In the present invention, a pressure measurement device for determining the vacuum level within the evacuated housing of a vacuum electrode device is provided that includes an electrically conductive enclosure secured to an interior surface of the housing, an electrically conductive electrode extending through an aperture in the housing, the electrode having a tip at one end positioned within the interior of the housing inside the enclosure to define a gap between the tip and the enclosure and a conductive lead at a second end disposed outside of the housing, and a voltage source connected to the conductive lead to supply a voltage potential to the tip of the electrode. A voltage difference produced between the electrode and the enclosure ionizes gas within the enclosure causing a measurable current to flow between the electrode and the enclosure which can be used to determine the vacuum level in the housing.

The disclosure includes an ionization chamber, a first electron multiplier, and a second electron multiplier. The ionization chamber is configured to receive gas molecules from an environment at a pressure. The first electron multiplier is configured to receive a plurality of photons from a photon source, generate a first plurality of electrons from the plurality of photons, and discharge the first plurality of electrons into the ionization chamber to generate a plurality of gas ions from at least a portion of the gas molecules. The second electron multiplier is configured to receive the plurality of gas ions from the ionization chamber and generate a second plurality of electrons from the plurality of gas ions that is proportional to a quantity of the plurality of gas ions. A quantity of electrons of the second plurality of electrons is indicative of the pressure.

The disclosure includes an ionization chamber, a first electron multiplier, and a second electron multiplier. The ionization chamber is configured to receive gas molecules from an environment at a pressure. The first electron multiplier is configured to receive a plurality of photons from a photon source, generate a first plurality of electrons from the plurality of photons, and discharge the first plurality of electrons into the ionization chamber to generate a plurality of gas ions from at least a portion of the gas molecules. The second electron multiplier is configured to receive the plurality of gas ions from the ionization chamber and generate a second plurality of electrons from the plurality of gas ions that is proportional to a quantity of the plurality of gas ions. A quantity of electrons of the second plurality of electrons is indicative of the pressure.

An electrical detection device carried by a rail vehicle traveling on a railway track to detect faults in at least one rail, including a contact support suitable for being mechanically linked to the rail vehicle, at least one reference contact and corresponding measuring contact applied to a rail, and carried by the support, a processing circuit to which each reference contact and measuring contact are connected, suitable for measuring the impedance between the corresponding reference and measuring contacts, means for positioning the contact support facing the surface of the rail in a measurement direction corresponding to the axis of the rail, such that each first reference contact and each corresponding measuring contact relate to the same rail, and at least two measuring contacts transversely offset relative to the measurement direction, wherein the processing circuit includes means for measuring the impedance between at least one reference contact and each measuring contact.

The disclosure includes an ionization chamber, a first electron multiplier, and a second electron multiplier. The ionization chamber is configured to receive gas molecules from an environment at a pressure. The first electron multiplier is configured to receive a plurality of photons from a photon source, generate a first plurality of electrons from the plurality of photons, and discharge the first plurality of electrons into the ionization chamber to generate a plurality of gas ions from at least a portion of the gas molecules. The second electron multiplier is configured to receive the plurality of gas ions from the ionization chamber and generate a second plurality of electrons from the plurality of gas ions that is proportional to a quantity of the plurality of gas ions. A quantity of electrons of the second plurality of electrons is indicative of the pressure.

The disclosure includes an ionization chamber, a first electron multiplier, and a second electron multiplier. The ionization chamber is configured to receive gas molecules from an environment at a pressure. The first electron multiplier is configured to receive a plurality of photons from a photon source, generate a first plurality of electrons from the plurality of photons, and discharge the first plurality of electrons into the ionization chamber to generate a plurality of gas ions from at least a portion of the gas molecules. The second electron multiplier is configured to receive the plurality of gas ions from the ionization chamber and generate a second plurality of electrons from the plurality of gas ions that is proportional to a quantity of the plurality of gas ions. A quantity of electrons of the second plurality of electrons is indicative of the pressure.

In the present invention, a pressure measurement device for determining the vacuum level within the evacuated housing of a vacuum electrode device is provided that includes an electrically conductive enclosure secured to an interior surface of the housing, an electrically conductive electrode extending through an aperture in the housing, the electrode having a tip at one end positioned within the interior of the housing inside the enclosure to define a gap between the tip and the enclosure and a conductive lead at a second end disposed outside of the housing, and a voltage source connected to the conductive lead to supply a voltage potential to the tip of the electrode. A voltage difference produced between the electrode and the enclosure ionizes gas within the enclosure causing a measurable current to flow between the electrode and the enclosure which can be used to determine the vacuum level in the housing.

In the present invention, a pressure measurement device for determining the vacuum level within the evacuated housing of a vacuum electrode device is provided that includes an electrically conductive enclosure secured to an interior surface of the housing, an electrically conductive electrode extending through an aperture in the housing, the electrode having a tip at one end positioned within the interior of the housing inside the enclosure to define a gap between the tip and the enclosure and a conductive lead at a second end disposed outside of the housing, and a voltage source connected to the conductive lead to supply a voltage potential to the tip of the electrode. A voltage difference produced between the electrode and the enclosure ionizes gas within the enclosure causing a measurable current to flow between the electrode and the enclosure which can be used to determine the vacuum level in the housing.

System (300, 400) and methods (500) for testing a reaction thruster (100) in a vacuum environment. The methods comprise: disposing the reaction thruster in a vacuum chamber which is at least partially connected to earth ground; removing at least one gas from the vacuum chamber to provide the vacuum environment; operating the reaction thruster so as to create a beam of electrons; and/or electrically isolating the electrons of the beam from at least one electrically conductive surface of the vacuum chamber. The electrical isolation can be achieved by applying an electrical bias voltage to the beam via an electrode. The electrode may comprise a conductive object disposed in the vacuum chamber and/or at least a portion of a vacuum chamber wall. In all cases, the electrode is electrically isolated from a portion of the vacuum chamber that is connected to ground.

System (300, 400) and methods (500) for testing a reaction thruster (100) in a vacuum environment. The methods comprise: disposing the reaction thruster in a vacuum chamber which is at least partially connected to earth ground; removing at least one gas from the vacuum chamber to provide the vacuum environment; operating the reaction thruster so as to create a beam of electrons; and/or electrically isolating the electrons of the beam from at least one electrically conductive surface of the vacuum chamber. The electrical isolation can be achieved by applying an electrical bias voltage to the beam via an electrode. The electrode may comprise a conductive object disposed in the vacuum chamber and/or at least a portion of a vacuum chamber wall. In all cases, the electrode is electrically isolated from a portion of the vacuum chamber that is connected to ground.