Pierre BOSLAND, CEA SaclayExternal WP5 leader

Christine Darve,ESS deputy WP leader

www.europeanspallationsource.seApril 21, 2015

Accelerator / Elliptical Cavities Cryomodules

MEDIUM-β HIGH-ββ 0.67 0.86

# CM 9 21

Cav. /CM 4 4

# Cav. 36 84

CM L [m] 6.584 6.584

Sector L [m] 77 179

Proton BeamElliptical cavities CryomodulesMedium-b and high-b

Annual Review 23rd April 2015 2

Elliptical Cryomodules Overview

Schedule

Technical performances

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Selected requirements:

Frequency: 704,42 MHz

Nb superconducting cavities at 2K: medium beta cavities: 6 cell at bgeo =0,67 high beta cavities: 5 cell at bgeo =0,86

Nominal accelerating gradients Eacc corresponding to 45MV/m peak field : 16,7MV/m : medium beta cavities 19,9MV/m : high beta cavities

Max RF power dissipation at nominal gradient corresponding to Q0=59 (RF duty cycle: 4,7%):– Medium beta cavities: 4,9W – High beta cavities: 6,5W

Maximum RF peak power: 1,1MW

No HOM coupler: All higher order modes (HOMs) shall be at least 5 MHz away from integer multiples of the beam-bunching frequency (352.21 MHz) for any HOMs whose resonant frequencies are below the cut-off frequency of the beam-pipe.”

The level-4 requirements for the medium and high beta cryomodules are listed in the DOORS management system (Dynamic Object-Oriented Requirements System).

Conformance of the design with these requirements has been presented at a-TAC (October 2013).

Similar to CEBAF/SNS cryomodule concept with 4 cavities per cryomodule Common design for medium (6 cells) and high beta (5 cells) cavities

Proton Beam

Jumper connection

Cold to warm transition

Magnetic shielding

Power couplerCavity with Helium tank

Diphasic He pipe

Thermal shielding

Regulation He valve

Intercavities belows

Vacuum valve

Spaceframe support Heat exchanger

Alignement fiducial

5Annual Review 23rd April 2015

Selected technologies

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Selected technologies

Segmented cryomodules 6,6 m long - beam gate valves4 cavitiesPower couplers located below the cavitiesSpace frame holding the cavity string

Superconducting elliptical cavities :Bulk niobiumStiff cavities to reduce the Lorentz force detuningNo HOM couplers

RF power coupler:HIPPI type coupler tested up to 1,2MW at 10% DC and pulse length of 2msNew door knob equiped with a bias system and RF trap

TunerHIPPI tuner modified with a second piezo stack for reliability improvement

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• Volumes of the helium circuits and vessels < 50 l• 1,431 bars< Working pressure• Ps = 1,9 bars

TUV Nord analysis report:The elliptical cryomodules are

classified according to PED article 3.3

Compliance with European PED 97/23/EC

Cryo pipes designed to reduce the overpressure in case of beam vacuum failure

continuous diphasic pipe F=100 with large

curvatures

2 F=100 bursting disks at each extremity

Annual Review 23rd April 2015

Both prototype cavities met the ESS requirements after the first test: very encouraging results!

Slight degradation of performances after thermal treatment for hydrogen removing (pollution) 8

P01 - E. ZANON

P02 - RI

Protypes with HOM ports for RF measurement

Annual Review 23rd April 2015

Integration and VerificationTwo high beta prototype cavities

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Dangerous Higher Order Mode close to 1408.8 MHz

704 MHz

1421,32 MHz

Slater coefficient analysis which represents frequency sensitivity to

volume changes:

Both high beta prototype cavities are not conform with the ESS HOM Requirement

Reminder: « All higher order modes (HOMs) shall be at least 5 MHz away from integer multiples of the beam-bunching frequency (352.21 MHz) for any HOMs whose resonant frequencies are below the cut-off frequency of the beam-pipe.”

Design (at 300K)

Measured on ESS086-P01

Calculated with measured

shape (HFSS)Measured on ESS086-P02

Calculated with measured

shape (HFSS)

1418.178 1402.254 1403.8 1407.848

1418.674 1404.666 1406.8 1408.258

3D measurements of the cavity shape have been performed Shape reconstructed in the simulation software HFSS

Þ On P01 cavity (from ZANON), a strong internal shape deviation in this dome region (more than 1 mm instead of 0.3 mm) explains very well the frequency decrease of the two dangerous HOM

Þ Study under progress on P02 cavity (from RI)

Cells reshaping has to be implemented in the fabrication process of future cavities

Annual Review 23rd April 2015

10Test of the HIPPI power coupler on the HIPPI cavity at 1.8 K, full reflection

HIPPI power coupler (KEK-type window) tested to 1.2 MW, 10% Duty factor at Saclay

New design of the doorknob waveguide transition including a HV bias capacitor with RF trap

Integration and VerificationFundamental power coupler

The new “ESS” clean room for the prototype ESS elliptical cryomodules ECCTD is now in operation.at Saclay.

11Annual Review 23rd April 2015

Training in the new clean room for assembling a HIPPI coupler with the tooling used for the ESS coupler.

Integration and VerificationStudy of the assembling tooling in clean room finalized

XFEL cavity string assembly at Saclay.

The ESS cryomodules will be assembled in this large clean room.

