Method for calibrating a pressure measurement in a vacuum switching tube and for determining a pressure in a measuring vacuum switching tube

Abstract

A method for calibrating a pressure measurement in a vacuum switching tube (1), comprising the steps of: providing a calibration device (52) with the vacuum switching tube and a vacuum system (40) comprising a tube (41) and a pressure sensor (42) by means of which the pressure (p) in the tube can be measured, wherein the vacuum switching tube has a through-hole (27) that fluidly connects the interior (26) of the vacuum switching tube to the tube; applying a magnetic field (24) and an electric field (23) to the interior, such that a gas discharge is generated, wherein the magnetic field has an orientation different from the electric field; measuring a time-resolved current (I(t)) of the gas discharge and simultaneously measuring a time-resolved pressure (p(t)) in the tube; Determining a time offset (Δt) between the beginning (t1) of an increase in the time-resolved current and the beginning (t2) of a decrease in the time-resolved pressure;Correcting the offset by shifting the time-resolved current and / or pressure over time; assigning a plurality of values ​​to a maximum in time (I; max ) the time-resolved current strengths to a pressure (p) corrected by the offset (Δt), thereby forming a calibration function (55).

Description

[0001] The invention relates to a method for calibrating a pressure determination in a vacuum switching tube and for determining a pressure in a measuring vacuum switching tube.

[0002] A vacuum switching tube, such as that known from US 3,263,162 A, is designed to perform electrical switching operations under a vacuum. To interrupt an electric current, the two electrodes in the vacuum switching tube are moved from a contact state, in which the two electrodes are in contact, to a spaced-apart state, in which the two electrodes are spaced apart. In the spaced-apart state, the vacuum electrically isolates the two electrodes from each other. To ensure the function of the vacuum switching tube, it is necessary that the vacuum pressure be low. Conventionally, the vacuum pressure is determined using the magnetron method. In this method, electrons are accelerated in an electric field and forced by a magnetic field onto spiral paths, so that the electrons have to travel a much longer path to the anode.Gas molecules struck by these electrons can be ionized, allowing a gas discharge to build up in the vacuum. The current of the gas discharge correlates with the vacuum pressure. To deduce the vacuum pressure from the current, a calibration is required in which a variety of known pressures are set in the vacuum switching tube, a gas discharge is generated at each pressure, and the current of the gas discharge is measured. However, this is disadvantageously complex.

[0003] The object of the invention is therefore to provide a method for calibrating a pressure determination in a vacuum switching tube and a method for determining a pressure in a measuring vacuum switching tube, which are easy to carry out.

[0004] The inventive method for calibrating a pressure measurement in a vacuum switching tube comprises the steps of: a) providing a calibration device with a vacuum switching tube having a first electrode and a second electrode, which have a contact state in which the first electrode and the second electrode are in contact with each other and a separation state in which the first electrode and the second electrode are separated from each other, and a housing that defines an interior space in which the first electrode and the second electrode are arranged and which is configured to maintain a vacuum in the interior space so that, in the separation state, the first electrode and the second electrode can be electrically isolated from each other by the vacuum, a vacuum system comprising a tube and a pressure sensor by means of which the pressure in the tube can be measured, wherein the vacuum switching tube has a through-hole,a) connecting the interior to the pipe via a fluid-conducting connection; b) applying a magnetic field and an electric field to the interior so that a gas discharge is generated in the interior, the magnetic field having an orientation different from the electric field in the interior; c) measuring a time-resolved current of the gas discharge and simultaneously measuring a time-resolved pressure in the pipe using the pressure sensor; d) determining a time offset between the onset of an increase in the time-resolved current and the onset of a decrease in the time-resolved pressure; e) correcting the offset by shifting the time-resolved current and / or the time-resolved pressure over time; f) assigning a plurality of currents occurring after a maximum of the time-resolved current to a pressure (p) corrected by the offset (Δt), thereby forming a calibration function.

