Effects of Radiation Damage in ATLAS Roman Pot Detectors (ALFA & AFP)

The ATLAS Roman Pots are a part of the ATLAS Forward detector system which consists of two subsystems, the ALFA (Absolute Luminosity For ATLAS) and the ATLAS Forward Proton (AFP) detector. ALFA was designed to determine the total proton-proton cross-section as well as the luminosity at the Large Hadron Collider (LHC) by measuring elastic proton scattering at very small angles, in a low luminosity environment, while the AFP is optimized for diffractive measurements and substantially improves ALFA coverage in a wide range of resonance mass. Together with the envisaged Time-of-Flight (ToF) system, AFP will also be able to conduct measurements at high instantaneous luminosities, by providing information on the diffractive vertex position. The ALFA detector is based on scintillator fibers placed in Roman Pots close to the LHC proton beam at around 240m from the ATLAS Interaction Point (IP) on each side, while the AFP uses FEI4b 3D pixel based Silicon Tracker (SiT) placed at around 210m from the IP on both sides. To increase the physics sensitivity, the fibers and sensors have to be placed as close as possible to the proton beam (around 2-3mm). Thus, the system is required to sustain high radiation doses. Particularly challenging is the non-uniform nature of the dose distribution. This poster presentation would shed a light on how these challenges are (being) mitigated and give an overview of the sustained radiation damage in both sensors and readout electronics of the ATLAS Roman Pots Forward Detector System.