Showing papers in "Particle Accelerators in 1976"

Superfish-a Computer Program for Evaluation of RF Cavities with Cylindrical Symmetry

Abstract: The difference equations for axisymmetric fields are formulated in an irregular triangular mesh, and solved with a direct, noniterative method. This allows evaluation of resonance frequencies, fields, and secondary quantities in extreme geometries, and for the fundamental as well as higher modes. Finding and evaluating one mode for a 2000 point problem takes of the order of 10 sec on the CDC 7600.

Control of the low energy characteristics of the lsr electron ring using wiggler magnets

Abstract: I n an electron storage ring the emittance, the polarization time and the betatron and energy damping times are strongly dependent on the energy. In electron-proton (e-p) rings where bunched electrons collide with coasting proton beams, the emittance variation is of secondary importance, while considerable emphasis is placed on polarization phenomena. A general theory of wiggler magnets designed to control the polarization time at low energies is developed with all the parameters normalized to the standard lattice. The equations are of general validity and are applied to the e-p option of the CERN LSR (Large Storage Rings) project, as an example. It is demonstrated that the polarization vector may be reversed over a considerable range of energies being limited only by the available rf voltage. An exact formula for the emittance is given taking into account the variation of the dispersion function in the wiggler magnets. Byjudicious placing of the wiggler in the ring and a suitable choice of the wiggler magnet length, the emittance and polarization time may both be maintained approximately constant over a wide energy range while the increase in damping times at low energy is reduced but cannot be maintained constant. .

Ohmic losses of a relativistic electron ring moving along a conducting cylinder

Abstract: A relativistic electron ring moving along a conducting wall is acted on by a retarding force due to the ohmic losses of the image currents in the wall. This force is calculated for an electron ring moving coaxially along a cylinder of arbitrary thickness. The dependence of the force on the thickness and conductivity of the cylinder and on the ring velocity is discussed.