[0005] The invention is based on the understanding that in a gas discharge, gas particles in the vacuum are ionized and subsequently removed from the interior by the electric field. This reduces the vacuum pressure. According to the invention, in step f), a plurality of pairs of values ​​are determined from the current and the pressure, each of which can serve as a reference point for the calibration function. This allows several pairs of values ​​to be determined with a single measurement, making it easier to determine the calibration function than in a conventional method where only one pair of values ​​can be determined in each gas discharge.

[0006] The through-hole and the pipe preferably have an inner cross-section of at least 1 cm at their narrowest point. 2This means that the pressure is transferred particularly quickly from the interior to the pipe, allowing the pressure sensor to measure changes in pressure very quickly.

[0007] It is preferred that the through-hole is provided in the housing. Alternatively, it is preferred that the through-hole is provided in the first electrode.

[0008] The vacuum system preferably includes a pump configured to evacuate the interior via the pipe. This allows any desired vacuum pressure to be set before step b). It is preferred that the vacuum system includes a shut-off device located in a flow path extending from the pressure sensor to the pump, which keeps the flow path closed during step c). This prevents gas from entering the interior via the pipe during step c). Gas ingress would distort the calibration curve.

[0009] The inventive method for determining a pressure in a measuring vacuum switching tube comprises the steps of: g) providing the measuring vacuum switching tube, which has a first electrode and a second electrode, which have a contact state in which the first electrode and the second electrode are in contact with each other, and a separation state in which the first electrode and the second electrode are spaced apart from each other, and a housing that defines an interior space in which the first electrode and the second electrode are arranged, and which maintains a vacuum in the interior space, so that in the separation state the first electrode and the second electrode are electrically isolated from each other by the vacuum; h) providing the calibration function;i) Applying a magnetic field and an electric field to the interior of the measuring vacuum switching tube, such that a measuring gas discharge is generated in the interior of the measuring vacuum switching tube, wherein the magnetic field in the interior has an orientation different from the electric field; j) Measuring a time-resolved current of the measuring gas discharge and determining a maximum of the time-resolved current of the measuring gas discharge; k) Determining the pressure of the vacuum of the measuring vacuum switching tube from the maximum of the time-resolved current of the measuring gas discharge and from the calibration function.

[0010] It is preferred that the interior of the vacuum switching tube is identical in construction to the interior of the measuring vacuum switching tube, except for the presence of the through-hole. This allows the vacuum pressure of the measuring vacuum switching tube to be determined with high accuracy. The walls that delimit the interior of the vacuum switching tube preferably consist of the same material(s) as the walls that delimit the interior of the measuring vacuum switching tube. This allows the vacuum pressure of the measuring vacuum switching tube to be determined with particularly high accuracy.

[0011] The invention will be explained in more detail below with reference to the attached schematic drawings. These show Fig. 1 a section through a vacuum switching tube, Fig. 2 a section through a calibration device, Fig. 3 an exemplary time-resolved current and an exemplary time-resolved pressure and Fig. 4 an example calibration curve.

[0012] With reference to Fig. Figures 1 to 4 describe a method for calibrating a pressure measurement in a vacuum switching tube 1, comprising the steps of: a) providing a calibration device 52, which includes a vacuum switching tube 1 and a vacuum system 40. The calibration device 52 has a first electrode 3 and a second electrode 4, which have a contact state in which the first electrode 3 and the second electrode 4 are in contact with each other, and a spaced-away state in which the first electrode 3 and the second electrode 4 are spaced apart from each other. The vacuum switching tube 1 also has a housing 2, which defines an interior space 26 in which the first electrode 3 and the second electrode 4 are arranged. The housing 2 is configured to maintain a vacuum in the interior space 26, so that in the spaced-away state the first electrode 3 and the second electrode 4 can be electrically isolated from each other by the vacuum.The vacuum system 40 has a tube 41 and a pressure sensor 42, by means of which the pressure p in the tube 41 can be measured. The vacuum switching tube 1 has a through-hole 27 that connects the interior 26 to the tube 41 in a fluid-conducting manner; b) Applying a magnetic field 24 and an electric field 23 to the interior 26 (see . Fig. 1) so that a gas discharge is generated in the interior 26, wherein the magnetic field 24 in the interior 26 has an orientation that is different from the orientation of the electric field 23; c) measuring a time-resolved current I(t) of the gas discharge and simultaneously measuring a time-resolved pressure p(t) in the tube 41 using the pressure sensor 42 (see Fig. 3); d) Determining a time offset Δt between the start t1 of an increase in the time-resolved current I(t) and the start t2 of a decrease in the time-resolved pressure p(t); e) Correcting the offset Δt by shifting the time-resolved current I(t) and / or the time-resolved pressure p(t) in time; f) Assigning a plurality of values ​​according to a time maximum I max The currents I lying on the time-resolved current I(t) to the simultaneously arranged pressure p, thereby forming a calibration function 55 (cf. Fig. 4) The through hole 27 and the pipe 41 can have an internal cross-section at their narrowest point that is at least 1 cm 2 amounts. Fig. Figure 2 shows that in one example the through-hole 27 can be provided in the housing 2. In another example, the through-hole 27 can be provided in the first electrode 3.

