1. Materials to support the discussion: - Recall of TAC11 (1-2 April 2015) recommendations -HOM and PED -Possible QA applicable to SRF collaboration projects

2. Elliptical Cavity Cryomodules Recommendations –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. –Qualification of sub-components and finally of the completed cryo modules requires smoothly running infrastructure. A complete list of all related infrastructure with commissioning and training plans should be established. –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. –At the time of the cryo module CDR the final design has to be absolutely stable. Series production of components requires precise specifications for all components and procedures. A clear timeline for all related project decisions should be established. 1-2 April 2015 ; ESS TAC11

3. Elliptical Cavity Cryomodules (con‘ –CEA Saclay / Irfu is strongly contributing to ESS and XFEL cryo module assembly. Lessons learned should be discussed and documented / presented. –The cryo module QC at ESS Lund will lead into some repair actions. The planned coordination meetings between ESS/CEA/INFN/STFC should address this issue. –Identify cryo module tooling to be made available to ESS for long term. Either at ESS or through long-term binding contracts at the IKC labs. 1-2 April 2015 ; ESS TAC11

4. Elliptical Cavities (high beta) Comments Cavity vendors need to modify existing infrastructure and tooling for surface treatment. Since STFC has no prototypes to be simply copied by industry, good coordination between STFC, INFN and industry is required. What can one learn from other lab infrastructures? Knowledge exchange / transfer is of utmost importance. Recommendations – The presented STFC schedule includes time for infrastructure modification, commissioning and training. But self-assessment of technical risks should be made. Comparison with other similar infrastructures already used for series production should be done as much as possible. – Industrial infrastructure needs to be developed and supervised. Identify what can be learned from others. – If STFC is building to print clarify responsibilities. 1-2 April 2015 ; ESS TAC11

5. Medium beta cryomodules Comments – degradation after heat-treatment : possible explanation is an insufficient chemical etching, – there will be no feedback from first cryomodule power testing on the assembly of the following cryomodules, and this is a serious concern Recommendations – Degradation cause should be confirmed as soon as possible In order to secure the global process – 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 1-2 April 2015 ; ESS TAC11

6. Elliptical Cavities (medium & high beta) Comments – Using large grain niobium for producing cavities at INFN adds some risk to the project schedule. Should a problem occur with this R&D, definite milestones should be established that would trigger a decision to revert to known fabrication techniques with small grain niobium. – It has been decided to not scan sheets of niobium for acceptable RRR. Experience at DESY in the construction of X-FEL have shown a 3% failure rate of niobium sheets. This presents a risk to cavity construction, especially since production did not include the fabrication of spare cavities. This decision needs to be reassessed. 1-2 April 2015 ; ESS TAC11

7. Elliptical Cavities (medium & high beta) - Recommendations – There are many common issues between medium and high beta elliptical cavities. try to avoid double work; profit from each other; develop common strategies for industry supervision Check common Nb procurement across work-packages use identical clean room and vacuum specs – Work to understand the source of cavity performance degradation following the additional treatment. Contact SRF community experts. – In case the currently used elliptical cavity design is questioned, establish schedule decision point milestones for elliptical cavity redesign efforts (e.g. geometry optimization and material selection). – Identify cavity tooling to be made available to ESS for long term. Either at ESS or through long-term binding contracts.

8. HOM and PED

9. 9 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) 1418.1781402.2541403.81407.848 1418.6741404.6661406.81408.258  3D measurements of the cavity shape have been performed  Shape reconstructed in the simulation software HFSS  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  Study under progress on P02 cavity (from RI)  Cells reshaping has to be implemented in the fabrication process of future cavities Annual Review 23 rd April 2015

10. 10 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  =100 with large curvatures 2  =100 bursting disks at each extremity Annual Review 23 rd April 2015

11. Recall: October 15-16, 20 Requirements Conformance for SRF Cryomodules Workshop Home Requirements Conformance for SRF Cryomodules Workshop Home Indico link: https://indico.esss.lu.se/indico/event/185/timetable/#all.detailed Indico link: https://indico.esss.lu.se/indico/event/185/timetable/#all.detailed Preliminary approach - CNRS Possible QA applicable to SRF collaboration projects

