1. Magnet developments for the ESRF-EBS
LER 2016, SOLEIL, October 26-28, 2016
C. Benabderrahmane, J.C. Biasci ,F. Bouteille, J.Chavanne, D. Einfeld, L. Eybert, D. Gibson, G. Le Bec, S. Liuzzo, P. Raimondi, F. Villar
On behalf of the Accelerator Project Phase II Team
OUTLINE
1- Magnet design & magnetic measurements strategy
2- Resistive magnets
3-Permanent magnet dipoles
4- New sources for Bending Magnet Beamlines
5- Summary

2. ESRF-EBS Storage ring magnets
Important design effort, new types of magnets
Compact magnet lattice
4 supporting girders/cell
Combined dipole/quadrupole magnets
New sources for BM beamlines
Octupole
High gradient sextupoles
ID straight 5m
ID straight 5m
Permanent magnet dipoles
with longitudinal gradient (DLs)
Moderate gradient quadrupoles
High gradient quadrupoles
LER 2016, Soleil | J.Chavanne

3. MAGNET DESIGN: Boundary conditions
Magnet pole
Vacuum Chamber
Vertical
pole gap
coil
Magnet apertures are significantly reduced (3GLS-> DLSR)
50-80 mm  ~ 25 mm
Higher field gradient
Quadrupoles: 20 T/m  T/m
Sextupoles : 600T/m2  T/m2
Compromise with vacuum chamber technology & beam stay clear
Vertical pole gap ( photon beam path)
Space for coils
TRANSVERSE SPACE:MAGNET APERTURES
LONGITUDINAL SPACE ! ?
Compact magnet lattice
Present ESRF dipoles: 64+1 units, 0.85 T
Procurement: 2.3 MEuros
Running cost: 6.8 MEuros over 25 Years
(costs updated to present)
RUNNING COST !
Reduce wall plug power
LER 2016, Soleil | J.Chavanne

4. Magnet design philosophy
space limitation
Wall plug power
Performance …. etc
Permanent magnets
Resistive magnets
Copper cross section adapted for reasonable current density
~ 3 A/ mm2 @ nominal working point
Can only be adapted radially
~ similar or larger transverse size compared to magnets in 3GLS
Primarily for fixed field magnets
Dipoles
Affordable technology and cost
Wall plug power=0
LER 2016, Soleil | J.Chavanne

5. Good field regions in magnets (GFR)
Center low beta
Smaller transverse beam size
Outer , higher Beta
GFR
Two (elliptical) GFRs defined:
Outer HxV [mm2]
Center HxV [mm2]
GRF radius (HxV)
13x9
7x5
LER 2016, Soleil | J.Chavanne

6. Magnetic measurements strategy
The majority of magnets measured with benches provided by ESRF
Stretched wire, several developments
Different types of measurements (linear, circular … etc)
Easy adaptation of measuring radius
< 1 “unit” (10-4 of main multipole) accuracy
5 benches under delivery to magnet manufacturers
3 benches for ESRF internal needs
Translation stages
Wire support
Granite support
High gradient quadrupole prototype under measurement
LER 2016, Soleil | J.Chavanne

7. Stretched wire magnetic measurement bench
Calibration system
Easy to install and to transport
Fast calibration
Based on 3 interferometers
Measurements of scale errors
Measurement of stage angles
Implementation of correction tables
Position errors ~0.001 mm after calibration
Interferometers
Retro-reflectors
LER 2016, Soleil | J.Chavanne

8. Magnetic design tools All magnetic design made using RADIA *:
3D simulations
Electrons tracking in magnets for DLs and DQs
Combined function
Dipole/Quadrupole (DQ)
P.M DL
MG quadrupole
HG quadrupole
Sextupole
Octupole *:
LER 2016, Soleil | J.Chavanne

9. QUADRUPOLES High Gradient (HG) Moderate gradients (MG) Parameter Value
Unit
Nominal strength
Up to 54
T/m
Mech. length mm
Bore radius
16.4
Nominal current A
Power
0.7 – 1.1 kW
# pre-series 8
# of series
384
GFR (HxV)
13x9
∆G/G in GFR
<10-3
Parameter
Value
Unit
Nominal strength
T/m
Mech. length mm
Bore radius
12.7
Nominal current A
Power
1.9 – 1.7 kW
# pre-series
2 - 2
# of series
GFR (H x V)
7x5
∆G/G in GFR
<10-3
G L [T]
87 T/m
(L=493 mm)
I [A]
LER 2016, Soleil | J.Chavanne

