Overview of linear collider designs

Linear collider design and development have become focused on a center-of-mass energy E_CM = 0.5 TeV and a luminosity L = 5×10³³ cm^-2sec^-1. There are diverse approaches to meeting these general objectives. The diversity arises from different judgements about the ease of developing new and improving existing technology, costs, extension to higher energies, experimental backgrounds and center-of mass energy spectrum, tolerances and beam power. The parameters of possible colliders are given, which are based on a compilation made by Loew at the LC-92 Conference and is reproduced with his permission. The colliders described are: TESLA (being developed by an international collaboration) which is based on superconducting RF. All the others would use room temperature RF. DLC (DESY/Darmstadt) which uses S-band (3 GHz) RF where there is extensive operating experience. NLC (SLAC) which uses higher frequency X-band (11.4 GHz) RF in a modulator-klystron-accelerator configuration similar to S-band linacs. JLC-1 (KEK) which has three frequency options, S-band, C-band (5.7 GHz), and X-band. Multiple bunches are accelerated in each RF pulse as they are in TESLA, DLC, and NLC. VLEPP (INP) which employs a single high intensity bunch rather than multiple bunches. CLIC (CERN) which is a two-beam accelerator with klystrons replaced by an RF power source based on a high-current, low-energy beam travelling parallel to the high energy beam. The discussion below focuses on some of the common themes of these designs and the differences between them