Difference between revisions of "LE algo"

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*Page still under edit, incomplete
 
*Page still under edit, incomplete
  
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Results using Gerard's leading edge algo with CDC prototype, cosmics
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Results using Gerard's leading edge algo to extract drift-time from CDC prototype cosmics data
  
 
*50/50 mixed Ar, CO<sub>2</sub>
 
*50/50 mixed Ar, CO<sub>2</sub>
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The original algorithm is here [http://npvm.ceem.indiana.edu/~gvisser/GlueX/rdat.c|LE algo code]    It takes 50 samples from the ADC data, convolutes them with the filter which I think is the inverse of the filter which the fADC uses when it digitises its input, optionally interpolates 4 extra points between each sample, and returns the first value above a predefined threshold.
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The original algorithm is here [http://npvm.ceem.indiana.edu/~gvisser/GlueX/rdat.c| LE algo]    It takes 50 samples from the ADC data, convolutes them with the filter which I think is the inverse of the filter which the fADC uses when it digitises its input, optionally interpolates 4 extra points between each sample, and returns the first value above a predefined threshold.  There are a variety of implementations below.
  
  
  
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Events with ADC data going above pedestal mean + 5 sigma are selected. 50 samples starting 25 samples before the threshold crossing are sent to the LE algo after subtracting mean pedestal.  The threshold for the LE algo is 2 sigma.
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[[#saturation pics|Saturated event pics]]
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Left: drift-time with interpolation; Right: no interpolation
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Below: cosmics with new fADC, preamp4 (top) and newest modified preamp (below).  Blue histograms are tracked hits, runtimes were not equal.
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The fADC range is 0-4096.  These are histograms of the first maximum in ADC value for each event, pedestal has been subtracted, maximum must be above threshold.  Threshold is pedestal mean + 5sigma.  
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Pedestal mean was approx 100, sigma is 9-12.
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{| border="0" cellpadding="2"
 
{| border="0" cellpadding="2"
 
