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A set of cold cathode discharge tubes. A cold cathode [1] is a cathode that is not electrically heated by a filament. [note 1] A cathode may be considered "cold" if it emits more electrons than can be supplied by thermionic emission alone. It is used in gas-discharge lamps, such as neon lamps, discharge tubes, and some types of vacuum tube.
Penning ionization is a form of chemi-ionization, an ionization process involving reactions between neutral atoms or molecules. [ 1 ] [ 2 ] The Penning effect is put to practical use in applications such as gas-discharge neon lamps and fluorescent lamps , where the lamp is filled with a Penning mixture to improve the electrical characteristics ...
The Penning source is a low gas pressure, cold cathode ion source which utilizes crossed electric and magnetic fields. The ion source anode is at a positive potential, either dc or pulsed, with respect to the source cathode. The ion source voltage is normally between 2 and 7 kilovolts.
A duoplasmatron is a type of glow discharge ion source that consists of a hot cathode or cold cathode that produces a plasma that is used to ionize a gas. [1] [22] THey can produce positive or negative ions. [23] They are used for secondary ion mass spectrometry, ion beam etching, and high-energy physics. [24] [25] [26]
The physical principles of ion traps were first explored by F. M. Penning (1894–1953), who observed that electrons released by the cathode of an ionization vacuum gauge follow a long cycloidal path to the anode in the presence of a sufficiently strong magnetic field. [6]
The basic element of the common ion pump is a Penning trap. [6] A swirling cloud of electrons produced by an electric discharge is temporarily stored in the anode region of a Penning trap. These electrons ionize incoming gas atoms and molecules. The resultant swirling ions are accelerated to strike a chemically active cathode (usually titanium ...
A cylindrical version of a Penning trap, with open endcaps to permit axial access. B indicates the magnetic field, and E indicates the electric field used for storage of the particles in the trap centre. A Penning trap is a device for the storage of charged particles using a homogeneous magnetic field and a quadrupole electric field.
Penning vacuum gauge (cut-away) There are two subtypes of cold-cathode ionization gauges: the Penning gauge (invented by Frans Michel Penning), and the inverted magnetron, also called a Redhead gauge. The major difference between the two is the position of the anode with respect to the cathode.