1. SCU R&D Motivation
P. Emma …for the SCU R&D collaboration: ANL, LBNL, SLAC Close-Out Review Mar. 3, 2016

2. Outline of Presentations
Welcome (N. Holtkamp, 5 min)
SCU R&D Motivation (P. Emma, 10 min)
SCU Development at ANL (E. Gluskin, 20 min)
Technical Summary - ANL (Joel/Yury , 40 min)
SCU Development at LBNL (S. Prestemon , 20 min)
Technical Summary - LBNL (D. Arbelaez , 40 min)
Next Steps - SCU R&D (P. Emma , 15 min)
Adjourn at 11:30+

3. Superconducting Undulator Motivation
Advantages of an SCU:
Higher magnetic fields allow superior FEL performance.
No permanent-magnetic material to be damaged by radiation  longer life & smaller gaps.
Lower vacuum pressure  limits gas scattering.
Smaller footprint & simpler K-control than
typical, massive adjustable-gap PMU.
Easily oriented for vertical polarization*.
Untapped FEL performance advantage…
…but SCU’s need practical
development…
* Vertical polarization allows efficient x-ray transport in horizontal deflections

4. SCU Advantage SCU Can Extend LCLS-II HXR Spectral Range Nb3Sn (18 mm)
e- energy
4.0
GeV
Min. x-ray energy
1.5
keV
Emittance
0.4 mm
Energy spread
0.5
MeV
Peak current 1 kA
Mean beta 16 m
Bunch charge
0.1 nC
Max. und. length
145
Beam rate
300
kHz
Full magnetic gap
7.3
Safety factor 20 %
NbTi
(20 mm)
PMU
(26 mm)
baseline

5. “TW-FEL” with SCU & Cu-Linac (LCLS-II)
Step-wise tapered undulators (20%)
1.6 TW (4 keV) 
Self-seeding monochromator
4 GeV (1 MHz)
3-15 GeV (120 Hz)
1.5-m segment length allows fine taper  maximize peak power
Und. tech.
Nb3Sn -
Vac. full gap 4 mm
Photon energy
keV
e- Energy
6.6
GeV
Emittance
0.4
Peak current kA
C. Emma, C. Pellegrini, Z. Huang

6. Multiple FELs in a Single Cryostat ?
4 parallel helical
undulators
4 FEL’s
Joel Fuerst (ANL)

7. SCU R&D Plan ANL… LBNL… Both Labs…
Started in Feb. 2014
ANL…
Build 2-m test cryostat (existing design)
Build & test 1.5-m long NbTi prototype und. (lu  21 mm)
LBNL…
Build & test 1.5-m long Nb3Sn prototype und. (lu  19 mm)
Develop measurement & tuning schemes (test-cryostat)
Both Labs…
Develop field measurement and correction techniques
Demonstrate predicted field, field quality, end corrections, and cold-mass integration into cryostat
Goal: Deliver 2 fully functional, 1.5-m long, SCU prototypes meeting LCLS-II HXU spec’s (by July 2015)

8. 2 Prototype 1.5-m Superconducting Undulators
ANL - NbTi
LBNL – Nb3Sn
Identical stainless-steel support frames allow swapping magnets into cryostat

9. Status Thanks to the 3-Lab SCU team:
July ‘15 finish-date not achieved – ANL: Oct. ‘15, LBNL: Mar. ’16.
NbTi (ANL) magnet achieves all specs (no “shimming” needed).
Nb3Sn (LBNL) magnet still under study – limit at 535 A (of 800 A) - more results soon (March 2016).
Precision machining and winding are the keys 
LBNL stretched-wire system being further developed
HTS-tape “shimming” being developed
BES-funded R&D at ANL on helical undulators – very promising
Next steps are costly or incremental – need to develop full FEL cryomodule prototype, not just magnets
4 mm
HTS-tape
P. Emma, N. Holtkamp, H.-D. Nuhn, M. Rowen, SLAC; S. Bettenhausen, C. Doose, J. Fuerst, J. Gagliano, Q. Hasse, Y. Ivanyushenkov, W. Jansma, D. Jensen, M. Kasa, I. Kesgin, E. McCarthy, M. Merritt, G. Pile, Y. Shiroyanagi, D. Skiadopoulas, J. TerHaar, E. Trakhtenberg, M. White, E. Gluskin, ANL; D. Arbelaez, M. Barry, J. Corlett, D. Dietderich, H. Higley, T. Johnson, M. Leitner, T. Lipton, S. Myers, R. Oort, A. Pekedis, R. Schlueter, J. Swanson, M. Turqueti, X. Wang, K. Wislon, S. Prestemon, LBNL.
Thanks to the 3-Lab SCU team:

