1. Orbit Correctors in D2 and Q4 Design options
J. Rysti and E. Todesco
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2. Requirements Integrated field 4.5 Tm.
Multipoles below 10 units at all operational fields and configurations.
First-guess layout (baseline):
3 T field, two units 1.5 m long, one H and one V.
105 mm diameter apertures
Cross-talk problem
Not enough iron between apertures
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3. How to fix the problem?
Here we have tried to see how to optimize the field quality with the given constraints in a twin aperture configuration.
This is not a detailed design proposal.
Reduce aperture diam. 105 mm -> 100 mm.
H/V configuration
For H/H: B3 > 120 units at 2.7 T and for H/V: ~10 units).
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4. Various designs studied
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5. Best found design
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6. H/H vs. H/V
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7. Best found design
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8. Multipoles in aperture 1 (left)
All other multipoles are below 1 at all fields
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9. Multipoles in aperture 2 (right)
All other multipoles are below 1 at all fields
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10. The other magnet turned off
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11. Low field, changing other magnet
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12. How to implement this design
Collars from soft iron or thin steel collars?
Iron strong enough, but pre-stress lost in cooling.
Thin steel collar (6 mm) not strong enough and difficult to make.
No collars, compress entire yoke?
Challenging & cannot test magnets individually.
Increase collar thickness:
At 6 mm: max field 2.73 T
At 10 mm: max field 2.65 T
At 15 mm: max field 2.56 T
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13. 15 mm collars
6 mm ”collars”
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14. 6 mm vs. 15 mm collar/spacer
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15. Laminated iron/steel collars?
Make the ”floating collars” from iron.
Using stacking factor 0.5 in ROXIE iron file.
Preliminary results not very good (B3 > 100).
Fessia & Perini, IEEE Trans. Appl. Supercond. 12, 202 (2002).
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16. Other options Nested H & V dipoles in a single aperture.
Staggered magnets (double required length).
Exotic possibilities: NbTi sheets between apertures to shield fields?
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17. Conclusions Requirements fulfilled up to 2.7 T.
15 cm per magnet more length copared to baseline (1.5 m).
Mechanically difficult.
With realistic collars (15 mm) max field down to around T.
25-30 cm per magnet more length compared to baseline (1.5 m).
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19. Remarks
If aperture 1 goes from 3 T to 0 T, aperture 2 changes 0.02 T (0.8 %).
If aperture 2 goes from 3 T to 0 T, aperture 1 changes 0.03 T (1 %).
In aperture 1, ~15 units of A2 at 3 T.
In aperture 2, >20 units of A3 & B3 at 3 T.
Some constant multipoles around or above 10 units (B7/A7 ~11 units, B5/A5 ~8 units). These may be possible to correct with further optimization of the configuration.
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20. Extra slides