The SPL study and the cryomoduledevelopment work

TE magnet seminar, 5 October 2010

V.Parma, TE-MSC

(with lots of contributions from SPL members)

Outline

• Introduction to the SPL: why so interesting?• Work organisation and objectives• SPL Layout studies • Cavities, tuners and couplers• Cryomodule:

– Mechanics and alignment– Cryogenics– Schematics

• Summary and Next steps

Who says SPL is dead??

…so, SPL is alive and in (quite) good shape!

MTP

201

1-20

15, p

ag. 6

-7

The SPL study at CERN• Initially aimed at LHC luminosity up-grade (LP-SPL): now stopped• Now R&D study for a 5 GeV multi MW power beam, the HP-SPL• Major interest for non-LHC physics: Fixed Target/Neutrino Factory

(but also ISOLDEII/EURISOL)

Length: ~540 m

Ejec

tion

to

Euri

sol

High βcryomodules

12 x 8β=1 cavities

Medium βcryomodule

High βcryomodules

Ejec

tion

20 x 3β=0.65 cavities

5 x 8β=1 cavities

6 x 8β=1 cavities

TT6

toIS

OLD

E

Debunchers

To f

ixed

tar

get/μ

fact

ory

High βcryomodules

From

Lin

ac4

0 m0.16 GeV

110 m0.79 GeV

186 m1.4 GeV

~300 m2.5 GeV

HP-SPL beam characteristics

~500 m5 GeV

SPS

PS2

SPL

Linac4

PS

ISOLDE

Layout injector complex

J.P.Delahaye, IHEP 2010

J.P.Delahaye, IHEP 2010

J.P.Delahaye, IHEP 2010

Beyond elementary particle physics: Spallation Sources• SNS (US) and its power upgrade (1.4 MW3 MW)• MYRRHA Project. Irradiation research facility for:

• Fuel testing for fast reactors• Material testing for fusion• Transmutation testing of long-lived radiactive waste• Production of medical radio-isotopes (99Mo)

• ESS-Scandinavia: spallation for material research

• ESS linac: a first “spin-off” of the SPL study

SPL parameters(https://twiki.cern.ch/twiki/bin/view/SPL/SPLparameterList, by F.Gerigk)

Parameter Unit HP-SPL HP-SPL LP-SPLlow-current high-current

Energy [GeV] 5 5 4 Beam power [MW] 4 4 0.192 Repetition rate [Hz] 50 50 2 Average pulse current [mA] 20 40 0-20

Peak pulse current [mA] 32 64 32 Source current [mA] 40 80 40 Chopping ratio [%] 62 62 62 Beam pulse length [ms] 0.8 0.4 0.9

filling time constant taul (b=0.65/1.0)

[ms] 0.54/0.55 0.27/0.27 0.54/0.55

actual cavity filling time: ln(4) x taul

[ms] 0.75/0.76 0.37/0.38 0.75/0.76

RF pulse length (filling time + flat top)

[ms] 1.55/1.56 0.78/0.78 1.65/1.66

Protons per pulse for PS2

[1014] 1.0 1.0 1.13

Beam duty cycle [%] 4 2 0.18 RF duty cycle [%] 7.8 3.9 0.33 Cryogenics duty cycle [%] 8.2 4.1 0.35

Coordinator External partners

WG1: RF hardware (low level & high power)

E. Ciapala Cockcroft Institute, ESS + (FNAL, SNS, JLAB, ANL)

WG2: Cavities (structures & auxiliary equipment)

W. Weingarten CEA-Saclay, CNRS-Orsay, TRIUMF, StonyBrook + RHUL + (JLAB, SNS)

WG3: Cryomodule (cryostat &cryogenics)

V. Parma CEA-Saclay, CNRS-Orsay, Stony Brook + (FNAL)

WG4: Beam dynamics (beam parameters)

A. Lombardi CEA-Saclay, TRIUMF, Soltan Institute,ESS

Architecture (layout & geometry, extraction, transfer)

F. Gerigk

Surface treatment and vacuum S. Calatroni

Mechanical design and construction

O. Capatina

Working Groups

Study leader: R. Garoby

Organization

SPL documentation in EDMS [ https://edms.cern.ch/nav/SLHC-000008 ]

SPL meetings in Indico [ http://indico.cern.ch/categoryDisplay.py?categId=1893 ]

SPL Collaboration

(Courtesy R.Garoby)

Milestones for cavities and cryomodule2011 2012 2013 2014 2015

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4SM18 - 2K Cryogenics

Vcryo.

