Optical Transmission of Ultra-Pure Fused Silica Fibers Irradiated at The LHC

For the future high luminosity (HL) upgrade to the Large Hadron Collider (LHC), the associated detectors and instruments must undergo upgrades to accommodate the increase in luminosity. The HL Zero-Degree Calorimeter (ZDC) upgrade is a joint effort between ATLAS and CMS groups to upgrade the existing ZDCs for the HL-LHC. With an increase in radiation levels expected in the HL-ZDCs, fused silica materials used in the detector need to be radiation hard. In collaboration with Polymicro, the manufacturer of the fused silica fibers, eight ultra-pure fused silica fiber candidates were selected and irradiated in the LHC for a combined integrated luminosity of 0.11 pb^-1 of pp collisions at 13.6 TeV and 1.91 nb^-1 of Pb+Pb collisions at 5.36 TeV. The transmission of the fused silica samples is being measured using a dedicated spectroscopy setup. The transmission will subsequently be correlated to specific radiation doses with the help of CERN FLUKA simulations. Based on these measurements, the fused silica materials for the HL-ZDCs will be selected. Future applications for the radiation-hard fused silica include other devices in high-radiation environments such as satellites, other high-energy detectors, or radiation detectors for post-accident nuclear reactors.