[0013] Fig. Figure 1 shows that the vacuum switching tube 1 provided in step a) can have an axial direction 31, a radial direction 32 related to the axial direction 31, and a circumferential direction 33 related to the axial direction 31. The first electrode 3 can be fixedly arranged relative to the housing 2, and the second electrode 4 can be longitudinally displaceable in the axial direction 31 relative to the housing 2. For this purpose, the vacuum switching tube 1 can have a bearing 9 on which the second electrode 4 can slide in and against the axial direction 31. It is conceivable to displace the second electrode 4 mechanically, in particular by using a spring accumulator. Starting from the in Fig. 1 and Fig. In the contact state shown in Figure 2, the first electrode 3 and the second electrode 4 can be brought into a spaced-away state by displacing the second electrode 4 away from the first electrode 4 in the axial direction 31. The first electrode 3 can have a first contact surface 7 and the second electrode 4 can have a second contact surface 8, with the first contact surface 7 and the second contact surface 8 being arranged in the interior space 26. The first electrode 3 can have a thickening at its longitudinal end facing the second electrode 4, and the second electrode 4 can have a thickening at its longitudinal end facing the first electrode 3.The first contact surface 7 and the second contact surface 8 are in contact in the contact state, allowing a current to flow from the first electrode 3 to the second electrode 4, and are spaced apart from each other in the separation state, preventing the current from flowing from the first electrode 3 to the second electrode 4.

[0014] The first electrode 3 can have a first terminal 5 located outside the housing 2, and the second electrode 4 can have a second terminal 6 located outside the housing 2. Electrical conductors can be connected to the first terminal 5 and the second terminal 6 in an electrically conductive manner. The vacuum switching tube 1 can have a bellows 10 which is attached to the bearing 9 and to the first electrode 3, in particular to an electrode projection 25 extending radially 32 from the remaining first electrode 3, enclosing the first electrode 3 and sealing the interior 26 against a vacuum.

[0015] How it looks Fig. 1 and Fig. As can be seen in Figure 2, the housing 2 can be formed from several sub-housings. The housing 2 can, for example, have a switching chamber housing 14, which is made of or consists of a metal or alloy. The switching chamber housing 14 can completely enclose a switching chamber 13 in the circumferential direction 33, which is part of the interior 26. The first contact surface 7 and the second contact surface 8 are arranged in the switching chamber 13.

[0016] The housing 2 can, for example, comprise a first ceramic housing 17 arranged opposite the axial direction 31 of the switching chamber housing 14, and / or a second ceramic housing 18 arranged in the axial direction 31 of the switching chamber housing 14. The switching chamber housing 14 can be electrically isolated from other components of the vacuum switching tube 1 by means of the first ceramic housing 17 and / or the second ceramic housing 18. It is conceivable that the first ceramic housing 17 and / or the second ceramic housing 18 are formed in one piece or are formed from a plurality of partial ceramic housings 19 arranged side by side in the axial direction 31.

