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Reliability of Beam Loss Monitors System for the Large Hadron Collider. Dump. RF. Cleaning section. Cleaning section. Proton injection. Proton injection. LHC Superconductive Magnets. In LHC there are: 514 main quadrupoles (MQ), 1232 main dipoles (MD).
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Reliability of Beam Loss Monitors System for the Large Hadron Collider Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni
Dump RF Cleaning section Cleaning section Proton injection Proton injection LHC Superconductive Magnets In LHC there are: 514 main quadrupoles (MQ), 1232 main dipoles (MD). Favorite loss location: quadrupole and transitions. We will monitor only the MQ (and some other critical locations). If losses exceed a threshold, a dump signal is generated. Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni
SIL approach Safety Integrity Levels (IEC 61508): our guideline for LHC protection systems. Event frequency Faced risk Events definition Suggested system failure rate Expected (LHC) system failure rate Event gravity Dangerous losses/y False dump/y Magnet Destruction False Dump Unavailability of protection system Failure rate frequency Destruct magnets/y False dumps/y Suggested/Tolerable failure rates Substitution downtime Recovering downtime Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni
Events Definition System fault events Prevent superconductive magnet destruction (MaDe) due to an high loss (~30 downtime days for substitution). Avoid false dumps (FaDu) ( ~3 downtime hours to recover previous beam status). Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni
Frequency Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni
Gravity Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni
SIL levels For high demand / continuous mode of operation systems Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni
LHC Systems Resistive magnets Beam Loss Interlocks Dump Beam Energy Cryogenics Lifetime Power converter Access Timing Vacuum Experiments Beam position Quench protection Collimation RF FaDu >10s Loss Duration middle MaDe <10ms 4 first line systems: average l 2.5E-8/h ~20 dump generator systems: average l 5E-8/h Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni
Integrator Treshold comparator Iin(t) 450 GeV Iref One-shot DT Switch Reference current 7 TeV fout BLMS BIC (Dump) Ionization Diode Multi- Current to Beam Permit Threshold Demulti- chamber plexer frequency comparator Beam Energy plexer LASER converter VME Bus Below Quad. in ARC At surface (SR, SX) Analogue Electronics Digital Electronics Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni
Availability improvements Test (continuously, 20 hours and yearly) of detector and analog electronic, to face integral dose degradation; voting for digital part, to avoid single event effects. Actions against the weakest elements (lasers, CRC, decisions table,…):redundancy. Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni
Failure Rates Reference:MIL-HDBK-217F IC calculated with 60% confidence level of no fails over 140 IC in 30 years in SPS Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni
FPGA TX FPGA RX Com- biner Beam interlock DUMP IC 2oo3 System failure 2 Monitor Front end electronic Surface electronic Dump electronic Dump line 1 Dump line 2 Dump line 3 Laser line 1 Laser line 2 Software possibilities Component failure rate predictions. References: MIL-217 (electronic), Telcordia (telecommunication), IEC (electronic), NSWC (mechanical) System dependability. Reliability Block Diagram Fault Tree Assembly failure mode. Failure Mode Effect and Criticality Analysis Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni
0.6 0.45 Relative importance Unreliability 0.3 0.15 0 IC JFET1 JFET2 OPA1 OPA2 LASER1 LASER2 40 ms 80 ms 20 h 40 h Software outputs Time profiles Unavailability, failure rate,… Importance diagram Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni
“Focused” dangerous losses per years: pessimistic! Number of channels Results Foreseen event frequency: MaDe (single channel): 5.0 10-7/h * 4000 h/y * 100 = 0.2/y SIL suggested rate: 2.5 10-8/h Beam hours: 200 d*20 h/d FaDu (no Power Supply): 2.4 10-7/h * 4000 h/y * 3200 = 3/y SIL suggested rate: 5.0 10-8/h We are beyond the Functional limits, but tolerable for Malfunction approach: good confidence that in 20 year we will lose (less than) the 16 spares magnets and BLMS generate around 3 false dump per year. Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni
Conclusions • Probable multi-detection per loss (further simulations on going): MaDe OK. • FaDu improving with better electronic components (and better power distribution). • The systematic reliability approach guide the BLMS design (redundancies, testing, sensitivity evaluations). Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni
Don’t shoot the messenger. Questions? Reliability of BLMS for the LHC. G.Guaglio, B Dehning, C. Santoni