2012

- 1st meeting (11-04-2012) - EVO info: Discussions about the Work Breakdown Structure (EM) => See EM's talk given at the 3rd HiLumi WP2 Task Leaders meeting and update (after comments) on the Task 2.4 web site.

- 2nd meeting (13-06-2012) - EVO info: Some IBS studies for the current LHC, nominal LHC and HL-LHC and set-up of a benchmarking case with all the IBS contributors (Michaela Schaumann with JJ), CMS chamber (RW).

- 3rd meeting (05-09-2012) => No minutes of the meeting - EVO info: Operating Experience with Electron Cloud Clearing Electrodes at DAFNE (AD) and Simulation of e-cloud buildup with clearing electrodes at DAFNE (TD), Negative mass effect in nonlinear oscillatory system and its influence on stability of coherent betatron oscillations (MZ), Relevant MD results and current LHC performance / issues (EM): Summary LHC MDs Block#2 (CERN LSWG meeting, 03/07/12) and Impedances, instabilities and implications for the future (CMAC#6, 16-17/08/12).

- 4th meeting initially planned => Finally did not take place, but here are the talks given at the 2nd Joint HiLumi LHC-LARP Annual Meeting in Frascati on 14-16/11/2012 (https://espace.cern.ch/HiLumi/2012/SitePages/Home.aspx): Collective effects: status and plan (EM, 2nd Joint HiLumi LHC-LARP Annual Meeting, Frascati, 14/11/2012), Where are we on the impedance model of HL-LHC? (BS, 2nd Joint HiLumi LHC-LARP Annual Meeting, Frascati, 14/11/2012).

2013
   
-
The (main) goal of the year is to have an initial estimate of the HL-LHC machine impedance for 01/11/2013:
https://espace.cern.ch/HiLumi/WP2/task4/SiteAssets/SitePages/Home/ImpedanceStudiesPlan_HL-LHC_v2.pdf
=> To be discussed mainly with all the CERN Impedance Team (with all the impedance experts).

- 5th meeting (15-11-2013, in Daresbury): Discussions about the next steps (see also summary in the 20th WP2 Task Leader meeting on 06-12-2013: https://indico.cern.ch/getFile.py/access?contribId=1&resId=0&materialId=slides&confId=283926). Here are the talks given at the 3rd Joint HiLumi LHC-LARP Annual Meeting in Daresbury on 11-15/11/2013: Transverse impedance in the HL-LHC era (NM), Heat load from impedance on existing and new hardware in the LHC era (BS), Present understanding of the instabilities observed at the LHC during Run I and implications for HL-LHC (EM) and Electron cloud effects at the HL-LHC (GI).

- On 20-12-2013 => HL-LHC impedance model released: http://impedance.web.cern.ch/impedance/HLLHC.htm  (also accessible from the Task 2.4 web page, on the left).

2014
   
- 6th meeting (22-01-2014), CERN room 6/R-018 or Vidyo, 11:00 to 12:30 (=> See info on indico event): First estimates of intensity limitations from HL-LHC transverse impedance (Nicolas Mounet).

- 7th meeting (26-02-2014), CERN room 6/R-018 or Vidyo, 11:00 to 12:30 (=> See info on indico event): Review of e-cloud estimates in the HL-LHC triplets/D1 (G. Rumolo) and Impedance considerations for the design of the triplet/D1 beam screen (N. Mounet).

- 8th meeting (26-03-2014), CERN room 6/R-018 or Vidyo, 11:00 to 12:30 (=> See info on indico event): HL-LHC (and LHC) longitudinal collective effects with 1 RF system (400 MHz) or 2 RF systems (Elena Shaposhnikova and Juan Esteban Muller): Part 1/2. Test simulations of TT2-111R lossy dispersive material properties (Oscar Frasciello).

- 9th meeting (09-04-2014), CERN room 6/R-018 or Vidyo, 11:00 to 12:30 (=> See info on indico event): LHC longitudinal collective effects (Juan Esteban Muller): Part 2/2. Transverse beam stability studies in the presence of 2 RF systems (Kevin Li).