X

SM18modulator 1 2

SM18 - 704 MHz High Power RF X

High Power RF couplers 4 >4 >8

Superconductingcavities >4 >8

Assembled string of 4 cavities X

Horiz. test cryostat (4 cav.) X

Equipped horiz. test cryostat X

High power RF tests in test cryo. X

Assembled string of 8 cavities X

8 cavities cryomodule X

Equipped cryomodule X

High power RF tests in full CM X

From industry

(ESS)

~ in-phase with ESS

design update

(Courtesy R.Garoby)

WG3: cryomodulesSystem/Activity Responsible/member Lab

Machine architecture F.Gerigk CERN

WG3 coordination V.Parma CERN

Cryo-module design & Integration CERN V.Parma (A.Vande Craen). Team: N.Bourcey, P.Coelho, O.Capatina, D.Caparros, Th.Renaglia

CERN

Cryo-module detailed design/Integration & Cryostat assembly tooling (CNRS)

P.Duthil (P.Duchesne) + CNRS Team

CNRS/IN2P3-Orsay

WG 2 activity (RF cavities/Hevessel/tuner, RF coupler)

W.Weingarten/S.Chel/O.Capatina/E.Montesinos

CERN, CEA-Saclay

Vacuum systems S.Calatroni CERN

Cryogenics U.Wagner CERN

Survey and alignment D.Missiaen CERN

WG3: where to find relevant docs

• Minutes of meetings of the WG3:– https://edms.cern.ch/nav/P:SLHC-000008:V0/P:SLHC-000047:V0/TAB3

• Baseline documentation on cryomodule:– https://twiki.cern.ch/twiki/bin/view/SPL/CryoModules

• Other relevant docs. (collaboration meetings, workshops, reviews…) in the “SPL study” EDMS space:– https://edms.cern.ch/nav/P:SLHC-000008:V0/P:SLHC-000008:V0/TAB3

The SPL study: a new orientationNew objective of the SPL study (after Chamonix 2010 + a first budget cut):

Up to 2013:• Focus on R&D for key technologies for the high intensity proton source (HP

SPL)

In particular:• Development, manufacture and test of high-gradient β=1, 5 cells, 704 MHz

cavities• Development, manufacture and test of RF couplers• Testing of a string of 4 β=1 cavities in machine-type configuration:

Need for a short cryomodule for testing purposes

Short cryo-module: Goal & MotivationGoal:• Design and construct a ½-lenght cryo-module for 4 β=1 cavities (as close as

possible to a machine-type cryomodule)

Motivation:• Test-bench for RF testing on a multi-cavity assembly driven by a single or

multiple RF source(s)• Enable RF testing of cavities in horizontal position, housed in machine-type

configuration (helium tanks with tuners, and powered by machine-type RF couplers)

• Validate by testing critical components like RF couplers, tuners, HOM couplers in their real operating environment

Cryo-module-related goals:• Learning of the critical assembly phases:

– preparation of a long string of cavities in clean room– alignment/assembly in the cryostat;

• Proof-of-concept of the innovative supporting of cavities via the RF couplers• Explore cryogenic operation issues

Planned supplies for the β=1short cryo-module

Institute Responsible person

Description of contribution

CEA – Saclay (F) S. Chel(G.Devanz)

1. Design & construction of 1 β=1 cavities (EuCARD task 10.2.2)2. Design & construction of 5 helium vessels for β=1 cavities

(French in-kind contribution)3. Supply of 8 tuners (French in-kind contribution)

CNRS - IPN – Orsay (F) P. Duthil(P.Duchesne)

1. Design and construction of short cryo-module cryostat (French in-kind contribution)

2. Design & construction of cryostat assembly tools (French in-kind contribution)

CERN O.Capatina 1. 4 β=1 cavities (cavities from industry, surface treatment at CERN)

CERN E.Montesinos 1. 8 +1 RF couplers (testing in CEA, 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

SPL longitudinal layoutstudies

Workshop on cryogenic and vacuum sectorisations of the SPL(November 9-10, 2009)

Large participation from other labs: FNAL, JLAB, SNS, XFEL...

