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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? - PowerPoint PPT Presentation


Why a course

Why a courseWe will try to answer the following questions:How do know I am in a risky areaI 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

1Federico Faccio - CERNDealing with the radiation hazardDefine the requirements for the componentsIdentify the candidate componentsTest the candidate componentsGet a good knowledge of the environmentUnderstand the effectsEngineer the system2SummaryMake sure you understand the requirementsSimulation of the environment is essentialTry to select the components/technologiesPay attention to the requirementsTest your componentsLook around, you may find some information about the selected componentsTry to assess the riskSEU may not be critical, or it can be catastrophicMitigateVerify2/6/2009R2E Radiation School: SEU effects in FPGA33June 2nd, 2009R2E Radiation Workshop&School - F.Anghinolfi PH/ESE4

4Federico Faccio - CERNSummaryRadiation effectsRisk managementrisk avoidance impossible with COTS!more efficiently applied at system level!Steps to deal with the radiation hazardknow the environmentunderstand the effectsdefine the requirementsidentify the candidate componentstestengineer the system

5June 2nd, 2009R2E Radiation Workshop&School - F.Anghinolfi PH/ESERadiation Concerns in Power Supplies6 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 ANALYSIS6What risks to take ?Risk analysisWhat local failures provokes what system failures ?This is often more complicated than initially thoughtCan a given failure destroy other equipmentHard and soft failuresHow long does it take to recover from this ?Fold in radiation induced failure types and ratesZero risk do not existVery low risk will be very expensiveAnything else than low risk will be unacceptable

77Radiation zonesHigh 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 -> TMRASICsIntermediate zones: 100Gy 1kGy, 1011 1010 >2oMev h cm-2 (calorimeters and muon)ASICsPotential use of COTSRadiation tests for TID, (NIEL), SEE (Use available tests if appropriate)Special design principles for SEE (e.g. Triple Modular Redundant, TMR in FPGAs)Low level zones: < 100Gy, 2oMev h cm-2 (cavern),Extensive use of COTS TID and NIEL not a major problemSEE effects can be severely underestimatedSafe 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 !!!88The 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/experienceKey part of project requirementsReviews

99What to avoidUnderestimate the problemSafety systems in radiationForget 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 environmentComputers, PLC, Complicated Communication interfaces , , High power devices in radiation zonesSEE effects can become catastrophicParticular known weak componentsSome types of opto couplers, etc.Uncritical use of complicated devices (e.g. FPGAs)101011Triple Module RedundancyTriple redundancyThree copies of same user logic + state_registerVoting logic decides 2 out of three (majority)Used regularly in:High reliability electronicsMainframes Problems:300% area and powercorrects only 1 errorcan get very wrong with two errorsProblem: How do you make sure that the voting logic itself is not affected by SEU?FSM1FSM2FSM3Voting logicInputOutputCLKA. Marchioro / PH-ESEABACBCLogic for Voting1112What to duplicate?RegInputOutputA. Marchioro / PH-ESELogicRegComparison logicRegInputOutputLogicRegComparison logicLogicUse this:If clock frequency is high and technology is advanced.Use this: If clock frequency is low and technology is old.RegLogicReg12What is the duration of a hit disturbance with respect to the cycle time? If low, the probability of catching a spurious pulse generated in the logic is low and therefore the scheme on the left is recommended. If the clock rate is high and the ratio of sampling to storage is small, then it is more probable to catch a spurious hit and the scheme on the right should be used.Radiation EngineeringCERN Radiation school DivonneDoseDisplacementSingle EventsEM cascadeh > 100 KeVh > 20 MeV60Co sourcenuclear reactorp,n,p or HI beams nuclear cascaderadiation damage semiconductorsRadiation Testing6/3/200913Lessons LearnedPreparation has to be impeccable :Dedicated team of at least 2 persons/deviceComplete test setup preparedIrradiation planSufficient sparesDry run before leaving CERNData validation: back to home, it is too lateTo have the beam data in real timeto perform a data analysis (first check) upon completion of each runSet-up installation: trouble issuesCables and connectors:inversion, pin integrity,cables blocked or damaged during a tilt, etcElectrical noiseParasitic lightCERN Radiation school Divonne6/3/200914A systematic, unified approach is being followed by a unique inquiry form (EDMS 998529) to collect the equipment exploitation data. The form covers: Equipment Identification Structuring the collected data, (traceability, existing documentation); Characteristics Scoring the relevance of the need/equipment (operational, radiological, economical) Maintenance Identifying the technical needs (maintenance, machining, radiological) Storage Locating where the needs are/could be fulfilled (technical, operational, radiological, present & future needs).How we are doing it?A unified inquiry form

BufferMedium TermLong TermOper. Waste

15Material Controls & Waste ZoningZDRZDC ZOZone operationnelIndividual controls of material and wasteby DG-SCR not required - follow up by samplingDG-SCR controls required(comprises all CERN accelerator tunnels, target areas and experiments of SPS, PS complex, ZO of LHC experiments And NOW?

17LHC tomorrowAreas and system classified in terms of criticality:Radiation levels assessed (or under assessment)Priorities for systems:Safety of personnelSafety of the machineOperation of the machine (reduction of downtime)Short term measures (now!!) for 1 and partially for 2Long term measures (shutdown 2010/2011) for 2 and 318Radiation levelshttp:\\Cern.ch\R2E

If not sure, contact Markus Brugger19Design reviewsIf 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.20A big THANKMarkus Brugger & C., for organisation

PH-ESE for support and for being here the two days (and finding the speakers).


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