[0017] The housing 2 can, for example, comprise a first flange housing 15, which is arranged opposite the axial direction 31 to the first ceramic housing 17 and is attached to the first electrode 3, and a second flange housing 16, which is arranged in the axial direction 31 to the second ceramic housing 18 and is attached to the bearing 19. The first flange housing 15 and the first ceramic housing 17 can fully delimit a first flange chamber 11 in the circumferential direction 33, which is part of the interior 26. The second flange housing 16 and the second ceramic housing 18 can fully delimit a second flange chamber 12 in the circumferential direction 33, which is part of the interior 26. The first flange chamber 11 and the second flange chamber 12 can have a smaller cross-section than the switching chamber 13, the cross-section having a normal parallel to the axial direction 31.

[0018] The vacuum switching tube 1 can have two chamber shields 20 attached to the switching chamber housing 14 and projecting into the interior 26, one of the two chamber shields 20 electrically shielding the first flange chamber 11 from switching chamber 13 and against metal vapor, and the other chamber shield 20 electrically shielding the second flange chamber 12 from switching chamber 13 and against metal vapor. The chamber shields 20 can be electrically connected to the switching chamber housing 14. Furthermore, for electrical shielding and shielding against metal vapor, a flange shield 21 can be attached to the first flange housing 15, which projects into the interior 26, and another flange shield 21 can be attached to the second flange housing 16, which also projects into the interior 26.In the area where the partial ceramic housings 19 meet, an intermediate shield 22 can be arranged for electrical shielding and for shielding against metal vapor, with the intermediate shield 22 projecting into the interior 26.

[0019] Fig. Figure 1 shows that the electric field 23 applied in step b) can extend from the first electrode 3 and / or the second electrode 4 to the housing 2. Both polarities are conceivable, i.e., the anode can be formed by the housing 2 as well as by the first electrode 3 and / or the second electrode 4. The first electrode 3 and the second electrode 4 can be in contact or separated state. In particular, the electric field 23 can extend to the switching chamber housing 14. The electric field 23 and the magnetic field 24 can enclose an angle in the interior 26, which lies, for example, in the range of 70° to 90°, in particular from 80° to 90° or from 85° to 90°. The electric field 23 can, for example, enclose an angle with the radial direction 32 which lies in a range of 0° to 30°, in particular in a range of 0° to 15° or of 0° to 5°.The magnetic field 24 can, for example, enclose an angle with the axial direction 31 which lies in a range of 0° to 30°, in particular in a range of 0° to 15° or of 0° to 5°, cf. . Fig. 1.

[0020] Alternatively, instead of the electric field 23 applied in step b) extending from the first electrode 3 and / or the second electrode 4 to the housing 2, the first electrode 3 and the second electrode 4 can be arranged in a spaced-apart state, and the electric field 23 can extend from the first electrode 3 to the second electrode 4. Both polarities are conceivable; that is, the anode can be formed by the first electrode 3 or the second electrode 4. The electric field 23 and the magnetic field 24 can enclose an angle within the interior 26, which lies, for example, in the range of 70° to 90°, in particular 80° to 90° or 85° to 90°. The electric field 23 can, for example, enclose an angle with the axial direction 31 which lies in a range of 0° to 30°, in particular in a range of 0° to 15° or of 0° to 5°.The magnetic field 24 can, for example, enclose an angle with the radial direction 32 which lies in a range of 0° to 30°, in particular in a range of 0° to 15° or from 0° to 5°.

[0021] Fig. Figure 2 shows that the calibration device 52 can have a voltage source 53 configured to generate the electric field 23. Furthermore, the calibration device 52 can have a magnet 54 configured to generate the magnetic field 24. The magnet 54 can be, for example, a permanent magnet and / or a coil. It is conceivable that the magnetic field 24 is switched on first and then the electric field 23 is switched on. Alternatively, it is conceivable that the electric field 23 and the magnetic field 24 are switched on simultaneously. The calibration device 52 can have an ammeter 56 configured to measure the current I of the gas discharge.

