Difference between revisions of "CDC transfer func attempt"

Revision as of 11:38, 15 April 2014

Setup

Setup (GS 4001)

Circuit

Charge injection circuit from Fernando's GlueX-doc-1364

Actual component values used were... 51.1 Ohms, 908 Ohms and 2pF

Early results

100mV leading edge of sq wave step up (yellow) and trigger from pulser (purple) - average

output of shaper - average	output of shaper - expanded time scale
output of fadc - average	output of fadc - expanded time scale

Final results

Borrowed Phillips 5771 (no attenuators needed)

pulser output - single

pulser output - average

pulser output - average

output of shaper - single

output of shaper - average

output of shaper - average

fADC data

upsampled fADC data

Fitted function

mean of upsampled fADC data

fitted function

blue=refit with powers fixed, pink= pars 137, 118, 8, 91.4, 9

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

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