetic ion beam can be modulated to 3×10 3 m / s~4.3×10 4 m / s, with the ion beam current measuring device 2-9 for the velocity v and flux of the ion beam After the ion beam flow measuring device 2-9 measures the characteristic parameters of the ion beam, the ion neutralization device 2-10 is moved axially to the measurement position so that the measured ion beam is consistent with the ion beam entering the ion neutralization device 2-10, and the experimental parameters such as the gas flow rate and the discharge voltage are adjusted so that the current I n =3.5×10 -8 A~0.9A. Most of the ions in the ion beam capture electrons in the ion neutralization device 2-10 to become neutral atoms, forming a composite particle beam, but no momentum loss occurs. Then the composite particle beam enters the charged particle stripping device 2-13, and the charged particles in the composite particle beam are stripped out to form a collimated, monoenergetic, standard high-speed directional flow with known speed and flux. The working gas used is a high-purity monatomic gas, which can be considered to have an ion mass m i Equal to the atomic mass m, the pressure P of the standard high-speed directional flow can be calculated by the following formula:

[0064]

[0065] By adjusting the gas flow rate of the gas supply module 1, the discharge voltage of the plasma source 2-1, and the voltage of the ion beam deceleration device 2-8, a high-speed directional flow with different pressures at a certain speed can be obtained. The space pressure sensor to be calibrated is fixed on the posture control device 3-2. The posture control device 3-2 is adjusted so that the space pressure sensor to be calibrated is located at the gas outlet of the high-speed directional flow generation module 2 and remains coaxial with it. In this way, the space pressure sensor can be calibrated on the ground with the high-speed directional flow pressure output by the high-speed directional flow generation module 2 as the standard.

[0066] In an embodiment of the present invention, the ion beam flow measuring device 2-9 is used to perform in-situ time-sharing measurement of the ion beam flow. The position of the ion beam flow measuring device 2-9 on the axis of the second chamber 2-16 is the ion beam measurement position, and the ion beam measurement position is coaxially arranged with the gas outlet of the second chamber 2-16. A first transmission mechanism is arranged on the ion beam flow measuring device 2-9, which is used to drive the ion beam flow measuring device 2-9 to reach or leave the ion beam measurement position. The first transmission mechanism can be a lifting device arranged perpendicular to the axial direction of the second chamber 2-16, and the ion beam measurement device 2-9 is lifted and lowered to reach or leave the ion beam measurement position. A second transmission mechanism is arranged between the ion neutralization device 2-10 and the gas outlet of the second chamber 2-16, and the second transmission mechanism is used to drive the ion neutralization device 2-10 to translate along the axial direction of the second chamber 2-16 to reach or leave the ion beam measurement position. The second transmission mechanism can be a driving device for driving the ion neutralization device 2-10 to translate and a bellows 2-11 arranged between the ion neutralization device 2-10 and the air outlet of the second chamber 2-16. The ion neutralization device 2-10 is connected to the second chamber 2-16 through the bellows 2-11 to realize the axial parallel movement of the ion neutralization device 2-10, thereby ensuring that the ion flow measured by the ion beam flow measuring device 2-9 is consistent with the ion flow entering the ion neutralization device 2-10.

[0067] In an embodiment of the present invention, Figure 4 As shown, with the horizontal plane where the axis of the calibration chamber 3-1 is located as a reference, the posture control device 3-2 has at least four degrees of freedom: horizontal axial, horizontal radial, vertical diameter, and horizontal circumferential, so that the spatial pressure sensor installed on the posture control device 3-2 can move and rotate in the calibration chamber 3-1.

[0068] In an embodiment of the present invention, the plasma source 2 - 1 is an ECR plasma source or a laser plasma source.

[0069] In the embodiment of the present invention, preferably, the first ultra-high vacuum pump group 3-4 and the second ultra-high vacuum pump group 2-17 are composed of a dry pump, a molecular pump, an ion pump and a cryogenic pump, and the pumping speed is ≥1×10 4 L / s, so as to establish a pressure of <5×10 -8 Pa background vacuum environment.

[0070] In the embodiment of the present invention, preferably, the measuring area of ​​the ion beam current measuring device 2-9 is the same as the effective neutralization area of ​​the ion neutralization device 2-10, both of which are A. The ion neutralization device 2-10 can be a grid plate, and the transparency of the ion neutralization device 2-10 is the ratio of the effective neutralization area of ​​the ion neutralization device 2-10 to the grid plate area. The transparency of the ion neutralization device 2-10 is α (α=0.4), and it is grounded when used, and a high-precision ammeter is used to measure the current I on it. n .

[0071] In the embodiment of the present invention, preferably, a DC high voltage U is applied to the charged particle stripping device 2-13. 2 (U 2 =2000V), using the electric field to achieve the effect of stripping charged particles in the beam.