Issues discussed• Machine availability:

• Reliability and operational risks

• Maintainability

• Design and operation complexity

• Installation and commissioning

• Safety. Coping with incidents: Loss of beam and/or insulation vacuum (helium and air leaks):

• Cost

« Continuous » cryostat version (more compact):

HP-SPL length = 485 m (550 m max available space)

« segmented » version (with cryo distribution line):

HP-SPL length = 535 m (550 m max available space)

«Continuous» vs. «fully segmented» SPL layouts

• Drivers:– Availability:

• Reliability/Maintainability. Components with technical risk: calls for quick replacement of complete cryo-module (spares needed)

– Safety: coping with incidents: accidental loss of beam/cavity vacuum:• Cold valves not available (XFEL is considering their development)Adopt warm (moderately fast) interlocked beam vacuum valves

“Segmented” layout with CDL preferred

• Additional advantages:– Magnets warm: less critical, accessible, individual alignment,– Cryo-module alignment requirements can ne relaxed (by a factor of 3)

• Drawbacks:– Less compact layout (~+10% extra lenght) – More equipment (CDL, CWT, instrumentation...):– Higher static heat loads (but dynamic loads dominate!)

Conclusions on sectorisation

β=0.65 cryo-module

β=1 cryo-module

From 8 to 4 cavities…How??

…just remove 4 cavities!

Coping with the “ghost” cavities…

• Assume they still exist and design the systems as if they where there:– Cryogenics (p,T, mass flows)

– Distribution lines (ID, pres.drops)

Cryo-module development

What is cryostat design all about??

But…providing:

• Supporting and stable positioning

• Low (enough) heat inleaks

• Feed-throughs for integrated systems:– Powering (current, RF)

– Cryogenics

– Instrumentation

• Integration of key equip.:– BPM, ancillaries:

– Cryogenic/vacuum equip: phase sep., valves, …

– …

Passive element(cryostat and

ancillaries)

Active element(magnet, cavity…)

Active elements:

- Cavities/tuners- RF couplers

SC CavitiesParameter Units Beta = 1 (nominal/ultimate)Cavity bath temperature [K] 2.0 Frequency [MHz] 704.4

Accelerating gradient [MV/m] 25 Quality factor (x10^9), Qo 10/5 R/Q value 570 Cryogenic duty cycle [%] 4.11/8.22 Dynamic heat load p. cavity [W] 5.1/20.4

Nominal: 40 mA/0.4 ms beam pulse ; Ultimate: 20 mA/0.8 ms beam pulse.

Typical Qo-Eacc curveQoQR

accVPd⋅

=/

2

Power dissipation

What we know (= deterministic) and can cope with

(O.Brunner et al. “Assessment of the basic parameters for the CERN Superconducting Proton Linac”, Phy. Rev. ST Accel. Beams, 12, 070402, (2009))

( )K/

K/18exp

GHz/10n/ 25

TTfRBCS

s

−

⋅⋅=Ω

“Wolgangs’s recipe” (based on BCS and Mattis-Berdeen theory), in CW: fix parameters:

wall thickness = 3 mm Nb (RRR = 100) geometrical length β = 1 residual resistance Rres

with T-dependent surface resistance Rs (Tc/T) thermal conductivity λ nucleate boiling heat transfer coefficient α Kapitza resistance in HeII

under the constraints of max. magnetic field of

Bp = 200 mT∙[1-(T/Tc)2] max. nucleate boiling heat flux in He of 0.5 W/cm2

max. heat flux in HeII of 0.5 W/cm2

Cavity vacuum

helium

Nb wall

T

Kapitza

Bp

for β=1:• 25 MV/m can be achieved (also @ 4.5K)• even more true in pulsed mode

Local cavity surface

What we still do not understand well (stocastic) (the Devil is in the detail!)

