Transcript Note
Particle Accelerator Particle accelerators • It is a device that provides – forces on charge particles – by some combinations of electric & magnetic fields, – and brings the ions to high speed & kinetic energy A particle accelerator is a device that uses electromagnetic fields to propel charged particles to high speeds and to contain them in well-defined beams. Two basic classes of accelerators, 1. Electrostatic accelerators & 2. Oscillating field accelerators Electrostatic accelerators 1. Electrostatic accelerators use static electric fields to accelerate particles. A small-scale example of this class is the cathode ray tube [CRT] in an ordinary old TV set. Other examples are the Cockcroft–Walton generator and the Van de Graaf generator. The achievable kinetic energy for particles in these devices is limited by electrical breakdown. Oscillating field accelerators 2. Oscillating field accelerators, use radio frequency electromagnetic fields and circumvent the breakdown problem. This class, which was first developed in the 1920s, is the basis for all modern accelerator concepts and large-scale facilities Apps. Particle accelerators are used in a large variety of applications, • best known use in particle physics as colliders (e.g., LHC [Large Hadron Collider] in CERN, RHIC, Tevatron), • including particle therapy for oncological purposes, • and as synchrotron light sources for fields such as condensed matter physics. Oscillating field particle accelerators • Linear particle accelerators: – In a linear accelerator (linac), particles are accelerated in a straight line with a target of interest at one end. – They are often used to provide an initial lowenergy kick to particles before they are injected into circular accelerators. – The longest linac in the world is the Stanford Linear Accelerator, SLAC, which is 3 km (1.9 mi) long. SLAC is an electron-positron collider. – Linear accelerators are also widely used in medicine, for radiotherapy and radiosurgery. • Circular or cyclic accelerators: – Here, particles move in a circle until they reach sufficient energy. – The particle track is typically bent into a circle using electromagnets. – The advantage of circular accelerators over linear accelerators (linacs) is that it allows continuous acceleration, as the particle can transit indefinitely. – It is smaller than a linac of comparable power (i.e., a linac would have to be extremely long to have the equivalent power of a circular accelerator). • Cyclotrons: – The earliest operational circular accelerators were cyclotrons, invented in 1929 • Betatrons: – Another type of circular accelerator, invented in 1940 for accelerating electrons, is the Betatron Next Isotope Separator • In-course – 30 April