Beam-beam Simulations for a Single Pass Superb-factory

A study of beam-beam collisions for an asymmetric single pass SuperB-Factory is presented [1]. In this scheme an e and an e + beam are first stored and damped in two Damping Rings (DR), then extracted, compressed and focused to the IP. After collision the two beams are re-injected in the DR to be damped and extracted for collision again. The explored beam parameters are similar to those used in the design of the International Linear Collider, except for the beam energies. Flat beams and round beams were compared in the simulations in order to optimize both luminosity performances and beam blowup after collision. With such approach a luminosity of the order of 10 36 cm -2 s -1 can be achieved. SINGLE-PASS SUPERB-FACTORY The concept of combining linear and circular collider ideas to make a linear-circular B-Factory was discussed in the late 1980’s, although only circular B-Factories were built in the 1990’s. Recent advances in B-Factory performance and solid linear collider design progress has reopened this design avenue. The design presented here is based on the work done at the First SuperB Workshop held in November 2005 in Frascati [2]. Schematic drawings of a first Linear Super-B Factory design are shown in Fig. 1. An e + bunch from a 2 GeV damping ring is extracted and accelerated to 7 GeV in a SC linac. Simultaneously, an e bunch is accelerated in a separate SC linac to 4 GeV. The two bunches are transported to the IP through bunch compressors, then focused to a small spot and made to collide. The spent beams are returned to their respective linac with transport lines where they return their energies to the SC accelerator. The 2 GeV e + are returned to the damping ring to restore the low emittances. The spent e beam is discarded. Each bunch collides at 120Hz, there will be about 10000 bunches. Thus, the collision rate is about 1.2 MHz. A small electron linac and positron source is used to replenish lost positrons in the colliding process and natural beam lifetime. This scheme would reduce the demands on the electron gun but increase the site AC power. These schemes present several complexities and challenging requirements for several subsystems. Moreover several technical solutions proposed have never been tested and proven before, a lot of R&D and extremely detailed studies, in order to ensure the success of the machine, is henceforth required. BEAM-BEAM SIMULATIONS The beam parameters are listed in Table 1. Table 1: Preliminary Super-B Factory collision parameters.