Status of the SPL cryo-module development
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Transcript of Status of the SPL cryo-module development
Status of the SPL cryo-module development
V.Parma, TE-MSC(with contributions from WG3 members)
SPL seminar, CERN 18th February 2010
Content
• SPL architecture and parameters• Work organisation• Layout studies and machine sectorisation
(vacuum+cryogenics)• Cryogenic scheme (for the prototype)• Supporting schemes• Next steps• Summary
SPS
PS2
SPL
Linac4
PS
ISOLDE
Layout injector complex
The SPL studyGoals of the study (2008-2012):• Prepare a Conceptual Design Report with costing to present
to CERN’s management for approval• This is the low power SPL (LP-SPL) optimized for PS2 and
LHC
Length: ~430 m
Medium b cryomodule
High b cryomodules
Ejec
tion
10 x 6b=0.65 cavities
5 x 8b=1 cavities
13 x 8b=1 cavities
TT6
toIS
OLD
E
Debunchers
To P
S2High b cryomodules
From
Lina
c4
0 m0.16 GeV
110 m0.73 GeV
186 m1.4 GeV
427 m4 GeV
Kinetic energy (GeV) 4Beam power at 4 GeV (MW) 0.16Rep. period (s) 0.6Protons/pulse (x 1014) 1.5Average pulse current (mA) 20Pulse duration (ms) 1.2
LP-SPL beam characteristics
The SPL study (cont.d)• Study a 5 GeV and multi MW high power beam, the
HP-SPL• Major interest for non-LHC physics:
ISOLDEII/EURISOL/Fixed Target/Neutrino Factory
Length: ~500 m
Ejec
tion
to
Euris
ol
High b cryomodules
12 x 8b=1 cavities
Medium b cryomodule
High b cryomodules
Ejec
tion
10 x 6b=0.65 cavities
5 x 8b=1 cavities
6 x 8b=1 cavities
TT6
toIS
OLD
E
Debunchers
To P
S2High b cryomodules
From
Lina
c4
0 m0.16 GeV
110 m0.73 GeV
186 m1.4 GeV
~300 m2.5 GeV
Option 1 Option 2
Energy (GeV) 2.5 or 5 2.5 and 5
Beam power (MW) 3 MW (2.5 GeV)or
6 MW (5 GeV)
4 MW (2.5 GeV)and
4 MW (5 GeV)
Rep. frequency (Hz) 50 50
Protons/pulse (x 1014) 1.5 2 (2.5 GeV) + 1 (5 GeV)
Av. Pulse current (mA) 20 40
Pulse duration (ms) 1.2 0.8 (2.5 GeV) + 0.4 (5 GeV)
HP-SPL beam characteristics
~500 m5 GeV
Cryo-module: Goal & MotivationGoal:• Design and construct a full-scale cryo-module prototype
(part of the SPL Design Study)
Motivation:• Develop technologies and demonstrate construction
capability on a cryo-module with 8 β=1 cavities
• Learning of the critical assembly phases (e.g. clean-room)
• Enable RF testing on a multi-cavity assembly in real operating conditions (horizontal cryostat)
• Investigate and acquire experience on cryogenic operation issues (e.g. process control)
Working group (WG3) members System/Activity Responsible/member Lab
Machine architecture F.Gerigk CERN, BE/RF
WG3 coordination V.Parma CERN, TE-MSC
Cryo-module conceptual design & Integration
V.Parma, N.Bourcey, A.Vande Craen, D.Caparros, P.Coelho, Th.Renaglia
CERN, TE/MSC, EN-MME
Cryostat detailed design P.Duthil CNRS/IN2P3-Orsay
Cryostat assembly tooling S.Chel CEA-Saclay
WG 2 activity (RF cavities/He vessel/tuner, RF coupler)
W.Weingarten/S.Chel/O.Capatina/E.Montesinos
CERN BE/RF, CEA-Saclay
Vacuum systems S.Calatroni CERN, TE/VSC
Cryogenics U.Wagner CERN, TE/CRG
Survey D.Missiaen CERN, BE/ABP
Quad.doublet D.Tommasini CERN, TE/MSC
• Regular WG meetings since May 2009– Web page: https://twiki.cern.ch/twiki/bin/view/SPL/CryoModules
• Topics covered (or in progress): – Cryomodule longitudinal study– SPL mechanical layouts– Sectorisation issues– Cryogenic cooling schemes– Integration of RF Coupler– Cryo-module design: supporting systems, thermal shielding,...
