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

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

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 BPM 2 BPM 3 Raw waveforms & residuals from fits Display other statistics: amplitude, frequency, decay time, etc. Can also replay offline and change calibrations, etc. Online monitoring to steer BPMs

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 Beam Position & Tilt Calibration movers move cavity in 50  m position steps (500  rad for tilt calibration) event Q Similar procedure to calibrate tilt event I Q I IQ Phase  tan -1 (slope) Slope = position scale Slope = tilt scale

NanoBPM Signals – Toyoko Orimoto Calibration Check 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)… Q vs. I

NanoBPM Signals – Toyoko Orimoto “Bow-tie” Correlation 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 Position vs Tilt

NanoBPM Signals – Toyoko Orimoto Frequency & Position Correlation Frequency dependence on sign of position Difference ~ 0.05 MHz Such sensitivity occurs with small amplitude BPM1 Y Freq vs event BPM1 Y Amplitude vs event BPM1 Y Q vs event

NanoBPM Signals – Toyoko Orimoto Frequency & Position Correlation … Study this by looking at data with beam centered in different quadrants of the BPMs Y1 Q Y1 Frequency See S. Smith’s talk

NanoBPM Signals – Toyoko Orimoto Position & Tilt Correlations Correlation matrix: Dec 02 data Correlations from fits computed X Pos Y Pos X Tilt Y Tilt Ref BPM 1, 2, 3 X Pos Y Pos X Tilt Y Tilt Ref Red: high correlation Green: no correlation Blue: anti-correlation Use this as a debugging tool: Sign error in X2 calibration Intensity correlated to X2 tilt – problem with the fitting

NanoBPM Signals – Toyoko Orimoto Position & Tilt Correlations X Pos Y Pos X Tilt Y Tilt Ref BPM 1, 2, 3 X Pos Y Pos X Tilt Y Tilt Ref Red: high correlation Green: no correlation Blue: anti-correlation Similar to July 2003 data Y tilt anti-correlated with X position Tilts should be more correlated Correlation matrix: Dec 07 data

NanoBPM Signals – Toyoko Orimoto Conclusions Continue to analyze data offline Improve fitting algorithm Improve calibration technique Study correlations in further detail