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Project X 650 MHz Cryomodule Conceptual Design. Yuriy Orlov, Tom Peterson (Fermilab). 650 MHz Cryomodule, 30 November 2011. Page 1. Page 1. Project X Reference Design. Cryomodules for CW linac. Page 2. Project X Cryomodules. =0.9 is the present focus of our 650 MHz cryomodule work.
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Project X 650 MHz Cryomodule Conceptual Design Yuriy Orlov, Tom Peterson (Fermilab) 650 MHz Cryomodule, 30 November 2011 650 MHz Cryomodule, 30 November 2011 Page 1 Page 1
Project X Reference Design Cryomodules for CW linac 650 MHz Cryomodule, 30 November 2011 Page 2
Project X Cryomodules =0.9 is the present focus of our 650 MHz cryomodule work 650 MHz Cryomodule, 30 November 2011
Design team 650 MHz cryomodule team leaders Tom Peterson (650 MHz cryomodule subproject manager) Camille Ginsburg (650 MHz cavity subproject manager) Yuriy Orlov (Fermilab 650 MHz cryomodule point of contact) Prashant Khare (Indian Institutions 650 MHz cryomodule point of contact) 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 650 MHz Cryomodule, 30 November 2011 Page 4
Design 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 (Project X beta=0.9) as opposed to about 12 W at 2 K per cryomodule (ILC estimate) We have a (draft) requirements document and fundamental CM parameter lists Analyses, modeling, and reviews of various concepts based on existing designs 650 MHz Cryomodule, 30 November 2011 Page 5
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 over one or a few cryomodules Prefer small heat exchangers, distributed with cryomodules Prefer stand-alone cryomodules, allowing 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 (posts, tension rods, space frame) 650 MHz Cryomodule, 30 November 2011 Page 6
Draft requirements document 650 MHz Cryomodule, 30 November 2011
Summary from cryomodule requirements document 1.1 The baseline design concept includes cryomodules closed at each end, individual insulating vacuums, with warm beam pipe and magnets in between cryomodules such that individual cryomodules can be warmed up and removed while adjacent cryomodules are cold. 1.2 Provide the required insulating and beam vacuum reliably 1.3 Minimize cavity vibration and coupling of external sources to cavities 1.4 Provide good cavity alignment (<0.5 mm) 1.5 Allow removal of up to 250 W at 2 K per cryomodule 1.6 Protect the helium and vacuum spaces including the RF cavity from exceeding allowable pressures. 1.7 Intercept significant heat loads at intermediate temperatures above 2.0 K to the extent possible in full CW operation 1.8 Provide high reliability in all aspects of the cryomodule (vacuum, alignment stability, mechanics, instrumentation) including after thermal cycles 1.9 Provide excellent magnetic shielding for high Q0 1.10 Minimize cost (construction and operational) 650 MHz Cryomodule, 30 November 2011 Page 8
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 650 MHz Cryomodule, 30 November 2011 Page 9
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. 650 MHz Cryomodule, 30 November 2011 Page 10
Cryomodule requirements -- slot length 650 MHz cavities at 2 K 11.3 meters Warm magnets and instrumentation 650 MHz Cryomodule, 30 November 2011 Page 11
Cryomodule requirements -- thermal 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 650 MHz Cryomodule, 30 November 2011 Page 12
Cryomodule requirements -- vessel and piping pressures 650 MHz Cryomodule, 30 November 2011 Page 13
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. 650 MHz Cryomodule, 30 November 2011 Page 14
Design status 650 MHz Cryomodule, 30 November 2011
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 String assembly and handling in clean room follows DESY and Fermilab experience regarding support, tooling, etc. 300 mm pipe open for handling with present tooling outside of clean room No end forces on 300 mm pipe or connections to it 650 MHz Cryomodule, 30 November 2011 Page 16
Alternate cool-down valve connection 650 MHz Cryomodule, 30 November 2011
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, 30 November 2011 Page 28