• Close collaboration with WG2 (cavities and ancillaries)• Relevant workshops 2009:
– Workshop on Mechanical issues of SPL cavities/cryomodules: http://indico.cern.ch/conferenceDisplay.py?confId=68968
– Workshop on Cryogenic and vacuum sectorisation of the SPL: http://indico.cern.ch/conferenceDisplay.py?confId=68499
• Coming up soon (16-17 March): Review of the RF Couplers
Activity of WG 3
Planned supplies for prototype cryo-moduleInstitute Responsible
personDescription of contribution
CEA – Saclay (F) S. Chel 1. Design & construction of 2 β=1 cavities (EuCARD task 10.2.2)2. Design & construction of 2 helium vessels for β=1 cavities
(French in-kind contribution)3. Design & construction of cryostat assembly tools (French in-
kind contribution)4. Supply of 8 tuners (French in-kind contribution)
CNRS - IPN – Orsay (F) P. Duthil 1. Design and construction of prototype cryomodule cryostat (French in-kind contribution)
Stony Brook/BNL/AES team
I.Ben-zvi (Under DOE grant)1. Designing, building and testing of 1 β=1 SPL cavity.
CERN O.Capatina 1. 8 β=1 cavities2. 7 He tanks in titanium3. 1 He tank in st.steel
CERN E.Montesinos 1. 10 RF couplers (testing in CEA, French in-kind contribution)
Cryo-modulelongitudinal integration study (β=1)
+
Continuous cryostat "Compact" version (gain on interconnections):
5 Gev version (HP): SPL length = 485 m (550 m max available space)
"Warm quadrupole" version (with separate cryoline):
5 Gev version (HP): SPL length = 535 m (550 m max available space)
Longitudinal mechanical layouts«Continuous» vs. «fully segmented» cryostat SPL layouts
CRYOGENICS AND VACUUM SECTORISATIONOutcome of workshop on cryogenic and vacuum sectorisations of the SPL
(November 9-10, 2009)
Possible cryogenic feeding:“continuous” cryostat
Cryogenic Interconnect BoxCryo UnitCryogenic bridge
Cryo-plant
Isolde extractionEurisol extraction
CIB
CIB
10 β=0.65 + 5 β=1 cryo-modules17 β=1 cryo-modules + 2 demodulators
6 β=1 cryo-modules
1.7% tunnel slope
“continuous” cryostat
String of cryo-modules between TSM
Technical Service Module (TSM)
Cold-Warm Transition (CWT)
• “Long” and “continuous” string of cavities in common cryostat• Cold beam tube• “straight” cryogenic lines in main cryostat• common insulation vacuum (between vacuum barriers, if any
present)
Insulation vacuum barrier
Warm beam vacuum gate valve
Possible cryogenic feeding:Cryogenic Distribution Line
Cryogenic Interconnect BoxCryo-module UnitsCryogenic Distribution Line
Cryo-plant
Isolde extractionEurisol extraction
CIB
CIB
10 β=0.65 + 5 β=1 cryo-modules17 β=1 cryo-modules + 2 demodulators
6 β=1 cryo-modules
1.7% tunnel slope
“segmented” cryostat
String of (or single) cryo-modules
Technical Service Module (TSM)
Cold-Warm Transition (CWT)
• Cryostat is “segmented”: strings of (or single) cryo-modules, 2 CWT each• Warm beam zones• Cryogenic Distributio Line (CDL) needed• Individual insulation vacuum on every string of cryo-module (Vacuum
Barriers, w.r.t. CDL)
Cryogenic Distribution Line (CDL)
Insulation vacuum barrier
Warm beam vacuum gate valve
Main issues• Machine availability:
– “work-horse” in the injection chain
• Reliability of built-in components and operational risks– Typical faults expected on: cavities, couplers, tuners...– Operation with degraded performance (cavities, optics, leaks...)
