Beam-beam and Luminosity Studies Meeting

Friday 13 Mar 2020, 16:00 → 17:20 Europe/Zurich

6/R-012 - conference room (CERN)

Guido Sterbini (CERN), Yannis Papaphilippou (CERN)

Preparation for the HL-LHC Collaboration Meeting

 

Participants:

Philippe (remotely)

Ilias (remotely)

Adriana (remotely)

Yannis

Guido

Axel

Kyriacos

 

Axel after having presented the need for the wire quadrupole feed-forward, presented the limits to use the Q4-Q5 in the optics of Run3:

- chromatic effect due to the residual beta-beating and high tele-index 

- limited conditioning of  the system

- limited linearity of the knob

- relatively large trims of Q4/Q5

- knob tele-index dependent

Axel presented an alternative solution considering the two Q4s (left and rights).

This address all the previous limitation at the cost of a beta-beating in the luminous region.

Yannis commented that:

- the beta-beating has to be compared with the one of BB, in particular our goals should be to quantify the bbb BB beta-beating and having a consistent beta-beating studies (strong-strong). 

- the beta-beating has to be evaluated also for other optics (the phase advance between IP1/5 is optics dependent in Run3).

Guido commented that one could also consider using the trim power converter of the triplet.

Ilias pointed out that in doing so one could have a problem in terms of dipolar feed-down (more important than the one of Q4). 

 

 

16:00 → 16:40 Proposal of a new tune feed-forward for the wires in Run3

Speaker: Axel Poyet (Universite Grenoble-Alpes (FR))

BB_LUMI_031320_v1.pptx

16:40 → 16:50 AOB