[0022] Fig. Figure 2 shows that the pressure sensor 42 can be arranged outside the vacuum switching tube 1. It is conceivable that the pressure sensor 42 uses a different measuring principle than the magnetron method to determine the pressure p. Alternatively, it is conceivable that the pressure sensor 42 is based on the magnetron method and that the pressure sensor 42 has different electrodes for the first electrode 3 and the second electrode 4.

[0023] How it looks Fig. As can be seen in Figure 1, the vacuum system 40 can include a pump configured to evacuate the interior 26 via the pipe 41. Furthermore, the vacuum system 40 can include a shut-off device 44 located in a flow path extending from the pressure sensor 42 to the pump, the shut-off device 44 keeping the flow path closed while step c) is performed. The pump can be a turbomolecular pump 47. The vacuum system 40 can also include a diaphragm pump 48.

[0024] The interior 26 is fluidly connected to the tube 41, in particular by means of a flange connection. For example, the tube 41 can have a first flange 49, and the vacuum switching tube 1 can have a second flange 50 that completely encloses the through-hole 27. The first flange 49 and the second flange 50 can form the flange connection. A flange gasket 51 can be provided between the first flange 49 and the second flange 50, which contacts both the first flange 49 and the second flange 50 and thus seals the through-hole 27 and the tube 41 to the outside. For example, the flange gasket 51 can be made of or consist of an epoxy resin, or it can be made of or consist of a Viton O-ring.

[0025] The vacuum system 40 can include an additional pressure sensor 43 configured to determine the pressure in a flow path extending from the shut-off device 44 to the pump. This additional pressure sensor 43 can be based on a different measuring principle than the magnetron method. The vacuum system 40 can include a gas reservoir 46 containing a gas that can flow into the interior 26 via the pipe 41. The vacuum system 40 can include an additional shut-off device 45 through which the gas reservoir 46 can be opened and closed.

[0026] In Fig. Figure 3 shows a graph plotting the current I and the pressure p against time p. An example of the time-resolved current I(t) and an example of the time-resolved pressure p(t) are shown. The time-resolved current I(t) is characterized by the fact that the current I initially rises steeply, reaching a maximum I maxThe pressure is reached and then falls less steeply. The pressure profile p(t) is characterized by the fact that at times earlier than the start t1 of the rise in the time-resolved current I(t), the pressure p is essentially constant. It is conceivable that a pressure p is established before the onset of the gas discharge (i.e., before t1), which lies within a range of 10 -9 mbar up to 10 -3 The pressure p before the onset of the gas discharge can be set, for example, using the pump and / or the gas reservoir 46. The time-resolved current I(t) begins to rise at t1, and the time-resolved pressure p(t) begins to fall at t2. The delay Δt is therefore calculated as Δt = t2 - t1.

[0027] It is conceivable to smooth the time-resolved current I(t), particularly by means of a low-pass filter. The low-pass filter can, for example, have a cutoff frequency in the range of 1 Hz to 500 Hz, especially from 1 Hz to 20 Hz. Additionally or alternatively, it is conceivable to adjust the time-resolved current I(t), at least in a temporal sub-range, using a matching function to smooth the time-resolved current I(t). Similarly, it is conceivable to smooth the time-resolved pressure p(t), particularly by means of a low-pass filter and / or by adjustment with a matching function. The low-pass filter can, for example, have a cutoff frequency in the range of 1 Hz to 500 Hz, especially from 1 Hz to 20 Hz.Additionally or alternatively, it is conceivable to measure a plurality of the time-resolved currents I(t) and a plurality of the time-resolved pressures p(t) and then to average the plurality of the time-resolved currents I(t) and the plurality of the time-resolved pressures p(t).

[0028] To correct the offset in step e), it is conceivable, for example, to shift the time-resolved current profile I(t) and / or the time-resolved pressure p(t) in time so that the beginning t1 of the increase in the time-resolved current I(t) and the beginning t2 of the decrease in the time-resolved pressure p(t) are simultaneous. For example, it is conceivable to shift the time-resolved current I(t) by Δt or the time-resolved pressure p(t) by -Δt.

