1. RAPPEL TITRE PRESENTATION
lundi 19 novembre 2018
SPIRAL 2 SRF ACTIVITIES
On behalf of Spiral2 team
(Ganil, Cea Saclay, LPSC, IPNO)
Unité mixte de recherche CNRS-IN2P3
Université Paris-Sud Orsay cedex
Tél. :
Fax :
19/11/ Longuevergne David

2. RAPPEL TITRE PRESENTATION
lundi 19 novembre 2018
OUTLINE
SPIRAL 2 Accelerator
Overview of the SC linac
Status
SC Linac Milestones
CRYOMODULES A
Last results (RF)
Cryogenic performances
CRYOMODULES B
Solutions (RF)
Last results (other)
Solutions (other)
CONCLUSION
19/11/2018 – Longuevergne David

3. Spiral 2 Accelerator \ Overview of SC linac
RAPPEL TITRE PRESENTATION
lundi 19 novembre 2018
Spiral 2 Accelerator \ Overview of SC linac
Cryomodules A :
12 QWR β = 0.07
Removable bottom in copper
tuning by deformation
Cryomodules B :
14 QWR β = 0.12
Welded bottom
Moving Nb plunger A B
F [MHz]
opt
0.07
0.12
Epk/Ea
5.36
4.76
Bpk/Ea [mT/MV/m]
8.70
9.35
r/Q []
599
515
6.5 MV/m & opt
1.55
2.66
Lacc [m]
0.24
0.41
Qext
5e5
1e6
19/11/2018 – Longuevergne David

4. Spiral 2 Accelerator \ Status
RAPPEL TITRE PRESENTATION
lundi 19 novembre 2018
Spiral 2 Accelerator \ Status
All cavities A (but 1) & B have been tested in vertical cryostat and validated.
All couplers are fabricated. They are cleaned and conditionned on the go before cryomodule assembly.
All parts (vacuum vessels, tuning systems, …) are constructed
2 cryomodules A fully assembled have been validated so far,.
No cryomodule B are validated, next test end of this year. Delayed due to upgrade of test zone.
19/11/2018 – Longuevergne David

5. Spiral 2 Accelerator \ SC linac Milestones
RAPPEL TITRE PRESENTATION
lundi 19 novembre 2018
Spiral 2 Accelerator \ SC linac Milestones
Installation of cryomodule valve box frames
Beginning of January 2013
Installation of room temperature sections (quadrupoles + diagnostics)
Beginning of July 2013
Installation of He liquifier
Middle of July 2013
Start installation of cryomodules
Availability of utilities (water, electricity)
Middle of February 2014
Authorization for beam operations
Spring 2014
First cool down of linac
19/11/2018 – Longuevergne David

6. SPIRAL 2 Accelerator CRYOMODULES A CRYOMODULES B CONCLUSION OUTLINE
Overview of the SC linac
Status
SC Linac Milestones
CRYOMODULES A
Lasts results (RF)
Cryogenic performances
CRYOMODULES B
Last results (RF)
Solutions (RF)
Last results (other)
Solutions (other)
CONCLUSION
19/11/2018 – Longuevergne David

7. CRYOMODULE A \ LAST RESULTS (RF)
RAPPEL TITRE PRESENTATION
lundi 19 novembre 2018
CRYOMODULE A \ LAST RESULTS (RF)
No problems to condition power coupler (off-frequency)
RF Duty cycle from 1 to 100 %, Power from 1W to 3kW
Only CW from 3kW to 9kW
Some events but smooth and fast (< 500 min)
No multipacting at low field
Many quenches (starting from 4.6 MV/m) when ramping up the first time
CW processing up to 4.6 MV/m
Pulsed (30%) to limit field emission
Same hard quench limit than in vertical test (~10 MV/m)
Some limited field emission at operating gradient (6.5 MV/m) but acceptable (no additionnal dissipations)
About 10h to fully condition the cavity
Long runs (30h) at operating gradient show good stability
No need to re-process cavity after a warm up/cool down cycle
19/11/2018 – Longuevergne David

8. CRYOMODULE A \ cryogenic performances
No problems to cool down the cryomodule
Cooling time is about 1h
Tuning system takes time (6 days) to thermalize but working nicely
Cryomodule loads :
Static load :25W on thermal shield (LN2), 5W at 4K (Spec 8.5W)
Dynamic load : 6W at 6.5 MV/m => same in vertical test (Spec 12W)
Cavity alignment is OK.
Sensibility: 24kHz/mm
Hysteresis below 5 Hz
19/11/2018 – Longuevergne David

9. SPIRAL 2 Accelerator CRYOMODULES A CRYOMODULES B CONCLUSION OUTLINE
Overview of the SC linac
Status
SC Linac Milestones
CRYOMODULES A
Last results (RF)
Cryogenic performances
CRYOMODULES B
Solutions (RF)
Last results (other)
Solutions (other)
CONCLUSION
19/11/2018 – Longuevergne David

10. CRYOMODULE B \ LAST RESULTS (RF)
Power coupler conditioning OK at room temperature and 4K
Limited accelerating field (last year)
Cryomodule n°1: Eacc max 4.4 MV/m (8.9 in VT) & 5.1 MV/m (8.7 in VT)
Cryomodule n°2: Eacc max 5.2 MV/m (10.4 in VT) & 8.4 MV/m (10.4 in VT)
WHY ? :
Plunger NO as re-tested in VT and max Eacc recovered
Power coupler MAYBE as discharges marks on coupler tips!
Cleanliness YES as strong field emission, probable pollution (leak during assembly and venting) and some vacuum pipes with rust !!
MV/m (Qi = 5e5 for cavity type A)
19/11/2018 – Longuevergne David

