• R. Versteegen, O. Delferrière, O. Napoly, J. Payet, D. Uriot
  CEA, Gif-sur-Yvette

The International Linear Collider reference design is based on a collision scheme with a 14 mrad crossing angle. Consequently, the detector solenoid and the machine axis do not coincide. It provokes a position offset of the beam at the Interaction Point in addition to a beam size growth. These effects are modified by the insertion of the anti-DID (Detector Integrated Dipole) aiming at reducing background in the detector. Furthermore a crab cavity is necessary to restore a 'head on' like collision, leading to higher luminosity. This introduces new beam distortions. In this paper, optics studies and simulations of beam transport in the Interaction Region taking these elements into account are presented. Correction schemes of the beam offset and beam size growth are exposed and their associated tolerances are evaluated.

• R.D. Duperrier, D. Uriot
  CEA, Gif-sur-Yvette

A main interest in the high intensity ion linacs is the control of the particle loss in the vacuum chamber. A extremely low fraction of the beam (10^-4 or 10^-7) is sufficient to complicate the hands on maintenance in such accelerator. Beam mismatching being a major source of halo, it is proposed a non invasive technique to adapt the beam to a periodic focusing channel of a linac based on a FDO of FODO lattice. It is demonstrated that only the matched beam can correspond to a particular signature of the quadrupolar moment of the Beam Positions Monitors. This technique allows also to measure the emittance value or evolution along the channel.

• D. Boutin, M. Authier, F. Dechery, O. Delferrière, A. Drouart, J. Payet, D. Uriot
  CEA, Gif-sur-Yvette
• M. Amthor, H. Savajols, M.-H. Stodel
  GANIL, Caen
• S.L. Manikonda, J.A. Nolen
  ANL, Argonne

S3 (Super Separator Spectrometer) [1] is a future device designed for experiments with the high intensity heavy ion stable beams of SPIRAL2 [2] at GANIL (Caen, France). It will include a target resistant to these very high intensities, a first stage momentum achromat for primary beam extraction and suppression, a second stage mass spectrometer and a dedicated detection system. This spectrometer includes large aperture quadrupole triplets with embedded multipolar corrections. To enable the primary beam extraction one triplet has to be opened on one side, which requires an appropriate design of such a multipolar magnet. The final mass separation power required for S3 needs a careful design of the optics with a high level of aberration correction. Multiple symmetric lattices were studied for this purpose. A 4-fold symmetric lattice and the achieved results are described in this paper.

[1] A. Drouart et al., Nucl. Phys. A 834 (2010) 747c. [2] SPIRAL2, http://pro.ganil-spiral2.eu/spiral2