Minutes of the ICE section
53th meeting on Wednesday 11/04/2012 (08:40-10:30, 6/2-004)
ICE members: Benoit Salvant (BS), Christian Hansen (CH), Carlo Zannini (CZ), Hugo Alistair Day (HD), Elena Benedetto (EB), Elias Metral (EM), Elena Wildner (EW), Frank Schmidt (FS), Giovanni Iadarola (GI), Giovanni Rumolo (GR), Jean-Luc Nougaret (JLN), Kevin Shing Bruce Li (KL), Nicolo Biancacci (NB), Nicolas Mounet (NM), Olav Ejner Berrig (OB), Serena Persichelli (SP), Tatiana Pieloni (TP), Werner Herr (WH), Xavier Buffat (XB).
Present/Excused: BS, CH, CZ, HD, EB, EM, EW, FS, GI, GR, JLN, KL, NB, NM, OB, SP, TP, WH, XB, Mauro Pivi (SLAC).
1) Newcomers / visitors
- None.
2) Comments on the minutes of the previous 52nd meeting + Actions
- No comement.
3) General infos
- No particular comment from anyone.
- SL meeting:
- BE Newsletter => Is someone willing to write something?
- Eric Montesinos is replacing Paula Carvalho for approval of training.
- News from LHC:
- Instabilities observed during the long Easter week-end => Linked to beam-beam and in particular a bad procedure in LHCb. When this was solved the issue disappeared. Would be interesting nevertheless to try and fully understand what happened from the beam dynamics point of view => See Action 1 below.
- Some leveling studies at 75% and 95% luminosity will be reported by TP at this afternoon's LMC.
- EM visited last Thursday building 187 with Sune Jakobsen to see a prototype of an ALFA detector. Some temperature measurements are currently made and then one could make some bench impedance measurements => To be followed up by the Impedance team. Picture 1 and 2.
- Email from Ahmed Cherif: Ferrites from Skyworks received => To be followed up by Impedance team.
- Follow-up of LHC single-bunch instability observed at 4 TeV/c with negative chromaticity when the ADT was switched-off => Followed up by NM.
- Important => IPAC12 papers (see ICE list of abstracts for IPAC12): Deadline is 30/04/12 (see below for new procedure).
- NEW => Link to deadlines and important dates for ICE.
4) SPS UA9 impedance studies (HD): pdf
- HD presented an update of his impedance simulations for the SPS UA9 goniometer, looking in particular to the Parked OUT and Parked IN positions.
- HD compared time-domain and frequency-domain simulations for the real part of the transverse (H and V) impedances and longitudinal (with also imaginary part in this case).
- In the Parked IN position, the 2 most critical modes are:
- fr1 = 442 MHz, Q1 = 493 and R1 = 3729 Ohm.
- fr2 = 984 MHz, Q2 = 1338 and R2 = 33044 Ohm.
and HD looked at the field distribution and in particular the maximum of the magnetic field to be able to optimize the place where ferrite plates could be located to damp these modes.
- In the Parked OUT position, the situation is much less critical.
- In summary, few hundreds watts could be obtained which necessitates to install some ferrite to damp these modes.
- Would be good to have the possibility to make a wire measurement before installing it into the SPS.
- See Actions 2 and 3.
5) Actions to be taken for the next meeting
- Old actions.
- New actions:
- Action 1 (beam-beam team): Try and fully understand how the beam could be unstable (due to beam-beam) on FR 06/04/12 with the wrong LHCb procedure.
- Action 2 (impedance team): Set up a common procedure for our RF heating estimates for sharp resonances.
- Action 3 (impedance team => Maybe OB): Put some info on the impedance web page about all the materials we use in our impedance simulations (different types of ferrite etc.) => For everybody to be able to use the same data.
6) Miscellaneous
- Deadlines and important dates for ICE.
- The next (54th) meeting will take place on 18/04/2012 => Agenda:
1) Recent beam-beam effects observed in the LHC (TP),
2) Possible contributions to the CERN PS impedance model (Mauro Migliorati from Roma, La Sapienza).
- See preliminary agendas for the next meetings.
Minutes by E. Metral, 12/04/2012.