10. Sextupoles & Octupoles
Solid iron yoke
Sextupole Magnets
Parameter
Value
Unit
Nominal strength
1700
T/m2
Mechanical length mm
Bore radius
19.2
Nominal current 62 A
Power consumption
0.5 kW
# of pre-series
2 - 2
#of series
GFR
13x9
∆H/H
10 %
Octupole Magnets
Parameter
Value
Unit
Nominal strength
36900
T/m3
Mechanical length 90 mm
Bore radius
18.6
Nominal current 54 A
Power consumption
0.1 kW
# of pre-series
1 - 1
# of series
GFR (HxV)
13x9
∆O/O
10%
Corrector coil
Main coil
Solid iron yoke
LER 2016, Soleil | J.Chavanne

11. Combined functions dipole-quadrupole (DQ)
Parameter
Value
Unit
Nominal dipole
0.55 – 0.39 T
Nominal strength
T/m
Mechanical length mm
Nominal current A
Power consumption
1.6 – 1.2 kW
Number of pre-series
2 - 2
Number of series
GFR (HxV)
7x5
∆G/G in GFR
<
Main Coil
Solid Iron Yoke
Correction coil
Auxiliary coil
Independent tuning of B and G
±2.5 % at fixed B and ±2 A in correction coils
LER 2016, Soleil | J.Chavanne

12. preliminary magnetic measurement results (sextupole)
Sextupole iron length: 200 mm
Sextupole at magnetic measurements (Danfysik)
Excellent agreement between simulation & magnetic measurements
< 1 %
B’’ [T/m2]= 65 A, 100 A)
3D Radia model
Field quality to be checked in details
LER 2016, Soleil | J.Chavanne

13. preliminary magnetic measurement results (HG quadrupoles)
Iron length 388mm
88.8 T/m
LER 2016, Soleil | J.Chavanne

14. Magnet construction & magnetic measurements: next steps
Complete pre-series acceptance
October-December 2016
Mechanical and magnetic measurements
Electrical and hydraulic tests
Delivery of magnet to ESRF for final validation
Detailed magnetic ESRF
Magnet serial production
Several batches to be delivered / magnet type
Mechanical and magnetic measurements
Hydraulic and electrical tests
QA documents
Few magnets ESRF
April 2016 ~ December 2018
LER 2016, Soleil | J.Chavanne

15. Dipoles with longitudinal gradient (DL)
In-House development
DL1
DL2
DL2
DL1
Permanent magnet structure
5 modules /dipole
Sm2C017 permanent magnet material
Br=1.1 T
High coercivity > 2100 KA/m
High resistance to radiation damages
Low temperature coefficients
Low carbon steel yoke
Pure iron pole
Sm2Co17
blocks
pole
yoke
LER 2016, Soleil | J.Chavanne

16. DLs Parameter Value Unit Field 0.64 to 0.17 (DL1) 0.53 t0 0.17 (DL2) T
Mech. length
1784 mm
Gap
25.5
Power kW
Mass
500 (100/module) kg
# pre-series 2
# of series
64+64
GFR (HxV)
13x9
∆B/B in GFR
<10-3
244 mm
183 mm
LER 2016, Soleil | J.Chavanne

17. DL Magnetic design 3D models Individual module Complete assembly
Modules positioned on trajectory
3D tracking
Longitudinal magnetic crosstalk between modules
Passive thermal compensation ( Fe-Ni shims)
Magnetic interaction with neighboring quadrupoles
LER 2016, Soleil | J.Chavanne

18. PM DLs: temperature stability
Material
dB/dT
Sm2Co17
Nd2Fe14B
10-3
Dominated by PM material temperature coefficient
Can be compensated by passive FeNi shunts
The FeNi shunts are ~ saturated
The magnetization in Fe-Ni has large temperature dependence
Pole
Yoke
PM block
Special FeNi shunt
(low Curie temperature)
Passive thermal compensation of PM material
DB/DT after compensation:< 40 ppm/C for DLs
Field integral measurements on PM DL modules
NdFeB PM, Sm2C017 PM
LER 2016, Soleil | J.Chavanne

