Abstract: A dry vacuum pump is provided, including two shafts, respectively supporting at least one pumping rotor being configured to synchronously rotate in reverse in order to convey a gas to be pumped from an intake of the dry vacuum pump to an outlet; and a synchronous motor configured to rotate one shaft of the two shafts, the synchronous motor including a rotor coupled to the shaft, a first stator with windings arranged around the rotor, and at least one second stator with windings arranged around the rotor, the windings of the stators being configured to be supplied individually or simultaneously in order to adapt a power of the synchronous motor to a pumping load. A method for controlling a synchronous motor of a vacuum pump is also provided.

Abstract: A dry vacuum pump is provided, including two shafts, respectively supporting at least one pumping rotor being configured to synchronously rotate in reverse in order to convey a gas to be pumped from an intake of the dry vacuum pump to an outlet; and a synchronous motor configured to rotate one shaft of the two shafts, the synchronous motor including a rotor coupled to the shaft, a first stator with windings arranged around the rotor, and at least one second stator with windings arranged around the rotor, the windings of the stators being configured to be supplied individually or simultaneously in order to adapt a power of the synchronous motor to a pumping load. A method for controlling a synchronous motor of a vacuum pump is also provided.

Abstract: The invention relates to a method for monitoring a leak detector comprising: a secondary vacuum pump designed to be connected to a primary vacuum pump, the secondary vacuum pump comprising a motor, a rotor and a stator, the said rotor being capable of being rotated in the stator by the motor when the motor is powered, and at least one information means capable of being powered electrically, in order to inform a user of the operating state of the leak detector, characterized in that, in the event of the motor power supply being cut off, the kinetic energy of rotation of the secondary vacuum pump rotor in the form of electrical power (101) is recovered in order to power the information means (102). The invention also relates to a leak detector (1) using the said monitoring method.

Abstract: A device for controlling the dehydration operation during a freeze-drying treatment comprises a freeze-drying chamber (1) connected to a vacuum line, and a gas analyzer, for analyzing the gases contained in the chamber. The gas analyzer comprises a gas ionization system (8) comprising a plasma source (13) in contact with the gases, which plasma source is combined with a generator (15) capable of generating a plasma from said gases, and a system for analyzing the ionized gases, comprising a radiation sensor (17) located close to the plasma generation zone and connected to an apparatus (18) for analyzing the change in the radiative spectrum emitted by the plasma. According to the invention, the device includes a means (16) for repeatedly turning the plasma source (13) on and off. The device may further include an optical port (25) placed between the gas ionization system (8) and the freeze-drying chamber (1).

Abstract: A device for controlling the dehydration operation during a freeze-drying treatment comprises a freeze-drying chamber (1) connected to a vacuum line, and a gas analyzer, for analyzing the gases contained in the chamber. The gas analyzer comprises a gas ionization system (8) comprising a plasma source (13) in contact with the gases, which plasma source is combined with a generator (15) capable of generating a plasma from said gases, and a system for analyzing the ionized gases, comprising a radiation sensor (17) located close to the plasma generation zone and connected to an apparatus (18) for analyzing the change in the radiative spectrum emitted by the plasma. According to the invention, the device includes a means (16) for repeatedly turning the plasma source (13) on and off. The device may further include an optical port (25) placed between the gas ionization system (8) and the freeze-drying chamber (1).

Abstract: The invention relates to a method for monitoring a leak detector comprising: a secondary vacuum pump designed to be connected to a primary vacuum pump, the secondary vacuum pump comprising a motor, a rotor and a stator, the said rotor being capable of being rotated in the stator by the motor when the motor is powered, and at least one information means capable of being powered electrically, in order to inform a user of the operating state of the leak detector, characterized in that, in the event of the motor power supply being cut off, the kinetic energy of rotation of the secondary vacuum pump rotor in the form of electrical power (101) is recovered in order to power the information means (102). The invention also relates to a leak detector (1) using the said monitoring method.

Abstract: The regeneration method relates to a hydrogen sensor, which comprises a transistor of the MOS type whose gate is covered with a palladium catalyst and which is placed in a low-pressure enclosure. After a leak has been detected, a voltage is imposed on the gate of the transistor by means of an electronic circuit in order to regenerate the catalyst. The electronic circuit comprises a low-frequency DC generator and a switch for changing from the “measurement” mode to the “regeneration” mode, and vice versa.

Abstract: The monitor device according to the invention comprises an axial excroissance bounded by a gastight peripheral wall permeable to magnetic fields and connected to a chamber, such as a process chamber, where gaseous species to be monitored are present. A light radiation sensor is placed at the end of the axial chamber excroissance and allows the light to be transported via an optical fiber (4a) to an optical spectrometer. A plasma generator generates a monitoring plasma in the internal space of the axial chamber excroissance. One or more magnets are placed outside the peripheral wall of the axial chamber excroissance and generate a magnetic field near the sensor in order to form a magnetic barrier that prevents the ionized particles of the monitoring plasma from propagating toward the sensor. Thus, the sensor and the chamber are prevented from becoming fouled.

Abstract: A system in accordance with the invention which generates electrons by means of a field-emission cathode comprises an array of electron-emitting micropoints associated with a grid and carried by a substrate with integral heater means for heating the micropoints to a temperature in the range approximately 300° C. to approximately 400° C. and maintaining them at that temperature during emission of electrons. The cathode can therefore function at higher residual air pressures with no risk of breakdown.

