Notes from July 2006 SWMD Telephone Meeting

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1. July ESA run data
   
   • Processing chain - (.dat -> .root -> .mat), calibration procedure
     Jonny will be at CERN during the run, so will arrange with Adriana so that she can help with this while she is at SLAC. Details are in the ESA Elog.
   • Collimator scanning procedure
     Continue with upwards scanning to get measurements which can be compared with those from April/May run. If time, consider upward/downward (etc.) studies, but at lower priority.
   • Detailed plan for measurements in 2 (-4?) shifts
     Plan to repeat 1-2 complete scans with both sandwiches, starting with sandwich 2 as already installed in wakefield box. Beam time for T480 is limited in this run!
   • Preparations - measurements of collimator jaws? Mover reliability? Magnet configuration?
     Steve had discussed mechanics of the y and x movers with Ray, still no solid mechanism understood for the "hysteresis" effects seen in first run. Relative phase of the three y mover cams could be an influencing factor? Alignment of BPMs currently with +/-0.5mm. Metrology of aperture to be studied after the run ends.

2. T-480 Data analysis
   
   • ...
   • Luis plots
     Not discussed at meeting, see 27-Jul-2006 notes.
   • results directory - Jonny
   • Run classification by MCCData - Nigel
     Found that of the of the ~40 runs in which there was an apparent difference between the Vdes/Vact for x mover average over a given run, which made determination of slot uncertain, all of these except 5 could be removed if the first MCC reading was excluded. Attribute this to a timing mismatch between the MCC data in SCP and assumed local copy used by the DAQ. Of the remaining 5 "problem" cases, only 1 (run 355) not understood.

3. Outcomes of EPAC
   • Wire/bench test preparations
   • Wakefield simulations
     Jonny discussed with Japanese group on boundary element method, following their poster in Wed. EPAC session. Also with Christian Schmidt (Rostock) about beams taking diagonal trajectory across cells; and with Diamond group carrying out similar studies to us on Mafia/GdfidL.
     Igor Zagorodnov suggested using ABCI before major computation as this also showed similar effects as he found using ECHO (reported at EPAC) between collimators 2 and 3 for geometric wakes
   • Material damage -
   • Plans for prototype construction (jaws, full collimator)?
     Justin et al discussions with Nick Simos at EPAC, learned about Japanese company using thin layer of silver to facilitate bonding between graphite and titanium.
     George will investigate construction of small prototype using Ti/graphite/Ag brazing to find out what are the important issues, e.g. does differing thermal expansion cause problems such as cracking at the boundary region? Plan to carry out a 2D FEA study on such effects.

4. Next meeting - ...