Notes of Meeting Arc Half Cell Mock-up in reduced committee

29^th August 2023

List of people attending the meeting:

F. Carra , A. Piccini, C. Tetrault, M. Timmins, L. Hutin.

SUBJECT: Status of simulations and next steps for the AHCM project

1. Experimental campaigns:

Step 1: The modal analysis of the prototype quadrupole will take place between 30/08 and 05/09/2023 in the building 311. The FEM modal analysis is ongoing.

Step 2: The transfer function of the big UAP will follow. The dates still to be determined with M. Guinchard (in July it was planned to take the measurements in September/October 2023). 

For the Weplate, it was questioned to do the measurements on the Weplate already installed near to Point 8 à issue: there is not enough space to do the measurements according to Michael. So, it is possible to find a Weplate not installed apart from the prototype in Prevessin?

Step 3: This step is planned for Q1 2024, but it is decided to start this step already now, by designing and producing jacks and one dummy girder within MME. It would also be interesting to study the possibility of making measurements on the various PSI girder systems that are already available. An additional dummy girder might be in the scope of the Pakistani collaboration production. Possibly a third one could be produced by Hydropol or another company.

1. Collaborations:

PAEC Pakistan: E. Tsesmelis should get back to us in September to plan another meeting.

PSI: F. Carra will relaunch E. Tsesmelis concerning the signing of PSI’s Addendum.

Chula University: Purinut is leaving CERN, but he will continue his collaboration as a user, and he will do his master thesis on a topic related to the FCC arc half-cell. F. Carra will also discuss with E. Tsesmelis whether there is the interest of formalizing this through a MoU.

1. Collider’s simulations:

The methodology to assess the stability at the level of the mechanical axis of the collider has been established. Apart from all the assumptions the results were acceptable. The experimental campaigns results will be used to refine these simulations.

In the frame of the manufacturing of the dummy girder, Solène did calculations to study the impact of the numbers and position of jacks. As expected, the stability is improved with 4 jacks instead of 3.

To be able to push for the new design of the girder, which is bulkier, it could be interesting to compare:

• The steel girder with 3 jacks (already done);
• The steel girder with 4 jacks;
• The same geometry as the steel girder but fill with Hydropol material with 4 jacks;
• The new design, which is bulkier, with 3 and 4 jacks.

All simulations must include modal and vibration analysis to study the impact of damping (Action Audrey).

1. Booster’s simulations:

The methodology to assess the stability at the level of the mechanical axis of the booster has been established but the results were surprising.

Louis has already worked on the previous modal and vibratory simulations of the booster to try to identify errors and improve the simulations.

For the new geometry of the ceiling support, Callum will produce a preliminary design, enabling the first calculations to be made. At the same time, Callum will contact SCE to check the feasibility of this design and which other measures must be implemented to realize it (e.g. reinforce the ceiling, etc.)

1. Other simulations:

Concerning SPS jacks (PSI type), the simulations to assess the stiffness are ongoing. Problems have been encountered with the modelling of the spherical contact. Audrey will try to play with the contact and will get back to Marc and Callum if any 3D modifications are required.

The final step will be to combine the collider and booster simulations and include the crosstalk phenomenon. Collaboration with Roma, Malta?

Actions follow up

1. Audrey will continue the simulations of the modal analysis of the prototype quadrupole.
2. Audrey will plan with Michael the measurements of the UAP (step 2 of the experimental campaign).
3. Marc and Callum will finalize, with the help of Louis for calculations, the design a dummy girder for fabrication within MME.
4. Fede will relaunch E. Tsesmelis concerning the signing of PSI’s Addendum and about collaboration with the Chula University.
5. Audrey will compare the current collider random vibration analysis results with two additional configurations:
   1. Current girder design with steel profiles, with filling of the voids via concrete-like material, with expected positive effect due to increased stiffness/mass ration and damping.
   2. New steel girder with 4 jacks to replace the previous girder design and supporting.
6. Louis will continue to work on the modal and vibration analysis of the booster (previous designs and after the new one).
7. Callum will contact SCE to check the measures to be taken in case of hanging the booster to the ceiling.
8. Callum will design the new geometry of the ceiling support.
9. Audrey will continue the simulations of the SPS jacks.
10.  Federico and Audrey will define the frame of the crosstalk research, investigating the possibility of assigning it to Purinut at the Chula University.