• P. He, M. Anerella, S. Aydin, G. Ganetis, M. Harrison, A. K. Jain, B. Parker
  BNL, Upton, Long Island, New York

The conceptual design of compact superconducting magnets for the International Linear Collider final focus is presently under development at BNL. A primary concern in using superconducting quadrupoles is the potential for inducing additional vibrations from cryogenic operation. We have employed a Laser Doppler Vibrometer system to measure the vibrations at resolutions ~1 nm (at frequencies above ~8 Hz) in a spare RHIC quadrupole coldmass under cryogenic conditions. Some preliminary results of these studies were presented at the Nanobeam 2005 workshop*. These results were limited in resolution due to a rather large motion of the laser head itself. As a first step towards improving the measurement quality, an actively stabilized isolation table was used to reduce the motion of the laser holder. The improved set-up will be described, and vibration spectra measured at cryogenic temperatures, both with and without helium flow, will be presented.

*A. Jain, et al., Nanobeam 2005, Kyoto, Japan, Oct.17-21, 2005; paper WG2d-05; available at http://wwwal.kuicr.kyoto-u.ac.jp/NanoBM .

• B. Parker, M. Anerella, J. Escallier, P. He, A. K. Jain, A. Marone
  BNL, Upton, Long Island, New York
• Y. Nosochkov, A. Seryi
  SLAC, Menlo Park, California

A wide variety of superconducting magnets are needed in the ILC Beam Delivery System (BDS) to maximize luminosity and minimize experimental backgrounds. Compact final focus quadrupoles and multifunction correction coils are used with 14 mr total crossing angle to focus incoming beams to few nanometer spot sizes while focusing outgoing disrupted beams into a separate extraction beam line. Large aperture anti-solenoids correct deleterious nonlinear effects that arise due to the overlap of focusing fields with the main detector solenoid. Far from the interaction point (IP) sets of strong small aperture octupoles help minimize backgrounds at the IP due to beam halo particles while weak large aperture dipoles integrated with the experimental detector reduce backgrounds due to beamstrahlung pairs generated at the IP. The physics requirements and magnetic design solutions for these magnets are reviewed in this paper.