The Care Accelerator R&D Programme in Europe

CARE, an ambitious and coordinated programme of accelerator research and developments oriented towards high energy physics projects, has been launched in January 2004 by the main European laboratories and the European Commission. This project aims at improving existing infrastructures dedicated to future projects such as linear colliders, upgrades of hadron colliders and high intensity proton drivers. We describe the CARE R&D plans, mostly devoted to advancing the performance of the superconducting technology, both in the fields of RF cavities for electron or proton acceleration and of high field magnets, as well as to developing high intensity electron and proton injectors. We highlight some results and progress obtained so far

Power loss estimation in the Electrostatic Separators of the ILC alternative head-on scheme at 500 GeV in the center-of-mass

This memo presents the power loss estimation in the Electrostatic Separators of the ILC alternative head-on scheme at 500 GeV in the center-of-mass, for the Nominal and High Luminosity beam parameters set, induced both by beam particles and radiative Bhabha processes

Beam-beam instability driven by wakefield effects in linear colliders

The vertical beam profile distortions induced by wakefield effects in linear colliders (the so-called ``banana effect'') generate a beam-beam instability at the collision point when the vertical disruption parameter is large. We illustrate this effect in the case of the TESLA linear collider project. We specify the tolerance on the associated emittance growth, which translates into tolerances on injection jitter and, for a given tuning procedure, on structure misalignments. We look for possible cures based on fast orbit correction at the interaction point and using a fast luminosity monitor

A New Beam Delivery System (BDS) for the TESLA Linear Collider

An overview of the proposed new BDS for the TESLA linear collider is presented. Several major changes have been incorporated since the publication of the TESLA Conceptual Design Report (CDR) [1]. The most notable of these modifications are: incorporation of the photonbasedpositron source upstream of the interaction point (IP), i.e. at the exit of the electron linac; a new concept for the collimation system, including integration of the emittance measurement section; an increase in the length of the final telescope, which, together with a new spent beam extraction line, allows for cleaner extraction of both the spent electron (positron) beam and the beamstrahlung photons

Final-Focus System for CLIC at 3 TeV

We describe a base-line optics for a 3-TeV final-focus system of the Compact Linear Collider (CLIC). The proposed system consists of an initial beta-matching region, two chromatic correction sections, and a final transformer, and it provides a total demagnification by a factor 90 horizontally and 346 vertically. The length per side amounts to 3.3 km. The effect of synchrotron radiation and higher-order aberrations is minimised by an odd dispersion function in the chromatic correction section. For a total flat energy spread of 1%, the system promises a luminosity of about 80% of the ideal. The 20-30% spot-size dilutions in the two transverse planes reflect a trade-off between the Oide effect and higher-order chromo-geometric aberrations