Spoke section of the ESS linac: - the Spoke cryomodules - the cryogenic distribution system P. DUTHIL (CNRS-IN2P3 IPN Orsay / Division Accélérateurs) on behalf of the IPNO team and ESS colleagues March 8 th 2016

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 2 Thermal shield T°  80 K Supports A cryomodule: what is it and what for? Thermal conduction Introduction RF electro magnetic wave (352 MHz) Superconducting radiofrequency (SRF) cavity T°  4 K Thermal radiation Room T° Vacuum 1/ To provide a cryogenic environment to the cold mass (cavity) = horiz. cryostat: - distributing the cryofluids to cool-down and maintain at cold T° (LHe, LN 2 ) - limiting the heat loads Vessel

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 3 A cryomodule: what is it and what for? Supports Introduction Vacuum vessel 2/ To support the cavities and perform accurate alignment - with respect to the beam axis - with respect to other linac components (cryomodules, diagnostics, tunnel) NB: alignment must be preserved during thermal and pressure cycles Supports Tunnel Cryomodule Diag

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 4 A cryomodule: what is it and what for? Introduction Vacuum vessel 3/ To offer magnetic shielding - from the local magnetic sources - from the earth magnetic shield NB: the magnetic shield might be cooled (for better performances) Magnetic shield

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 5 A cryomodule: what is it and what for? Introduction Vacuum vessel 4/ To provide all interfaces between the cavity and the tunnel: - beam pipe - RF - cryogenic - vacuum - diagnostic (instrumentation) - mechanical (support and alignment)

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 6 The European Spallation Source (ESS) LINear ACcelerator ESS MACHINE Moderated neutrons To experiments lines Protons SRF linac (T=2K)Warm linac Top-level requirements Pulse length (ms)2.86 Energy (GeV)2 Peak current (mA)62.5 Pulse repetition frequency (Hz)14 Average power (MW)5 Peak power (MW)125 ESS Linac is special and innovative: Mainly based on SRF (Superconducting Radio Frequency ) technology Very powerful (~4 times higher than SNS) First accelerator to use (double) Spoke cavities Challenging accelerating gradients

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 7 The European Spallation Source (ESS) LINAC CNRS CONTRIBUTION (CNRS/IN2P3/IPNO) ESS MACHINE Moderated neutrons To experiments lines LENGTH: SRF LINAC: ~312 m Elliptical section (~256 m): -design of the 40 cryomodules (collaboration with) P SRF cavity cooling: 2 K in saturated He II bath (  simple techno.+ few energy stored + pressure control) Design, construction and installation of the Spoke section (~56 m)

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 8 Spoke section x 13 VALVE BOX SPOKE CRYOMODULE -13 cryomodules -Spoke Cryogenic Distribution System (CDS): o 13 valve boxes (managing cryofluids distribution and cryogenic process) o Cryogenic Distribution Line (CDL)

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 9 The ESS Spoke cryomodule Spoke section Vacuum vessel Cryodistribution Interface to VB 2,86 m

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 10 The ESS Spoke cryomodule Cryomodule heat facts 2 double Spoke 2 K (sat. HeII): Dynamic heat loads: 2 x 2.5 W Beam loss: 1.5 W 2 RF power couplers 2 x 1,75 2 K Heat intercept: SHe 3 bara; K Liquefaction power: 2 x 0.50 g/s Rest of static heat 2 K: ~ 6,5 W Spoke section 2 spoke cavities 2 Magnetic shields Cavities Supporting system Instrumentation (measurement of T, P, cryo levels) 2 RF power couplers 2 Cold to warm transitions

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 11 The ESS Spoke cryomodule Cryomodule heat facts 1 thermal shield + heat intercepts: K Spoke section Thermal shield Instrumentation (measurement of T, P, cryo levels) 2 Cold to warm transitions

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 12 Spoke section Flow scheme (PID): machine version Cryo Distribution line Valve box Cryomodule x 13

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 13 Spoke section Flow scheme (PID): machine version Key features: All cryovalves are in the valve box (none in the cryomodule) He II locally produced in the valve box by: - isobaric cooling (subcooler 2,5 g/s) - JT expansion RF coupler heat intercept: SHe (3 bara; K)  liquefaction power  26 x 50 mg/s ESS cryoplant supplies: He: 3 bara; 4.5 K He: 20 bara; 40 K

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 14 Prototyping the Spoke section Prototype Valve box Prototype Cryomodule Uppsala univ. IPNO A prototype and test valve box: Prototype valve box  to validate the valve box concepts  to validate the prototype Spoke cryomodule Test valve box  to validate 13 series Spoke cryomodules  Compromise between an optimized test stand and a demonstrator (cryoprocess, assembly) A versatile (flexible) valve box Tests at IPNOrsay (FRANCE) Tests at Uppsala University (SWEDEN)  To manage different cryogenic infrastructures ESS Series cryomodules and test

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 15 Prototyping the Spoke section Flow scheme (PID): prototype version Main differences with machine: Instrumentation Saturated LHe supply Saturated LN 2 supply  phase separator in the VB  same subcooler  RF coupler heat intercept cold sat vapours used (instead of SHe)  Interfaces with the infrastructures

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 16 The Spoke cryomodule prototype Cryomodule thermal shield Material: Al6062 Thickness: 2 mm He 20 bars (machine) Sat N 2 (Proto) Thermal shield fabricated Assembled and supported (rods) Instrum. and cool-down test  K

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 17 Other components (all are fabricated) The Spoke cryomodule prototype Gate valves Gate valves Assembly tests Assembly tests Smaller/less parts inside the clean room Smaller/less parts inside the clean room Thermal optimization Thermal optimization Cold warm transitions Cold warm transitions 2 x 0,5 2 K

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 18 The Spoke cryomodule prototype Cavities magnetic shield Tuner side ends Cavity bellow side ends External shield Coupler shield Internal shield Cooling circuit Shield support Shrim Material: Cryophy® Actively cooled (better performances) Magnetic shields fabricated Assembly test performed To be tested within the cryomodule

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 19 Prototype valve box Prototype Spoke valve box He phase separator Cryodistribution line Cryoliquids supply Cold vapours exhaust

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 20 Prototype Spoke valve box status Cryodistribution components He/He Heat exchanger Cryodistribution piping Vacuum vessel Instrumentation

P. DUTHIL - 8-O-2A-1 – ICEC2016 March 08 th 21 Conclusion Crymodule components All components received Assembly phase started start of real components assemblies but also test of the assembly procedures Cool-down of the thermal shield started (heat loads + time constant) Spoke prototype valve box Manufacturing still under progress (instrumentation) Cryogenic IPNO this spring.

Thank you for your attention CSP12 28 Novembre 2014