At IUCF, we have performed a series of emittance dilution experiments. Figure 3.5 shows an example of the mountain range plot when the cooler beam at is modulated by a secondary rf system at . The data has been carefully analyzed. In particular, the square of the rms bunch length shows interesting dependence on time t . Working on diffusion modeling, the experimental data can un-ambiguously be identified as beam particles streaming along the separatrix of a dominant parametric resonance.
Particles then diffuse into the chaotic sea at a slower rate.
Detailed report of our studies will be reported shortly. Using an rf dipole, coherent betatron motion can be adiabatically excited without inducing emittance growth. Adiabatically transporting the beam bunch onto the resonance island the coherent beam motion can be sustained without emittance dilution. Employing coherent betatron motion in vertical plane, the intrinsic spin resonance can be overcome without using betatron tune jump. Results of this experiment will be published in Ref.