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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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THANK YOU FOR YOUR ATTENTION
19/11/2018 – Longuevergne David
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“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
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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
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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
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« 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
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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
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Assembly outside de clean room
CRYOMODULE ASSEMBly Clean room Assembly outside de clean room Cryomodule test bench
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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
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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
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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
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