(O.Brunner et al. “Assessment of the basic parameters for the CERN Superconducting Proton Linac”, Phy. Rev. ST Accel. Beams, 12, 070402, (2009))

Influencing quantity Impact quantity Physical explanation Cure

Field emission sites (foreign particles sticking to the surface, size, density)

Q – value / acc. gradientγ radiationHOM coupler quench

Modified Fowler-Nordheim-theory

Electro-polishingAssembling in dust-free airRinsing with ultrapure water (control of resistivity and particulate content of outlet water) and alcoholHigh pressure ultrapure water rinsing (ditto)“He- processing”Heat treatment @ 800 – 1400 °C

Secondary emission coefficient δ

Electron-multipacting Theory of secondary electron emission

Rounded shape of cavityRinsing with ultrapure waterBake-outRF - Processing

Unknown Q – slope / Q-drop(Q – value / acc. gradient)

Unknown Annealing 150 °CElectro-polishing

Metallic normal-conducting inclusions in Nb

Acc. gradient Local heating up till critical temperature of Nb

Inspection of Nb sheets (eddy current or SQUID scanning)Removal of defects ( ≈ 1 µm)Sufficiently large thermal conductivity (30 - 40 [W/(mK)])

Residual surface resistance

Q – value / acc. gradient Unknown to large extent

Quality assurance control of a multitude of parameters

Experience from other labs

(O.Brunner et al. “Assessment of the basic parameters for the CERN Superconducting Proton Linac”, Phy. Rev. ST Accel. Beams, 12, 070402, (2009))

So, for β=1: • 16-23 MV/m range possible (90% yield)• 20-30 MV/m within reach (but 50% yield!)

(S.Chel et al. (CEA), 4th SPL Collaboration meeting, Lund, 1st July 2010)

Cavities for the SPL short cryo-module: CEA• 1 cavity (+ ancillaries) from CEA (EuCARD, CNI-PP-SLHC, French in-kind)

– Manufacture in industry (September 2011)

– Surface preparation in Saclay (SupraTech)

– Low power RF tests (vertical cryostat) in Saclay (SupraTech)

– Cavity/helium vessel assy (+ tuner) delivery to CERN: December 2012

Vertical EP station (ready by end 2010)

HP rinsing (in commissioning)Courtesy: S.Chel (CEA/IRFU)

Cavities for the SPL short cryo-module: CERN4 cavities to be made by CERN (joint BE/RF, EN/MME, TE/VSC effort):

• Manufacture: – Nb sheets purchased, now under qualification

– Call for Tender for cavity manufacture: by end 2010

– Cavities manufactured by end 2011

• Surface preparation @ CERN in 2012– EP station in preparation

– Simulation of EP process is ongoing

– Cathode for EP of β = 1 cavities completed to be manufacture by end 2010

Manufacture/surface preparation (using DESY’s recipe for XFEL)

Main manufacturing/surface preparation steps

Spinning of half-cells

Machining for iris and stiffening rings welding preparation

RF measurement of half-cell frequency

Ultrasonic cleaning; Etching (20 µm)

3 µm chemical cleaning if storage time > 8h after previous step

EB welding of the iris from inside

EB welding of stiffening rings

Frequency measurement of dumb-bell

Machining of both equator ends / evaluation of frequency

Ultrasonic cleaning; Etching 20 µm

Anodization of dumb-bell and inspection

Grinding if needed + 20 µm etching, rinsed, dried, anodized again

3 µm chemical cleaning

EB welding from outside of all equators (intermediate 3µm etching)

EP 150 microns

UHV annealing at 800°C

Field flatness measurement

flash BCP 10 microns or final EP 30 microns

alcohol rinsing, drying in class 10

UHV baking at 120°

HPR at 100 bars (6 times), drying in class 10

Dumb-bell (Desy, 1.3 GHz)

Input: O.Capatina (EN-MME)

Pipework and acid tank

Ready to be installed in the safety cabinet foreseen for the treatment

Courtesy: Sergio Calatroni (TE-VSC)

