1. Recent Result for the STF-2 Cryomodule Operation
T. Dohmae, M. Egi, K. Hara, T. Honma, E. Kako, Y. Kojima, T. Konomi, T. Kubo, T. Matsumoto, T. Miura, H. Nakai, K. Nakanishi, G. Park, T. Saeki, H. Shimizu, T. Shishido, T. Takenaka, K. Umemori, Y. Yamamoto
Kirk
07/Dec/2016

2. Outline Progress of STF Cryomodules Brief History of STF-2 Cryomdoule
Result from 2nd Cooldown Test in 2015
Result from 3rd Cooldown Test in 2016
Summary & Future Plan
07/Dec/2016

3. Outline Progress of STF Cryomodules Brief History of STF-2 Cryomdoule
Result from 2nd Cooldown Test in 2015
Result from 3rd Cooldown Test in 2016
Summary & Future Plan
07/Dec/2016

4. STF Cryomodules 4 cavities per batch STF Cavity Package 07/Dec/2016
STF-1 (4 cavities) in 2008
S1-Global (4+4 cavities) in 2010
4 cavities per batch
Proc. in SRF2011
Proc. in SRF2009
STF-2 (12 cavities) in 2014~
STF Cavity Package
Quantum Beam (2 cavities) in 2012
Capture CM in STF-2 accelerator
Proc. in IPAC12
WEPMB017 in IPAC16
07/Dec/2016

5. Outline Progress of STF Cryomodules Brief History of STF-2 Cryomdoule
Result from 2nd Cooldown Test in 2015
Result from 3rd Cooldown Test in 2016
Summary & Future Plan
07/Dec/2016

6. Brief History for STF-2 Cryomodule
Date
Content
2011 ~ 2013
V.T. for 12 cavities / RF conditioning for 12 couplers
Jun/2013
Cleaning up STF tunnel
Jul/2013 ~ Apr/2014
Cavity string assembly (three times)
Oct/2013 ~ Jan/2014
Module assembly (CM1/CM2a)
Jul/2014
Complete certification for High pressure Gas Code
Oct/2014 ~ Dec/2014
1st cool-down / low power test
Apr/2015 ~ Jul/2015
5MW Klystron / Single waveguide system completed
Jul/2015 ~ Sep/2015
Coupler conditioning at room temperature
Oct/2015 ~ Dec/2015
2nd cool-down / high power test
Jan/2016 ~ Jul/2016
Multi-beam Klystron & Waveguide system completed
Jul/2016 ~ Sep/2016
Sep/2016 ~ Nov/2016
3rd cool-down / LFD, Q0 measurement, 8 Cavities Operation & LLRF study
F.Y. 2017
4th cool-down test (?)
F.Y ~
Beamline construction / Beam operation starts (?)
07/Dec/2016

7. Brief history of STF-2 project
07/Dec/2016

8. STF-2 Accelerator Layout
To be constructed
CM2a
Cold box
CM1
View from downstream
Waveguide system
Capture CM
To be constructed
Cold box
Chicane
RF Gun
View from upstream
07/Dec/2016

9. Outline Progress of STF Cryomodules Brief History of STF-2 Cryomdoule
Result from 2nd Cooldown Test in 2015
Result from 3rd Cooldown Test in 2016
Summary & Future Plan
07/Dec/2016

10. Performance for STF-2 Cryomodule
RF conditioning was done very carefully as monitoring
heating at HOM couplers, unusual RF output from HOM couplers, and radiation level.
Short pulse  Full pulse  Long run
STF-2 RF Parameters
QL : 5.0 x 106
Filling time : 900μsec
Flat-top : 100μsec (short pulse)
Flat-top : 800μsec (full pulse)
Total width : 1700μsec
First and third cavity string achieved “No degradation” in CM test.
(Q0 measurement will be done from this autumn)
Second had significant trouble (heavy field emission)
due to additional (and irregular) clean room work (probably).
07/Dec/2016

