• J. Resta-López, J. Dale
  JAI, Oxford
• B. Dalena, D. Schulte, J. Snuverink, F. Stulle, R. Tomás
  CERN, Geneva
• A. Latina
  Fermilab, Batavia

We present the current status of the beam tracking simulations of the Compact Linear Collider (CLIC) from the exit of the damping ring to the interaction point, including the ring to main linac (RTML) section, main linac, beam delivery system (BDS) and beam-beam interactions. This model introduces realistic alignment survey errors, dynamic imperfections and also the possibility to study collective effects in the main linac and the BDS. Special emphasis is put on low emittance transport and beam stabilization studies, applying beam based alignment methods and feedback systems. The aim is to perform realistic integrated simulations to obtain reliable luminosity predictions.

• F. Stulle, D. Schulte, J. Snuverink
  CERN, Geneva
• A. Latina
  Fermilab, Batavia
• S. Molloy
  Royal Holloway, University of London, Surrey

Over the last months the general layout of the CLIC main beam RTML has stabilized and most important lattices are existing. This allowed us to perform detailed studies of tolerances on magnetic stray fields and on magnet misalignment. Additionally, beam lines could be improved in terms of performance and flexibility. We discuss the overall layout as will be described in the CLIC conceptual design report, highlight the improvements which have been made and show results of tolerance studies.

• R. Tomás, B. Dalena, J. Pfingstner, D. Schulte, J. Snuverink
  CERN, Geneva
• J.K. Jones
  Cockcroft Institute, Warrington, Cheshire
• A. Latina
  Fermilab, Batavia
• J. Resta-López
  JAI, Oxford

The CLIC BDS tuning, alignment and feedbacks studies have been typically performed independently and only over particular sections of the BDS. An effort is being put to integrate all these procedures to realistically evaluate the luminosity performance.

• A. Saini
  University of Delhi, Delhi
• A. Latina, A. Lunin, K. Ranjan, N. Solyak, V.P. Yakovlev
  Fermilab, Batavia

It is well known that insertion of a coupler into a RF cavity breaks the rotational symmetry of the cavity, resulting in an asymmetric field. This asymmetric field results in a transverse RF Kick. This RF kick transversely offsets the bunch from the nominal axis & it depends on the longitudinal position of the particle in the bunch. Also, insertion of coupler generates short range transverse wake field which is independent from the transverse offset of the particle. These effects cause emittance dilution and it is thus important to study their behavior & possible correction mechanisms. These coupler effects, i.e. coupler's RF kick & coupler's wake field are implemented in a beam dynamics program, Lucretia. Simulations are performed for main linac & bunch compressor of International Linear Collider (ILC) like lattices. Results are compared with Placet results & a good agreement has been achieved.

• A. Latina, N. Solyak
  Fermilab, Batavia
• D. Schulte
  CERN, Geneva

Polarized positron and electron beams are ideal for searching for new physics at the Compact Linear Collider (CLIC). In order to properly orient and preserve the polarization of the beam at the interaction point, the beam polarization must be manipulated by a spin rotator along the beam line. In this paper a spin rotator design for the CLIC is presented and its integration into the CLIC ring to main linac transport system is discussed.

• A. Latina, N. Solyak
  Fermilab, Batavia

The Project Management Design Team of the International Linear Collider has recently proposed fundamental changes to the published ILC RDR baseline with the goal of presenting a potential alternate design providing a more cost-effective solution. In this framework a new lattice for the Damping Rings has been presented, shortening the exit bunch length from the RDR value of 9 mm down to 6 mm. The shorter bunch length allowed the adoption of a simpler single-stage bunch compressor, instead of the RDR two-stage compressor. The new single-stage compressor has a compression ratio of 20 and still achieves the nominal RDR value of 0.3 mm bunch length at the Interaction Point. The new design has been optimized to generate the required compression while having a small SR emittance growth, and reduced energy spread. The new lattice and its optimization procedure are presented in this paper.