• Maintainability:– Warm-up/cool-down . Time and reliability. Need for partial or complete warm-up of
strings to replace built-in components or even one cryo-module– Accessability of components for regular maintenance or repair
• Design complexity of compared solutions
• Operational complexity (e.g.cryogenics with 1.7% slope)
• Installation and commissioning
• Safety. Coping with incidents (MCI): Loss of beam and/or insulation vacuum (helium and air leaks):
• Cost differences between options
VACUUM
SPL Sectorisation Variants
09/11/09Vacuum sectorisation 22
Continuous
SegmentedOption B
SegmentedOption A
P.Cruikshank
Summary: comparison of vacuum aspects“continuous” cryostat Segmented with CDL
Advantages Drawbacks Advantages Drawbacks
Design
-Compact long.layout-fewer components-Reduced vac systems (integrated He lines)
- Long beam vacuum sectors , cold sector valves don’t exist!- Some sensitive equipment needs vacuum compatibility and validation
-Modular design- Easier access, repairs, upgrades- Modules are complete & tested before installation
-More vacuum components (eg CWT)-More vacuum instrumentation
Installation
-Insulation vacuum systems are exposed to tunnel environment- Beam/cavity vacuum more exposed?
-Minimize tunnel work/problems modules are complete and tested before installation- Staged acceptance tests- Decoupling of problems
Repair
- Less tasks for systematic repairs on modules – venting, re-pumping..
- Equipment will see more thermal cycles –> create leaks?
- Reduced search/repair zones- Reduced coactivity- Local warm-up and opening of vacuum system – cost & downtime
- Difficult access at CWT – not std interconnect design
Commisioning
- Cavities re-commissioning after venting -RF processing with helium required for field above < 6 MV/m- Movable blocks or valves to absorb field emission electrons?
-Pre-commissioning before installation- Staged tests – smoothing of resources, - Earlier identification of problems- Decoupling of problems - Re-commissioning of ‘weak’ module possible
- More volumes to commission
Operation
Simpler controlsRedundancy in fixed pumping systems
MCI would affect more equipment - Limit MCI affected zone by interlocked beam vacuum valves- Limit zone of degraded ins vacuum (helium leak)- Easier diagnosis of problems
- More equipment (fixed pumping systems & valves)- More interlocks- More risk of equipment failure- More maintenance
CRYOGENICS
2.2 K forward
5 K forward
40 K forward
2 K 2-phase
cavity
2 K return
80 K return
8 K return
cool down/warmup
support
coupler
300 mm
• Cavities cooled with helium II at ~ 2.0 K (3.1 kPa), similar to XFEL– Cavities inside saturated bath (slightly sub-cooled due to hydrostatic head)– Profit from low Δp and good p-stability
Cryogenics
JTVapourLiquid
Gas returntube
Two phasetubeBeam tube
Vapor flow large
XFEL
Effect of slope
Module Schemes
6/11/2009SPL Workshop NOv. 2009 26
Scheme no 3: “ILC-like”
LP SPL HP SPL
Diameter “x” [mm]
40 80
1.7 %
U.Wagner
Module Schemes
6/11/2009SPL Workshop NOv. 2009 27
Scheme no 7 : “ILC like SPL version “A” with separate cryogenic line equipped for independent cool-down,
warm-up and purge”
1.7 %
U.Wagner
Separate cryogenic line
· Advantages· Less complexity for the main cryostat· Potential to completely isolate “faulty” modules
· Disadvantages· Requires more tunnel space· Higher static heat load
· Cost aspect· Not easy to identify separate line most probably
more expensive· More complex cryostat and installation vs. cryostat
plus line, two installations and more tunnel space
6/11/2009SPL Workshop NOv. 2009 28
Advantages / Disadvantages
U.Wagner
modified cryogenic scheme (proposal)
Warm recovery lineWarm valves
Cryogenic issues (ongoing)• High dynamic heat load: ~200 W/cryo-module (~25 W/m)!