Walk-in booth

All cabling and services connections have been performed

Separated environment with dedicated air washer for safety

Courtesy: Sergio Calatroni (TE-VSC)

Manufacture/processing of cavityMain steps (DESY’s recipe for XFEL)

Spinning of half-cells

Machining for iris and stiffening rings welding preparation

RF measurement of half-cell frequency

Ultrasonic cleaning; Etching (20 µm)

3 µm chemical cleaning if storage time > 8h after previous step

EB welding of the iris from inside

EB welding of stiffening rings

Frequency measurement of dumb-bell

Machining of both equator ends / evaluation of frequency

Ultrasonic cleaning; Etching 20 µm

Anodization of dumb-bell and inspection

Grinding if needed + 20 µm etching, rinsed, dried, anodized again

3 µm chemical cleaning

EB welding from outside of all equators (intermediate 3µm etching)

EP 150 microns

UHV annealing at 800°C

Field flatness measurement

flash BCP 10 microns or final EP 30 microns

alcohol rinsing, drying in class 10

UHV baking at 120°

HPR at 100 bars (6 times), drying in class 10

Freq.measurement (DESY 1.3 GHz dumb-bell)

Spinning trials at CERN

(S.Chel et al. (CEA), 4th SPL Collaboration meeting, Lund, 1st July 2010)

“Dressed” Cavity (CERN mods of CEA’s design)

Includes specific features for cryo-module integration (inter-cavity supports, cryogenic feeds, magnetic shielding …)

Cavity (Nb)He vessel (Ti)Tuner

RF coupler port

Magnetic shielding (cryoperm™)

HOM port

Th.Renaglia, EN-MME

Pumping port

Cool-down line port

March 2010 SPL Coupler Review:Launch Coaxial and Cylindrical air cooled couplers

Keep open the three possible designs:

• SPL-CEA HIPPI coaxial disk water cooled window (if necessary, to be modified with an air cooled window)

• SPL-SPS coaxial disk air cooled window

• SPL-LHC cylindrical air cooled window

All use the same double walled tube

All use the same vacuum gauge, electron monitor and arc detector

All designed to be compatible without modifying the cryomodule

42

SPL coupler with LHC Window

SPL coupler with SPS Window

Fourth SPL Collaboration Meeting - Jointly with ESS, Lund, June 2010.

Courtesy E. Montesinos, Ed Ciapala (BE-RF)

Coaxial disk air cooled window (SPS window)

43

Antenna and outer ceramic air cooling

Ceramic and waveguide air cooling

Spring washers

RF contact

SPS Window: very simple brazing process

RF contact without stress to the ceramicby compression of the outer line through the air “cane”

Air “cane”

Fourth SPL Collaboration Meeting - Jointly with ESS, Lund, June 2010.

Courtesy E. Montesinos, Ed Ciapala (BE-RF)

Putting it all together

Actively cooled RF coupler tube

Vacuum vessel

Heater

Helium gas cooling the double wall

4.5 K

300 K

No cooling T profile 21W to 2K

Cooling (42 mg/sec) T profile 0.1 W to 2K

SPL coupler double walled tube, active cooling to limit static heat loads• Connected at one end to cavity at 2K, other end at RT (vessel)• Requires elec. Heater to keep T > dew point (when RF power off)

(O.Capatina, Th.Renaglia)

Massflowmgram/sec

21 23 28 35 42

Power ON OFF ON OFF ON OFF ON OFF ON OFF

Temp.gas out

286 K 277 K 283 K 273 K 271 K 242 K 255 K 205 K 232 K 180 K

Q thermal load to 2K

2.4 W 0.1 W 1.7 W 0.1 W 0.4 W 0.1 W 0.1 W 0.1 W 0.1 W 0.1 W

Q heater 19 W 32 W 21 W 34 W 29 W 38 W 39 W 41 W 46 W 44 W

∆L 0.1 mm

(0.63-0.53)mm0.05 mm

(0.66-0.61)~ 0 mm

(0.67-0.67)

Yields a certain degree of position uncertainty (<0.1 mm?)

Vacuum vessel

Coupler position: top or bottom...?

