Detector Safety System overview

1. Detector Safety System overview • DSS is a PLC based system designed to protect ATLAS detector from damages. • Front end (hardware) • 2 redundant PLC • ~700 input signals (sensors) • ~400 actuators (actions) • accommodated in 7 racks underground and on surface. • ~700 alarms • Alarm is a logical element, which links inputs signals with DSS actions. • Back end (software) • PVSS based application, provides human-machine interface • 2 active workstations + 2 hot swap workstations • DSS includes proprietary sensors • temperature, pressure, water leak etc. • and inputs from external systems • gas systems, electricity, cooling, ATASL subsystems, smoke detection, SNIFFERS, gas detection • All this equipment need to be maintained and tested. • New detecting systems and sensors being added regularly, following detectors requirements. • Alarm-action logic must be kept up-to-date with detectors.

2. LS1 DSS maintenance and consolidation • Alarm-action matrix (DSS logic) • has been reviewed together with detectors and modified to better satisfy ATLAS detectors safety requirements. • Implementation is nearly finished (some cross checks and cleaning still to be done). • Next step – comprehensive test of DSS matrix, will be done later on this year, when all detectors are closer to running conditions. • Hardware maintenance and consolidation of DSS hardware is ongoing • Local UPS and batteries replaced, • DSUs powering scheme improved, adding redundancy to 230V power supply • reduces risk of detector shutdown due to UPS failure • Consolidation of various sensors • temperature sensors, water detecting in racks and caverns, ventilation, etc. • Implementation of new systems and sensors • IBL CO2 cooling + water leak, leak detection in TileCalSc garages, new racks interlock, • temperature sensors etc. • Test of DSS • Alarm-action matrix • Propagation of signals from external systems to DSS • DSS sensors • DSS actuators

3. Atlas safety systems • External to DSS safety systems are linked to DSS providing input signals • Atlas proprietary systems, maintained by ATALS • Gate monitors – HW maintenance + PC and software upgrade • Seismic sensors - HW maintenance + PC and software upgrade • Water leak detection - in racks, UX15, USA15 caverns, to be implemented in US15 and SDX1 • External safety systems, maintained by GS • Gas detection • Central has been upgraded recently • New FG gas detection system under development by GS • Smoke detection, environment and in racks • Install sensors in new racks in USA15 and UX15 • SNIFFERS (maintained by GS and ATLAS together) • PLC firmware upgrade (GS) • modules maintenance (ATLAS) • pipes cleaning (ATLAS) • Access systems • software upgrade • new access doors installed in sectors 11 and 15

4. Cabling activity • A lot of new cables being installed at LS1 • Currently team of 7 people are working on cable installation • Cabling activity includes: • Communicating with detectors • Defining the cable routing • Estimation/calculation of cable length • Preparing labels and entering info to DB • Organization of installation, cable trays • Cabling team managing • Cabling done, ongoing or planned for the systems: • nSQP (new PIXEL services) • IBL detector • IBL CO2 cooling • New evaporative cooling (thermo syphon) system • New optical cables for MUON detector • New MEDIPIX detectors • BCAM • Beam pipe services and motor movement • Detector cooling • DSS • Various single cables

5. Other activities Response to issues raised during LS1 period, like new flexible chains in sector 11 to install LAr optical fiber bundles and new cables; Tilecal Cs garages drain lines and leak detection, etc. SLIMOS activity (4 shifters) RPE activity TC RPE team was particularly important at detector opening OPM and other activity support