Schulte, D.

Paper	Title	Page
MOP43	The Impact of Longitudinal Drive Beam Jitter on the CLIC Luminosity	138
	D. Schulte, E. J. N. Wilson, F. Zimmermann CERN, Geneva
	In the compact linear collider (CLIC) now under study at CERN, the RF power which accelerates the main beam is provided by decelerating a high current drive beam. Errors in the timing and intensity of the drive beam can turn into RF phase and amplitude errors that are coherent along the whole main linac and the resulting error of the final beam energy, in combination with the limited bandwidth of the beam delivery system, can lead to a significant loss of luminosity. We discuss the stability tolerances that must be applied to the drive beam to avoid this loss. We also examine one of the most important sources of this jitter, which stems from the combination of RF jitter in the drive beam accelerator and subsequent bunch compression. Finally we give details of a potential feedback system that can reduce the drive beam jitter.
MOP44	Electron-Cloud Effects in the Positron Linacs of Future Linear Colliders	141
	D. Schulte, A. Grudiev, F. Zimmermann CERN, Geneva K. Oide KEK, Ibaraki
	Inside the rf structures of positron linacs for future linear colliders, electron multipacting may occur under the combined influence of the beam field and the electromagnetic rf wave. The multipacting could lead to an electron-cloud build up along the bunch train. We present simulation results of this effect for various proposed designs, and discuss possible consequences and eventual countermeasures.
	Transparencies
MOP45	A Potential Signal for Luminosity Optimisation in CLIC	144
	D. Schulte CERN, Geneva
	Luminosity optimisation will be challenging in the compact linear collider (CLIC) studied at CERN. In particular, the signals which can be used for luminosity optimisation need to be identified. The strong beam-beam interaction in CLIC will give rise to the emission of a few megawatts of beamstrahlung; this is a potential candidate for such a signal. In this paper luminosity optimisation using the beamstrahlung is attempted for realistically shaped bunches.
TUP88	CLIC Magnet Stabilization Studies	483
	S. Redaelli, R.W. Assmann, W. Coosemans, G. Guignard, D. Schulte, I. Wilson, F. Zimmermann CERN, Geneva
	One of the main challenges for future linear colliders is producing and colliding high energy e+e- beams with transverse spot sizes at the collision point in the nanometre range. Preserving small emittances along several kilometres of linac requires the lattice quadrupoles to be stable to the nanometre level. Even tighter requirements are imposed on the stability of the final focus quadrupoles, which have to be stable to a fraction of the colliding beam size to reliably steer the opposing beams in collision. The Compact LInear Collider (CLIC), presently under investigation at CERN, aims at colliding e+e- beams with a vertical spot size of 0.7 nm, at a centre-of-mass energy of 3 TeV. This requires a vertical stability to the 1.3 nm level for the 2600 linac quadrupoles and to the 0.2 nm level for the two final focus quadrupoles. The CLIC Stability Study has demonstrated for the first time that CLIC prototype quadrupoles can be stabilized to the 0.5 nm level in a normal working area on the CERN site. Detailed tracking simulations show that with this level of stability, approximately 70% of the CLIC design luminosity would be achieved. This paper summarizes the work and the achievements of the CLIC Stability Study.
	Transparencies