12.  S. Bousson, Workshop on Requirements Conformance for SRF Cryomodules, Lund, 15 th Oct. 2014 QA / QC Plans for the ESS spoke production Main goal and path: Develop all the necessary tools and documentation to insure a high quality/traceability of the fabrication and assembly of the ESS spoke cryomodule parts. Take benefit of the ongoing prototyping phase to draft and later on modify/correct these tools Once ready, transfer and/or adapt to the overall ESS QA system that will be developed. We started to set our QA/QC plans only a few months ago, the basis is here, but it’s only a start… Based on our past contributions to LHC, SPIRAL-2…

13.  S. Bousson, Workshop on Requirements Conformance for SRF Cryomodules, Lund, 15 th Oct. 2014 QA / QC Plans for the ESS spoke production HOW ? Based on the following pillars: A Product Breakdown Structure to list all components, equipments, tooling to be used for the spoke production A detailed life cycle of the components that could also serve as a Work Breakdown Structure to list in details all the production/preparation/assembly/test of the components and associate the required input/output A component identification/naming convention to be able to identify all basic component / assembly

14.  S. Bousson, Workshop on Requirements Conformance for SRF Cryomodules, Lund, 15 th Oct. 2014 QA / QC Plans for the ESS spoke production HOW ? Based on the following pillars: A set-up of documentation (procedure, travelers, reports, legal/purchase documents, publications…) to properly insure a reliable, stable, not company or people-dependent quality of production A document management system to insure access, ordering, sorting, traceability of all documentation produced. A configuration table to trace which sub-system is installed in each cryomodule.

15. General overview & Component life cycle

16.  S. Bousson, Workshop on Requirements Conformance for SRF Cryomodules, Lund, 15 th Oct. 2014 Spoke cryomodule overall life cycle Appro Niobium Fabrication Cavité Traitement surface Cavité Assemblage cavité Salle blanche Test en CV COMPONENT PHASE Export / delivery Test / validation Préparation/ assembly SUpply/ Production NiobiumCavitiesCouplers vessel Vacuum Cryomod. Full. compon.. Cryomod. string Cavity CTS… Transport -> site assemblage Transport -> Fabriquant cavités … … … … Fabrication Enceinte Cryomodule Transport -> site assemblage Appro Compos. cryomodule Transport -> site assemblage Assemblage train cavités Transport -> site assemblage Fabrication SAF Assemblage SAF Test à chaud SAF Transport -> site assemblage Assemblage cryomodule Test à chaud Transport -> Uppsala Fabrication Coupleur Préparation salle blanche coupleurs Conditionn- ement coupleurs Transport -> site assemblage

17.  S. Bousson, Workshop on Requirements Conformance for SRF Cryomodules, Lund, 15 th Oct. 2014 Spoke cryomodule detailed life cycle Phase_Name Validation stage -> Go / No Go Stage name (number Phase and stages Names, shapes and colors

18.  S. Bousson, Workshop on Requirements Conformance for SRF Cryomodules, Lund, 15 th Oct. 2014 Spoke cryomodule detailed life cycle Names, shapes and colors Requirement Administrative / Contractual Milestone Technical Report Minutes Contractual/legal document Input /Output documents Document type Color convention

19.  S. Bousson, Workshop on Requirements Conformance for SRF Cryomodules, Lund, 15 th Oct. 2014 Spoke cryomodule detailed life cycle 1 st example: Niobium production

20.  S. Bousson, Workshop on Requirements Conformance for SRF Cryomodules, Lund, 15 th Oct. 2014 Spoke cryomodule detailed life cycle 2 nd example: Cavity production

21.  S. Bousson, Workshop on Requirements Conformance for SRF Cryomodules, Lund, 15 th Oct. 2014 Spoke cryomodule detailed life cycle 3 rd example: Cavity preparation