Minutes of 22 Feb. 2007 SWMD Telephone Meeting

Brief reports on progress since 26 Jan

1. Collimator fabrication status
   Significant delays over expectation in polishing. Decision taken since last meeting that collimators would be taken in person by George E. rather than shipping to ensure they arrived in time for run. Collimators now prepared, in transit today with George to SLAC. [23-Feb: arrived safely at SLAC now.]

2. Discussion of collimator damage studies
   Separate meetings initiated for the near future, see 01-Feb-2007 meeting and 20-Feb-2007. Next meeting, 28-Feb-2007 at DL.

3. Wakefield Simulations
   Jonny has ~80% of ~1k jobs completed (sigma_z x 3 geometries x mesh resolution x (position in x) x (position in y)), necessary to get azimuthal and radial dependence of kicks for cylindrical geometry. Will compare these to analytic formula, if disagree then would parametrise GdfidL results (or make look up table/interpolate) so they could be included in PLACET. Subsequent stage would be to repeat with the rectangular geometry. Ideally will have some results to show at COLSIM meeting at CERN next week on cylindrical geometry.

4. Preparations for T480 / Run 3 operation
   
   • Faster (real-time?) reconstruction in data taking
     Asked Yuri for latest stripchart code so we could modify it, currently he is modifying this to allow easier implementation of new displays without having to write raw C++/root code. NKW will look at the existing version of the code to see how straightforward it would be to implement directly what we need. Luis noted that we need to subtract reference orbit to get a sensible trajectory reconstructed, which is an added complication.
   • Matlab reconstruction
     Steve had confirmed that chicane magnets will be off when T480 runs. Possibility of some (small) residual fields remaining, but assumed to be insignificant for 30 GeV beam. Also, if stable and uniform, the reference orbit subtraction would account for them. Variation of any such residual field with varying position of the beam would be a second order effect so assume can be neglected completely.
   • Bunch length measurment/monitoring
     Steve noted LOLA images in sect. 28 difficult to explain (double stripe feature), perhaps a genuine satellite bunch following the main bunch, or artefact of the camera itself. Intervention in beam switch yard to clean optical components was made, hope this will resolve the problem. If optical artefact, Steve has Matlab code prepared to clean up existing data. Stability of the correlation between LOLA measurements and ceramic gap diode measurements with time should be adequate to use the latter to infer bunch length measurement at ESA.
   • Revised scanning strategy (need for slot 0 data?)
     Luis noted no gain in resolution by using slot 0 as reference for scanning a given collimator, therefore we will only take data at slot 0 at start/end of sandwich scan.
   • Matlab processing of data
     Andre had been working through Adriana's instructions for running the data processing at Manchester's linux cluster, most of the difficulties were now understood. Problems arising from security incident still to be resolved in coming days.
   • Finalised dates for run, shift shedule
     No changes
   • Availability to travel within ~6-27 Mar
     After discussion, decided that the (only) people travelling for the test beam run would be: Luis and Jonny: 5-28 Mar, Adriana 10-17, Nigel 15-25 Mar.., so that we would have at least four experienced people at SLAC at any one time. Adriana could also contribute with data processing on the Manchester cluster after her return to the UK.

5. T-480 Data analysis - Luis's plots

6. Wire Tests

AOB

• UK Funding: negotiation just starting within LC-ABD/PPARC. Not as good as hoped for...
• Eurotev duration: consortium agreed to extension to end of calendar year 2008 (awaiting response from EU).
• Travel for ESA run 3 - submit claims asap on return, before end of FY06-07.
• Meetings
  • Collimator damage (with Lew K., 28 Feb, DL)
  • COLSim meeting, 1-2 Mar., CERN.
  • Next group meeting: Thu 8 Mar, 1530-1700 GMT