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[[Image:run_31599_amp6.png|thumb|420px|Max amplitude histo for cosmics, new fADC, modified HVB, mixed 50/50 at 60 sccm 2050V]]
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[[Image:run_31660_track11_2_drift23.png|thumb|420px|Drift time ch23, with interpolation]]
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{| border="0" cellpadding="2"
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[[Image:run_31646_thr5_amp6.png|thumb|420px|Max amplitude histo for cosmics, new fADC, modified HVB, modified preamp, mixed 50/50 at 60 sccm 2050V]]
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[[Image:run_31646_thr5_amp6_unz.png|thumb|420px|Max amplitude histo for cosmics, new fADC, modified HVB, modified preamp, mixed 50/50 at 60 sccm 2050V]]
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Below: threshold pedestal mean + 4sigma
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{| border="0" cellpadding="2"
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[[Image:run_31646_thr4_amp6.png|thumb|420px|Max amplitude histo for cosmics, new fADC, modified HVB, modified preamp, mixed 50/50 at 60 sccm 2050V]]
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Below: 2100V (threshold pedestal mean + 5sigma)
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[[Image:run_31649_amp6_z.png|thumb|420px|Max amplitude histo for cosmics, new fADC, modified HVB, modified preamp, mixed 50/50 at 60 sccm 2100V]]
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Earlier new fADC results are on this page: [[New_fADC_with_cosmics]]
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Below: 55Fe spectra with preamp 4 and Struck ADCs set to half-range, 550mV
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{| border="0" cellpadding="2"
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[[Image:run_31632_amp.png|thumb|420px|Max amplitude histo, 55Fe, 2050V, Struck fADC range 550mV]]
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[[Image:run_31632_amp_z.png|thumb|420px|Max amplitude histo (x-axis expanded), 55Fe, 2050V, Struck fADC range 550mV]]
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[[Image:run_31632_e.png|thumb|420px|Integrated, 96ns, 55Fe, 2050V, Struck fADC range 550mV]]
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Below: 55Fe spectra with newest preamp (preamp4 minus terminating resistors) and Struck ADCs set to full-range, 1.1V
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{| border="0" cellpadding="2"
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[[Image:run_31635_amp.png|thumb|420px|Max amplitude histo, 55Fe, 2050V, Struck fADC range 1.1V]]
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[[Image:run_31635_amp_z.png|thumb|420px|Max amplitude histo (x-axis expanded), 55Fe, 2050V, Struck fADC range 1.1V]]
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[[Image:run_31635_e.png|thumb|420px|Integrated, 96ns, 55Fe, 2050V, Struck fADC range 1.1V]]
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Below: Scope pics with Fe55, preamp4 (left) and preamp5 (right) (preamp5=preamp4 minus terminating resistors), 2050V
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{| border="0" cellpadding="2"
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[[Image:preamp4_Fe55_2050.png|thumb|420px|Preamp4, Fe55, 2050V]]
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[[Image:preamp5_Fe55_2050.png|thumb|420px|Preamp5, Fe55, 2050V]]
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Below: Scope pics with cosmics, preamp4 (left) and preamp5 (right) (preamp5=preamp4 minus terminating resistors), 2050V
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{| border="0" cellpadding="2"
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[[Image:preamp4_cos_2050.png|thumb|420px|Preamp4, cosmics, 2050V]]
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[[Image:preamp5_cos_2050.png|thumb|420px|Preamp5, cosmics, 2050V]]
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Below: Pedestal, mean of samples 0-99 in groups of 100 events, preamp4 (left) and preamp5 (right) (preamp5=preamp4 minus terminating resistors), 2050V
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{| border="0" cellpadding="2"
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[[Image:run_31599_pedmean6.png|thumb|420px|Preamp4, pedestal: mean of samples 0-99 in groups of 100 events, 2050V]]
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[[Image:run_31646_pedmean6.png|thumb|420px|Preamp5, pedestal: mean of samples 0-99 in groups of 100 events, 2050V]]
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Below: Pedestal standard deviation of samples 0-99 in groups of 100 events, preamp4 (left) and preamp5 (right) (preamp5=preamp4 minus terminating resistors), 2050V
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{| border="0" cellpadding="2"
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[[Image:run_31599_pedsig6.png|thumb|420px|Preamp4, pedestal: standard deviation of samples 0-99 in groups of 100 events, 2050V]]
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[[Image:run_31646_pedsig6.png|thumb|420px|Preamp5, pedestal: standard deviation of samples 0-99 in groups of 100 events, 2050V]]
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Below: Max amplitude histograms fitted for ch6, required > 5 hits but no track, hit threshold is pedestal mean + 5sigma
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{| border="0" cellpadding="2"
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[[Image:run_31599_amp6fit.png|thumb|420px|Preamp4 max amplitude histo ch6 cosmics 2050V]]
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[[Image:run_31646_amp6fit.png|thumb|420px|Preamp5 max amplitude histo ch6 cosmics 2050V]]
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Below: Residuals for ch23, 5+ hits, hit threshold is pedestal mean + 5sigma, added 8ns to fitted tzero
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{| border="0" cellpadding="2"
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[[Image:run_31599_resid.png|thumb|420px|Preamp4 residuals ch23 cosmics 2050V]]
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[[Image:run_31646_resid.png|thumb|420px|Preamp5 residuals ch23 cosmics 2050V]]
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Below: Residuals for ch23 omitting ch23 from the track-fit, 5+ hits, hit threshold is pedestal mean + 5sigma, added 8ns to fitted tzero
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{| border="0" cellpadding="2"
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[[Image:run_31599_residresol.png|thumb|420px|Preamp4 residuals ch23 cosmics 2050V]]
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[[Image:run_31646_residresol.png|thumb|420px|Preamp5 residuals ch23 cosmics 2050V]]
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Below: Event pictures - fADC values for 49k cosmics events, 2100V, 45degrees - to show that the preamp saturates before the fADC
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{| border="0" cellpadding="2" id="saturation pics"
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[[Image:run_31659_events22.png|thumb|420px|Events ch22 cosmics 2100V]]
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[[Image:run_31659_events23.png|thumb|420px|Events ch22 cosmics 2100V]]
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[[Image:run_31660_track11_2_off_drift23.png|thumb|420px|Drift time ch23, without interpolation]]
 
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Revision as of 10:39, 18 May 2011

  • Page still under edit, incomplete

Results using Gerard's leading edge algo to extract drift-time from CDC prototype cosmics data

  • 50/50 mixed Ar, CO2
  • Recalibrated MFCs
  • Outer plenum added to CDC prototype to prevent leaks
  • New modified HVB
  • 2050V
  • Modified preamp4 (terminating resistors removed)
  • Prototype tilted at 45o to enclosing scintillators (which trigger daq)


The original algorithm is here LE algo It takes 50 samples from the ADC data, convolutes them with the filter which I think is the inverse of the filter which the fADC uses when it digitises its input, optionally interpolates 4 extra points between each sample, and returns the first value above a predefined threshold. There are a variety of implementations below.


Events with ADC data going above pedestal mean + 5 sigma are selected. 50 samples starting 25 samples before the threshold crossing are sent to the LE algo after subtracting mean pedestal. The threshold for the LE algo is 2 sigma. Left: drift-time with interpolation; Right: no interpolation

Drift time ch23, with interpolation
Drift time ch23, without interpolation
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