Improved CLIC performances using the beam response for correcting alignment errors

Abstract

A new wire scanner was installed in LEP for the 1994 run. It incorporates an improved mechanical design for the wire movement and can accept three mechanisms, two for horizontal and one for vertical scans. Wires of different materials and of various diameters were fixed to new ceramic forks. Viewing ports were installed opposite each wire to allow the direct observation of the wires with a TV camera during a scan. Recordings of the wire resistance and of the light emitted by the wire were made during scans. These observations have provided the first experimental evidence of the various wire heating mechanisms by the beams. The heating due to coupling to the electromagnetic field generated by the beam exceeds the heating due to particle collisions. An evaluation is made on the behaviour of Carbon and Quartz wires. Conclusions are drawn for defining a safe operating regime.

Quadrupole Alignment and Trajectory Correction for Future Linear Colliders: SLC Tests of a Dispersion-Free Steering Algorithm

“…This algorithm was first suggested by Raubenheimer and Ruth in 1990 [5]. It h as been studied in simulations for NLC [5], TESLA [6], the S-BAND proposal [7] and CLIC [8]. The dispersion-free steering technique can be applied to the whole linac at once and returns the alignment (or trajectory) that minimizes the dispersive emittance growth of the beam.…”

CLIC-a compact and efficient high energy linear collider

“…Nominal emittances can be achieved with rms alignment tolerances of about 10µm on both accelerating structures and beam position monitors using a dispersion-free trajectory correction algorithm with three monitors between quadrupoles. Emittances below the nominal values have been obtained by applying a new correction algorithm which uses differences between trajectories for variable bunch currents and momentum [9]. The tolerance on quadrupole position jitter for a 10 % emittance dilution is estimated to be about 30 nm.…”