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Why a course

Why a course. We will try to answer the following questions: How do know I am in a “risky” area I design a rad -tolerant electronic system (hardware/software)? How do I make sure the device is really radiation tolerant? What should I test it and where can I do it?

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Why a course

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  1. Why a course • We will try to answer the following questions: • How do know I am in a “risky” area • I design a rad-tolerant electronic system (hardware/software)? • How do I make sure the device is really radiation tolerant? • What should I test it and where can I do it? • What kind of support may I receive for the test? • What kind of resources my group (leader) has to provide for the preparation and test? • How can I do all that, and deal with irradiated electronics SAFELY

  2. Dealing with the radiation hazard Get a good knowledge of the environment Define the requirements for the components Understand the effects Identify the candidate components Test the candidate components Engineer the system Federico Faccio - CERN

  3. Summary • Make sure you understand the requirements • Simulation of the environment is essential • Try to select the components/technologies • Pay attention to the requirements • Test your components • Look around, you may find some information about the selected components • Try to assess the risk • SEU may not be critical, or it can be catastrophic • Mitigate • Verify R2E Radiation School: SEU effects in FPGA

  4. R2E Radiation Workshop&School - F.Anghinolfi PH/ESE

  5. Summary • Radiation effects • Risk management • risk avoidance impossible with COTS! • more efficiently applied at system level! • Steps to deal with the radiation hazard • know the environment • understand the effects • define the requirements • identify the candidate components • test • engineer the system Federico Faccio - CERN

  6. Radiation Concerns in Power Supplies • Some conclusions : • The SEB, specific defect of “high voltage” power devices, is easily turned down by the proper derating of VDS (tests are necessary) • TID, NIEL (neutrons) can still be a problem for long term operations, upgrades … (Voltage reference drifts, optocouplers functional loss) • Logic circuits in exposed areas are subject to functional failures, some of them may be critical in power systems (SEU) • Custom made power units (in the case of experiments, “customized” because of the radiation and/or magnetic field tolerance …) were always (?) presenting some reliability issues after fabrication. • THE TESTS IN APPROPRIATE PARTICLE ENVIRONMENT (Ionizing, NIEL, high energy PROTONS) PROVED TO BE USEFUL FOR THE DEFECT ANALYSIS R2E Radiation Workshop&School - F.Anghinolfi PH/ESE

  7. What risks to take ? • Risk analysis • What local failures provokes what system failures ? • This is often more complicated than initially thought • Can a given failure destroy other equipment • Hard and soft failures • How long does it take to recover from this ? • Fold in radiation induced failure types and rates • Zero risk do not exist • Very low risk will be very expensive • Anything else than low risk will be unacceptable

  8. Radiation “zones” • High level zones: 1MGy – 1KGy, 1015 – 1011 >2oMev h cm-2 , 10 years (trackers) • Everybody knows (must be made to know) that radiation has to be taken into account and special systems based on special components needs to be designed/tested/qualified/etc. • TID, NIEL, SEE - Estimate of soft failure rates -> TMR • ASIC’s • Intermediate zones: 100Gy – 1kGy, 1011 – 1010 >2oMev h cm-2 (calorimeters and muon) • ASIC’s • Potential use of COTS • Radiation tests for TID, (NIEL), SEE (Use available tests if appropriate) • Special design principles for SEE (e.g. Triple Modular Redundant, TMR in FPGA’s) • Low level zones: < 100Gy, <1010 >2oMev h cm-2 (cavern), • Extensive use of COTS • TID and NIEL not a major problem • SEE effects can be severely underestimated • Safe zones: < ? (LHC experiments: counting house with full access) • One has to be very careful of how such zones are defined. Do not confuse with low rate zones !!!