- 10th meeting (16-04-2014), CERN room 6/R-018 or Vidyo, 11:00 to 12:30 (=> See info on indico event): Impedance of the crab cavities (Rama Calaga and Benoit Salvant). Some answers to the actions (Nicolas Mounet).

- 11th meeting (30-04-2014), CERN room 6/R-018 or Vidyo, 11:00 to 12:30 (=> See info on indico event): Follow-up of e-cloud effects in HL-LHC (Giovanni Iadarola). Impedance comparison between analytical estimates, CST and GdFidL.

- 12th meeting (07-05-2014), CERN room 6/R-018 or Vidyo, 11:00 to 12:30 (=> See info on indico event): Answers to the remaining actions (http://emetral.web.cern.ch/emetral/Task2point4OfHLLHCWP2/ListOfActions.htm), knowing that EliasM will have to send the milestone report to GianluigiA on 16/05/2014.

- 13th meeting (14-05-2014), CERN room 6/R-018 or Vidyo, 11:00 to 12:30 (=> See info on indico event): Answers to the remaining actions (http://emetral.web.cern.ch/emetral/Task2point4OfHLLHCWP2/ListOfActions.htm), knowing that EliasM will have to send the milestone report to GianluigiA on 16/05/2014 => Update on transverse beam stability in the presence of 2 RF systems (KevinL).

- 14th meeting (01-10-2014), CERN room 6/R-018 or Vidyo, 11:00 to 12:30  (=> See info on indico event): Update of beam-induced RF heating issues for HL-LHC: ALICE beam pipe, etc. (BenoitS).

- 15th meeting (08-10-2014), CERN room 6/R-018 or Vidyo, 11:00 to 12:30  (=> See info on indico event): Interplay with beam-beam: stability diagrams in the presence of both octupoles and beam-beam, transverse mode-coupling with both impedance and beam-beam (Claudia Tambasco and TatianaP). Some questions which will need to be addressed at some point:

1) What is the maximum separation we can tolerate during the beta* levelling in IP1 and 5?

2) What should be the speed at which we go in collision (sigma per s) to avoid any instability?

3) At which beta* should we go in collision?

- 16th meeting (15-10-2014), CERN room 6/R-018 or Vidyo, 11:00 to 12:30  (=> See info on indico event): Review of the impedance model => Estimates for crab-cavities (since at the last collaboration meeting critical values have been mentioned), collimators (TCTP mode, etc.), etc. (Nicolo Biancacci).

- 17th meeting (29-10-2014), CERN room 6/R-018 or Vidyo, 11:00 to 12:30  (=> See info on indico event): Wake fields and impedances simulations of LHC collimators with GdfidL code (Oscar Frasciello).

- 18th meeting (10-12-2014), CERN room 6/R-018 or Vidyo, 11:00 to 12:30  (=> See info on indico event): Follow-up of the impedance of the crab cavities (N. Biancacci et al.).

2015

-  19th meeting (04-03-2015), CERN room 6/2-008 or Vidyo, 11:00 to 12:30 (=> See info on indico event): Follow-up of the impedance of the crab cavities and other equipment (N. Biancacci and B. Salvant) and operational scenarios (T. Pieloni and E. Metral).

-  20th meeting (18-03-2015), CERN room 6/R-018 or Vidyo, 11:00 to 12:30 (=> See info on indico event): Review of all the past recommendations for the impedance of the Crab Cavities (E. Metral and B. Salvant) and follow-up of the operational scenarios (T. Pieloni and E. Metral).

-  21th meeting (25-03-2015), CERN room 6/R-018 or Vidyo, 11:00 to 12:30 (=> See info on indico event): Impedance and beam stability studies (N. Biancacci and K. Li) and follow-up (finalization) of the operational scenarios (T. Pieloni, E. Metral, E. Shaposhnikova and J.E. Muller).

=> Task 2.4 (and 2.7) meetings on indico.