TECH1ICAL SPECIFICATIO1 FOR THE CLIC TWO-BEAM MODULE

A high-energy (0.5–3 TeV centre-of-mass), high-luminosity Compact Linear Collider (CLIC) is being studied at CERN [1]. The CLIC main linacs, 21-km long each, are composed of 2-m long two beam modules. This paper presents their current layout, the main requirements for the different sub-systems (alignment, supporting, stabilization, cooling and vacuum) as well as the status of their integration. I1TRODUCTIO1 CLIC is based on the two-beam acceleration method in which the RF power for sections of the main linac is extracted from a second, low-energy, high-intensity electron beam running parallel to the main linac (drive beam) [1, 2]. For a 3 TeV collider, there are 24 such drive-beams, each providing enough power to accelerate the main beam. The stagger between the two linacs is made to give the correct relative RF to beam timing. Each main linac contains more than 10000 “repeated “modules. The drive-beam, running parallel to the main linac, regularly powers two ACcelerating Structures (ACS) from one Power Extraction and Transfer Structures (PETS). The main-linac module defines the length of one drive linac module, which is about 2 m long. The drive-linac module comprises then four PETS and two quadrupoles forming a FODO cell, as a very dense lattice is required for the low-energy drive beam. The main parameters for PETS and ACS are given in Table 1. In the standard modules, the main linac contains only accelerating structures (about 80 % of the modules). In the quadrupole-type modules, pairs of accelerating structures are removed at regular intervals to liberate space for a quadrupole of a FODO lattice