• E.S. Fischer, J. Macavei, A. Mierau, P. Schnizer, P.J. Spiller, St. Wilfert
  GSI, Darmstadt

The FAIR SIS100 accelerator at GSI Darmstadt will be equipped with fast ramped superconducting magnets. The high current Uranium beam modes with intermediate charge states, require ultra low vacuum pressures that can be achieved in long term operation only by cold beam pipes acting as a cryopump with stable temperatures well below 12 K for all operating cycles. The straightforward layout for reliable cooling usually conflicts with an efficient design for fast ramped superconducting accelerator magnets, strongly affected by AC loss generation, field distortion and mechanical stability problems. A full functional vacuum chamber design for SIS 100 has to take into account all these conflicting boundary conditions and trade off between mechanical stability, acceptable field distortions, AC loss minimisation and achievable temperatures. We discuss the cooling conditions for the dipoles and for the beam pipe including first test results. The analysis of the principal design aspects for the vacuum chamber with respect to the magnets operation parameters and an integral design approach are given. We present a technological feasible solution for model testing and full scale manufacturing.

• P. Schnizer, E.S. Fischer
  GSI, Darmstadt
• K. Aulenbacher, A. Jankowiak, U. Ludwig-Mertin
  IKP, Mainz
• C. Montag
  BNL, Upton, Long Island, New York

The Electron Nucleon Collider, proposed as an extension to the High Energy Storage Ring (HESR), is currently investigated and a first layout of the Interaction Region (IR) proposed. The limited size of the machine, the low beam energy and the Lorentz force vector pointing in the same direction for both beams make the IR design demanding. In this paper we present the parameters of the IR magnets, show the boundary conditions given by the beam dynamics and the experiments. We present first 2D designs for the electron and proton triplet magnets along with the separating dipole next to the collision point. Different methods to shield the beam in the spectrometer dipoles are investigated and presented.

• K. Sugita, E.S. Fischer, P. Schnizer
  GSI, Darmstadt
• P.G. Akishin
  JINR, Dubna, Moscow Region
• A. Mierau
  TEMF, TU Darmstadt, Darmstadt

Superconducting magnets are planned to be installed at the SIS100 accelerator ring for FAIR. The error compensation multipole corrector and the steerer are built as nested magnets to save longitudinal space in the ring, the chromaticity sextupole is a superferric magnet. We present the dynamic field quality of the SIS100 dipole and the vacuum chamber deterioration next to the 2D and 3D field quality of the multipole corrector and of the chromaticity corrector. The quality of the injection field of the SIS100 dipole is mainly dominated by eddy currents as soon as the field ramp starts. We show its AC losses concerning the hydraulic limits for cooling the magnet with forced two phase helium flow and conclude on the maximum chromaticity correction which is feasible for the foreseen magnet design. The results are discussed in respect of recent beam dynamic calculations on the ramp.

• P.J. Spiller, U. Blell, L.H.J. Bozyk, H. Eickhoff, E.S. Fischer, E. Floch, F. Hagenbuck, M. Kauschke, A. Krämer, J.P. Meier, C. Mühle, N. Pyka, S. Ratschow, H. Reich-Sprenger, P. Schnitzer, J. Stadlmann, St. Wilfert
  GSI, Darmstadt

The engineering design, including the specifications for the accelerator components of the FAIR synchrotron SIS100 has been summarized in the Technical Design Report. The final stage of technical planning shall approach production readiness for the major technical systems in 2010. Significant progress has been achieved in the design of the cryomagnetic system with its main dipole and quadrupole modules, enabling the production of the first pre-series dipole magnet. Slight modifications of the lattice have been implemented to equalize most of the cryostat interconnections, leading to a simplified design and installation effort, and a reduced variety of components and spar parts. The new parallel tunnel allows optimal short interconnections between the supply units and power converters and the accelerator components. The status of the engineering design of SIS100 will be reported.