[0029] Several methods are conceivable for determining the start t1 of the increase in the time-resolved current I(t) and the start t2 of the decrease in the time-resolved pressure p(t). For example, the start t1 of the increase in the time-resolved current I(t) can be determined as the time at which the current I first exceeds a threshold current. Similarly, the start t2 of the decrease in the time-resolved pressure p(t) can be determined as the time at which the pressure first falls below a threshold value.

[0030] From the time-resolved current I(t) and the time-resolved pressure p(t), in which, after step e), the beginning t1 of the increase in the time-resolved current I(t) and the beginning t2 of the decrease in the time-resolved pressure p(t) are simultaneous, a plurality of pairs of values ​​can be determined, formed by a current I and a pressure p that are arranged simultaneously. The calibration function 55 can be created from these pairs of values; see [reference]. Fig. 4. Fig. Figure 4 shows a plot of pressure p against current I, in which the pairs of values ​​can be entered. These pairs of values ​​can, for example, serve as reference points for the calibration function 55. The calibration function 55 can be in the form of a lookup table and / or in the form of an adjustment function (as shown in Figure 4). Fig. 4 is shown).

[0031] A method for determining a pressure in a measuring vacuum switching tube 30 comprises the steps of: g) providing the measuring vacuum switching tube 30, which has a first electrode 3 and a second electrode 4, which have a contact state in which the first electrode 3 and the second electrode 4 are in contact with each other, and a spaced-away state in which the first electrode 3 and the second electrode 4 are spaced apart from each other, and a housing 2 which delimits an interior space 26 in which the first electrode 3 and the second electrode 4 are arranged, and which maintains a vacuum in the interior space 26 such that in the spaced-away state the first electrode 3 and the second electrode 4 are electrically isolated from each other by the vacuum; h) providing the calibration function 55;i) Applying a magnetic field 24 and an electric field 23 to the interior 26 of the measuring vacuum switching tube 30, such that a measuring gas discharge is generated in the interior 26 of the measuring vacuum switching tube 30, wherein the magnetic field 24 in the interior 26 has an orientation different from the electric field 23; j) Measuring a time-resolved current intensity I(t) of the measuring gas discharge and determining a maximum I; max the time-resolved current I(t) of the measuring gas discharge; k) Determining the pressure p of the vacuum of the measuring vacuum switching tube 30 based on the maximum I maxthe time-resolved current I(t) of the measuring gas discharge and based on the calibration function 55. The interior 26 of the vacuum switching tube 1 can be identical in construction to the interior 26 of the measuring vacuum switching tube 30, except for the presence of the through-hole 27. The walls that delimit the interior 26 of the vacuum switching tube 1 can be made of the same material or materials as the walls that delimit the interior 26 of the measuring vacuum switching tube 1. Reference symbol list 1 vacuum switching tube 2 cases 3 first electrode 4 second electrode 5 first connection 6 second connection 7 first contact surface 8 second contact surface 9 warehouses 10 bellows 11 first flange chamber 12 second flange chamber 13 Switching chamber 14 Switch chamber housings 15 first flange housing 16 second flange housing 17 first ceramic housing 18 second ceramic housing 19 partial ceramic housings 20-chamber screen 21 Flange screen 22 Intermediate screen 23 electric field 24 Magnetic field 25 electrode protrusion 26 Interior 27 Through hole 30 measuring vacuum switching tubes 31 Axial direction 32 Radial direction 33 Circumferential direction 40 vacuum system 41 pipe 42 Pressure sensor 43 additional pressure sensors 44 Shut-off device 45 additional shut-off device 46 Gas reservoir 47 Turbomolecular pump 48 Diaphragm pump 49 first flange 50 second flange 51 Flange gasket 52 Calibration device 53 Voltage source 54 Magnet 55 Calibration function 56 ammeters I electric current p print t time I(t) time-resolved current p(t) time-resolved pressure t1 Start of an increase in the time-resolved current I(t) t2 Beginning of a fall of the time-resolved pressure p(t) Δt offset I max Maximum of I(t)