11. Performance Degradation
Statistics for cavity performance;
Above 31.5 MV/m: 11 cavities
Degradation: 4 cavities
Three types of performance limit;
One cavity: Quench w/o F.E.
Two cavities: F.E. Quench
One cavity: Quench by enormous heat loss
Three degraded cavities in STF-2 are connected in series.
 Common cause for degradation
Q0 measurement is not done yet in STF-2.
It will start from this autumn.
Heavy F.E. in V.T.
22 cavities in 6 cavity strings
Statistics for cavity string (four cavities per batch);
Four cavity strings: No degradation
Quantum Beam: Degradation, but around ILC spec.
CM-1b in STF-2: Significant degradation
07/Dec/2016

12. Cavity string/Beam pipe connection in Tunnel
Local clean booth
Ion pump
Ion pump
Three degraded cavities in series
Use of simply local clean booth
Local clean booth was used for four beampipe connection parts
Exchange of metal valve near cavity string #2
Metal valve was a little bit bigger, disturbed thermal shield attachment
Extra Argon gas purging at gate valve opened
Usually, when gate valve opens, both sides should be under vacuum
but, we had to do Argon gas purging for the both sides
due to complicated process of cryomodule assembly
07/Dec/2016
A little bit bigger metal valve

13. Improvement of clean room items
Many experiences in
High quality local clean booth
Slow pumping system
High quality particle counter
Ultrasonic rinsing for ion pump
Will be introduced in 2017(?)
07/Dec/2016

14. Outline Progress of STF Cryomodules Brief History of STF-2 Cryomdoule
Result from 2nd Cooldown Test in 2015
Result from 3rd Cooldown Test in 2016
Summary & Future Plan
07/Dec/2016

15. 8 Cavities Operation by Vector-sum @31MV/m
Preliminary result
8 Cavities were tuned on resonance by piezo, and stable vector-sum operation was done at 31MV/m.
07/Dec/2016

16. Q0 – Eacc Curve in STF-2 CM Miss! Q0 was uniformly lowered?
Lower Q0 is not related to F.E.
Main error is generated from reproducibility of static heat load
and distribution of helium mass flow
Data analysis is still on-going (To be presented in TTC Meeting at MSU)
07/Dec/2016

17. Comparison of Q0 – Eacc Curve between V.T. and C.T.
Light F.E.
Preliminary result
Heavy F.E.
07/Dec/2016

18. Outline Progress of STF Cryomodules Brief History of STF-2 Cryomdoule
Result from 2nd Cooldown Test in 2015
Result from 3rd Cooldown Test in 2016
Summary & Future Plan
07/Dec/2016

19. Summary STF-2 cryomodule test have been done three times since 2014
Eight cavities achieved above 31.5 MV/m as ILC spec.
Three cavities had significant degradation from V.T.
One cavity already had heavy F.E. in V.T.
8 cavities operation was successfully done at 31MV/m
Vector-sum control by LLRF was used
LFD compensation by Piezo drive was perfectly done
Two cavities in Capture CM were also simultaneously operated
Q0 in 3rd cooldown test was uniformly lowered from V.T.
Data analysis and investigation are still on-going
Static Heat Load was significantly large
07/Dec/2016

20. Future Plan 4th cool-down test is done in F.Y. 2017 (?)
Beamline construction is done in F.Y (?)
Beam commissioning starts from F.Y (?)
07/Dec/2016

21. Thank you very much for your attention
We will present the detailed result for 3rd cooldown test
in IPAC17 and SRF2017!
07/Dec/2016

22. Back-up slides
07/Dec/2016

23. Additional items for beam commissioning
Multi-beam Klystron (10MW)
Waveguide system for eight cavities
Pumping unit for 2K liq. helium
Quadrupole magnet system
07/Dec/2016

24. Radiation level near Cryomodule
Position of radiation detector:
Upstream beampipe
Downstream beampipe
Below cryomodule (cavity)
Radiation property:
Cavity #5 & 7: Heavy F.E.
Cavity #6: No x-rays, but enormous heat loss
Cavity #9: Heavy F.E. already in V.T.
07/Dec/2016