11. CRYOMODULE B \ solutions (RF)
Couplers are now electro-polished (50 µm)
Cryomodule A show no problem with new coupler cleaning procedure during last test
Assembly procedures upgraded and particule counting on all components before mounting
Confirmation during next test
Planned end of this year
19/11/2018 – Longuevergne David

12. CRYOMODULE B \ LAST RESULTS (other)
Cooling rate is good
10h for thermal shield
5h for cavities ( ~1h between 150K and 50K)
Cavities alignment is good
Tuner system shows strong hysteresis, freeze and overshoot
Hysteresis ~ 500 Hz
Overshoot ~ Hz
19/11/2018 – Longuevergne David

13. CRYOMODULE B \ solutions (other)
WHAT HAS BEEN DONE FOR TUNER MECHANISM ?
To remove hysteresis and freeze
Tie rod end bearing changed with less play
One internal column (over 2) removed
One external column (over 2) removed
Internal column aligned to have plunger swing parallel to beam
19/11/2018 – Longuevergne David

14. CRYOMODULE B \ LASTS RESULTS (other)
Set up to measure frequency shift of few hertz at room temperature
RF synthetizer
LOAD
RF mixer
Lock-in amplifier
Amplitude modulation
TO BE CONFIRMED AT 4K DURING NEXT TEST
Overshoot ~ 1-2 Hz
Hysteresis ~ 5-20 Hz
19/11/2018 – Longuevergne David

15. 2 modules validated. Results with good repeatability
conclusion
CMA :
2 modules validated. Results with good repeatability
3rd to be validated end of this year
All of them (12) to be validated by end of 2013
CMB :
None validated so far
Next test end of this year
Confirmation of cleaning procedure and tuner system
Last CMB to be delivered in march 2014
LINAC :
First cool down in spring 2014
19/11/2018 – Longuevergne David

16. THANK YOU FOR YOUR ATTENTION
19/11/2018 – Longuevergne David

17. 19/11/2018

18. 19/11/2018

19. 19/11/2018

20. “CLASSICAL” BCP CHEMISTRY
PREPARATION [1]
“CLASSICAL” BCP CHEMISTRY
Goals: “coarse” frequency tuning + etching>100µm min.
Standard process: 2 x 2h in 2 phases (cavity turned upside down after phase 1)
Active cooling (water) inside the helium vessel
PHASE2 in
out
PHASE1 in
out
180°
Data for13 BCP processes
Etching rate
[µm/min]
0.35 … 0.45
Sensitivities
[kHz/min]
0.13 … 0.15
[kHz/µm]
19/11/2018 – Longuevergne David

21. PREPARATION [2] High Pressure Rinsing PHASE2 PHASE3 90° 180° PHASE1
80 bars
3 phases:
20min/beam ports for phase 1
45 min/port for phases 2 and 3
Drying: 72h (in phase 3 position)
PHASE2
PHASE3
90°
180°
PHASE1
Through beam ports
19/11/2018 – Longuevergne David

22. Heater (not shown) glued onto the copper cap
PREPARATION [3]
After 72h drying  48 h 120°C
“Forced” air flow inside the helium vessel + heater on the cavity bottom
Cavity wrapped in a foil blanket
Input
~120°C
Output
~110°C
Heater
Heater (not shown) glued onto the copper cap
19/11/2018 – Longuevergne David

23. « No baking » results
Cavities: MB01, 02, 03, 04, 05, 06, 07, 09 and 10 (08/ /2009)
Cavity
6.5 MV/m [W]
MB01
8.5
MB02
6.9
MB03
7.0
MB04
8.4
MB05
7.2
MB06
7.5
MB07
MB09
8.9
MB10
7.1
Mean value
7.6

24. Losses divided by ~2 @ Eacc=6.5 MV/m
« With baking » results
Cavity
6.5 MV/m [W]
No baking
With baking
MB01
8.5
3.7 (-56%)
MB02
6.9
4.1 (-41%)
MB03
7.0
4.4 (-47%)
MB04
8.4
3.6 (-58%)
MB05
7.2
3.5 (-51%)
MB06
7.5
4.8 (-36%)
MB07
3.4 (-51%)
MB08 X
4.0
MB09
8.9
3.9 (-56%)
MB10
7.1
MB11
3.1
MB12
3.8
MB13
3.0
MB14
MB15
MB16
3.9
Mean value
7.6
3.7
Losses divided by Eacc=6.5 MV/m

25. Assembly outside de clean room
CRYOMODULE ASSEMBly
Clean room
Assembly outside de clean room
Cryomodule test bench

26. Cavity 0.12 with its helium jacket ready for vertical test
Cavity preparation
Cavity 0.12 with its helium jacket ready for vertical test
Buffered chemical polishing for both QWR families
Standard etching: 150 µm
High Pressure Rinsing in ISO4 clean room
Horizontally for QWR 0.07
Vertically for QWR 0.12

27. From cavity qualification test in vertical cryostat to fully equipped cryomodule tests
In house
Cavity design
Made by industrials
Cryomodule design
In house
In house
Cavity fabrication
Cryomodule fabrication
Cavity preparation (BCP, HPR)
Qualification test of each single cryomodule
Vertical test
Cryomodules assembly
RF conditioning
Delivery to GANIL
Coupler design
Coupler fabrication

28. Cryomodule assembly in ISO4 clean room
CMA
CMB
CMA
CMA
Cavity assembly on the vacuum vessel
100 bar
Coupler assembly
End of the assembly outside the clean room
CMB
CMA
CMB