Presents:

BE-BI:                   Hermann SCHMICKLER (Ch.) , JJ GRAS (Sec.), Rhodri JONES,  Thibaut LEFEVRE

BE-OP:                 Laurette PONCE, Jorg WENNINGER

TE-MPE:              Markus ZERLAUTH

BE-ABP:               Bernhard HOLZER, Daniel SCHULTE,

                              Rogelio TOMAS GARCIA, Frank ZIMMERMANN

Comments on Laurette’s presentation:

• The current baseline now is to inject in FCC at 3.3 TEV from the LHC.

• The 5ns separation option is still discussed. We have to study the feasibility and the cost of this option (including impact on injectors + LHC) to have all the info needed to eventually hope for a conclusion on the topic.

• The favourite flavour for ions remains lead

• A mandatory and not yet clear input for us is the total intensity spread we will have to cope with. The main uncertainty is the expected lower limit. This has to be decided and fixed soon (taking into account machine protection, machine commissioning but also the ion case)

• Beam parameters have also to be defined and given for the expected ion beams.

• Proposed list of instruments:

  • Replace ‘AC dipole+k modulation’ by ‘instrumentation to measure beam optics’

  • Add an instrument to make beam transverse profiles with a time resolution shorter than the bunch length

  • Add an halo measurement monitor

• On BPM:

  • We should agree that alignment tolerance for our BPM specs are with respect to  beam screen and not magnet axes.

  • SR may impose monitors at 45 degrees

  • An orbit is based on a 20 ms average to get rid of  possible 50Hz effects

  • Due to the wide diversity of the needs we should describe separately 2 different kinds of requirements. One for the whole machine orbit and feedback, one for special BPMs with BtB capabilities, higher resolutions, interlocks…

• On BLM:

  • Even if we are far from a design of the magnets, we need an estimation of what we should monitor (dynamic ranges, cross talk, integration windows…)

  • Due to the wide diversity of the needs we should describe separately 2 different kinds of requirements. The one for the OP needs and the specific ones for machine protection.

• A conservative approach is proposed: Copy and scale the LHC system for machine protection. Add distributed fibres and fast monitors (diamonds) for complementary diagnostics. Within the next 12 months a more deep study on magnet and machine protection will not be possible.

• For tune FB:

  • Can we rely on the principle that a few bunches could be systematically dedicated to measurement (i.e. not touched by dampers)

Next Step:

1. In 3 weeks, Laurette will send to Hermann an updated presentation (that could also benefit from the feedback we will give on Jorg’s one next week)

2. After iteration based on BE-BI first comments, this will be presented and discussed again in a dedicated be-bi-fcc-spec meeting.

3. The result will then be presented as a first draft for discussion and comment in a FCC Design meeting.

4. Their comments would then be reviewed in a dedicated be-bi-fcc-spec meeting.

5. Next bi-fcc-spec-hh meeting in 4 weeks.