What was done in RHIC Insertion dipoles?
Approach used in RHIC insertion dipoles for faster progress
(Goal: attempt to make the first magnet itself a field quality magnet):
- A flexible design (opposite to fixing parameters ASAP).
- Geometric: midplane caps, pole shims and wedge insulation.
- Saturation control: Holes in the iron, later filled with iron rods.
Moke up model showed wrong pre-stress and harmonics, as usual.
- Fixed in the first magnet assembly itself and obtain the desired pre-stress and small body harmonics.
- Used the adjustments (as planned and outlined above). The above adjustments were further used in later magnets for compensating end harmonics and for reducing measured current dependence (saturation-induced) in harmonics.
- The above adjustments are faster and cheaper than normal cross-section iterations. The coil cross-section was specified before the first magnet was tested and was never changed during production.
This shows the progress, confidence and the field getting matured.