650 MHz Cryomodule Design, 21 Feb 2011Page 1650 MHz Cryomodule Design, 21 Feb 2011Page 1 Project X Cryomodules Tom Peterson and Yuriy Orlov with material

650 MHz Cryomodule Design, 21 Feb 2011 Page 1650 MHz Cryomodule Design, 21 Feb 2011 Page 1Page 1

Project X Cryomodules

Tom Peterson and Yuriy Orlov

with material from our SRF cavity and cryomodule design team

21 February 2011

650 MHz Cryomodule Design, 21 Feb 2011 Page 2650 MHz Cryomodule Design, 21 Feb 2011 Page 2

Project X Reference Design

Cryomodules for CW linac

Page 3

SRF LinacTechnology Map

=0.11 =0.22 =0.4 =0.61 =0.9

325 MHz2.5-160 MeV

=1.0

1.3 GHz3-8 GeV

650 MHz0.16-3 GeV

Section Freq Energy (MeV) Cav/mag/CM Type

SSR0 (G=0.11) 325 2.5-10 18 /18/1 SSR, solenoid

SSR1 (G=0.22) 325 10-42 20/20/ 2 SSR, solenoid

SSR2 (G=0.4) 325 42-160 40/20/4 SSR, solenoid

LB 650 (G=0.61) 650 160-460 36 /24/6 5-cell elliptical, doublet

HB 650 (G=0.9) 650 460-3000 160/40/20 5-cell elliptical, doublet

ILC 1.3 (G=1.0) 1300 3000-8000 224 /28 /28 9-cell elliptical, quad

CW Pulsed

InPAC 2011 – J. Kerby Page 3


Design team

• 650 MHz cryomodules – Camille Ginsburg, Yuriy Orlov, and Prashant Khare

are leading and organizing the effort with me

• Cavities, input couplers, magnets, magnet current leads, tuners, instrumentation, 325 MHz cryomodules, microphonics, etc. – Many other people within Fermilab and within the

Project X collaboration


Approach

• CW cryomodules with as much as 25 W per cavity at 2 K and tight constraints on cavity frequency present some different problems from TESLA/ILC cryomodules – Over 200 W at 2 K per cryomodule as opposed to

about 12 W at 2 K per cryomodule

• Let’s look at the requirements, consider what other labs have already done, and select best features for our own design


Our plan

• Analyses, modeling, and reviews of various concepts based on existing designs

• Following visits to HZB, DESY, and TTC meeting (Feb 21 - Mar 3), down-select a more specific design approach – Goal is to have a specific 650 MHz cryomodule

design proposal for discussion before the Project X Collaboration meeting (April 11)

– Also complete (draft) specifications and fundamental CM parameter lists in this timeframe


General arrangements under consideration

• Segmentation level and cavity support structure – String: BESSY/HZB (and Cornell ERL) liquid managed

separately for each CM, 2-phase pipe closed at each end, but otherwise a string, TESLA style piping and supports

– Stand-alone: three options for configuration at the individual cryomodule level

• Completely close a TESLA style CM at each end • Eliminate 300 mm pipe -- space frame support• Eliminate 300 mm pipe -- support posts and frame (325 MHz

concept from Tom Nicol)

• Helium vessel – Closed, TESLA-style, 2-phase pipe connected to helium vessel – Open, Jlab/SNS style, 2-phase flow through helium vessel


Cryomodule style

• Very high heat flux (200 W per CM) and relatively short linac (not large quantity production nor several km long strings) ==> – Need separated liquid management – Prefer small heat exchangers, distributed with cryomodules – Prefer stand-alone cryomodules, warm magnets and

instrumentation between cryomodules like at SNS

• Stand-alone CM ==> – “300 mm” pipe is unnecessary for helium flow

• Not need 300 mm pipe for helium flow ==> – Empty 300 mm pipe as support ‘backbone” or – Different support structure (space frame or posts)


Helium vessel style

• Helium vessel style (open vs. closed) is independent of support style (hung from 300 mm pipe or not)

• High heat loads and tight pressure stability ==> – Large liquid-vapor surface area for liquid-vapor equilibrium – Acts as thermal/pressure buffer with heat and pressure changes

• Linac is short enough that total helium inventory not an issue ==> – Open helium vessel is feasible

