Profiling Quartz Activation in ATLAS ZDC BRAN Rods

The Nuclear Physics Group at the University of Illinois collaborates on the development of a new Zero Degree Calorimeter (ZDC) for the ATLAS experiment. The upgraded ZDC is intended to withstand the harsh radiation environment expected from the high luminosity LHC. For the past two years, the BRAN luminosity group at the LHC has irradiated highly pure fused silica rods at the ZDC’s shower max. These samples were then provided to the University of Illinois for detailed study of the impact of radiation dosage on the rods' chemical and optical properties. The total dosage received as well as particle species and spectrum have been estimated from simulation and nearby radiation monitors. To verify this, we measured the 7-Be and 22-Na activation along the length of the fused silica rods. This information will then be used along with the cross sections for isotopic production to extrapolate total dosage. This poster will present the position dependent profiles of 7-Be and 22-Na concentration along the length of the rods. These concentrations have been determined from the gamma decay spectra observed with a high-purity germanium detector.