Pros ContrasEasier mounting of waveguides

Interferes with bi-phase tube move sideways

Easier access (needed?) Waveguides/coupler more exposed to personnel/handling (damage, breaking window?)

... ...

Pros ContrasCentered bi-phase tube symmetry

Space needs for waveguides under cryostat

Waveguides/coupler protected

If coupler not a support (bellows) support on top, i.e. centered tube not possible

... ...

No strong decision-making argument...

HOM coupler• Provisions made to house an HOM coupler (resonator type)• Port foreseen opposite to RF coupler port• Superconducting, cooled at 2K• The HOM coupler needs to be on top• ...so the RF coupler is at the bottom

e.g. LHC HOM coupler

HOM port

RF coupler port

Cavity Supporting System: alignment

BUDGET OF TOLERANCE

Step Sub-step Tolerances (3σ) Total envelopes

Cryo-module assembly

Cavity and He vessel assembly ± 0.1 mm Positioning of the cavity w.r.t. beam axis

± 0.5 mmSupporting system assembly ± 0.2 mm

Vacuum vessel construction ± 0.2 mm

Transport and handling (± 0.5 g any direction)

N.A. ± 0.1 mm

Stability of the cavity w.r.t. beam axis

± 0.3 mmTesting/operation

Vacuum pumping

± 0.2 mm

Cool-down

RF tests

Warm-up

Thermal cycles

Cons

truc

tion

prec

isio

nLo

ng-t

erm

sta

bilit

y

Transversal position specification

Comparing supporting solutions

A) Coupler supporting scheme B) “standard” supporting scheme

Pros ContrasDesign simplicity: cost effectiveness

Vacuum vessel:- Stiffness (thickness,stiffeners)- Dim. stability- Precision machining- Cost

Single cavity adjustment at assy

Positioning stability(thermal, weld relieving...)

Inter-cavity guiding

Pros ContrasBetter mechanical isolation of cavities from external perturbations: dim.changes (thermal, weld relieving), vibrations...

Design complexity and cost

Vacuum vessel simplicity:-Reduced machining precision- reduced thickness

Central support needed (?)

Complex cavity adjustment at assy

A) Chosen as baseline (“simple is nice”)

Note: supported by calculations made by Paulo Azvedo Coelho, TE-MSC fellow

Need inter-cavity support structure?

l- If sag small enough- If strenght OK- isostatic

- couple cavities- hyperstatic

No

Yes

Equivalent sketchLayout

inter-cavity guides

P.Coelho Moreira de Azevedo

Inter-cavity supports

Scheme of link between cavities:

The stainless steel cylinders have a length of 420 mm and a diameter of 40mm.P. Coelho, TE-MSC

W Wtuner (x4) Wcav (x4)

Vertical displacement in mm - body deformation amplified 100 times

The cavities are not part of the model. The loads are the distributed weight of the represented components, tuners and cavities.

P. Coelho, TE-MSC

Vertical deflections < 0.15 mm, considered acceptable

He vessel and cavity

Vertical displacement (m); Total deformation amplified 300x.

WWtuner

Cavity Max. Displacement – 0.18 mm

He Vessel Max. Displacement – 0.10 mm

P. Coelho, TE-MSC

Assembly possibilities...

• Single-window RF coupler needs assembly to cavities in clean room

• Defines minimum diameter of “pipeline” type vessel:– Lenght of double-walled tube– Integration of thermal shield

A) Either...

B) Or...

• Simple in the cross section...But...• Non trivial design of end-caps• Leak-tightness: seal? welded?

Cryogenics

Heat Loads (per cavity)Heat loads @ 2K (He bath) beta=0.65 beta=1

nominal/ultimate

beam loss 1 W 1 W

static losses <1 W (tbc) <1 W (tbc)

accelerating field 19.3 MV/m 25 MV/m

quality factor 6/3 x 109 10/5 x 109

cryo duty cycle 4.09%/8.17% 4.11%/8.22%

power coupler loss at 2 K <0.2/<0.2 W <0.2/<0.2 W

HOM loss in cavity at 2 K <1/<3 W <1/<3 W

HOM coupler loss at 2 K (per coupl.)

