[esa-t474] t474 analysis

[Bino Maiheu]

Hi All,

I thought I'd provide with some sort of input to the analysis
discussion...

Cheers,
   bino



Recapitulate where we stand with 2007 data : 

* focus on understanding systematic effects on the resolution/stability 
  of the BPM system
* hopefully show the calibration tone system actually works
* need to condensate the best knowledge we have in a library which will
  be the legacy of our BPM work

----> I believe the only way to acutally get to that state is to go 
      through the data step by step from scracth, which is what I'm 
      currently doing...  !!!!

- Repository with evironmental monitoring plots is done : needed to 
  fully understand systematic effect : 
    - so far we never looked at e.g. the spill counter signals for beam 
      quality
    - plots vs run at the moment to sort of have an indication where 
      the interesting effects are, for publication will need them vs 
      timestamp....


- BPM data, some changes are needed w.r.t. previous runs
    - need to incorporate the calibration tone data : correct amplitude
      ---> some discussion needed : 
            o correct amp/qamp & phase-qphase (as well ?), or correct I 
               & Q ? 
            o a calibration fixes the gain level : so effectively we 
              introduce another
              calibration constant !!
            o figure out how to best handle the calibration tone data, 
              fitting the caltone seems to work fine, not the fastest 
              but don't really care... should to some
              decent studies with fit vs. ddc
            o correlate the caltone data with temperature

 #### ---> will continue with this for the moment as 
          - goes straight into a publication
          - a good understanding of this will determine it's input into 
            the main BPM signal processing !!


    - take out beam jitter at least to first order by subtracting 
      x{31,32} and y{31,32} in the HH calibrations where possible... 

    - thought : donno if we can do anything smart for the trigger pulse 
      if it turns out to be needed, since we ran on internal clock but 
      did not have trigger signals in every SIS, can think of abusing 
      one BPM waveform and determine a trigger t0 from 
      that. But have to study the stability of the fitted t0 times, 
      which are available on the repository...

    - Was not happy with the structure of the library as it was, 
      progressively improving and documenting it as I go through the 
      data with clear and transparant signal 
      processing routines


- Energy measurement
    - while in dubna : spectrometer simulation is done and compared with
sergey
    - did some error estimates for 4 magnet chicane, need further
studies & need to think
      where to position this in publication
    - method of calculating energy, so determining residual at center of
the chicane...
      o linear fit through the alignment corrected BPM positions seems
favourable
      o an SVD method seems to be worse since the position at center of
chicane
        isn't linearly dependant on the positions before the chicane
          --> maybe unless we regress against energy ( from energy BPM
reading ) as well...
              need to check this !  
    - Need to have a routine to calculate the field in every magnet...




-- 
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          @ -- Bino Maiheu, Dr. ;) ---------oOO----(_)----OOo------- @
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