  9. The Wall (not by Pink Floyd) • LHCb experience: • Physical (thin) walls does not make problem disappear. • What you do not see, you do not worry about. • When you see it, it is too late. • Lots of concrete needed to give effective radiation shielding. • Political/organisatorial walls does not make things better • All participants in global project (experiments + machine + ?) must be aware of the potential problems. • Extensive exchange of information/experience • Key part of project requirements • Reviews

  10. What to avoid • Underestimate the problem • Safety systems in radiation • Forget that local errors can propagate to the system level and make the whole system fall over (very hard to verify in advance for complex systems) • Assume that somebody else will magically solve this. • Complicated not well known electronics (black box) in radiation environment • Computers, PLC, Complicated Communication interfaces , , • High power devices in radiation zones • SEE effects can become “catastrophic” • Particular known weak components • Some types of opto couplers, etc. • Uncritical use of complicated devices (e.g. FPGA’s)

  11. Triple redundancy Three copies of same user logic + state_register Voting logic decides 2 out of three (majority) Used regularly in: High reliability electronics Mainframes Problems: 300% area and power corrects only 1 error can get very wrong with two errors Problem: How do you make sure that the voting logic itself is not affected by SEU? Triple Module Redundancy FSM1 Output FSM2 Input Voting logic FSM3 A B CLK A C B C Logic for Voting A. Marchioro / PH-ESE

  12. What to duplicate? Logic Logic Input Input Reg Reg Output Logic Output Reg Reg Comparison logic Comparison logic Logic Reg Reg • Use this: If clock frequency is low and technology is “old”. • Use this: • If clock frequency is high and technology is “advanced”. A. Marchioro / PH-ESE

  13. Radiation Engineering h > 20 MeV Single Events h > 100 KeV EM cascade nuclear cascade Displacement p,n,p or HI beams Dose radiation damage semiconductors nuclear reactor 60Co source Radiation Testing CERN Radiation school Divonne

  14. Lessons Learned • Preparation has to be impeccable : • Dedicated team of at least 2 persons/device • Complete test setup prepared • Irradiation plan • Sufficient spares • Dry run before leaving CERN • Data validation: back to home, it is too late • To have the beam data in real time • to perform a data analysis (first check) upon completion of each run • Set-up installation: trouble issues • Cables and connectors: • inversion, pin integrity,cables blocked or damaged during a tilt, etc • Electrical noise • Parasitic light CERN Radiation school Divonne

  15. How we are doing it?A unified inquiry form • A systematic, unified approach is being followed by a unique inquiry form (EDMS 998529) to collect the equipment exploitation data. The form covers: • Equipment IdentificationStructuring the collected data, (traceability, existing documentation); • CharacteristicsScoring the relevance of the need/equipment (operational, radiological, economical) • MaintenanceIdentifying the technical needs (maintenance, machining, radiological) • StorageLocating where the needs are/could be fulfilled (technical, operational, radiological, present & future needs). Buffer Medium Term Long Term Oper. Waste

  16. Material Controls & Waste Zoning ZDC Individual controls of material and waste by DG-SCR not required - follow up by sampling ZO Zone operationnel DG-SCR controls required (comprises all CERN accelerator tunnels, target areas and experiments of SPS, PS complex, ZO of LHC experiments ZDR

  17. And NOW?

  18. LHC tomorrow • Areas and system classified in terms of criticality: • Radiation levels assessed (or under assessment) • Priorities for systems: • Safety of personnel • Safety of the machine • Operation of the machine (reduction of downtime) • Short term measures (now!!) for 1 and partially for 2 • Long term measures (shutdown 2010/2011) for 2 and 3

  19. Radiation levels • http:\\Cern.ch\R2E • If not sure, contact Markus Brugger

  20. Design reviews • If you need help, volunteer for a design/test review. • If your system is critical, it is not excluded that you will be requested to organise a review. • Please participate to RADWG, and contact Thijs who can advise you or send you to the right people. • Share your experience with the others.

  21. A big THANK • Markus Brugger & C., for organisation • PH-ESE for support and for being here the two days (and finding the speakers). • DG-SCR (RP) • All the lecturers

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