Summary notes of the LCU meeting on 19/04/2011

Present:

Report from meetings

• SLM and general information -> MG
  It is planned to have a general group meeting by the beginning of the Summer. It will comprise a presentation from Oliver and short activities overview from the SLs, followed by a BBQ.
  A BE newsletter is being launched. The editor will be J.-P. Matheys with linkpersons in each group. For ABP it was decided that this role is taken by each section leader on a regular basis.
  In addition to the proposed solution to install cryo-collimators in IR3/7 by moving dipoles in the DS, it is being investigated the option of installing few 11-T Ni3Sn dipoles. These will be shorter that the nominal dipoles and would enable installing the collimators in between two of such dipoles. Another possibility would consists of reviewing the Q8 and Q10 quadrupoles, going to Ni3Sn magnets, and reducing the length of the orbit corrector.

Symplectic integrator for a relativistic particle in a RF cavity -> RdM  (slides)
Since the last LHC-CC10 workshop the issue of field quality for crab cavity is being discussed and reviewed. The key point is to provide specifications to the cavity-builders based on the results of tracking simulations. Of course, the field quality will be only one aspect of the specification, others being impedance, transparency to operation, description of failure modes etc. (mode details can be found here).
Based on a number of assumptions, RdM shows that the transverse kick imparted by the crab cavity can be derived from a Hamiltonian and is harmonic. This provides a way of implementing a multipole development of the cavity field in tracking simulations that could be used to set limits to the various components. This formalism is already implemented in PTC by E. Forest and RdM is going to check that the field obtained by numerical simulations does satisfy the properties derived.
During the presentation a number of comments on the assumptions used were made. It could be possible to come back to this topic with another presentation based on an alternative approach to compare them.

AOB

None

Last update: 04-May-2011

MG & HB

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