<0.2/<0.2 W <0.2/<0.2 W

dynamic heat load per cavity 4.2/16.8 W 5.1/20.4 W

Total @ 2 K 7.6/22.2 W 8.5/25.8 W

+15% margin (for testing) 8.7/25.3 W 9.8/30 W

(For 8 beta=1 cavity cryomodule: 8x30=240W, equivalent to 11.5 g/s helium flow)

Where are we on the phase diagram?

31 mbar

Slightly pressurized (ϱgz 1.4-7 mbar)

Tsat +25-100 mK

Cryogenic scheme (latest version)

EE’ C

C2

XB

X YC3C1

L

U.Wagner, TE-CRG

Filling and cooling Lines X and Y

• Line X– Bi-phase saturated helium, co-current two-phase flow

– “Roman fountains” on string of cavities (excess liquid pours to next cavity)

– Limit gas mass flow to preserve stratification (avoid liquid droplets entrainment): for ID 100, with m= 11 g/s v< 2 m/s , OK

• Line Y– Heat extraction in LHeII (minimum X section) ID80 OK

– On highest point of He vessel can evacuate vapours if operated @ 4.5 K– Local cavity filling (line C3, for prototype only?)

– Local level measurement (for prototype only?)

– Local feed-through of cool-down line (C1)

C3LT

C1

C1

Pipe sizes and T, p operating conditions

Short cryomodule: layout sketch

Connection to cryo distribution line

CW transition

RF coupler, bottom left sideCavity additional support

1.7% Slope (adjustable -2% to +2%)

Cryo fill line (Y), top left Technical Service Module

EndModule

Phase sep.

A.Vande Craen (MSC-CI)

Master Schedule

Preliminary Design Review

Detailed Design Review

Start of assembly at CERN

Summary and Next steps• Despite budget cuts, the SPL study is now well settled in CERN’s MTP and enjoys a

great interest from external labs and projects

• Existing collaborations (French institutes in particular) are well in progress and momentum is catching up with ESS (=resources round the corner)

• Major components are in preparation: Cavities, tuners, couplers…

• CERN is learning back about cavities manufacture, profiting from CEA and XFEL experience

• CERN is setting up its own surface treatment facilities for EP processing

• Cryomodule conceptual design well advanced

Next steps:

• Short Cryo-module specification meeting: 19th October next– Address Test plan in SM18

– Discuss/freeze requirements for the short cryomodule

• 5th Collaboration meeting (workshop): CERN, 25th-26th November next

• Short Cryomodule Preliminary Design Review: beginning of 2011

Thank you for your attention!

SPL

“The Sacred Bird”

Spare slides

“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

“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 (where warm quads can be)• 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

Cryogenic-specific parameters(https://twiki.cern.ch/twiki/bin/view/SPL/SPLparameterList, by F.Gerigk)

Parameter Units Beta = 0.65 Beta = 1nominal/ultimate nominal/ultimate

Cavity bath temperature [K] 2.0 2.0 Beam loss [W/m] 1.0 1.0 Static loss along cryo-modules at 2 K [W/m] TBD TBD

Static loss at 5-280 K [W/m] TBD TBDAccelerating gradient [MV/m] 19.3 25 Quality factor (x10^9) 6/3 10/5 R/Q value 290 570 Cryogenic duty cycle [%] 4.09/8.17 4.11/8.22 Coupler loss at 2.0 K [W] <0.2/0.2 <0.2/0.2 HOM loss at 2.0 K in cavity [W] <1/<3 <1/<3

HOM coupler loss at 2.0 K (per coupler) <0.2 /0.2 <0.2/0.2

HOM & Coupler loss 5-280 K [g/s] 0.05 0.05 Tunnel slope [%] 1.7% 1.7% Magnet operating temperature [K] ambient ambient

No of cavities 60 200 No of cryostats 20 25 Cavities per cryostat 3 8 Dynamic heat load p. cavity [W] 4.2/16.8 W 5.1/20.4 W

Nominal: 40 mA/0.4 ms beam pulse ; Ultimate: 20 mA/0.8 ms beam pulse.