Abstract: In accordance with the invention, the ion source of a time-of-flight mass spectrometer includes an electron gun having an electron source and at least one electrode for conditioning the flow of electrons, followed by at least one microchannel wafer for generating a pulsed secondary electron beam containing a greater number of electrons from a pulsed primary electron beam. The secondary electron beam enters a gas ionization area of an ion gun which produces a flow of ions which is then passed through the flight tube in order to be analyzed by an ion detector. This provides a high-performance ion source which is compact, sensitive and easy to integrate.

Abstract: In accordance with the invention, the ion source of a time-of-flight mass spectrometer includes an electron gun having an electron source and at least one electrode for conditioning the flow of electrons, followed by at least one microchannel wafer for generating a pulsed secondary electron beam containing a greater number of electrons from a pulsed primary electron beam. The secondary electron beam enters a gas ionization area of an ion gun which produces a flow of ions which is then passed through the flight tube in order to be analyzed by an ion detector. This provides a high-performance ion source which is compact, sensitive and easy to integrate.

Abstract: The pulse mode electron generator of the invention includes a field emission cathode with electron-emitting micropoints associated with a grid biased by means for positively biasing the grid and an anode attracting electrons emitted by the cathode. The grid is biased by a permanent positive pre-bias voltage generator delivering a rest voltage which is slightly lower than the emission threshold voltage of the cathode and in series with a positive pulse voltage generator delivering a pulse component of sufficient value to exceed the emission threshold voltage of the cathode. This facilitates the pulse mode production of electrons and reduces the power consumption needed to produce the electrons.

Abstract: In a system in accordance with the invention for detecting leaks, a mass spectrometer is connected to the aspiration side of a secondary pump whose discharge side is connected to the aspiration side of a primary pump driven by a rotational drive system adapted to vary the rotation speed of the primary pump between at least two different rotation speeds. An aspiration inlet is selectively connected by control valves either to the aspiration side of the primary pump or to the aspiration side or an intermediate area of the secondary pump. Variation of the rotation speed of the primary pump is used to perform faster pre-evacuation before the test, to detect grosser leaks, to compensate for a high level of outgassing or to adapt the sensitivity of the device, and equally to eliminate helium background noise from the primary pump.

Abstract: A micropoint type cold cathode comprises a substrate including an array of micropoints and a plate disposed parallel to the substrate carrying the points. The plate includes a hole facing each point and thereby constitutes a grid. An insulator fills the space between the substrate and the grid except at the location of the points. The nominal distance between the summit of a point and the face of the grid farthest from the substrate is zero, the nominal radius of curvature at the summit of each point is 25 nm and the nominal radius of the holes in the grid is 1.3 &mgr;m.

Abstract: A mass spectrometer ionization cell includes a micropoint type cold cathode which emits electrons, an amagnetic material anode forming an ionization cage positively biased relative to the cathode and including an entry slot for emitted electrons facing the cathode, and an ion collector electrode which is held at a potential lower than that of the cathode. The electrode is disposed laterally of and outside the space between the cathode and the anode and extends from the cathode to the anode. An axial magnetic field is generated in the cathode-anode direction.

Abstract: A turbomolecular pump comprising a stator and a rotor, said rotor comprising a central shaft and a bell-shaped active portion, said stator comprising an outer portion and an inner portion that penetrates into the cavity of said bell-shaped active portion, and that supports the stator portion of the drive motor, the shaft of said rotor supporting the rotor portion of said drive motor, wherein said central shaft and the bell-shaped active portion of the rotor are made in one piece, without any assembly being necessary, and of a non-magnetic material, said shaft being provided with a central bore which receives the rotor portion of said drive motor, which portion is constituted by a cylindrical permanent magnet.

Abstract: An electromagnetic bearing including a stator portion having sixteen magnetic cores facing the rotor portion. The sixteen cores are divided into four groups of four cores, and each group is equipped with suspension electric windings disposed such that the magnetic flux produced thereby is in the same direction in the first two cores of the group and in the opposite direction in the following two cores, each core in each group further being equipped with a position-detection electric coil, the coils on the four cores in any one group being connected together in series and powered by an AC electric current, the magnetic flux produced by the coils at any determined time being in opposite directions in the first two cores of any group, and also in opposite directions in the following two cores.

Abstract: A vacuum pump for producing a clean molecular vacuum, the vacuum pump comprising a stator (1A, 1B) and a rotor (2), the rotor being driven by a drive motor (6, 7, 8) integrated in the pump, the rotor being supported by magnetic bearings, and being bell-shaped fitting over an internal projection (3) protruding from the stator, the stator components (7, 8) of the drive motor and of the bearings (11B, 12B, 13B, 15, 16) being situated on the periphery of the internal projection (3), the rotor components (11A, 12A, 13A, 14) of the drive motor and of the bearings being situated on the internal periphery of the bell-shaped rotor (2), the vacuum pump being characterized in that a first gastight coating (29) made of non-magnetic material covers the projection (3) overlying the stator components of the motor and of the bearings, and in that similarly in the rotor a second gastight coating (30) made of non-magnetic material covers the rotor components of the drive motor and of the bearings.