Compton analysis (for experts)

How to Plot Asymmetry Histories Using the Old (Saclay) DAQ

Runs should already have been analyzed. In this method, we are using the semi-integrated asymmetries that the logbook publishes as a plot of two Gaussians (laser right and laser left) with a legend showing the mean and statistical error. Sometimes the fit fails and then this method will fail.

At present the mean and statistical error are obtained by reading the .eps file printed by the analyzer. The analyzer, for unknown reasons, does not write these histograms to file.

• Log onto compton@compton.
• The code you need is in /home/compton/diana. You may wish to copy it into your directory:
  • ParsingAsymNum.pl -- This is a perl script written by Jin Huang. It extracts the asymmetries (from .eps files) for a range of runs; you need to modify the run numbers in the script itself. It writes its results to screen and to the file ComptonAsym.log.
  • PlotLoggedAsymmetries.C -- This ROOT macro reads the asymmetries from ComptonAsym.log and produces a plot showing the measured left and right asymmetries as functions of run number. (Only their absolute values are displayed, not their signs.) Runs where the fit failed are marked by statistical errors of exactly 1.414; these are discarded by the macro.

• The Perl script may be run as follows

 > ./ParsingAsymNum.pl

• The ROOT macro can be run as any ROOT macro (it does not take any arguments):

 > root PlotLoggedAsymmetries.C

How to Analyze Data from the New (CMU/FADC) DAQ

CMU Analysis Help

If you have any questions about the CMU analysis, please contact Diana Parno at CMU: dparno AT cmu.edu