1. Magnets for the ESRF upgrade phase II
G. Le Bec, J. Chavanne
on behalf of the ESRF upgrade project team
European Synchrotron Light Source XXII, Grenoble November 2014

2. Overview Context Where are we? Summary and conclusion
The ESRF phase II magnets
Design and prototyping challenges
Where are we?
Dipoles
Combined dipole-quadrupoles
Quadrupoles
Sextupoles, octupoles
Summary and conclusion
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

3. Context
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

4. The ESRF phase II magnets
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

5. The ESRF phase II magnets
Reduced gradient
100 T/m 85 T/m
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

6. The ESRF phase II magnets
Reduced field and gradient
0.85 T  0.54 T
49 T/m  34 T/m
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

7. The ESRF phase II magnets
Challenges
High gradients
Combined magnets
Small bore radius
Tight tolerances
No space longitudinally
More than 1000 magnets
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

8. Design constraints Field quality
Integration and mechanical constraints
Magnet length
Vacuum chambers
Vibrations
Supports
Alignment
Tunability
Power consumption
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

9. Field quality and tunability
Magnet type
GFR radius
[mm]
Field quality
(systematic)
Tuning range [%] DL 13
DB/B < 10-3 DQ 7
DG/G < 10-2
Gradient: +/- 2
Q – 50 T/m
DB/B <
55 – 110
Q – 85 T/m
DB/B <
95 – 105 S
DH/H < 0.1
20 – 130 O
0 – 145
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

10. High gradient  Small bore radius  Tight tolerances
Small bore magnets
Assembly errors
Errors at the GFR boundary
Mechanical error
Multipolar error
at the bore radius
Bore radius
(GFR radius = r)
r =R/4
r0=R
r0=R/2
Quadrupolar e2
4e2
Sextupolar e3
8e3
Octupolar e4
16e4
High gradient  Small bore radius  Tight tolerances
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

11. Status
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

12. Dipole with longitudinal gradient
Field ranging from 0.17 T up to 0.55 T or 0.67 T
Total length: 1.85 m
Gap: 25 mm
Magnet mass: 400 kg
PM Mass: 25 kg/Sm2Co17 and 25 kg Strontium ferrite per dipole
(Design and measurements of the DL magnet: J. Chavanne)
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

13. Dipole with longitudinal gradient
Aluminium spacers
Iron pole and yoke
PM blocks
DL module
Number of PM blocks is module dependent.
Temperature compensation is not shown here.
Complete DL magnet on its support
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

14. Dipole with longitudinal gradient
Homogeneity of central field
Quality dominated by pole faces parallelism
May need refinement of mechanical tolerances
Easy and fast mechanical correction (shimming)
Tolerance: DB/B < mm
Module 2 without shim (Hall probe meas.)
Module 1 without shim (Hall probe meas.)
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

15. Dipole with longitudinal gradient
Integrated field
Preliminary study on straight integrals
Stretched wire method
Two modules with 0.62 T and 0.41 T
Longitudinal gap 5 mm between poles
End effect (sextupole) shims not installed
Will improve with additional modules
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

16. Dipole with longitudinal gradient
Longitudinal field
Flat top field at longitudinal gap gs = 5 mm
The optimum gs may change between the modules of the full magnet (field step dependence) gs
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

17. Dipole – quadrupoles (DQ)Bz Bz x x
Tapered dipole
High field
Low gradient
Offseted quadrupole
High field
High gradient
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

18. Dipole – quadrupoles (DQ)Bz x
DQ specifications
GFR radius 7 mm
Field 0.54 T
Gradient 34 T/m
Offseted quadrupole
High field
High gradient
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

19. Dipole – quadrupoles (DQ)
Field of an offset quadrupole
GFR Bz x
Additional power consumption, weight, etc.
Region of interest
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

20. Dipole – quadrupoles A new target for DQ field Pro Cons
Lower power consumption and weight
Easy access on one side (vacuum chamber, magnetic measurements)
Cons
Design is more complex
GFR Bz x
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

21. Dipole – quadrupoles (DQ)
Single sided dipole – quadrupole
2 poles + 2 “half” poles
0.54 T field, 34 T/m gradient
Iron length: 1.1 m
Magnet mass ~ 1 ton
Power consumption: 1.5 kW
Main coil
Main pole
Auxiliary pole
Auxiliary coil
(in series with main coil)
Trimming coil
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

22. Dipole – quadrupoles (DQ)
Magnetic design
GFR
Vertical field vs. position.
Field is almost zero on one side.
DG/G expressed in Specification: DG/G < 10-2.
GFR: 7x5 mm
Field integration along an arc.
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

23. Quadrupoles Two quadrupole families Moderate gradient 51 T/m
Bore radius: 15.5 mm
Iron length ranging from 160 up to 300 mm
Working point: 50 – 110 % of nominal gradient
Power: 1 kW for the largest quadrupole
High gradient 85 T/m
Bore radius: 12.5 mm
Iron length ranging from 390 up to 480 mm
Working point: 95 – 105 % of nominal gradient
Power: 1.6 kW for the largest quadrupole
Moderate gradient
High gradient
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

24. Quadrupoles Design criteria Field quality Overall dimensions
Fast pole shaping algorithm developed
Overall dimensions
Power consumption
Cooling and PS constraints
Sensitivity to background field
Decreased magnet’s power consumption
Decreased current density
Increased magnet’s transverse dimensions
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

25. Quadrupoles WPOLE & WYOKE constant WCOIL constant (magnet length)
RCOIL
WPOLE & WYOKE constant
WCOIL constant (magnet length)
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

26. Excitation curve of quadrupoles
Excitation curve and saturation
Moderate gradient quads optimized at a linear working point
High gradient quads optimized at a saturated working point T T
(a)
(b)
Magnetization m0M [T] of the moderate gradient (a) and high gradient (b) quadrupoles at nominal current.
Excitation curve of quadrupoles
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

27. Quadrupoles Magnet design properties Prototyping
DG/G = within the GFR
Iron length 480 mm 540 mm total length
Magnet mass ~ 1 ton
90 A, 69 turns, 1.7 kW
Prototyping
Prototype being manufactured
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

28. Other magnets Sextupole Octupoles 900…1600 T/m2 nominal strength
Magnetic design stabilised
Engineering design almost completed
Opening/closure repeatability
Octupoles
Nominal strength 52 T/m3
Maximum strength 65 T/m3
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

29. Other magnets Sextupole Octupoles 900…1600 T/m2 nominal strength
Magnetic design stabilised
Engineering design almost completed
Opening/closure repeatability
Octupoles
Nominal strength 52 T/m3
Maximum strength 65 T/m3
Prototype built
Measured int. strength: 4504 T/m2 @ 6.2A (shorter, air-cooled coils)
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014

30. Conclusion Magnet design Prototyping DL, DQ and quads are challenging
Magnetic design stabilized for all the magnets
Engineering design well advanced
Prototyping
DL prototype measurements in progress
Manufacturing of 85 T/m quadrupole prototype in progress
Octupole prototype delivered
G. Le Bec et al. -- ESLS XXII, Grenoble, November 2014