1. Recent high-gradient testing results from the CLIC XBoxes
Jorge Giner-Navarro
Ben Woolley
Linear Collider Workshop 2015 (LCWS15)
Whistler (Canada)
03/11/2015

2. Outline The Xboxes Results from completed tests Xbox-1
Dogleg experiment
Xbox-2
Ongoing tests
Summary
J. Giner Navarro - LCWS15
03/11/2015

3. The Xboxes Current test:
Xbox-3A: OPERATIONAL
OPERATIONAL
OPERATIONAL
Xbox-3B/C/D: COMMISSIONING
CPI 50MW 1.5us klystron
Scandinova Modulator
Rep Rate 50Hz
CPI 50MW 1.5us klystron
Scandinova Modulator
Rep Rate 50Hz
4x Toshiba 6MW 5us klystron
4x Scandinova Modulators
Rep Rate 400Hz
Current test:
Dogleg beam-loading experiment, TD26CC#1 (in CTF3 LINAC)
Previous tests:
TD24R05 (CTF2, 2013)
TD26CC#1 (CTF2, 2013)
T24 (Dogleg, )
Current test:
T24_OPEN (in halves)
Previous test:
CLIC Crab cavity ( )
LLRF, pulse compressors and waveguide network to be completed at the end 2015
Medium power test:
3D printed Ti waveguide (Xbox-3A)
J. Giner Navarro - LCWS15
03/11/2015

4. Xbox-1: TD26CC_N1
First complete CLIC High-Power test performed at CERN
CLIC-G prototype, 26 regular cells, HOM Damping
Conditioning from July to December 2013
100MV/m
250ns
1.5E-6bpp
6.9E-6bpp/m
J. Giner Navarro - LCWS15
03/11/2015

5. Dogleg experiment Dogleg XBOX1 12 GHz RF 12 GHz RF: 90 MW RF power
Up to 50 Hz rep. rate
CTF3 Injector
35 m low loss waveguide
Beam:
CTF3 Drive Beam modified
3GHz beam at ~1.2 A
Pulse length up to 250 ns
Energy ~125 MeV at structure
Up to 25 Hz pulse rep. rate
MKS02
3 GHz RF
High Gradient Accelerating Structure
MKS03
MKS05
MKS06
MKS07
Gun
Luis Navarro
J. Giner Navarro - LCWS15
03/11/2015

6. Xbox-1/Dogleg: T24
Hot cell developed at the beginning of the structure
J. Giner Navarro - LCWS15
03/11/2015

7. Xbox-1/Dogleg: T24 BD distribution history (hot cell development)
Gradient profile
J. Giner Navarro - LCWS15
03/11/2015

8. Crab Cavity Design Backward wave E-field e H-field Sc=|ReS|+|ImS|/6
Property
CLIC T24 (unloaded)
LCLS deflector
CLIC Crab (un-damped)
Input Power
37.2 MW
20 MW
13.35 MW
Transverse Kick -
24 MV
2.55 MV
Peak surf. E-field
219 MV/m
115 MV/m
88.8 MV/m
Peak surf. H-field
410 kA/m
405 kA/m
292 kA/m
Peak Sc [3]
3.4 MW/mm2
MW/mm2
Group Velocity %c
-3.2%c
-2.9%c
# Cells 24
117 12
Location of each surface property is different on the iris. May be able to determine which surface property causes the most breakdowns/damage using post-mortem analysis.
G. Burt
B.Woolley – HG2015
A. Grudiev
V. Dolgashev
P.Ambattu

9. Xbox-2: CRAB cavity 51 MW 100ns 3E-5bpp 43 MW 200ns 3E-6bpp
Es=154 MV/m
Hs=505 kA/m
Sc=5.48 MW/mm2
Operating limit 13.35MW 200ns
J. Giner Navarro - LCWS15
03/11/2015

