User name D. Lhuillier
Log entry time 15:16:30 on June13,2004
Entry number 125582
Below is a plot of the rate of the right hand side electron detector versus time for dithering run number 2090.
One can clearly see the dithering pattern. Kent came in and fitted the dithering slopes (which I was tediously trying to do, searching for relevant variables in the forest of TTrees). Here are the online results:
Det1: Alpha_X=-20ppm/um Alpha_E=-80ppm/ppm
Det3: Alpha_X=+20ppm/um Alpha_E=+20ppm/ppm
No sensitivity to Y is observed.
Sensitivities to X position nicely flip sign between left and right sides. Simulation predicts +/-35 ppm/um.
Energy sensitivity is large. Prediction is 8ppm/ppm. The large values and different signs of the left and right arms could be due to edge effects. These effects depend on the positioning of the electron detector with respect to the elastic line. One argument in favor of different positionings of the left and right spectrometers is the observed detector asymmetry width (Det1=2445ppm, Det3=1927ppm at 30uA).