Beam Optics

1. Avoidance of transition crossing. Although there are many ways to reduce beam loss during transition crossing [1], e.g., a γt-jump with a special quadrupole system, it is not possible to eliminate the loss completely. Furthermore, any source of longitudinal emittance dilution of the beam should be avoided in order to achieve a short bunch length in the extracted beam. The design presented here avoids transition crossing by choosing γt to be imaginary or the transition energy to be much higher than the extraction energy of the beam [2,3].