ctf3 may 2013 data analysis
DESCRIPTION
FONT Meeting 2 nd August 2013. CTF3 May 2013 Data Analysis. Phase Profile Plots and ADC Droop Correction with IIR Filter. Overview. Phase profile with unfiltered Mixer/Diode. Calibration with IIR filter, Mixer/ sqrt (Diode). Phase profile with filtered, Mixer/ sqrt (Diode). - PowerPoint PPT PresentationTRANSCRIPT
Jack Roberts 1
CTF3 May 2013 Data Analysis
Phase Profile Plots and ADC Droop Correction with IIR Filter
02/08/2013
FONT Meeting 2nd August 2013
Jack Roberts 2
Overview
• Phase profile with unfiltered Mixer/Diode.• Calibration with IIR filter, Mixer/sqrt(Diode).• Phase profile with filtered, Mixer/sqrt(Diode).• Unfiltered vs. Filtered phase reconstruction.• Mean pulse to pulse phase stability.
02/08/2013
Jack Roberts 3
Recap: Unfiltered Mixer/Diode Calibration
• Cancel ADC droop by using Mixer/Diode instead of Mixer/sqrt(Diode).
• Absorb beam current A in to calibration constant a.
• Fitted values for a:– M1: 1.67– M2: 3.11– M3: 1.92
02/08/2013
3 4 8 9Mixer∝ 𝐴sin (𝜙 ) exp (− 𝑡 /𝜏 )
Diode∝ 𝐴2 exp (−𝑡 /𝜏 )
sin (𝜙 )= 1𝑐𝐴MixerDiode
=1𝑎MixerDiode
• Best resolution near zero crossings of LO scan.
• Plots for the points circled here are outlined in red.
• All the plots are mean subtracted.
CALIBRATION LO SCAN
Jack Roberts 4
Phase Profile – No filtering, Mixer/Diode Calibration.
02/08/2013
Jack Roberts 5
Phase Profile – No filtering, Mixer/Diode Calibration
02/08/2013
Jack Roberts 6
Phase Profile – No filtering, Mixer/Diode Calibration
02/08/2013
• Good agreement between M1 and M3 near zero crossings of ADC output in LO scan.
• Saturation effects near min/max of ADC output in LO scan due to sin(phi)>1 values.
Jack Roberts 7
ADC Droop Exponential Fit
02/08/2013
• Fit an exponential to the diode data then use the fitted decay constants in an IIR filter:
• Fitted values for τ (in 357 MHz samples), Diode ADCs:- M1: 518 ± 1- M2: 440 ± 1- M3: 457 ± 2
• Also have droop in mixer channel but can’t fit exponential to it.- Use the mean of the diode ADCs: τ = 472. - Can get these values from lab tests (on going).
• Fitted values for τ can vary up to ~20% dependent on sampling window used, LO phase etc.
• Resolution seems fairly insensitive to τ.
Diode=𝐴2 exp (− 𝑡 /𝜏 )
Jack Roberts 8
ADC Droop Exponential Fit
02/08/2013
• Left: Points are mean diode channel data for each LO phase setting. Black lines are the exponential fit using the fitted decay constants.
• Seeing cross-talk from Mixer?
Jack Roberts 9
• Implement an IIR filter to remove the exponential droop using the fitted decay constants:
• Can now perform a calibration using Mixer/sqrt(Diode) as planned:
• Fitted values for a:• M1: 52.5• M2: 84.1• M3: 56.9
IIR Filter
02/08/2013
1
)()(k
xkxky
Mixer∝ 𝐴sin (𝜙 ) Diode∝ 𝐴2 sin (𝜙 )=1𝑎Mixer
√Diode
Jack Roberts 10
Phase Profile – Filtered, Mixer/sqrt(Diode) Calibration
02/08/2013
Jack Roberts 1102/08/2013
Phase Profile – Filtered, Mixer/sqrt(Diode) Calibration
Jack Roberts 1202/08/2013
Phase Profile – Filtered, Mixer/sqrt(Diode) Calibration
• At a first glance, very similar to the unfiltered calibration plots.
Jack Roberts 13
Resolution Comparison – Filtered vs. Unfiltered
02/08/2013
• Resolution appears to be a bit better for the filtered calibration.
Jack Roberts 14
Comparison – Unfiltered vs. Filtered
02/08/2013
M1
Jack Roberts 1502/08/2013
M1Comparison – Unfiltered vs. Filtered
Jack Roberts 1602/08/2013
M1Comparison – Unfiltered vs. Filtered
Jack Roberts 1702/08/2013
M2Comparison – Unfiltered vs. Filtered
Jack Roberts 1802/08/2013
M2Comparison – Unfiltered vs. Filtered
Jack Roberts 1902/08/2013
M2Comparison – Unfiltered vs. Filtered
Jack Roberts 2002/08/2013
M3Comparison – Unfiltered vs. Filtered
Jack Roberts 2102/08/2013
M3Comparison – Unfiltered vs. Filtered
Jack Roberts 22
M3
02/08/2013
Comparison – Unfiltered vs. Filtered
• There are differences in the relative scale of the reconstructed phase from the two calibrations.
Jack Roberts 23
Filtered vs. Unfiltered Calibration Constant
02/08/2013
• Filtered/unfiltered calibration constants divided by mean to make them comparable.
• Only mean value used in phase reconstruction.
• Differences vs. sample no. will cause phase shifts.
Mean
Mean
Mean
Jack Roberts 24
Mean Pulse Phase Stability
02/08/2013
Jack Roberts 2502/08/2013
Mean Pulse Phase Stability
Jack Roberts 2602/08/2013
Mean Pulse Phase Stability
• Only short runs, but around 0.5o – 1.0o of jitter in the mean pulse phase.
Jack Roberts 27
Summary• The IIR filter appears to do a good job but lab tests needed to
accurately determine decay constants.• Difference in relative scale of reconstructed phase for unfiltered
Mixer/Diode and filtered Mixer/sqrt(Diode) calibrations.• Can look in to cross-talk between the mixer and diode.
• Side notes:– Installation of kickers, rearrangement of magnets etc. in TL2 for
the feedforward system in progress.– M2 can’t be repaired due to radiation. Planned to test using
horizontal pickups instead of vertical. 4th monitor will be built.– May be delays in installing M3 in its final location.– Thinking about how to integrate FONT DAQ with CTF3 data.
02/08/2013