Safety Systems in ALICE

1. Safety Systems in ALICE Protecting ALICE ALICE Technical Forum

2. Definition Safetynoun • the condition of being safe from undergoing or causing hurt, injury, or loss • a device (as on a weapon or a machine) designed to prevent inadvertent or hazardous operation ALICE Technical Forum

3. Safety • What do we understand by Safety: • Safety of people (prevent injuries or worse) • Safety of equipment (protect capital investment) • This can be achieved by: • Limiting the risk of developing a hazardous situation • Preventive actions (passive and active) • Limiting the consequences of an incident • Corrective actions ALICE Technical Forum

4. Who is involved • Various Control Systems (Detector Control System, Magnet Control System, Gas Control System, …) • Ensure integrity through: • Alarm reporting (for operator intervention) and automation • Detailed control on detector level and control of infrastructure and services (with high granularity) • Interlocks or ‘local safety systems’ • CERN Safety System (CSS) • Covers Level3 alarms (Smoke, Gas etc.) • Immediate action by the Fire and Rescue Group • “switch off” (Safety Actions); inform relevant services ALICE Technical Forum

5. Primarypower, water, gas Experimentgas, cooling, magnet, power Experiment:detectors, crates, racks Context The technical Servicesprovide power, water, primary gas (general services) and distribute them to the different experiment services that are needed to operate the experiment This and following slides are inspired by slides of Stefan Lüders et al. (DSS Team) ALICE Technical Forum

6. Experimentgas, cooling, magnet, power Experiment:detectors, crates, racks Primarypower, water, gas Context • Control and safety systems will act directly on the equipment at the experiment site; such as: • Detectors with their related equipment • Racks and crates • Gas systems • Cooling systems • Magnets • Power distribution • Water distribution ALICE Technical Forum

7. Sensors Sensors Sensors Experimentgas, cooling, magnet, power Experiment:detectors, crates, racks Primarypower, water, gas Context • Sensors monitor the state of the equipment: • temperature (equipment, ambient air, water), • humidity, water leak • water-flow, • Smoke and gas, • status signals of the detectors • There are dedicated sensors for the different safety and control systems ALICE Technical Forum

8. Sensors Sensors Sensors Experimentgas, cooling, magnet, power Experiment:detectors, crates, racks Primarypower, water, gas Control systems • The various control systems are responsible for the overall monitoring and control of the detector or services • They will take corrective action to maintain normal operation • Are able to act with fine granularity • All control systems are interconnected DCS detector A ST/EL (power) GCS (gas) DCS detector B DCS detector C MCS (magnets) ST/CV (water) CCS (cooling) control monitor control monitor Trip ALICE Technical Forum

9. Sensors Sensors Sensors Experimentgas, cooling, magnet, power Experiment:detectors, crates, racks Primarypower, water, gas CERN Safety System • The safety for personnel is ensured by theCERN Safety System(CSS). It is required by law and conforms to relevant International, European, and National standards • It has its own sensors and reacts globally (in a more ‘crude’ way), i.e. on whole building or cavern DCS detector A CSS DCS detector B DCS detector C ALICE Technical Forum

10. Sensors Sensors Sensors Experimentgas, cooling, magnet, power Experiment:detectors, crates, racks Primarypower, water, gas CERN Safety System TCR Fire Brigade to P2 DCS detector A CSS DCS detector B DCS detector C safety action Smoke, Gas Leak ALICE Technical Forum

11. Sensors Sensors Sensors Experimentgas, cooling, magnet, power Experiment:detectors, crates, racks Primarypower, water, gas Local safety systems(e.g. MSS, Interlocks) • Local safety systems preserve the integrity of well defined systems. E.g.: • The Magnet Safety System (MSS) protects the magnets • Interlocks protect detectors DCS detector A MSS DCS detector B DCS detector C Ramp downhigh voltage Ramp downmagnet gasfail waterfailure ALICE Technical Forum

12. Sensors Sensors Sensors Experimentgas, cooling, magnet, power Experiment:detectors, crates, racks Primarypower, water, gas Is that all ? • Does this cover all events? • What happens if a counting room gets hot? • Only action if individual items overheat (or burn…) • What happens if there is a water leak in the racks? • Only action if electronics get wet and short-circuit… • What happens if temperature goesup in the detector volume? • Only action if one of the detectors sees it DCS detector A DCS detector B DCS detector C ALICE Technical Forum

13. Sensors Sensors Sensors Experimentgas, cooling, magnet, power Experiment:detectors, crates, racks Primarypower, water, gas Detector Safety System • Detector Safety System (DSS) was born • Name might be slightly misleading: Think of it as experimental area surveillance system • We are not inventing something new: • DSS covers some of the functionality that was covered by GSS in LEP times (and is not covered by CSS and DCS) DCS detector A DCS detector B DCS detector C ALICE Technical Forum

14. Sensors Sensors Sensors Experimentgas, cooling, magnet, power Experiment:detectors, crates, racks Primarypower, water, gas Detector Safety System • Also, note the analogy with the magnet control system: • DSS is the ‘safe’ part of the Detector Control System Magnet Control Detector Control DSS DCS detector A MSS DCS detector B MCS (magnets) DCS detector C Water Leak ALICE Technical Forum

15. DSS project • Four LHC experiments defined requirements • Started as a JCOP project in May 2002 • Prototype has been build by DSS team • Review has taken place earlier this month • Installation for CMS and LHCb this year • Installation for ALICE next year • Will have to define requirements for the first installation in ALICE by the end of this summer ALICE Technical Forum

16. Surface Shaft Optical Link CR4 DSS Implementation • A redundant PLC solution (Siemens) has been chosen for the ‘front-end’ (similar to the new safety system of the Mont Blanc tunnel) • CPUs are comfortably separated to minimize danger of accidental damage • Interconnection with optical link ALICE Technical Forum

17. CERN LAN Surface DSS COM PROFIbus Shaft Optical Link Cavern DSS Implementation gateway • Redundant cables running throughtwo cable paths.Spares for all cables are foreseen. • Internal DSS Network • Connection to outside world through “gateway” ALICE Technical Forum

18. 52 units standard LEP rack (here: 56U) Uninterruptible Power Supply (UPS) OPC Server / Gateway (in one rack) Front-End Display Redundant 24V Power Supply & a Distribution Module CPU crate (in two racks) Ethernet Switch for DSS COM (in racks with CPU crate) 2nd External Crate possible External Crate with dedicated Monitoring Module Table / Drawer Patch Panel Terminals to connect sensors / actuators DSS Rack Layout ALICE Technical Forum

19. DSS implementation • The ‘back-end’ is based on PVSS and will be integrated in the DCS • User panels for DSS and CSS (concentrating all ‘alarm’ information) • Configuration of the DSS system • Installation, maintenance and support will be done with the help of a central (LHC-wide) team ALICE Technical Forum

20. DSS in ALICE • Will cover mainly water temperature and ambient temperature measurements; some water leak detection • A limited amount of detector inputs and outputs are foreseen • Detector needs will be studied case by case • The activity is concentrated in the central DCS team, with the ‘point 2 operation’ team and Glimos ALICE Technical Forum