10. Xbox-2: CRAB cavity Good performance over nominal operation.
R.Rajamaki
Good performance over nominal operation.
BDR measurements consistent with other tests
The cavity was recently cut at CERN for the Post-mortem analysis to observe the possible breakdown features of E fields, H-fields or modified Sc.
J. Giner Navarro - LCWS15
03/11/2015

11. Summary of tested structures
J. Giner Navarro - LCWS15
03/11/2015

12. Summary of tested structures
Crab cavity
A. Degiovanni
In terms of peak surface E field and peak Modified Poynting vector
J. Giner Navarro - LCWS15
03/11/2015

13. Ongoing High-Gradient tests
Xbox-1 and Xbox-2 are currently running in parallel and providing significant data.
We are testing two different CLIC accelerating structure designs.
TD26CC_N1
T24_OPEN
Recent results will be summarized in the following slides
J. Giner Navarro - LCWS15
03/11/2015

14. Xbox-1/Dogleg: TD26CC_N1
TD26CC_N1, tested at Xbox-1 in 2013, was accidentally vented during an unknown period of time.
The structure was re-baken out and installed in the CTF3 Linac for the Dogleg Experiment
Need of reconditioning
J. Giner Navarro - LCWS15
03/11/2015

15. Xbox-1/Dogleg: TD26CC_N1 102MV/m 200ns 3E-5bpp Pulse length 100 ns
J. Giner Navarro - LCWS15
03/11/2015

16. Xbox-1/Dogleg: TD26CC_N1 Good performance (no evidence of hot cells)
Conditioning rate seems to be lowered
2013
2015
Good conditions to start beam loading experiment
CLIC pulse shape from Xbox-1
J. Giner Navarro - LCWS15
03/11/2015

17. Xbox-1/Dogleg: TD26CC_N1
Uniform breakdown distribution as expected (and as the previous test)
We are currently putting strong effort in breakdown localization techniques and diagnostics
J. Giner Navarro - LCWS15
03/11/2015

18. Xbox-2: T24CC_OPEN
V. Dolgashev
A. Grudiev
H. Zha
Milled structure built in halves and brazed (in SLAC)
24 regular cells, no HOM damping
J. Giner Navarro - LCWS15
03/11/2015

19. Xbox-2: T24CC_OPEN 94MV/m 80ns 3E-5bpp J. Giner Navarro - LCWS15
03/11/2015

20. Xbox-2: T24CC_OPEN Good performance so far at short pulse length.
Conditioning rate similar to CLIC-G prototypes built in disks.
(For the same gradient, T24OPEN presents higher peak surface E field and peak modified Poynting vector Sc)
J. Giner Navarro - LCWS15
03/11/2015

21. Summary of tested structures
T24_OPEN (Xbox-2)
TD26CC#1 (Dogleg)
Still conditioning…
J. Giner Navarro - LCWS15
03/11/2015

22. 3D Printed Waveguide Installation # Xbox-3A
6.5-7MW Klystron
Directional Coupler
Vacuum Port
3D Printed Waveguide
Solid state 320W amplifier
RF Stainless Steel Load

23. 3D Printed Waveguide Results
~150 Million Pulses acquired in just 2 weeks with only 50% uptime.
200 Hz rep. rate makes data taking faster!

24. Conclusions
Xbox-1 and Xbox-2 are currently running at full capabilities to perform the required high-power tests for CLIC prototypes.
Xbox-3 is on construction and the full components installation will be finished soon.
The Xboxes are completing the performance scope of the recent prototype designs, as well as the better understanding in BD phenomena in real cavities.
Dogleg experiment with Xbox-1 and CTF3 beam will study the beam loading effect on BDR.
Two test stands are running at the same time with different structures, which opens the possibility of testing different operation strategies.
J. Giner Navarro - LCWS15
03/11/2015

25. Thank you for your attention
Special thanks to all who shared their significant contributions during the Xboxes life.
J. Giner Navarro - LCWS15
03/11/2015