Parameter Scaling to Produce Different Charged-Particle Beam-Transport Systems Having Identical Equations of Motion

摘要

Designs are freuently required for charged-particle optics channels to transport space-charge (Coulomb) force-dominated beams for use with accelerators under design or construction. It is often desirable to experimentally test a design using an existing accelerator having different parameters from the one under consideration. This paper shows how to scale a charged-particle transport design to make a model experiment for testing the design with an existing accelerator. Sometimes, with the proper choice of accelerator, the model experimetn can be much less expensive than the target device. By scaling variables (beam current and emittance, magnetic fields, etc.) in a way that produces certain invariant quantities, we obtain identical equations of motion for different charged-particle beam channels transporting different beams. The scaling relations take a transport channel design for one application having a given time structure (for instance, the time structure determiend by the radio frequency of a beam bunching cavity), beam energy, current, etc., and determine an equivalent transport channel design for another device with different parameters. Therefore, we can predict particle and beam behavior in one situation by knowing it in another. Even growth in emittance will be modeled correctly in spite of the fact that the devices transport beams with different time structure, energy, and currents. 2 refs., 1 fig., 1 tab. (ERA citation 13:030931)