1 / 8

Some follow-ups

Some follow-ups. Convention on the use of the parameters “on_x” Update table for pre-collision separation and collision crossing angle values Changes in “as-designed” and proposal for an “as-built” MAD-X sequence. M. Giovannozzi

sonja
Download Presentation

Some follow-ups

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. Some follow-ups • Convention on the use of the parameters “on_x” • Update table for pre-collision separation and collision crossing angle values • Changes in “as-designed” and proposal for an “as-built” MAD-X sequence. M. Giovannozzi Acknowledgements: H. Burkhardt, S. Fartoukh, J. Jowett, W. Herr, P. Le Roux, T. Risselada, F. Schmidt LHC Beam Commissioning - MG

  2. Convention on the use of the parameters “on_x” - I • Three switches are used in the set-up of the optics settings: • on_x*: crossing angle. • on_sep*: parallel separation • on_lhcb, on_alice: spectrometer magnets in IR2/8 • So far, the value 1 of the switch provided the nominal value of the corresponding physical quantity. We would like to keep this philosophy. • Some remarks: • The physical parameters can be re-scaled by setting the switch to an appropriate value. LHC Beam Commissioning - MG

  3. Convention on the use of the parameters “on_x” - II • Some remarks: • Scaling with energy can be applied: • Parallel separation: the scaling can be applied to any insertion. • Crossing angle: the scaling can be applied to IR1/5, only. In IR2/8 the presence of the spectrometer breaks the scaling. • During the squeeze: • An appropriate crossing scheme is provided (the parallel separation remains constant). The aim is to vary the crossing smoothly (to the nominal value, e.g. for IR1/5 142.5 mrad). • What to do in case the squeeze is stopped at an intermediate beta* value? LHC Beam Commissioning - MG

  4. Convention on the use of the parameters “on_x” - III • Proposal: • An appropriate crossing scheme is provided: this could be selected with a new flag on_coll. • In general: we cannot hope to cover all possible configurations. Knobs should be generated to change easily the crossing scheme in operation. LHC Beam Commissioning - MG

  5. Update table for pre-collision separation and collision crossing angle values • Separation: • Standard value of 0.5 mm (half separation) re-scaled with energy • Crossing angles: values provided in Chamonix (W. Herr) and in the table by M. Ferro-Luzzi seems ok. Possible refinement in discussion. For IR8 (reviewed by W. Herr): Crossing angles compatible with both 5 TeV and 4 TeV. LHC Beam Commissioning - MG

  6. Changes in LHC sequence - I • Revision launched by Olav Berrig: • Equipment owned by RF Group is declared as RF cavity (even transverse damper…) • Proposal • Define two new elements (this requires changes in MAD-X, active in the next release): • TKICKER (transverse kicker): same as KICKER, but it is not used for closed orbit correction. • PLACEHOLDER: same as INSTRUMENT, but generic. • Then the following changes will be performed: • DFBs: will be defined as PLACEHOLDER (currently are RCOLLIMATORS) LHC Beam Commissioning - MG

  7. Changes in LHC sequence - II • APWL, BCTDC, BCTFR, BPLH, BPLV, BPLX, BPTX, BQSH, BQSV, BSRTA, BSRTM, BWS: will be defined as INSTRUMENT (currently are MONITORS). This will avoid using them in closed orbit correction. • XRPH, XRPV: will be defined as RCOLLIMATORS . • X1FCL, X1FCR, X1ZDC001, X2ZDC001, X2ZDC002, X5ZDC001, X5ZDC002: will be defined as INSTRUMENT (currently are ECOLLIMATORS). These elements are not in beam! • MU, ADTKH, ADTKV, MKQA, BQKH, BQKV: will be defined as TKICKER. LHC Beam Commissioning - MG

  8. Proposal for the “as-built” LHC sequence • It is not possible to maintain two independent LHC sequences in the layout database. Hence we will have an “as-designed” sequence (frozen) and an “as-built” one (updated according to NCs). • Three classes of NCs are relevant for MAD-X sequence: • Non-working magnet. • Magnet installed in wrong slot (e.g. repair sector 3-4) • Magnets with non-nominal performance (e.g. weak MQTLs in IR3/6/7). • In case of 1. and 2. the corresponding MAD-X elements should be represented with PLACEHOLDER. • In case of 3. the variables Imax and Kmax should be changed in the sequence. LHC Beam Commissioning - MG

More Related