The disclosure includes an outer electrode and an inner electrode. The outer electrode defines an inner volume and is configured to receive injected electrons through at least one aperture. The inner electrode positioned in the inner volume. The outer electrode and inner electrode are configured to confine the received electrons in orbits around the inner electrode in response to an electric potential between the outer electrode and the inner electrode. The apparatus does not include a component configured to generate an electron-confining magnetic field.

The disclosure includes an outer electrode and an inner electrode. The outer electrode defines an inner volume and is configured to receive injected electrons through at least one aperture. The inner electrode positioned in the inner volume. The outer electrode and inner electrode are configured to confine the received electrons in orbits around the inner electrode in response to an electric potential between the outer electrode and the inner electrode. The apparatus does not include a component configured to generate an electron-confining magnetic field.

The disclosure includes an outer electrode and an inner electrode. The outer electrode defines an inner volume and is configured to receive injected electrons through at least one aperture. The inner electrode positioned in the inner volume. The outer electrode and inner electrode are configured to confine the received electrons in orbits around the inner electrode in response to an electric potential between the outer electrode and the inner electrode. The apparatus does not include a component configured to generate an electron-confining magnetic field.

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.

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.

In a method for determining at least one physical parameter, a sensor unit which is activated by at least one periodic excitation (1.4) is provided, wherein the sensor unit has at least one detection region in which changes of the parameter in the surroundings of the sensor unit lead to output signal (1.7) from the sensor unit. The sensor unit is wired such that if there are no changes of the parameter in the detection region the output signal (1.7) is a zero signal or virtually a zero signal at the output of the sensor unit, whereas if there are changes of the parameter in the detection region the output signal (1.7) is a signal that is not zero and has a specific amplitude and phase. In a closed control loop, the non-zero signal in the receive path is adjusted to zero using a control signal to achieve an adjusted state even in the presence of changes of the parameter in the detection region. The control signal is evaluated in order to determine the physical parameter. The output signal (1.7) from the sensor unit is reduced substantially to the fundamental wave of the excitation (1.4) and the output signal (1.7) is controlled to zero in the entire phase space by means of at least one pulse width modulation. A temperature-stable, fully digital measuring system is provided as a result of the fact that the at least one pulse width modulation itself generates a correction signal with a variable pulse width and possibly a variable phase which is then added to the output signal (1.7) from the sensor unit and the output signal is thereby controlled to zero in the entire phase space, wherein the pulse width of the correction signal and/or the phase of the correction signal is/are determined by the deviations of the output signal (1.7) from zero.

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.

Described herein is an ion pump system implementing an electronic ratchet mechanism produced by modulating a spatially varying electric potential distribution that can result in a net ionic current and voltage. The ion pumping membrane system includes an ion-permeable layer integrated with ion-selective membranes. The electric potential distribution within the ion-permeable layer is modulated through external stimuli. When immersed in solution, ions within the ion-permeable layer experience a time varying, spatially asymmetric electric field distribution resulting in ratchet-driven direction pumping, which can be used in applications such as desalination.

A getter pump is described. The getter pump has a casing, whose shape is a solid of revolution with a revolution axis, and a plurality of getter cartridges mounted within the getter pump casing, each cartridge having a linear central support and spaced getter elements mounted on the linear central support. A getter cartridge orientation plane containing the linear central support and parallel to the revolution axis, and a getter cartridge positioning plane orthogonal to the revolution axis and intersecting the midpoint of a linear central support are defined. For each cartridge, the angle formed by the getter cartridge positioning plane with the linear control supports is equal to or less than 30.