AOSC Chicane Dipoles Specification 381112swk.pdf

Specifications for Rectangular Hybrid Chicane Dipoles:

Quantity 4

Minimum open Aperture (pole-to-pole); including any field-shaping bosses

1.6 cm; larger aperture is preferred provided that the same integrated strength can be achieved.

Nominal (Maximum) Integrated strength 33.2 kG*cm (49.8 kG*cm)

Approximate nominal (maximum) field strength 2.768 kG (4.152 kG)

Desired precision of nominal strength +/- 1%

Coarse-tuning range +/- 50%

Fine-tuning range +/- 5%

Approximate magnetic length 12 cm

Integrated field quality relative to dipole component (within a 6.3-mm radius aperture)

~1e-4

Nominal stray fields @ 9 cm from magnet center (on axis)

<1 G

Full vertical aperture of screens (minimum) >1.6 cm; larger aperture is preferred provided that the same stray-field strength can be achieved.

Maximum physical length (including screens) <13 cm

Maximum temperature rise for maximum excitation ~10 K

Comments on field stability and precision:

The intended application has stringent requirements on the ripple/noise of the field. Existing current-regulation systems are likely insufficient to achieve the required performance (ripple+noise ~ 1e-6). To relax the requirement on power stability, we are interested in a hybrid magnet that uses embedded permanent magnets to provide the bulk of the field to within ~1% precision of nominal and a fine-tuning coil to provide +/-5% tunability in the total field. A second coil should provide +/-50% tuning range to accommodate use at different beam energies. All tuning coils should have an appropriate number of turns such that operating currents for the maximum tuning range are in the one to few-ampere range. If the coarse-tuning range target cannot be met, vendors should contact technical personnel** at Fermilab to discuss alternatives.

Comments on geometry:

Open, C-shaped poles are strongly preferred for easier insertion and removal of vacuum chambers;

however, a closed geometry can be considered if needed for performance or fabrication reasons. Inform

Fermilab technical personnel** if a closed geometry is needed as there are additional geometric considerations to avoid collisions. Field screens should be included to clamp the stray fields at the entrance and exit of the magnet; the field-screen apertures should not be smaller than the pole-to-pole aperture (including field-shaping bosses on the poles). The magnet and field screen geometries must not interfere with the vacuum chambers in their nominal positions –drawings of the chambers and their nominal positions will be provided by Fermilab once their details have been finalized.

Comments on temperature stabilization:

Our preference is for a simplified indirect-cooling/temperature-stabilization system where water-cooled blocks are interfaced appropriately with the yoke segments. The maximum pressure drop across the magnet should be 60 PSI. The typical inlet temperature and pressure are 92F and 100 PSI, and outlet temperatures are typically software interlocked at 120 F.

Comments on surfaces:

The body of the magnet should be painted to prevent corrosion with the exception of the pole tips. The pole tips should be oiled appropriately to prevent corrosion. The pole tips should not be coated with nickel.

Comments on pinning:

Tangential pinning is preferred for the registration of any separable yoke surfaces.

Comments on field-quality measurements and performance:

The integrated field quality and performance of the magnet should be measured under nominal and maximum (i.e. +50% coarse adjustment) operating conditions and demonstrated to satisfy all specifications. The magnet under test should be thermally stabilized.

Comments on documentation:

Comprehensive documentation of the magnet design (mechanical/design, thermal, electrical, magnetic…) must be provided to Fermilab technical personnel for approval prior to the start of fabrication. Comprehensive documentation detailing measurements of the fabricated magnets must be provided (magnetic performance and field quality, electrical performance…).

Delivery: 14 weeks (or sooner) after receipt of order. If this timeline cannot be met, please specify clearly on your proposal and it will be reviewed.