19. Strategy & Status with DLs
~ Sm2C017 magnet blocks ( ~ 6 tons) manufactured , 2 batches
One manufacturer
Delivery October 2016 & November 2016
Iron material , machining & delivery of assembled empty modules
660 units, two manufacturers
Integration of PM in modules and magnetic ESRF
Batches of DL supports under delivery
Temporary assembly & magnetic measurement area ( ESRF Chartreuse Hall)
DL support
LER 2016, Soleil | J.Chavanne

20. DL iron material: control of steel quality
Raw hot rolled material ( low carbon steel)
Flame cutting + heat treatment
Delivery to sub-contractors for machining
Surface treatment
Assembly without PM
Painting
Semi finished product (iron blocks)
LER 2016, Soleil | J.Chavanne

21. DL magnetic measurements
Magnetic measurement of each module
Stretched wire
Field tuning (Iron shunt)
Assembly of modules on supports
Magnetic measurements of each DL
Hall probe mapping on prototype
Stretched wire (field integral) only for series
Field tuning (end iron shunt, ±0.25 %)
October October 2017, 130 DLs
Prototype measurements on modules: excellent agreement with 3D simulations
LER 2016, Soleil | J.Chavanne

22. DL Magnetic measurements (cont’d)
DL prototype #1
Measured field
Transverse field homogeneity
Stretched wire measurements
LER 2016, Soleil | J.Chavanne

23. Magnet technology: remarks
Resistive magnet close to limit (quadrupoles)
Complicated vacuum chamber technology with small magnet aperture
History of gap reduction in Insertion-Devices
In-air
In- vacuum
Vacuum chamber
magnet
Cryogenic cooling (LN2)
PrFeB magnets
~90 T/m
Vacuum Chamber
Magnet
T/m
Cryogenic cooling (LN2)
PrFeB Magnets
In-air
In- vacuum
LER 2016, Soleil | J.Chavanne

24. Bending magnet sources : ESRF Context
ESRF today has DBA 6 GeV lattice
BM beamlines use X-ray from
0.856 T dipole Ec=20.5 kev, 6 mrad max
0.4 T soft end Ec=9.5 keV, 6 mrad max
Very productive Beamlines
ESRF II will be 7BA 6 GeV lattice
Available BM field for Beamlines:
0.39 T dipoles Ec=9.3 kev , 2 mrad max
0.57 T soft end Ec=13.6 keV, 2 mrad max
I=0.2 A
BM sources are combined function dipole/quadrupoles
LER 2016, Soleil | J.Chavanne

25. Proposed alternative sources
Permanent magnet structures:
White beam at Beamline (~ 25 m)
All insertions have
0.86 TPeak field
3 different options available for each beamlines
Insertion of a Short Bending Magnet (SBM)
2 mrad X-ray fan
Insertion of a 2 Pole Wiggler (2PW)
1.7 mrad x-ray fan
2 possible configurations
Insertion of 3 Pole Wiggler (3PW)
1.6 mrad fan
Phot./s/0.1%/mrad2/mm2
Number of devices /type presently identified
6 SBMs, 6 2PWs, 2 3PWs +….
Procurement to be started in September 2016
Photon Energy [keV]
LER 2016, Soleil | J.Chavanne

26. Short wiggler development: higher field(BM18)
3PW
DQ2C
DQ1D
Compact high field 3PW
Improvement of photon flux above 50 keV
Flux in 2 mrad x0.5 mrad (HxV)
Must be limited to few units
(emittance growth)
LER 2016, Soleil | J.Chavanne

27. Short wigglers & SMB integration
SBM insertion
LER 2016, Soleil | J.Chavanne

28. ESRF-EBS magnets under construction in 2016-2018
Summary
ESRF-EBS magnets under construction in
Up to know consistent with expectation
Several pre-series acceptances in October- December 2016
First magnetic measurement results very positive
Magnet batches deliveries expected from April 2017 until December 2018
Construction of Permanent Magnet Dipoles
Segmented DL concept
130 Dipoles assembled in-house from October 2016 to October 2017
New more performing sources for bending magnet beamlines
Different possible sources
LER 2016, Soleil | J.Chavanne

29. THANK YOU
LER 2016, Soleil | J.Chavanne