Framework of the cryomodules development and production

1. Two prototype cryomodules:2. medium beta: M-ECCTD <= FR-SW agreement3. High beta: H-ECCTD <= CEA FR In Kind Contribution

2. Production of cavities of the series with RF tests:3. medium beta cavities <= LASA - IT In Kind Contribution4. High beta cavities <= STFC - UK In Kind Contribution

3. Production of all other components: <= CEA FR In Kind Contribution(including coupler production with RF power processing)

4. Cryomodule assembling : <= CEA FR In Kind Contribution(XFEL assembly infrastructure)

5. RF power tests of the cryomodules <= ESS Lund

12Annual Review 23rd April 2015

131st April 2015

TAC11

WPCryomodules

de sérieP. Bosland/XXX

WPTests IPHIB. Pottin

WPDiagnostics

F. Sénée

WPContrôle

CommandeF. Gougnaud

ACCSYS WP3ACCSYS WP5

Projet ESS / IRFU

CdP: P. BoslandAdjoint: A. Daël

Project Office

planning: X. Hanusressources: L. Lecourt

secrétaire: XX

Cellule QualitéA BruniquelC. Cloué

SécuritéO. Kuster

Management :Coordination C.Collaboration C.

In Kind Review C.

ACCSYS WP 3ACCSYS WP 5ACCSYS WP 7ICS WP 6ICS WP 10

ICS WP 6 / 10

WPBunker 352 MHz

JP. Charrier

ESS - AB

ESS - IRFU

Technique :Technical

BoardESS - AB

Responsables ScientifiquesG. DevanzD. UriotO. Piquet

WPTest

injecteur B. Pottin

ACCSYS WP3

M-ECCTD

IKCH-ECCTD

WP ECCTDF. Peauger

Design RFQ

IKCRFQ

WP RFQB. Pottin

ACCSYS WP7

IRFU reorganization on the 1rst of June 2015:

Florence Ardellier: Project Manager Pierre Bosland : Scientific Director

Organization at CEA Saclay

Budget and cost-book

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Activity ID Activity name

11.5.1 Management & Administration & others 6 077 068

11.5.2 Medium Beta Structures 35 966 36011.5.2.2 M-ECCTD Design, Build and test 4 647 00011.5.2.3 Medium Beta Cavity Fabrication 10 079 04011.5.2.4 Medium Beta Cavity follow up 1 221 14011.5.2.5 Medium Beta Cold Tuning System 8 121 00011.5.2.6 Medium Beta Power Coupler 687 00011.5.2.7 Medium Beta Cryomodule Equipment (Procurement through production) 4 729 00011.5.2.8 Medium Beta Cryomodule infrastructure and assembly 5 135 00011.5.2.9 RF Power Tests of first Medium-Beta Cryomodules 1 059 00011.5.2.10 Transport of Medium Beta Cryomodule 288 180

11.5.3 High Beta Structures 62 002 70011.5.3.2 H-ECCTD Design, Build and test 3 197 00011.5.3.3 High Beta Cavity Fabrication 23 517 42011.5.3.4 High Beta Cavity follow up 2 231 10011.5.3.5 High Beta Cold Tuning System 1 604 00011.5.3.6 High Beta Power Coupler 10 854 00011.5.3.7 High Beta Cryomodule Equipment (Procurement through production) 10 664 00011.5.3.8 High Beta Cryomodule infrastructure and assembly 8 204 00011.5.3.9 RF Power Tests of first High-Beta Cryomodules 1 059 00011.5.3.10 Transport of High Beta Cryomodule 672 180

Total 104 046 128

15Annual Review 23rd April 2015

Major Procurements

Main procurements for M-ECCTD launched:• 6 cavities• 6 power couplers• Vacuum vessel• Toolings• Clean room• Cryogenic lines and RF wave guides for RF power test stand• ….

H-ECCTD: Niobium and fabrication of the high beta cavities

Cryomodules of the series:• Niobium for the elliptical cavities (see LASA and STFC presentation)• RF power source for RF conditionning of the couplers of the series• RF power couplers• Cryostat components• Industrial cryomodule assembly

16Annual Review 23rd April 2015

Top risks

Some comments and recommendations for the TAC 1st April 2015:

• The success oriented schedule presented leaves almost(?) no room for iteration of any of the sub-components or the module itself. Thus an extremely careful self-assessment of technical risks is to be made.

• there will be no feedback from first cryomodule power testing on the assembly of the following cryomodules, and this is a serious concern

• The IKC concept for the cryo module and its‘ components requires precisely defined interfaces. Include in all IK negotiations aspects for technical, logistical and contractual issues.

• Regarding manufacturing geometry accuracy, analysis should be performed to determine the geometric tolerance to escape the HOMs from the harmonics with a minimum spacing of 5 MHz

(=> Analysis started and in progress)

Next Six Months

Follow up of the component production for the M-ECCTD prototype cryomodule

Test the first medium beta prototype cavity

Test the first prototype power coupler

Complete and test of the cryogenic line of the RF power test stand at Saclay

Development of the Control/command system of the RF power test stand at Saclay

Prepare the assembling area of the M-ECCTD outside the clean room

Organize and prepare all the In Kind activities at Saclay for the production of the cryomodules of the series

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Elliptical cavity cryomodules Summary

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• The design of the elliptical cavities and cryomodules complies with the ESS requirements.

• The prototype cryomodules M-ECCTD and H-ECCTD will validate the design. • The preliminary planning for the design/prototyping and for the production of the

elliptical cryomodules has been proposed in compliance with the RFI dates.• This planning is success oriented with major risks identified • The coordination between the In-Kind partners has to be quickly placed to start the

work as soon as possible:

Coordination between CEA, CNRS, INFN, STFC and ESS

ESS has to establish a "partnership with INFN and STFC, which will permit to make use of the best European competences in the field of SRF".