BCAL TDC Timing

Described below are a set of tools for beginning to look at the TDC timing in the BCAL. It is assumed the user has checked out and successfully built a version of sim-recon on the JLab farm. As of this writing, the tool is mainly set for looking at time-walk corrections of the individual BCAL channels, but can be extended to perform the remaining calibrations.

Running the code

We will assume that HALLD_HOME points to the sim-recon folder checked out from GitHub. The first thing to do is to get the latest version of the GitHub repository and switch to the BCAL_TDC branch

cd $HALLD_HOME
git pull
git checkout BCAL_TDC

This will grab the altered DBCALUnifiedHit factory and the BCAL_TDC_Timing plugin, located in the $HALLD_HOME/src/plugins/Calibrations/ directory. Since we have altered the libraries we need to rebuild from the src directory.

cd $HALLD_HOME/src/
scons install -j4

This will rebuild (mostly re-link) using 4 cores. Now navigate to the plugin directory and build the plugin.

cd  $HALLD_HOME/src/plugins/Calibrations/BCAL_TDC_Timing/
scons install

Now you are ready to run the plugin.

hd_root -PPLUGINS=BCAL_TDC_Timing -PNTHREADS=4 <some data file>

the output hd_root.root file can now be processed using the ROOT script found in $HALLD_HOME/src/plugins/Calibrations/BCAL_TDC_Timing/FitScripts/. Run the ExtractTimeWalk.C script in the same directory as the hd_root.root file.

root -l -b -q $HALLD_HOME/src/plugins/Calibrations/BCAL_TDC_Timing/FitScripts/ExtractTimeWalk.C

This will produce another ROOT file that contains the results of the fits. The results are also output in a format that is suitable for insertion into the CCDB database. Browse through the output root files and see if the results seem reasonable.