1. FEL SCU development at APS/ANL
E.Gluskin for the APS/ANL LCLS SCU Team Mar. 3, 2016

2. Outline SCU developments at the APS: Motivation APS/ANL LCLS SCU Team
APS SCU technical facilities
SCU fabrication process
SCU assembly process
Characterization of SCU magnetic performance
Summary

3. Development of SCUs at the APS
Activity
Years
A proposal of the helical SCU for the LCLS
1999
Development of the APS SCU concept
R&D on SCU in collaborations with LBNL and NHFML
R&D on SCU0 in collaborations with FNAL and
UW-Madison
Design (in the collaboration with the BINP) and manufacture of SCU0
SCU0 installed into the APS storage ring
December 2012
SCU0 is in routine user operation
Since February 2013
SCU1 installed into the APS storage ring and is in user operation
April 2015
FEL/LCLS 1.5-m long prototype designed, built and successfully tested
October 2015

4. Performance comparison: SCU and Hybrid Undulator at the APS
Brightness Tuning Curves (SCUs1.6 cm vs. UA 3.3 cm vs. Revolver U2.3 cm & U2.5 cm)
Tuning curves for odd harmonics of the SCU and the “Advanced SCU” (ASCU) versus planar permanent magnet hybrid undulators for 150 mA beam current. ASCU is Nb3Sn undulator with optimized performance.
The SCU 1.6 cm surpasses the U2.5 cm by a factor of ~ 5.3 at 60 keV and ~ 10 at 100 keV.
The tuning range for the ASCU assumes a factor of two enhancement in the magnetic field compared to today’s value – 9.0 keV can be reached in the first harmonic instead of 18.6 keV.

5. Budker Institute of Nuclear Physics
1997
1996
2000
2001
2000
1979
Development and production of SC magnets at Budker INP
2005
2004
Mezentsev Nikolay
Budker Institute of Nuclear Physics
2006
2002
2002
2012
2013
2002

6. LCLS SCU APS Team Yury Ivanyushenkov – head of the team
Joel Fuerst – cryogenic design, project management
Yuko Shiroyanagi – thermal and mechanical analysis
Quentin Hasse – epoxy impregnation, vacuum
Chuck Doose – magnet measurements, system assembly
Matt Kasa – magnet windings, magnet measurements, controls
Sue Bettenhausen – magnet winding, assembly
Engineering design support: E.Trakhtenberg, D.Jensen
D.Skiadopoulos
Special tasks: I.Kesgin
General support: G.Pile, M.White

7. APS SCU facilities Magnet winding lab Magnet measurement bench
Compressors
for cryocoolers
Small vertical
cryostat

8. ANL/APS deliverables to SLAC/ANL/LBNL FEL SCU Project
Design and fabrication of the cryostat
Design and fabrication of NbTi 2.1-cm period, 1.5-m long undulator. Assembly/integration of NbTi undulator and the cryostat
Design and fabrication of beam vacuum chambers
Design and fabrication of the magnet measurement system compatible with the small aperture undulators
Assembly/integration of Nb3Sn undulator and the cryostat
Cryogenic and magnetic characterization of both undulators
at the APS SCU facility

9. SCU: assembled cryostat

10. SCU: inside the vacuum vessel
Cryocoolers
1st thermal
shield

11. SCU: under 1st thermal shield
Current leads

12. SCU: under 2nd thermal shield – cold mass
Liquid He
vessel
Thermal
links
Liquid He plumbing

13. SCU: undulator and vacuum chamber
Thermal shields

14. Undulator coils and vacuum chamber

15. SCU1 undulator magnet 1.08-m long, 1.8-cm period
Highly controlled and precise winding - key to the magnet performance

16. LCLS SCU magnet’s cores and winding

17. Epoxy impregnation
Oven inside: 1.2mx1.5mx3.7m
Mold in the oven

18. LCLS SCU in the large vertical cryostat: quench training and magnet measurements
Current, sensors leads
Linear stage for the Hall probe scan
Undulator magnet

19. LCLS SCU assembly Undulator assembly Cold mass assembly
Cold mass before loading in the cryostat
Cold mass in the cryostat on Kevlar loops

20. Magnetic measurements of the LCLS SCU
SCU warm-sensor concept
Scanning Hall probe:
Specially developed three-sensor Hall probe (attached to carbon fiber tubing and driven by linear stage) to measure By , Bx , and Bz simultaneously. On-the-fly Hall probe measurements (2 cm/s, Δz 0.2 mm, typical z range ±100 cm) to determine local field errors and phase errors.
Stretched Wire Coil:
Stretched wire rectangular, delta and ‘figure-8’ coils to determine static and dynamic 1st and 2nd field integrals. Coils can be translated along x axis approximately ±0.2 cm to measure integrated multipole components.
SCU horizontal measurement system
Magnetic measurement system showing 3.5 m linear stage with the SCU cryostat located on the far end of the stage. The system can be configured for Hall probe or stretched-wire measurements without warming the cryostat.

21. Helical SCU – next step Concept of a new cryostat
(Joel Fuerst)
Short prototype on the winding machine

22. Summary
APS developed strong expertise in the design and construction of NbTi- based planar SCUs. It has the dedicated facility for construction and characterization of SCUs.
APS SCU team acquired and developed all theoretical and technical tools needed for SCUs design and construction. Two SCUs are successfully operating at the APS.
APS SCU team for the first time designed, built and characterized SCU that meets or exceed all FEL undulator specifications.
APS team worked closely and productively with SLAC and LBL SCU team to ensure the successful completion of the project.

23. END

24. Backup Material – SCU’s operational statistics
Calendar year
APS delivered
SCU0 operating
SCU0 down
SCU1 operating
SCU1 down
2013
4872 h
4169 h
20 h
2014
4927 h
4410 h
193 h [1]
2015
4941 h
4759 h
0 h
2984 h [2]
1 h
Total
14740 h
13338 h
213 h
2984 h
Total number of SCU0 self-quenches is 5.
E-beam has never been lost due to quenches.
[1] November: Partial loss of one cryocooler capacity
[2] Installed in May; operated May – December 2015
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