Photonics Dictionary

An electron tube whose electrical characteristics will not be affected by gaseous ionization because of its high degree of evacuation. Also known as a hard tube.

In the discharge of a vacuum tube, the narrow, nonluminous region that sometimes may be found between the cathode and its glow.

An instrument consisting of a high-voltage vacuum tube used to form hard x-rays or high-speed ion beams. By partitioning the tube into separate sections, the total voltage is divided.

A vacuum tube with an electron gun at one end and a fluorescent screen at the other. Electrons emitted from a heated filament are accelerated by a series of annular anodes at progressively higher...

A lamp that emits light when an electric current passes through a resistant metallic wire situated in a vacuum tube.

An instrument designed to measure the index of refraction of a gas by the interference patterns formed by two beams, one of which passes through a vacuum tube in which the gas is slowly released.

A vacuum tube in which a magnetic field is superimposed onto the tube's electrical field. When the two fields are aligned, electrons from the photocathode are accelerated through the tube in a spiral...

In a cold-cathode tube, the luminance between the cathode dark space and the Faraday dark space. In a vacuum tube, the luminance between the Crookes dark space and the Faraday dark space.

A photodetector, also known as a photosensor or photodiode, is a device that detects and converts light into an electrical signal. Photodetectors are widely used in various applications, ranging from...

A photomultiplier tube (PMT) is a highly sensitive vacuum tube that detects and amplifies low levels of light. It is widely used in various applications where high sensitivity, fast response times,...