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ArcCellMock-up Meeting #1
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Europe/Zurich
Description
Kick-Off Meeting
Notes of kick off meeting Arc Half Cell Mockup
24th May 2022
List of people attending the meeting:
F.Carra (chaiman), K. Artoos, J. Bauche, M. Benedict, A. Bertarelli, S. Chemli, J.P Corse, J. Coupard, J. Etheridge, C. Garion, S. Grillot, K.Hanke, R. Losito, H.Mainaud Durand, K. Oide, T. Raubenheimer, M.Timmins, JP Tock, F. Valchkova, F.Zimmermann
Slides of presentation are available in the Indico page related to the meeting (https://indico.cern.ch/event/1163471/)
Agenda:
- Presentation of the project (T. Raubenheimer)
- Related discussion
- Practical Information about meeting organisation(F. Carra)
- Related discussion
1)
Tor showed slides presenting the 3 phases of the Project which can be recapped as it follows: Phase1: 3D model, Phase 2: Engineering Design, Phase 3 : Construction Of the Half Arc Cell of FCC-ee... The goal of the project is to optimize the design a single cell “sufficiently detailed state”, the integration should also include the booster.
The components (and their characteristics) of each arc cell should be defined (presence of quadrupole, sextuple, length of the dipole…)
Strong interaction required with Technical Infrastructures Pillar (especially, Integration Working Group) and other Working Group of Accelerator pillar (especially FCC-ee booster design, and Technology R&D)
2)
Klaus asked what the biggest item would be to transport during installation?
Tor said that dipoles are largest item, their length should be 12 m (tbc). Also the vacuum chambers are 12m long.
Frank asked if there would be the possibility to assemble the dipole in the tunnel
Federico mentioned that this option is under discussion it was already mentioned during discussion between TE-MSC and TE-VSC
Federico underlined that the first step would be freezing a preliminary design and main design parameters. In the collider, recent discussion exhibited interference and incompatibility of the current design of magnet and vacuum systems of the dipoles themselves, and the dipole interconnection. The design of the absorber (and the associated water-cooling circuit is not yet done). That interference would require to enlarge the separation distance between e- and e+ lines. (Iteration with beam optics dedicated working group will have to be done on that topic)
The design of booster components is not yet done.
Katsunobu talked about the possibility to use girder in order to finely pre-align on the surface some of the arc components (quadrupoles and sextuples) before taking them underground in the tunnel.
About alignment issues, Helene asked what the current static alignment requirement are. Tor and Frank commented that this value is not stated yet (around 100 µm but it could be even reduced to 50 µm). Frank explained that the working group involved in the impedance simulation could first solve simulation issues before giving consistent figures about alignment requirement.
About Stability, Katsunobu commented that any resonance should be avoided below 100 Hz. Kurt underlined that avoiding the natural frequency of the structure’s support below 100 Hz will be a challenge which requires precaution during the design phase.
Federico has triggered discussion about the relative position of the booster and the collider. the two rings should be separated by not more than 30 cm. Is the position booster on the top of the collider already frozen? Based on the status of the integration study, having the booster on the same plan than the collider would not be possible regarding the available place in a tunnel of 5.5 m of diameter. This aspect, however, should be further investigated, as positioning the two accelerators one on top of the other is not ideal on the stability side, and for the RF cryomodules.
3)
Federico showed slides about practical information related to the meeting organisation: list of members, egroup, indico page
4)
Federico proposed to move the meeting to 3pm Geneva time. Everybody agreed.
Tor stated that the project will report every second week to the Technical coordination Meeting (not to the Accelerator Pillar meeting, as previously mentioned).
Discussion tools that we could use in order to share information and co-work on the common documents (top level Indico single page, EDMS, GitHub project, Overleaf project?)
Federico talked about deliverables and expectations related to the project. Most of them are related to integrations aspects, that require feedback and discussions with Integration Working Group (as well as with Working Group in charge of issues related to handling, transport and maintenance). The other category of deliverables concerns the aspect of interface between each magnet (dipole/dipole, dipole/quadrupole, quadrupole/sextupole, etc) and between the dipoles and the vacuum system. The aspects will be discussed with J. Bauche and C. Garion and also within the Technology R&D Working Group.
An idea of the budget needed for the project should be estimated based on the deliverable objectives. Offline followup, discussion with Tor: this exercise has been done for the “Phase I” (ballpark figure of 100 kCHF for the integration and design jobs), and must be completed also for the Phases II-III, also in view of the mid‑term review of the FCC feasibility study, foreseen mid-next year.
Actions follow up
- Define an updated table of key requirement and parameters related to the design on the collider and the booster. This table should be based on CDR and updated following presentations given at FCC week. à Federico, Lucie to trigger the action, and to crosscheck the tables with the stakeholders.
- Contact Andrey Abramov to ask how information are shared for Accelerator Pillar Meeting à Lucie.
- Add following members to egroup, and meeting invitation : M. DiCastro, J.P. Tock, C. Eriksson à Lucie.
There are minutes attached to this event.
Show them.