[0072] In an embodiment of the present invention, preferably, a ground calibration device for a space pressure sensor is used, and the calculation formula of the measurement uncertainty of the ground calibration device is as follows:

[0073]

[0074] In the formula, u[I n ] is the measurement uncertainty of the current on the ion neutralization device 2-10 (u[I n ]=0.01%); u[v] is the uncertainty introduced by the ion beam velocity measurement (u[v]=2.1%); u[L] is the length measurement uncertainty introduced when obtaining the transparency α and effective neutralization area of ​​the ion neutralization device 2-10 (u[L]=0.01%); u 2 is the uncertainty introduced by the stability of the high-speed directional flow generating module 2 (u 2 =0.08%); u 3 is the uncertainty introduced by the ambient temperature (u 3 =0.01%); u 4 is the uncertainty introduced by the background pressure measurement (u 4 =0.4%), then we can calculate u c =2.1%.

[0075] Then the expanded uncertainty of the ground calibration device of the space pressure sensor can be calculated by the following formula:

[0076] U=k·u c

[0077] Where U is the expanded uncertainty of the ground calibration device of the spatial pressure sensor, k is the coverage factor, and k is taken as 2. The expanded uncertainty of the ground calibration device of the spatial pressure sensor is U = 4.2%.

[0078] The present invention provides a method based on a ground calibration device for a space pressure sensor, comprising the following steps:

[0079] Step S1, fix the space pressure sensor to be calibrated in the calibration chamber 3-1, and adjust the position control device 3-2 so that the space pressure sensor to be calibrated is coaxial with the air inlet of the calibration chamber 3-1;

[0080] Step S2, start the first ultra-high vacuum pump group 3-4 and the second ultra-high vacuum pump group 2-17, evacuate the first chamber 2-15, the second chamber 2-16 and the calibration chamber 3-1, and record the pressure value of the calibration chamber 3-1 in the vacuum state as P 2 ; Wherein, the background vacuum degree of the first chamber 2-15, the second chamber 2-16 and the calibration chamber 3-1 in the vacuum state is less than or equal to 5×10 -8 Pa;

[0081] Start the first ultra-high vacuum pump group 2-17 and the second ultra-high vacuum pump group 3-4 to pump the pressure in the first chamber 2-15, the second chamber 2-16 and the calibration chamber 3-1 to ≤5×10 -8 Pa background vacuum, and record it as P 0 (P 0 =2.2×10 - 8 Pa), P 1 (P 1 =2.5×10 -8 Pa) and P 2 (P 2 =1.6×10 -8 Pa), and record the reading of the space pressure sensor to be calibrated as P 3 (P 3 =1.8×10 -8 Pa).

[0082] Step S3, supplying a stable flow of working gas to the plasma source 2-1 through the gas supply module 1, and starting the plasma source 2-1 to start discharging;

[0083] The gas supply module 1 provides a stable flow of He gas (m He =6.65×10 -27kg), and start the plasma source 2-1 to start discharging.

[0084] Step S4, start the ion acceleration extraction device 2-2, the first ion beam collimation device 2-3, the ion energy screening device 2-5, the second ion beam collimation device 2-7, and adjust the experimental parameters so that the ion beam meets the initial speed v 0 , emittance is ε; experimental parameters include the gas supply flow rate of the gas supply module 1, the discharge voltage of the plasma source 2-1 and the voltage of the ion beam deceleration device 2-8; wherein the initial velocity v 0 =2.2×10 5 m / s~3.8×10 5 m / s, emittance ε<0.2πmm·mrad;

[0085] Step S5, start the ion beam deceleration device 2-8, and modulate the speed of the ion beam output from the second chamber 2-16 to vm / s; v=7.8×10 3 m / s;

[0086] Step S6, move the ion beam current measuring device 2-9 out of the beam current area, and translate the ion neutralization device 2-10 to the ion beam measurement position, so that the measured ion beam current is consistent with the ion beam current entering the ion neutralization device 2-10, and use the current value on the ion neutralization device 2-10 as a reference to adjust the experimental parameters until the current indication value on the ion neutralization device 2-10 is stable, such as adjusting the experimental parameters to make I n =1.93×10 -7 A; the current indication number I on the ion neutralization device 2-10 n The range can be 7×10 -7 A~0.1A;

[0087] Step S7, starting the DC high voltage power supply of the charged particle stripping device 2-13, so that the charged particles in the neutralized ion beam are deflected and stripped off, forming a high-speed directional flow into the calibration chamber 3-1;

[0088] Step S8, calculating the standard pressure P of the high-speed directional flow according to the following formula:

[0089]

[0090] Wherein, α is the transparency of the ion neutralization device 2-10, I n is the current value on the ion neutralization device 2-10; m is the atomic mass; A is the measurement area of ​​the ion beam current measurement device 2-9;

[0091] Substituting the above parameters into the formula, we can calculate P = 5 × 10 -7 Pa.

