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see particle acceleratorparticle accelerator,
apparatus used in nuclear physics to produce beams of energetic charged particles and to direct them against various targets. Such machines, popularly called atom smashers, are needed to observe objects as small as the atomic nucleus in studies of its
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A device for accelerating charged particles in an orbit by means of the electric field E from a slowly changing magnetic flux &PHgr;. The electric field is given by E = -(1/2&pgr;ro) d&PHgr;/dt (in SI or mks units), where ro is the orbit radius. The name was chosen because the method was first applied to electrons. In the usual betatron both the accelerating core flux and a guiding magnetic field rise with similar time dependence, with the result that the orbit is circular. However, the orbit can have a changing radius as acceleration progresses. For the long path (usually more than 60 mi or 100 km), variations of axial and radial magnetic field components provide focusing forces, while space charge and space current forces due to the particle beam itself also contribute to the resulting betatron oscillations about the equilibrium orbit. In many other instances of particle beams, the term betatron oscillations is used for the particle oscillations about a beam's path.

Collective effects from self-fields of the beam have been found important and helpful in injecting. Circulating currents of about 3 amperes are contained in the numerous industrial and therapeutic betatrons, although the average currents are below 10-7 A. See Particle accelerator

McGraw-Hill Concise Encyclopedia of Physics. © 2002 by The McGraw-Hill Companies, Inc.


A device for accelerating electrons in an evacuated ring by means of a time-varying magnetic flux encircled by the ring. Also known as rheotron.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


Physics a type of particle accelerator for producing high-energy beams of electrons, having an alternating magnetic field to keep the electrons in a circular orbit of fixed radius and accelerate them by magnetic induction. It produces energies of up to about 300 MeV
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
Figures 6-9 have shown the asymptotic behaviors and the effects of the inner and outer radii on space charge and betatron modes for weak ion channel.
Besides, the beam radius of the solid beam and the outer radius of the annular beam have a similar effect on the space and betatron modes.
Figure 13 shows the influences of the betatron oscillation characteristic parameter [[omega].sub.[beta]] on the TM dispersion properties for strong ion channel.
Compared with the solid beam, from Figure 15, it can also be seen that the dispersion curve of the LF branch for the TM modes is close to the betatron modes gradually and the two dispersion curves almost coincident at large number wave.
The influences of the inner and outer radii of the beam and betatron oscillation parameter on the dispersion characteristics of space charge modes, betatron modes, and TM modes are revealed by numerical calculations.
Caption: Figure 13: The effect of betatron oscillation parameter [[omega].sub.[beta]] on the dispersion characteristics of the [TM.sub.01] modes for strong ion channel.
Since in the case, where betatron motion ([MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]) can be neglected the new longitudinal coordinate p should not depend on the new longitudinal canonical conjugate variable [??], the second sum in equation (72) must be identically zero.
The corresponding betatron tunes are determined according to the expression
Typical dependence of the horizontal and vertical betatron tunes on energy in the EMMA non-scaling FFAG is shown in Figures 1 and 2.
The lengthening of the time of flight for one period of the machine due to betatron oscillations can be expressed as