BCAL hadronic efficiencies

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Description of Method

This procedure determines a (biased) efficiency for each cell using charged tracks that are tracked with the drift chambers and point at the BCAL. The sample of tracks consists of charged particles with a reconstructed track and a matched shower in the BCAL. While the absolute value of the efficiency does not reflect the true efficiency of a cell, it is used to monitor the uniformity from run to run and can effectively identify issues with the data and the software reconstruction process. In checking the efficiency for a given layer, the algorithm requires a pointing track and a hit in at least one layer past the layer of interest, except for layer 4 since this is the last layer. The code then checks whether here is a hit close to the extrapolated track in the layer of interest (currently +/- 3 sectors). An inefficiency is tagged if no hit is found in this range. Efficiencies are computed, averaged over other variables, as a function of position along the calorimeter z, track momentum pmom, and cell id. The cell id is defined as id = (module -1)*4 + sector [1-192] for each layer.

Analysis Procedure

The code is located on Github. The user will be mainly interested in the scripts contained in the folder ROOT_macros.

Steps to extract the BCAL Hadronic Efficiencies (see README file on Github):

  1. Generate the root trees using the BCAL_Hadronic_Eff plugin. This is usually completed as part of the routine GlueX monitoring launches.
    • The output trees are located in files such as /cache/halld/offline_monitoring/RunPeriod-2019-11/ver12/tree_bcal_hadronic_eff/merged/tree_*.root
  2. Run python script Read_bcal_hadronic_eff2.py. Edit the file as needed to point to the correct directories.
    • Create directories with the names of 'root', 'dat' and 'pdf'
    • Execute the python script Read_bcal_hadronic_eff2.py.
    • This script iteratively executes the Read_bcal_hadronic_eff2.C script on each of the root trees.
    • The ROOT output files will be placed in the 'root/' subdirectory.
    • Summaries of the efficiencies are stored in the 'dat/' subdirectory. These will be used later for plotting summaries.
    • Output plots with details of the efficiency systematics are placed in the 'pdf/' subdirectory. These can be checked for problems.
  3. Run python script plot_bcal_hadronic_eff.py. Edit the file as needed to point to the correct directories.
    • The output of this script is just a file called plot_bcal_hadronic_eff.list, which contains the list of run numbers obtained from the 'dat' subdirectory.
  4. Run the ROOT script plot_bcal_hadronic_eff.C, Edit as needed to produce useful output.
    • The output of this script is the file bcal_hadronic_eff.pdf file with various plots of efficiency vs run number.

Data Studies

  • Log book entry for Spring 2020 data Log Entry 3812382
  • Log book entry for 2018 Log Entry 3642018
  • Log book entry for 2017 tracking improvements (comparison between versions 19 and 21) Log Entry 3486656
  • Log book entry for 2016 and 2017 efficiency studies Log Entry 3478578. Shows comparison of data and MC and including inefficient channels into the CCDB database.