[0092] Step S9, calibrating the space pressure sensor to be calibrated according to the calculated standard pressure of the high-speed directional flow and the indication of the space pressure sensor to be calibrated.

[0093] In step S9, it specifically includes:

[0094] By adjusting the experimental parameters, the current value on the ion neutralization device 2-10 was gradually increased to obtain a velocity of v = 7.8 × 10 3 m / s and high-speed directional flow with different standard pressures. In the high-speed directional flow generation pressure range (5×10 -7 ~1Pa) in each magnitude, three pressure calibration points are evenly selected to carry out the test, and the reading of the pressure sensor in the space to be calibrated at each pressure calibration point is recorded as P 4 , and calculate the calibration factor K according to the following formula:

[0095]

[0096] Among them, P 2 is the pressure value of the calibration chamber 3-1 under vacuum state, P 3 is the reading of the pressure sensor of the space to be calibrated corresponding to the pressure value of the calibration chamber 3-1 in the vacuum state; P is the standard pressure of the high-speed directional flow; P 4 It is the reading of the space pressure sensor to be calibrated at the calibration point.

[0097] The calibration coefficients corresponding to all pressure calibration points were averaged to obtain a final calibration coefficient of 0.94.

[0098] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0099] Finally, it should be noted that the above is a preferred embodiment of the present invention. It should be pointed out that although the preferred embodiment of the present invention has been described, for those skilled in the art, once the basic creative concept of the present invention is known, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention. Therefore, the attached claims are intended to be interpreted as including the preferred embodiment and all changes and modifications that fall within the scope of the embodiments of the present invention.

Claims

1. A ground calibration device for a space pressure sensor, characterized in that: include: A gas supply module (1), used for providing a working gas with a stable flow rate; A high-speed directional flow generating module (2) is connected to the gas outlet end of the gas supply module (1) and is used to output a high-speed directional flow; An ultra-high vacuum module (3) comprises a calibration chamber (3-1) and a first ultra-high vacuum pump group (3-4), wherein an air inlet of the calibration chamber (3-1) is connected to an output end of the high-speed directional flow generating module (2), and a pressure sensor of the space to be calibrated is arranged in the calibration chamber (3-1) and is coaxially arranged with the air inlet of the calibration chamber (3-1) and the first ultra-high vacuum pump group (3-4); The high-speed directional flow generating module (2) comprises a first chamber (2-15), a second chamber (2-16), an ion energy screening device (2-5), a charged particle stripping device (2-13) and a second ultra-high vacuum pump group (2-17); The first chamber (2-15) is provided with a plasma source (2-1), an ion acceleration extraction device (2-2) and a first ion beam collimation device (2-3) which are arranged in sequence and coaxially, and the first ion beam collimation device (2-3) is coaxially arranged with the gas outlet of the first chamber (2-15); The second chamber (2-16) is provided with a second ion beam collimating device (2-7), an ion beam decelerating device (2-8), an ion beam current measuring device (2-9) and an ion neutralizing device (2-10) in sequence, and the second ion beam collimating device (2-7), the ion beam decelerating device (2-8) and the ion neutralizing device (2-10) are coaxially arranged with an air inlet and an air outlet of the second chamber (2-16); The air inlet and the air outlet of the ion energy screening device (2-5) are respectively connected to the air outlet of the first chamber (2-15) and the air inlet of the second chamber (2-16); The charged particle stripping device (2-13) is arranged on the gas outlet of the second chamber (2-16); The second ultra-high vacuum pump group (2-17) is connected to the interior of the first chamber (2-15) and the second chamber (2-16), and is used to keep the interior of the first chamber (2-15) and the second chamber (2-16) in a vacuum state.

2. The calibration device for the ground of a space pressure sensor according to claim 1, characterized in that: The air supply module (1) comprises an air source (1-1), an air intake valve (1-2) and a mass flow meter (1-3) which are connected in sequence, and the output end of the mass flow meter (1-3) is connected to the input end of the high-speed directional flow generating module (2).

3. The ground calibration device for a space pressure sensor according to claim 1, characterized in that: The position of the ion beam flow measuring device (2-9) on the axis of the second chamber (2-16) is an ion beam measurement position, and the ion beam measurement position is coaxially arranged with the gas outlet of the second chamber (2-16); A first transmission mechanism is arranged on the ion beam flow measuring device (2-9) for driving the ion beam flow measuring device (2-9) to reach or leave the ion beam measurement position; a second transmission mechanism is arranged between the ion neutralization device (2-10) and the gas outlet of the second chamber (2-16), and the second transmission mechanism is used to drive the ion neutralization device (2-10) to translate along the axial direction of the second chamber (2-16) to reach or leave the ion beam measurement position.

