Difference between revisions of "LE algo"
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The original algorithm is here [http://npvm.ceem.indiana.edu/~gvisser/GlueX/rdat.c] 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. | The original algorithm is here [http://npvm.ceem.indiana.edu/~gvisser/GlueX/rdat.c] 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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+ | [[#saturation pics|Saturated event pics]] | ||
Revision as of 09:45, 18 May 2011
- Page still under edit, incomplete
Results using Gerard's leading edge algo with CDC prototype, cosmics
- 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 [1] 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.
Below: cosmics with new fADC, preamp4 (top) and newest modified preamp (below). Blue histograms are tracked hits, runtimes were not equal. 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. Pedestal mean was approx 100, sigma is 9-12.
Below: threshold pedestal mean + 4sigma
Below: 2100V (threshold pedestal mean + 5sigma)
Earlier new fADC results are on this page: New_fADC_with_cosmics
Below: 55Fe spectra with preamp 4 and Struck ADCs set to half-range, 550mV
Below: 55Fe spectra with newest preamp (preamp4 minus terminating resistors) and Struck ADCs set to full-range, 1.1V
Below: Scope pics with Fe55, preamp4 (left) and preamp5 (right) (preamp5=preamp4 minus terminating resistors), 2050V
Below: Scope pics with cosmics, preamp4 (left) and preamp5 (right) (preamp5=preamp4 minus terminating resistors), 2050V
Below: Pedestal, mean of samples 0-99 in groups of 100 events, preamp4 (left) and preamp5 (right) (preamp5=preamp4 minus terminating resistors), 2050V
Below: Pedestal standard deviation of samples 0-99 in groups of 100 events, preamp4 (left) and preamp5 (right) (preamp5=preamp4 minus terminating resistors), 2050V
Below: Max amplitude histograms fitted for ch6, required > 5 hits but no track, hit threshold is pedestal mean + 5sigma
Below: Residuals for ch23, 5+ hits, hit threshold is pedestal mean + 5sigma, added 8ns to fitted tzero
Below: Residuals for ch23 omitting ch23 from the track-fit, 5+ hits, hit threshold is pedestal mean + 5sigma, added 8ns to fitted tzero
Below: Event pictures - fADC values for 49k cosmics events, 2100V, 45degrees - to show that the preamp saturates before the fADC