10. End of Part-I
End Part-I

11. Next Steps for SCU R&D What are the next steps for SCU development?
Prototype of full FEL-cryomodule is costly (14M$, 3 yrs)
Might develop just components or alignment…
Cold phase shifters 
Cold quad
Cold BPM
Alignment strategy
More magnet R&D is useful (helical, short-period, gradient-integrated), but addresses only part of the need
SCU’s will not be a realistic choice for FELs until a full SCU cryo-module prototype is built and tested
Cold Phase Shifter

12. SCU Cryo-Module Concept
alignment
quad
undulator
segments (3)
phase
shifters (3)
focusing
quad
BPM
1.5 m
beam
direction
15 cm
15 cm
70 cm
x & y position
control
x & y position
control
5.5 m
Three 1.5-m long undulator segments in one 5.5-m cryostat
Short segments (1.5 m) easier to fabricate, measure, tune, and taper
Each segment independently powered to allow optimized TW-taper
Ancillary components needed (cold-BPM, cold-phase shifters, cold-quads)
Cryogenics system design
Magnet alignment critical (300 K  4 K) – needs plan/demo
Beam-based alignment as final correction using motorized pads
Need to build and test one 5.5-m FEL-cryomodule (as FEL building block)

13. SCU System Concept Joel Fuerst, ANL 0.7-m cold breaks
2-m long segments (+quad+BPM+PS)
lu = 20 mm, Vacuum gap = 5 mm
5-m cryostats
500-W cryo-plant at 4 K
Joel Fuerst, ANL

14. Selective R&D as Low-Cost Initiatives
Low-cost items (to kick-start the effort) include:
Cold Phase Shifter (3/CM) – 200k$
Cold Quadrupole Magnet (2/CM) – 240k$
Cold Cavity BPM (1/CM) – not costed
Alignment Development (using existing cryostat) – 510k$
Develop Conceptual Design for FEL-cryomodule – 700k$
SLAC might provide “M&S” and ANL/LBNL might provide “effort” *.
However, this is incremental R&D – SCU’s will not be “shovel-ready” until SCU cryo-module is built and tested.
* Cost estimates available for most items.

15. SCU Road Map 2014 2015 2016 2017 2018 2019 2020 Finish planar SCU R&D
Dev. Components
Alignment Dev.
Conc. Design
Build Prototype FEL-CryoModule
Proto. Helical SCU (ANL)
Grad SCU (SLAC, ANL)
Mar. 3, 2016

16. Finish Thanks to the fantastic teams at ANL and LBNL, especially:
Efim Gluskin, Joel Fuerst, Yury Ivanyushenkov (ANL)
Soren Prestemon, Diego Arbelaez (LBNL)
…and thanks to Norbert & BES for the support

17. Finish

18. SCU’s Provide Much Higher Fields than PMUs
SCU  much higher field for given period and gap
Nb3Sn
LCLS-II SCU
NbTi
In-Vac. PMU
PMU
LCLS-II PMU:
lu = 26 mm
Bpk = 1.0 T
gm = 7.3 mm
5-mm vac. gap for all (7.3-mm mag. gap)
In-Vac  same vac. gap (5.3-mm mag. gap)

19. Budget ( )
SLAC  ANL: k$
SLAC  LBNL: 626 k$

20. Selective R&D as Low-Cost Initiatives
Possible Next Steps
M&S (k$)
Effort (k$)
Total (k$)
SCU-Module Prototype -
14000
Cold Phase Shifter 32
170
208
Cold Quadrupole 52
190
242
Cold Cavity BPM ?
Alignment assembly
100
410
510
SCU-Module Design
SLAC provides “M&S” funds, ANL/LBNL may provide “Effort”

21. Planar vs. Helical SCU Fields
Magnetic full gap (or helical diam.) = 7.2 mm

22. Planar vs. Helical FEL
e- energy
4.0
GeV
Min. x-ray energy
1.4
keV
Emittance
0.4 mm
Energy spread
0.5
MeV
Peak current 1 kA
Mean beta 16 m
Bunch charge
0.1 nC
Max. und. length
145
Full magnetic gap
7.2
Safety factor 20 %
Magnetic full gap (or helical inner diam.) = 7.2 mm