Summary notes of the LCU meeting on 26/11/2013

Present: HB, RdM, LD, OD, SF, MF, GG, MG, PH, ALan, YL, SR, GR, AS, TP, MS, PS, RT, AV, RV

Report from meetings

• SLM and general information -> MG
  Massimo reminded that all IPAC'14 abstract should already by on the BE server. After approval, they can be submitted to the conference server within the conference deadline of 4 December. At least one of the authors must participate at the conference. The list of approved CERN participants was circulated by email. Students were not on the list. They can participate if the can find funding.
  Massimo asks the staff members to sent him a list of planned travel for them and the fellows and students working with them, by 6 December.
  A discussion on post LS1 optics is needed (w/o ATS etc.). A brainstorming discussion is planned for the next (and last 2013) LCU meeting.
  The ABP end of year party is planned for the 19 December. Invitations were sent by Delphine to all of you on the 22 November.
• LBS -> HB
  Helmut reported from the last LHC background study group meeting, with reports on 25 ns running and simulations. Slides are on indico.
• Collimation status -> Stefano
  Stefano announced a new OPAC fellow position at Royal Holloway with maybe up to 30% presence at CERN.
• MAD-X status -> LD
  As modoule keeper for Touschek, Ghislain identified two bugs which fill be fixed.
  As previously annonced, natural constants will soon be updated in MAD-X, to be followed by a pro release to be kept for a period of about 6 month.
  Special meetings with a subgroup of experts will be organized to follow up on the choice of canonical variables in MAD-X.
  There will be a panel review in the US on a broad range of scientific codes. Laurent will inform Robert Ryne and provide the link to MAD-X.
• SixTrack status -> RdM
  A bug was found in the crab cavity implementation. This is followed up by Rogelio.
  A small correction (related to pt) will also be required on RF-multipoles in MAD-X, followed up by Andrea Latina. Good testing is essential. This triggered a discussion on validity checks and responsibilities, which can be complicated in particular for code pieces like 6D beam-beam provided with help from outside collaborators.
  For the new beam-beam wire compensator, Daniel Schulte is expected to contribute. Massimo would like to have responsibilities better defined. Authors of new codes should also provide testing. Stefano said that user feedback is also essential.
• On-line model status -> GR
  Matthias is expected to join these efforts early next year once he finished the works on maps with Riccardo.

Update on powering for HL-LHC triplets -> MF (slides)

Miriam followed up on the powering of the triplet for the HL-LHC. The amount of ripple will depend on details of the powering scheme, and become generally more critical for the HL-LHC.
Driving the magnets in series would minimize the effect of ripple on the beam.
The required flexibility can be achieved with trim power converters. Constraints come also from fast discharge in case of quenches, as discussed by Amalia in the 4th PLC. The amount of tolerable ripple will be also assesed by dynamic aperture studies.

Considerations on TAN for LHCb after LS2 -> AS (slides, video1, video2, video3)

Andrea Santamaria presented studies on the planned minimal TAN for LHCb after LS2. She determined the angular coverage which would be required to catch neutral particles from the interactions before D2.
She used the current baseline scheme with horizontal crossing and both spectrometer polarities. For completeness she also checked the required angular coverage in case of vertical crossing angles. With the help of Reyes, she also looked for available space in the LHC close to D2. The minimal TAN for LHCb will be shorter than we we currently have for IP1 and IP5. Three to five interaction length copper (or 46 to 77 cm) should be sufficient, to be verified by energy deposition simulations.

Andrea will leave end of this week and is expected to return to CERN beginning of March to work for her thesis in the context of WP8 (collider machine interface for the HL-LHC).

AOB 

Next meeting planned for the 10 December during the crab cavity workshop will be moved to 13 of December.

Last update: 6-December-2013

MG & HB

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