CDC transfer func attempt
Circuit
Actual component values used were... 51.1 Ohms, 908 Ohms and 2pF
Early results
Final results
Borrowed Phillips 5771 (no attenuators needed)
Fitted function
Beware typos in filenames, this was run #31941!
Input charge: 2 pF x 103 mV = 206 fC
Input current: divide by 12ns peaking time of preamp: 206 fC / 12 ns = 17.2 uA
Peak value of output data is 635 adc_units ~ 635 * 495 mV / 4096 = 76.7 mV
Electronics gain is 76.7 mV / 206 fC = 0.37 mV/fC
(Gain of preamp alone measured by FJB as 0.57 mV/fC)
Convert to current using 50 Ohm resistance: 76.7 mV / 50 Ohm = 1.53 mA
Current gain is 1.53 mA / 17.2 uA = 89.0
Integrated value of output data is 19.03 adc_units.us ~ 19.03 * 495 mV / 4096 = 2.30 mV.us
Convert to charge using 50 Ohm resistance: 2.3 mV.us / 50 Ohm = 0.046 mA.us = 0.046 nC = 46 pC
Charge gain is 46 pC / 206 fC = 223
To convert histograms of summed ADC data (with 8ns sample time) to charge, multiply by 8 ns * 46 pC / 19.03 us = 19.3 fC
Garfield needs the transfer function expressed as current gain, but I want to see the results in adc units, so I need to scale the transfer function x 89 (current gain) x 635/1530 (adc units/uA). The remaining gain factor needed to match garfield adc data to real life data is the gas gain.