• For the stand-alone CW cryomodule, a closed TESLA-type helium vessel may be favored by – Tuner design – Input coupler design – And allowed by reduced pressure sensitivity


SNS vs TTF cryomodule

TTF: vacuum vessel string. End boxes and bellows would become part of vacuum/pressure closure

SNS (like CEBAF): self-contained vacuum vessel “stand-alone” style


Cryomodule requirements -- major components

• Eight (8) dressed RF cavities • Eight RF power input couplers • One intermediate temperature thermal shield • Cryogenic valves

– 2.0 K liquid level control valve – Cool-down/warm-up valve – 5 K thermal intercept flow control valve

• Pipe and cavity support structure • Instrumentation -- RF, pressure, temperature, etc. • Heat exchanger for 4.5 K to 2.2 K precooling of the liquid

supply flow • Bayonet connections for helium supply and return


Cryomodule requirements -- major interfaces

• Bayonet connections for helium supply and return • Vacuum vessel support structure • Beam tube connections at the cryomodule ends • RF waveguide to input couplers • Instrumentation connectors on the vacuum shell • Alignment fiducials on the vacuum shell with reference to

cavity positions.


Cryomodule requirements -- slot length

650 MHz cavities at 2 K

Warm magnets and instrumentation 11.3 meters


Cryomodule requirements -- thermal

2 K heat load basis for pipe size*per cavity (W) 38.75

per cryomodule (W) 311.775 K heat load basis for pipe size*

per cryomodule (W) 50.4870 K heat load basis for pipe size*

per cryomodule (W) 653.46

*Heat loads for pipe sizing include uncertainty/design factor 1.5

• Cavities at nominally 2 K – 1.8 K to 2.1 K, to be determined

• One radiative thermal shield at nominally 70 K – 35 K to 80 K to be determined

• Thermal intercepts at nominally 5 K and 70 K


Cryomodule requirements -- vessel and piping pressures


Design considerations

• Cooling arrangement for integration into cryo system • Pipe sizes for steady-state and emergency venting • Pressure stability factors

– Liquid volume, vapor volume, liquid-vapor surface area as buffers for pressure change

• Evaporation or condensation rates with pressure change

• Updated heat load estimates• Options for handling 4.5 K (or perhaps 5 K - 8 K) thermal intercept

flow • Alignment and support stability • Thermal contraction and fixed points with closed ends

• Etc.


Cryomodule Pipe Sizing Criteria

• Heat transport from cavity to 2-phase pipe – 1 Watt/sq.cm. is a conservative rule for a vertical pipe (less heat

flux with horizontal lengths)

• Two phase pipe size – 5 meters/sec vapor “speed limit” over liquid – Not smaller than nozzle from helium vessel

• Gas return pipe (also serves as the support pipe in TESLA-style CM)– Pressure drop < 10% of total pressure in normal operation– Support structure considerations

• Loss of vacuum venting P < cold MAWP at cavity – Path includes nozzle from helium vessel, 2-phase pipe, may

include gas return pipe, and any external vent lines



Concept -- TESLA style with open pipe as support

• Use an open 300 mm dia pipe as the support structure backbone – Open to insulating vacuum – Direct connection from 2-phase pipe to vapor return

line via heat exchanger – Direct connection from 2-phase pipe to vent line – 2-phase pipe sized large for venting from one end

• Advantages – 300 mm pipe open for handling with present tooling – No end forces on 300 mm pipe or connections to it


Stand-alone cryomodule schematic


End Plate

Beam

650 MHz Cryomodule (Tesla Style-Stand Alone)

Power MC (8)

Vacuum vesselCold mass supports (2+1)


Fix. support Sld. supportSld. support

300mm pipe (backbone)650 MHz cavity

Gate valveEnd plate

650 MHz layout


-48” vacuum vessel 300 mm pipe

-80K shield, pipes:(Nom: 35mm-ID)

-Warm up-cool downpipe (nom 25mm ID)

-4K return pipe(nom 25mm ID)

-650 MC

-Thermal interceptto MC 80k & 4K

-2-Phase pipe(161mm-ID)

-80K Forward pipe

-4K Forward pipe (?)

-Thermal intercept2-phase pipe to300mm pipe (?)

X-Y section


Heat exchanger(Location on themiddle of CM650??)

