Figures 2-4 below show the effect on energy deposited in the EC of the removal of various materials in front of the calorimeter. Otherwise the full detector geometry of CLAS is turned on.
Resolution is shown as light circles.
EC cover plate include stainless steel skin and polyurethane foam. SC geometry includes TOF bars, front Pb and rear foam and stainless steel backing panels. Comparison of Figures 2 with 3 and 4 shows clearly that the SC bars and the EC cover plate are the dominant contributions to the energy loss. The interactive version of GSIM was used to study the behavior of the photons produced in the TOF bars by electrons undergoing Bremsstrahlung radiation. Altogether the material preceding the Pb-scintillator sandwich in the EC is equivalent in radiation lengths to 1 sheet of Pb.