NanoBPM Signals by yurtgc548

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									         NanoBPM Signals
Second Mini-Workshop on Nano Project at ATF
           December 11-12, 2004

                 Toyoko Orimoto
                Yury Kolomensky
         Lawrence Berkeley Laboratory &
         University of California, Berkeley
               in collaboration with
                 SLAC, LLNL, UCL
                  Introduction


    Nano BPM
     Project
     @ ATF




•   Waveform fit
•   Strip charts for online monitoring
•   Offline analysis to determine calibration
•   Study of correlations from fits
                NanoBPM Signals – Toyoko Orimoto
 BPM Strip Charts




NanoBPM Signals – Toyoko Orimoto
                        BPM Strip Charts

                                                      • Strip charts display
                                                        position, tilt, and
                                                        phase from fits
                                                  BPM 1 • Online
                                                  BPM 2   monitoring to
                                                  BPM 3   steer BPMs

                                                              • Raw
                                                                waveforms
                                                                & residuals
                                                                from fits

• Display other statistics: amplitude, frequency, decay time, etc.
• Can also replay offline and change calibrations, etc.
                       NanoBPM Signals – Toyoko Orimoto
         Fit Residuals – “Fish Plots”
• Residuals from fit to waveform – our fit is not correct.




     • Change to double fit (see S. Smith’s talk)




                   NanoBPM Signals – Toyoko Orimoto
Q
          Beam Position & Tilt Calibration
                                                           movers move cavity in




                        I
                                                            50 mm position steps
                                                                (500 mrad for tilt
                                                                    calibration)
                event                      event
                                                            Slope =
                                                            position scale
I




                                                            Similar procedure to
    IQ Phase F =    Q                                                calibrate tilt
     tan-1(slope)
                                                             Slope =
                                                             tilt scale


                        NanoBPM Signals – Toyoko Orimoto
                     Calibration Check
                                                       Q vs. I
As a cross-check,
waveforms were re-fitted
with the calibration
constants produced using
the steps previously
outlined.

If calibration constants
were good, then Q →
position and I → tilt.

So we expect I vs Q plots
to be flat and tilt vs event
to be flat (in the case of
position calibration)…
                        NanoBPM Signals – Toyoko Orimoto
     “Bow-tie” Correlation
Position vs Tilt
                                     • See a “bow-tie” effect in
                                       position vs tilt after
                                       calibration
                                     • Further away from
                                       position, larger spread in
                                       tilt

                                     • Avoid such effects by
                                       working at smaller
                                       amplitudes for
                                       calibration for now…
                                     • Also will try to get
                                       reference cavity
                                       frequency closer to the
                                       other BPM frequencies

           NanoBPM Signals – Toyoko Orimoto
  Frequency & Position Correlation
 BPM1 Y Freq vs event




                                               • Frequency dependence
                                                 on sign of position
BPM1 Y Amplitude vs event
                                               • Difference ~ 0.05 MHz
                                               • Such sensitivity occurs
                                                 with small amplitude



   BPM1 Y Q vs event




                        NanoBPM Signals – Toyoko Orimoto
               Frequency & Position Correlation


                                                          … Study this by
Y1 Frequency




                                                          looking at data with
                                                          beam centered in
                                                          different quadrants
                                                          of the BPMs




                                              Y1 Q        See S. Smith’s talk


                       NanoBPM Signals – Toyoko Orimoto
                            Position & Tilt Correlations
                     Correlation matrix: Dec 02 data
                                                                 • Correlations from
                                                                   fits computed
Y Tilt Ref




                                                                   Red: high correlation
                                                                   Green: no correlation
                                                                   Blue: anti-correlation
X Pos Y Pos X Tilt




                                                                 • Use this as a
                                                                   debugging tool:
                                                                 • Sign error in X2
                                                                   calibration
                                                                 • Intensity correlated
                                                                   to X2 tilt – problem
               X Pos Y Pos X Tilt          Y Tilt Ref              with the fitting
           BPM 1, 2, 3
                                     NanoBPM Signals – Toyoko Orimoto
                          Position & Tilt Correlations
                     Correlation matrix: Dec 07 data

                                                               • Red: high correlation
Y Tilt Ref




                                                               • Green: no correlation
                                                               • Blue: anti-correlation
X Pos Y Pos X Tilt




                                                                • Similar to July 2003
                                                                  data
                                                                • Y tilt anti-correlated
                                                                  with X position
                                                                • Tilts should be
                                                                  more correlated
               X Pos Y Pos X Tilt         Y Tilt Ref
           BPM 1, 2, 3
                                   NanoBPM Signals – Toyoko Orimoto
                      Conclusions
• Continue to analyze data offline

• Improve fitting algorithm

• Improve calibration technique

• Study correlations in further detail




                    NanoBPM Signals – Toyoko Orimoto

								
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