300mm pipe

Cryo-feed snout withcryogenic connections(Location on the middle of CM650??) Gate Valve

650 MHz cryomodule. End plate not shown.

Access to bayonetconnections

Access toHX and U-turnconnections


Two He reservoirswith level sensor

Cavity needle supportsVAT needle supports (?)

Cavity string & 300mm pipe upstream side

Heat exchangerVent line with check valve2-phase pipeconnection to HX

650 MHz Cryomodule Design, 21 Feb 2011 Page 26

Cavity string & 300mm pipe downstream side

2-phase pipeThermal compensatorBlank Flange support


Dressed cavity 650 MHz. (proposal) with MC cold-part

Ti Helium vessel OD- 450.0 mmTi 2-Phase pipe ID- 161.5 mmTi 2-Phase chimney ID- 95.5 mm


Other concepts

• Single Spoke Resonator cryostat concept using support posts under the cavities and magnets – We may adapt that design to a 650 MHz CM

• SNS/Jlab 12 GeV upgrade style “space frame” supports – Well-developed design, works well

• BESSY/HZB CW cryomodule string rather than stand-alone cryomodules – Eliminate external transfer line (?)

• Cornell’s ERL cryomodule has some interesting features to consider although somewhat different issues


Conclusions

• Many very good ideas and much work have already gone into cryomodule design

• Systems are different with differing requirements – Generally means adapting but not copying design

concepts

• We greatly appreciate the exchange of ideas and information which have been and will continue to be an important part of our work

650 MHz Cryomodule Design, 21 Feb 2011 Page 30

Backup slides


Cryo Schematic -- flow through 300 mm pipe


Empty pipe for support only or no 300 mm pipe


SSR1 CM concept


Vacuum vesselCold mass650 MHz Cavity

2 Support posts for each cavity:Z-fix & Z-free Cavity MC port-stabile

Heat Exchanger pipe2- phase He pipe (Ti)

650 MHz Cryomodule layout (follwing SSR concept)


Control valvesBayonet connection

Heat exchangerVent line with check valve

650 MHz Cryomodule (following SSR concept)

Beam pipe:at the center of CM650


Heat exchanger

Cryo feed snout

80K shieldingCold mass trayTray supports

650 MHz Cryomodule section. (SSR-style concept)

Vacuum vessel pipe-48”OD

XFEL style cavity(SNS style)


Jlab space frame


Jlab space frame


Jlab space frame


Separate liquid management in each cryomodule but no external transfer line


ERL injector cryomodule


ERL cryomodule features

Figure 1 from CRYOGENIC HEAT LOAD OF THE CORNELL ERL MAIN LINAC CRYOMODULE, by E. Chojnacki, E. Smith, R. Ehrlich, V. Veshcherevich and S. Chapman, Cornell University, Ithaca, NY, U.S.A.

Published in Proceedings of SRF2009, Berlin, Germany


ERL cryomodule features

• TESLA-style support structure -- dressed cavities hang from gas return pipe (GRP), but– Titanium GRP – No invar rod, no rollers – 6 cavities per CM, 9.8 m total CM length – HOM absorbers at 40 - 100 K between cavities– GRP split with bellows at center, 4 support posts – Helium vessels pinned to GRP – Some flexibility in the input coupler – De-magnetized carbon-steel shell for magnetic shielding (this is

like TTF) – 2-phase pipe closed at each CM end, JT valve on each CM (like

BESSY design) – String rolls into vacuum vessel on rails


RRCAT contributions

• RRCAT (Indore) is collaborating with Fermilab on 650 MHz cryomodule designs – Present focus is TESLA-style



SCRF Cavity supported on HGR pipe

Information required on

Magnet package Tuner details Power Coupler

Glimpses of 3-D Model (contd…)

The model incorporates a modified Cavity support system.

2K helium supply line includes a bellow in vertical configuration


Thermal Shield with dressed Cavity

80K- Thermal shield 5K-Thermal shield is partial (Upper Part only).

Thermal shield 80K shield .

Thermal shield 5K shield is partial.

Glimpses of 3-D Model (contd…)

Documents

650 MHz Cryomodule Design, 21 Feb 2011Page 1650 MHz Cryomodule Design, 21 Feb 2011Page 1 Project X Cryomodules Tom Peterson and Yuriy Orlov with material