T-474 phone conference

Thursday 18 may 2006, 16:30 GMT

discussion points

• General
• thursday's at 16:30 is basically fine for all (bi-weekly meetings ?!)
• calibration and analysis chain using Yury's analysis code
• check all calibrations and reproduce data
• layout where/how temperatures, stray fields, etc are stored in datafiles (see T474 log @UCL)
• do we need to define default orbit ?
• straight line between BPMs 41 and 11 mean positions ?
• straight line between BPMs 31 and 41 ?
• further discussion...

minutes

 
 Minutes of the 18 May 2006 T474 Phone conference
 ------------------------------------------------

- Yury will distribute a stripped down of the analysis code based
  upon the BaBar framework, together with scripts to extract the
  cavity parameters. We will install this code at UCL and set up the
  processing of the data on our cluster. 

- Yury produced a somewhat of a 'chronological' list of analysis tasks:

  1. Need to define some quick algorithm to get the BPM resolutions 
     *Bino* will put this as a routine in libRooEsa which is 
     available from the UCL CVS repository and send around.

  2. We need to study in detail the extrapolation for saturated pulses
     and define some standard way of handling these events 
     We volunteered *Mark* to do this. 
   
     -> Steward raised the question whether the FFT for a saturated
        and unsaturated waveform are the same. This should be checked !

     -> One important point here brought up by Yury is the t0
        determination, he will study this. 

  3. Optimization of the DDC algorithm (frequencies, gamma) either by
     common sense tuning of the parameters or finding somehow a
     mathematical best optimization. *Fillimon* and *Bino* will look
     into this. 

  4. Go over the calibrations for all the runs, IQ

  5. Look at the resolution and stability

  6. Overall orbit fitting, see remark mike below. 

  7. Added here a little additional list from stewart on systematic
     studies :

     - correlate temperature (BPM, ambient) with resolution, stability
     - study effect of bunch charge, bunch length
     - internal vs. external clocking
     - beam optics (455 vs. 458)
     
- Mike brought up the point that we should first handle the
  last runs taken as these have the best data in, so it might be a
  good idea to process the runs in the opposite order. 

- Yury gave a brief explanation of how the BaBar framework is
  structured. The code is organized in different more or less
  independent modules (classes) which add different levels of
  processing to a central event object.

- Mike stated that we should start studying different ways of
  establishing the orbit as T480 can also benifit from this as well as
  the stability studies. A weighted (1/resolution^2) fit would be the 
  way to go, prefereably using a parabola to account for the earth's
  magnetic field. We also need to be aware here that Q38 was never
  completely off, albeit at very low field, so this might introduce
  a correction to the trajectory. Bino is working on a least squares
  fitting algorithm that will be able to extract the misalignments. 

- Fillimon will provide a runlist with calibration runs, with internal and
  external clock and send it around. 

- The online logbooks are copied over from SLAC and can be found under
      https://www.hep.ucl.ac.uk/elog/ILC+eSpec+@+ESA/
  Next to these we have setup a T474 analysis logbook as well under :
      https://www.hep.ucl.ac.uk/elog/Linear+Collider/

  Need to setup a wiki page either at Berkeley or UCL.

- We will try to organize a phone conference with SLAC during our visit to
  Dubna. Details will be sent around.

- The next T474 phone conference will be held 2 weeks from now on June
  1st 16:30 UK time. We will look for an alternative
  phonenumber. Details will be send around some days before the
  meeting.