Claims

[1] Method for calibrating a pressure measurement in a vacuum switching tube (1), comprising the steps: a) Providing a calibration device (52) with a vacuum switching tube (1) comprising a first electrode (3) and a second electrode (4) having a contact state in which the first electrode (3) and the second electrode (4) are in contact with each other and a separation state in which the first electrode (3) and the second electrode (4) are separated from each other, and a housing (2) which defines an interior space (26) in which the first electrode (3) and the second electrode (4) are arranged and which is configured to maintain a vacuum in the interior space (26) so that in the separation state the first electrode (3) and the second electrode (4) can be electrically isolated from each other by the vacuum, a vacuum system (40) comprising a tube (41) and a pressure sensor (42) by means of which the pressure (p) in the tube (41) can be measured, wherein the vacuum switching tube (1) has a through-hole (27),which connects the interior (26) to the pipe (41) in a fluid-conducting manner; b) Applying a magnetic field (24) and an electric field (23) to the interior (26) such that a gas discharge is generated in the interior (26), wherein the magnetic field (24) in the interior (26) has an orientation different from the electric field (23); c) Measuring a time-resolved current (I(t)) of the gas discharge and simultaneously measuring a time-resolved pressure (p(t)) in the tube (41) using the pressure sensor (42); d) Determining a time offset (Δt) between the beginning (t1) of an increase in the time-resolved current (I(t)) and the beginning (t2) of a decrease in the time-resolved pressure (p(t)); e) Correcting the offset (Δt) by shifting the time-resolved current (I(t)) and / or the time-resolved pressure (p(t)); f) Assigning a plurality of temporally after a maximum (I max) the time-resolved current (I(t)) currents (I) to a pressure (p) corrected by the offset (Δt) in time, thereby forming a calibration function (55). [2] Method according to claim 1, wherein the through hole (27) and the tube (41) have an internal cross-section at their narrowest point of at least 1 cm 2 amounts. [3] Method according to claim 1 or 2, wherein the through hole (27) is provided in the housing (2). [4] Method according to claim 1 or 2, wherein the through hole (27) is provided in the first electrode (3). [5] Method according to any one of claims 1 to 4, wherein the vacuum system (40) has a pump which is configured to evacuate the interior (26) via the tube (41). [6] Method according to claim 5, wherein the vacuum system (40) has a shut-off device (44) which is arranged in a flow path extending from the pressure sensor (42) to the pump and by means of which the flow path is kept closed while step c) is carried out. [7] Method for determining a pressure in a measuring vacuum switching tube (30), comprising the steps: g) Providing the measuring vacuum switching tube (30) which has a first electrode (3) and a second electrode (4) which have a contact state in which the first electrode (3) and the second electrode (4) are in contact with each other and a separation state in which the first electrode (3) and the second electrode (4) are separated from each other, and a housing (2) which defines an interior space (26) in which the first electrode (3) and the second electrode (4) are arranged and which maintains a vacuum in the interior space (26) so that in the separation state the first electrode (3) and the second electrode (4) are electrically isolated from each other by the vacuum; h) Providing a calibration function (55) according to any one of claims 1 to 6; i) Applying a magnetic field (24) and an electric field (23) to the interior (26) of the measuring vacuum switching tube (30) such that a measuring gas discharge is generated in the interior (26) of the measuring vacuum switching tube (30), wherein the magnetic field (24) in the interior (26) has an orientation different from the electric field (23); j) Measuring a time-resolved current (I(t)) of the measuring gas discharge and determining a maximum (I max ) the time-resolved current (I(t)) of the measuring gas discharge; k) Determining the pressure (p) of the vacuum of the measuring vacuum switching tube (30) based on the maximum (I max ) the time-resolved current (I(t)) of the measuring gas discharge and based on the calibration function (55). [8] Method according to claim 7, wherein the interior (26) of the vacuum switching tube (1) is identical in construction to the interior (26) of the measuring vacuum switching tube (30) except for the presence of the through-hole (27). [9] Method according to claim 8, wherein the walls that define the interior (26) of the vacuum switching tube (1) are made of the same material or materials as the walls that define the interior (26) of the measuring vacuum switching tube (1).

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