ArcHalfCellMock-up Meeting - BPM and interfaces # 1

Monday 3 Oct 2022, 16:00 → 17:00 Europe/Zurich

Notes of Meeting Arc Half Cell Mockup - BPM and Interfaces #1

3rd October 2022

List of people attending the meeting: 

J. Bauche, L. Baudin, F. Carra, S. Rorison, M. Timmins M. Wendt

Unformal discussion about the integration of BPMs in the Arc Short Straight Section with Manfred Wendt from SY-BI-BP.

Manfred showed the presentation FCC-ee BPMs: Required BPM Precision for FCC given to the FCC EPOL workshop at CERN on 28th of September 2022 (slides are available here:https://indico.cern.ch/event/1181966/contributions/5041464/attachments/2517676/4328766/BPMsForFCCee.pdf)

Manfred mentioned that the BPM design for FCCee is at very preliminary stage as the technical specifications from physics are still not frozen yet. Due to the low beam emittance, the large aperture of the vacuum chamber and tight alignment tolerances, beam instrumentation will have to be carefully studied. The question to add BPM on Sextupoles is still opened.

A PhD student will start working on that topic in spring 2023.

A  workshop dedicated to FCC beam instrumentation will be organized at CERN on the 22nd of November. Members of the Arc Half Cell project will join the session related to the BPMs.

 

First inputs have been given by Manfred about the requirement of the BPM interfaces with Vacuum and Magnet systems:

• Any discontinuity of the beam pipe should be avoided over a distance of 3 to 5 times the vacuum chamber diameter (so over roughly 20 cm)
• BPM pick-up should be rigidly connected to the magnet poles as the position of the vacuum chamber compared to magnet center is expected to significally changes because of temperature changes. A space of 150x150 mm has to be reserved between the magnet coils of the quadrupoles
• The characteristics of the BPM buttons and connecting cable (coaxial 2.4 mm in diameter) can be preliminary assumed similar than the existing devices (Manfred will share drawing and specifications) 
• The position of the 4 BPM buttons compared to the vacuum chamber relies on mechanical alignment 
• A calibration of the BPM center compared to the magnetic center has to be done during the assembly procedure. This operation will require to stretch wires inside the vacuum chamber. This has to be added in the considerations about SSS configuration (using girder/ one unique vacuum chamber...)

 

 

 

16:00 → 16:20 FCC-ee BPMs: Required BPM Precision for FCC

Speaker: Manfred Wendt (CERN)

BPMsForFCCee.pdf