Alignment Tolerances for the CLIC Decelerator

This note aims to quantify the alignment tolerances for the CLIC decelerator lattice elements by investigating the effects of wake fields and component misalignment. The tolerances comes from the requirements of transporting the entire beam through the lattice, while extracting the required amount of energy. First, we briefly discuss the beam energy spread and its effect on the beam envelope. Then, we analyze the effects of the PETS dipole wakes for a perfect machine. Finally, the effect of lattice element misalignment is studied. Beam based alignment schemes for quadrupole correction will be presented, including modifications of the schemes needed for the CLIC decelerating station. Simulations have been performed with the tracking code PLACET . The results indicate, for an energy extraction efficiency of 85%, that it would be possible to transport the entire decelerator beam through the lattice, if PETS misalignment are not larger than ~100 um and if beam based alignment methods are used for quadrupole correction

Beam-Based Alignment for the CLIC Decelerator

The CLIC Drive Beam decelerator requires the beam to be transported with very small losses. Beam-based alignment is necessary in order to achieve this, and various beam-based alignment schemes have been tested for the decelerator lattice. The decelerator beam has an energy spread of up to 90%, which impacts the performance of the alignment schemes. We have shown that Dispersion-Free-Steering works well for the decelerator lattice. However, because of the transverse focusing approach, modifications of the normal DFS schemes must be applied. Tune-up scenarios for the CLIC decelerator using beam-based alignment are also discussed

A study of Failure Modes in the CLIC Decelerator

The CLIC Drive Beam decelerator is responsible for producing the RF power for the main linacs, using Power Extraction and Transfer Structures (PETS). To provide uniform power production, the beam must be transported with very small losses. In this paper failure modes for the operation of the decelerator are investigated, and the impact on beam stability and loss levels is presented. Quadrupole failure, PETS inhibition and PETS RF break down scenarios are being considered

Beam Dynamics Issues in the CLIC Long Transfer Line

Both the main and the drive beam of the CLIC project must be transported from the central production site to the head of the main linacs over more than twenty kilometers. Over such distances chromatic error may be substantial. With long distances and large beam currents, ion-induced detuning and instabilities and multi-bunch resistive wall effects must also be considered. These effects are quantified and simulated. Based on these results, a baseline design has been established

Recent Improvements in the Tracking Code Placet

The tracking code Placet has recently undergone several improvements. A redesign of its internal data structures and a new user interface based on the mathematical toolbox Octave considerably expanded its simulation capabilities. Several new lattice elements, optimization algorithms and physics processes were added to allow for more complete start-to-end simulations. Finally, the use of the AML language and the Universal Parser Library have extended its interfacing capability. A review of these new features is presented in this paper

Achievements in CTF3 and Commissioning status

The aim of the latest CLIC test facility CTF3, built at CERN by an international collaboration, is to prove the main feasibility issues of the CLIC two-beam acceleration technology. Several of the main goals have been already achieved in the past years, like the full-loading linac operation mode and the delay loop principle. During 2008 also the combiner ring concept has been experimentally proven and the recombined beam has been used to generate the RF power. In parallel in the fall of the year also the probe beam line commissioning had started

Status of an automatic Beam Steering for the CLIC Test Facility 3

An automatic beam steering application for CTF 3 is being designed in order to automatize operation of the machine, as well as providing a test-bed for advanced steering algorithms for CLIC. Beam-based correction including dispersion free steering have been investigated. An approach based on a PLACET on-line model has been tested. This paper gives an overview of the current status and the achieved results of the CTF3 automatic steering

Halo and tail simulations with applications to the CLIC drive beam

We report about generic halo and tail simulations and estimates. Previous studies weremainly focused on very high energies as relevant for the beam delivery systems of linear colliders. We have now studied, applied and extended these simulations to lower energies as relevant for the CLIC drive beam