4. The ground calibration device for a space pressure sensor according to claim 1, characterized in that: The ultra-high vacuum module (3) further comprises: The position and posture control device (3-2) is arranged in the calibration room (3-1) and is used to fix the spatial pressure sensor to be calibrated and adjust its position and azimuth.

5. The ground calibration device for a space pressure sensor according to claim 4, characterized in that: The posture control device (3-2) has at least horizontal axial, horizontal radial, vertical radial and horizontal circumferential degrees of freedom.

6. The ground calibration device for a space pressure sensor according to claim 1, characterized in that: The plasma source (2-1) is an ECR plasma source or a laser plasma source.

7. The ground calibration device for a space pressure sensor according to claim 1, characterized in that: The measurement area of ​​the ion beam current measuring device (2-9) is the same as the effective neutralization area of ​​the ion neutralization device (2-10).

8. The ground calibration device for a space pressure sensor according to claim 1, characterized in that: The expanded uncertainty of the ground calibration setup is 4.2%.

9. A method for ground calibration of a space pressure sensor according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step S1, fixing the space pressure sensor to be calibrated in the calibration chamber (3-1) so that the space pressure sensor to be calibrated is coaxial with the air inlet of the calibration chamber (3-1); Step S2, starting the first ultra-high vacuum pump group (3-4) and the second ultra-high vacuum pump group (2-17), evacuating the first chamber (2-15), the second chamber (2-16) and the calibration chamber (3-1), and recording the pressure value of the calibration chamber (3-1) in a vacuum state as P2; wherein the background vacuum degree of the first chamber (2-15), the second chamber (2-16) and the calibration chamber (3-1) in a vacuum state is less than or equal to 5×10 -8 Pa; Step S3, providing a stable flow of working gas to the plasma source (2-1) through the gas supply module (1), and starting the plasma source (2-1) to start discharging; Step S4, starting the ion acceleration and extraction device (2-2), the first ion beam collimation device (2-3), the ion energy screening device (2-5), and the second ion beam collimation device (2-7), and adjusting the experimental parameters so that the ion beam satisfies the initial velocity v0 and the emittance ε; the experimental parameters include the gas supply flow rate of the gas supply module (1), the discharge voltage of the plasma source (2-1), and the voltage of the ion beam deceleration device (2-8); Step S5, starting the ion beam deceleration device (2-8) to modulate the speed of the ion beam output from the second chamber (2-16) to vm / s; Step S6, moving the ion beam current measuring device (2-9) out of the beam current region, and translating the ion neutralization device (2-10) to the ion beam measurement position, so that the measured ion beam current is consistent with the ion beam current entering the ion neutralization device (2-10), and using the current value on the ion neutralization device (2-10) as a reference, adjusting the experimental parameters until the current indication value on the ion neutralization device (2-10) is stable; Step S7, starting the DC high voltage power supply of the charged particle stripping device (2-13), so that the charged particles in the neutralized ion beam are deflected and stripped off, forming a high-speed directional flow into the calibration chamber (3-1); Step S8, calculating the standard pressure P of the high-speed directional flow according to the following formula: Wherein, α is the transparency of the ion neutralization device (2-10), I n is the current value on the ion neutralization device (2-10); m is the atomic mass; A is the measurement area of ​​the ion beam current measurement device (2-9); Step S9, calibrating the space pressure sensor to be calibrated according to the calculated standard pressure of the high-speed directional flow and the indication of the space pressure sensor to be calibrated.

10. The method according to claim 9, characterized in that In the step S9, it specifically includes: By adjusting the experimental parameters, the current value on the ion neutralization device (2-10) is gradually increased to obtain a high-speed directional flow with a speed of vm / s and different standard pressures. Several pressure calibration points are uniformly selected in each order of magnitude within the pressure range of the high-speed directional flow to carry out the test, and the reading of the space pressure sensor to be calibrated at each pressure calibration point is recorded as P4, and the calibration coefficient K is calculated according to the following formula: Wherein, P2 is the pressure value of the calibration chamber (3-1) in a vacuum state, P3 is the indication of the pressure sensor of the space to be calibrated corresponding to the pressure value of the calibration chamber (3-1) in a vacuum state; P is the standard pressure of the high-speed directional flow; P4 is the indication of the pressure sensor of the space to be calibrated at the calibration point; The calibration coefficients corresponding to all the pressure calibration points are averaged to obtain a final calibration coefficient.

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