1 / 5

LHC at 7 TeV/c: comparison phase 1 / IR3MBC

LHC at 7 TeV/c: comparison phase 1 / IR3MBC. N. Mounet, B. Salvant and E. M étral. First comparison between phase 1 and IR3MBC (combined momentum and betatron cleaning in IR3 – settings from A. Rossi) !! Preliminary results !! (some effects, such as temperature, not taken into account).

jeri
Télécharger la présentation

LHC at 7 TeV/c: comparison phase 1 / IR3MBC

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. LHC at 7 TeV/c: comparison phase 1 / IR3MBC N. Mounet, B. Salvant and E. Métral First comparison between phase 1 and IR3MBC (combined momentum and betatron cleaning in IR3 – settings from A. Rossi) !! Preliminary results !! (some effects, such as temperature, not taken into account)

  2. Reminders: Coupled-bunch modes from all the machine elements in the model (Collimators + MBWs/MQWs magnets + beam screens + warm pipe + broad band) – from dipolar impedance Better in horizontal, but…

  3. Reminders: Coupled-bunch modes from all the machine elements in the model (Collimators + MBWs/MQWs magnets + beam screens + warm pipe + broad band) – from dipolar impedance … worse in vertical. BUT this is supposed to be damped by transverse feedback. Now, is the real part of the tune shift an issue (for transverse mode coupling instability - TMCI - threshold) ?

  4. Vertical coupled-bunch modes from all the machine elements in the model – from dipolar + quadrupolar impedance In multibunch, the actual tune shift to be observed in the machine is lower in IR3MBC w.r.t phase 1. → Due to compensation between quadrupolar and dipolar impedances for the most critical horizontal collimators. The same kind of compensation occurs for single-bunch tune shift (-2e-4 in vertical, vs -3e-4 in phase 1) so no TMCI issue ?

  5. Headtail simulations for single-bunch TMCI threshold IR3MBC - vertical Phase 1 - horizontal The TMCI threshold seems to be 1.7e11 p/bunch in IR3MBC (in vertical) vs 3.4e11 p/bunch in phase 1 (in horizontal). In IR3MBC, it is due to a coupling between m=0 and m=-1 headtail mode, the m=-1 mode being shifted positively strange results, but if true, we don’t have any more margin for ultimate intensity …

More Related