– Thermal break-down to be checked (q<qfilm boiling?)– Keep (efficient) stratified flow in bi-phase pipe R&D & testing
• High dynamic heat loads requires large design capacity (=diameter) of helium Gas Return Pipe (GRP):– Limit number of cryomodules in series– Large GRP: better in a cryo distribution line
• Pipe sizing: – Bi-phase pipe:
– HL dependant (vapour mass flow). 200W ~ 14 g/s per module , for v=1m/s Φ 140
– GRP: – HL dependant (vapour mass flow). 200W – can be kept relatively small with a CDL
– Coupler gas cooling– Thermal shield pipes
• Desy (XFEL/FLASH): continuous cryostat– Maximise real estate gradient– Minimise capital cost– Safety issues (MCI, catastrophic venting)
• Recent full-scale tests (after LHC sect. 3-4 incident)• Considering installation of cold valves (R&D ongoing)
• FNAL (Project X)– Now addressing segmentation issues– IC-2 (CW) will be more finely segmented than IC-1 (pulsed)
• JLAB (CEBAF):– Next slide
Experience from other labs
CEBAFTotal of 57 independent Cryostats
• Planned as full segmented• Staged construction/upgrade• Remove and replace
cryomodules: ~ 1wk !• Refurbish cryomodules:
– 1 to 2 per year over next 3 years
Failure experienceReliability of built-in components
Component Type of faults Degraded performance
Mitigating measures Source
1
Cavity(ies) - Low gradient - Lower acceler. - Compensate with higher grad. on other cavities or built-in margin
- JLAB, SNS
2 Coupler - Leak to cavity vac.
3
Tuner - Motor failure - Cavity not tuneable
- Compensate with higher grad. on other cavities or built-in margin
- Flash, 1 case- KEK moved motor
outside the cryostat
4Quadrupole/steerers
- Misalignment- No powering
- beam quality- Unacceptable
- New correcting scheme
- None
5
He envelope He Leak to ins.vacuum
Degraded ins.vacuum (10-4mbar) high heat loads
Additional pumping capacity and cryogenic capacity
- Flash, 2 major leaks, He vessel and bellows.
- JLAB, Cebaf
6Ins.Vac. envelopes
Catastrophic air leak to cavity vacuum
XFEL experiments
• Drivers:– Availability:
• Reliability/Maintainability. Components with technical risk:– RF Coupler, single window. No in-situ repair possible– Cavity/tuner, reduced performance. No in-situ repair possible– Beam/cavity vacuum leaks. No in-situ repair possible
possibility for quick replacement of cryo-module (spare)
– Safety: coping with incidents: accidental loss of beam/cavity vacuum:• Cold valves not available (XFEL is considering their development)
Adopt warm interlocked valves (not necessarily very fast, XFEL experience)
“Segmented” layout with CDL has clear advantages in these respects
• Additional advantages:– Magnets can be warm: classical “off-the shelf”, easy alignment/maintainability/upgrade – and cryo-module internal positioning requirements can ne relaxed (by 3)
• Drawbacks:– Less compact layout (~10%) – More equipment (CDL, CWT, instrumentation...):
• Capital cost• More complexity = less reliability?
– Higher static heat loads (but dynamic loads dominate!)
Conclusions on sectorisation
β=0.65 cryo-module
β=1 cryo-module
Fixed support
Sliding support
Inertia beam
Invar longitudinal positioner
External supports (jacks)
RF coupler
Possible supporting schemes
Fixed support
Sliding support
Inertia beam
Invar longitudinal positioner
External supports (jacks)
RF coupler
Possible supporting schemes
Fixed support
Sliding support
Inertia beam
External supports (jacks)
RF coupler + longitudinal positioner
Possible supporting schemes
External supports (jacks)
RF coupler + longitudinal positioner + vertical support
Intercavity support structure
Possible supporting schemes
RF coupler as cavity support
• Issues:– Mechanics– Cavity RF gasket – Stability w.r.t. T profile changes
(gas cooling control?)– Assembly sequence/tools...
Next steps– Refine design parameters for HP SPL (HL in particular)– Refining test objectives of the prototype
• Test program: RF, cryogenics• Infrastructure needs: RF power, cryogenic test station and
feedbox – Finalise choice of cryogenic scheme– Finalise operational scenarios, pressures and
temperatures – Piping sizes – Continue investigation of supporting systems (RF
coupler) Finalise conceptual design by mid 2010
Schedule for prototype
Summary• Cryo-module prototyping is mandatory to demonstrate
technology and provide a machine-representative test bed for RF and cryogenic testing
• An important involvement (with H/W contributions) from external labs is now firmly engaged
• The conceptual design is well progressed but still needs some months of work
• RF coupler design will be reviewed in March• Detailed cryostat design should start in the 2nd half of
the year• Assembly of the prototype cryo-module by end 2012