Magnets Design

The lower energy arcs (1, 2, 3) are composed of four 45.6 cm long curved 45° bends, while the higher arcs (4, 5, 6) use ‘double length’, 91.2 cm long, curved bends. The usage of curved bends is dictated by a large bending angle (45°) and strong edge focusing effects if rectangular magnets were used. They also eliminate the problem of magnet sagitta, which would be especially significant for longer, 91.2 cm, bends. Each arc contains: 4 dipoles, powered in series within that arc

A cost effective arc bend design is based on the following requirements:

  • Iron-dominated resistive magnets preferred for improved tunability
  • Engineering current density of 7-8 A/mm2
  • H-design to reduce the magnet height for stacking
  • Homogeneous field as low as possible due to the use of one power supply by arc
  • Cost minimization with a design of the arc magnets coupled to studies of the power converters, the vacuum system and cooling as well as only one magnet per bend with a 45° deflection.

The magnet specs are collected in Table1.

There are are total of 114 15 cm long quadrupoles, which are powered individually. The quadrupole specs are collected in Table2.

Each spreader starts with a vertical bending magnet, common for all three beams, which initiates the separation. Again, the lowest energy spreader is configured with three curved bends following the common magnet, because of a large bending angle (45°). The higher Spreaders/Recombiners are configured with conventional rectangular magnets. There are total of 46 shorter (20, 30 and 40 cm) vertical bends, which are powered individually.








Figure 1

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