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The basic components of a typical electron-beam processing device include: [1] an electron gun (consisting of a cathode, grid, and anode), used to generate and accelerate the primary beam; and, a magnetic optical (focusing and deflection) system, used for controlling the way in which the electron beam impinges on the material being processed ...
Electron-beam machining is a process in which high-velocity electrons are concentrated into a narrow beam with a very high planar power density. The beam cross-section is then focused and directed toward the work piece, creating heat and vaporizing the material. Electron-beam machining can be used to accurately cut or bore a wide variety of metals.
Electron beam therapy is performed using a medical linear accelerator.The same device can also be used to produce high energy photon beams. When electrons are required, the X-ray target is retracted out of the beam and the electron beam is collimated with a piece of apparatus known as an applicator or an additional collimating insert, constructed from a low melting point alloy.
Over time, electron acceleration at the SLAC National Accelerator Laboratory would extend to a size of 2 miles (3.2 km) and an output energy of 50 GeV. [10] As linear accelerators were developed with higher beam currents, using magnetic fields to focus proton and heavy ion beams presented difficulties for the initial stages of the accelerator.
EBM equipment in construction is similar to electron beam welding machines (see electron beam welding). EBM machines usually utilize voltages in the range of 150 to 200 kV to accelerate electrons to about 200,000 km/s. Magnetic lenses are used to focus the electron beam to the surface of the work-piece.
Accelerating voltages can be between 3 and 40 kV. When the accelerating voltage is 20–25 kV and the beam current is a few amperes, 85% of the electron's kinetic energy can be converted into thermal energy. Some of the incident electron energy is lost through the production of X-rays and secondary electron emission.
Intraoperative electron radiation therapy is the application of electron radiation directly to the residual tumor or tumor bed during cancer surgery. [1] [2] Electron beams are useful for intraoperative radiation treatment because, depending on the electron energy, the dose falls off rapidly behind the target site, therefore sparing underlying healthy tissue.
Electron gun from an oscilloscope CRT Setup of an electron gun. 1. Hot cathode.2. Wehnelt cylinder.3. Anode. A direct current, electrostatic thermionic electron gun is formed from several parts: a hot cathode, which is heated to create a stream of electrons via thermionic emission; electrodes generating an electric field to focus the electron beam (such as a Wehnelt cylinder); and one or more ...