Improved timing

• Work in progress - intended more as a logbook than presentation of results*

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 pre-production HVB
• 2050V
• Modified preamp4 (terminating resistors removed)
• Prototype tilted at 30^o to enclosing scintillators (scints trigger the daq)

Fed scintillator signals post-discriminator and coincidence signal through then level converter to ECL, then attentuator, into fADC. Took threshold as half peak value (also tried 1/4 and 3/4 peak but these broadened the timing spectra). Used interpolation algo. (The DAQ is triggered by the coinc signal.)

Interpolated signals for many events

Threshold crossing times

Threshold crossing times - coincidence time

Below: Events with ADC data going above pedestal mean + 5 pedestal sigma are selected. 20 samples starting 10 samples before the threshold crossing are sent to the LE algo after subtracting mean pedestal. Pedestal mean is for 10 samples starting 15 samples before the threshold crossing. The threshold for the LE algo is 2 pedestal sigma. Pedestal sigma is for 100 early samples in 100 events. Left: all samples Right: zoomed

Event 11, ADC data, LE with interpolation, green=threshold, pink=pedestal (horiz.) and pedestal window (vert.), blue=LE threshold (horiz.) and LE window (vert.), grey=LE extracted

Event 11, ADC data, LE with interpolation, green=threshold, pink=pedestal (horiz.) and pedestal window (vert.), blue=LE threshold (horiz.) and LE window (vert.), grey=LE extracted