The Strong RF Focusing: a Possible Approach to Get Short Bunches at the IP

Short colliding bunches are required in the next generation particle factories to increase the luminosity by reducing the transverse beta functions at the interaction point (IP). The strong RF focusing consists in obtaining short bunches by substantially increasing the lattice momentum compaction and the RF gradient. In this regime the bunch length is modulated along the ring and could be minimized at the IP. If the principal impedance generating elements of the ring are located where the bunch is long (in the region near the RF cavities) it is possible to avoid microwave instability and excessive bunch lengthening due to the potential well distortion. By properly choosing the machine design parameters, 2 mm rms bunch length at the IP seems to be a realistic goal at the energy of the {Phi} resonance (1 GeV in the center of mass).