single event upset vulnerability - radiation...

SINGLE EVENT UPSET VULNERABILITYR. LOSITO, EN/STI for R2E teamLHC Risk Review,

5/3/2009

OUTLOOKOUTLOOK

h bl2

The problemOverview of LHC points and prioritiesCriticality

By areaBy equipment

The strategy for the future:Working groups and organisationRadiation MonitoringHow to develop a new culture

Conclusions

LHC Risk Review, 5/3/2009Single Event Upset Vulnerability, R. Losito EN/STI

The ProblemThe Problem

Si l E t U t t d b hi h3

Single Event Upsets are generated by high energy hadrons (typically >20 MeV) They generally corrupt memory registers or induceThey generally corrupt memory registers, or induce spurious signals that can lead to Single Event ErrorsSingle Event Upsets lead to Single Event Errors g p g(equipment failure, component burn-out etc…), if no precaution is taken in the selection of electronic component and designcomponent and design.Commercial Off The Shelf (COTS) electronics is generally not immune by itself to SEU, but in few cases g y y ,can be hardened by re-programming or by using hardware redundancy.


The ProblemThe Problem4

Failure in some COTS electronics in CNGS in Oct. 2007 triggered an investigation in LHCAt the base of the problem there are 2 main causes:

Several areas were declared as “radiation free” because the dose was low, but hadron fluence remains because e dose was ow, bu ad o ue ce e a sconsiderable. The level of awareness of the problem was low, inThe level of awareness of the problem was low, in particular in groups not having equipment in areas not classified as radioactive.



In 2008, the R2E team assessed the most critical areas, recommending either shielding or moving equipment from most critical areas to cope with increasing intensity and luminosity in LHCStarted to organise the approach across different departments to avoid “panic” mode.departments to avoid panic mode.



In most of those areas (e.g. UJ76) dose (1 MeV eq.) is “negligible” (no more than few gray/year)

Disclaimer: numbers as of end 2007.


UJ76 Examples – Downstairs

7

UJ76


Overview of LHC points and prioritiesOverview of LHC points and priorities8

Work documented in a website, for the moment with restricted accesshttp://ab-div.web.cern.ch/ab-div/Meetings/r2eThe database contains:The database contains:

Existing simulationsD i d l t i l di k iti dDrawings and layouts, including rack position and compositionR di i i i h (RP R d BLM )Radiation monitors in the area (RP, Radmon, BLMs …)Any other useful information



Maximum priority was set to UJ76 (at nominal intensity 1 SEE every few minutes)RR76/RR77 UA63/67 (to protect dump system controls)/ 7 ( p p y )Cryo equipment in UX85


Overview of LHC points and prioritiesOverview of LHC points and priorities

SO ONS11

SOLUTIONSUJ76:

M t d TZ76 hi ldi ibl ( t f )Move towards TZ76: no shielding possible (apart safe room). Civil engineering and cabling works on-goingEquipment will be moved only after first shutdown – no time to q p ymove -recommission

RR76/RR77 C l h ld f llComplete shielding as foreseen initially

UA63/67 (to protect dump system controls)ShieldShield

Cryo equipment in UX85Replace with existing rad-hard solutionp g


CriticalityCriticality14

First prioritySEE should not compromise safety of the machine and personnel

Priority (if needed) will be given to equipment that enter into the machine protection scheme and AL3

Second prioritySEE should not lead to downtime

Then all the othersThen all the others


Criticality by areaCriticality by area15

[ Loss/Intensity-Scaling: M. Lamont] LHC Risk Review, 5/3/2009Single Event Upset Vulnerability, R. Losito EN/STI

Criticality by equipmentCriticality by equipment16

Movable Detectors

Beam LossMonitors

BCM

Experimental Magnets

CollimatorPositions

Environmentalparameters

Special-

LHCDevices

LHCDevices

LHCDevices

Safe Beam Parameter Distribution

B

LHCExperiments

CollimationSystem

Transverse Feedback

Beam ApertureKickers

pBLMsOperator

ButtonsCCC

SafeLHC

Parameter

SoftwareInterlocks

Sequencer

Beam Interlock SystemBeam

Dumping SystemInjection

P P M B S /A VB l

SafeBeamFlag

jInterlockPowering

Interlockssc magnets

PoweringInterlocks

nc magnets

Magnet Current Monitor

RFSystem

BeamLifetimeFBCM

Screens / Mirrors

BTV

Access System

VacuumSystem

Beam loss monitors

BLM

M it M it

Timing System (Post Mortem

Trigger)

QPS Power AUG UPS

Power Converters

Magnets

Cryo Doors EIS Vacuum Access RF

Monitorsaperture

limits(some 100)

Monitors in arcs

(several 1000)

Trigger)

QPS(several 1000)

Power Converters

~1500

AUG UPS CryoOK

Doors EIS Vacuumvalves

AccessSafetyBlocks

RF Stoppers

© R. Schmidt, M. BruggerLHC Risk Review, 5/3/2009Single Event Upset Vulnerability, R. Losito EN/STI

The Strategy for the futureThe Strategy for the future

P li f El t i LHC M hin C itt17

1. Policy for Electronics installed in areas with elevated radiation levels

LHC Machine Committee

(R2E)2. Evaluation of Radiation

Levels: simulationsR2EPoint-

OwnersLevels: simulations, monitoring, proposal of measures (R2E)S i l

RadWG

T ti

Monitoring

3. Structure to implementthe Policy (RadWG)

4 Radiation TestsEquipment

Owners

Testing

4. Radiation Tests (RadWG)

5. Control (Point Owners)Installations

Electronics PolicyElectronics Policy


The Strategy for the futureThe Strategy for the future18

R2E Improve knowledge of “as built” caverns and identify equipment installed

Point owners (with the help of R2E members and equipment owners) in charge of filling the database

RADWG Improve knowledge of sensitivity of equipment installedq p

Equipment groups to name representative in RADWG to follow up on technical aspectsfollow up on technical aspectsTest equipment for which sensitivity is not known.



RADWG – Radiation testsWill steer testing process through

component testing in monoenergetic beamsSystem testing in CNGS irradiation facility

Efficiency limited by available manpower and beam time in facilities need to increase and differentiate resources.Test know-how centralised in EN/STI to cope with urgent work, but every group should little by little acquire some know-how (as e.g. PO, QPS etc…).


The Strategy for the futureThe Strategy for the future

M20

Radiation MonitoringCombine data from all available radiation monitors (BLM RP RADMON ) i i l i f i h(BLMs, RP, RADMONs) in one single interface with coherent unitsCompare with simulationCompare with simulationCorrelate with known equipment failuresDefine new needs for monitorsDefine new needs for monitors

Application will be available in CCC for beamApplication will be available in CCC for beam commissioning



How to develop a new culture:Only a few groups have already a very good knowledge of the problem and how to cope with itRaise awareness by having a clear policy, to which directors, department heads and group leaders should commit.In particular, each group shall have a linkman, participating to RADWG and diffusing information in the groupSpecific training will be organised (one day school)


ConclusionsConclusions22

Single Event upset can compromise operation of LHC as intensity and luminosity increaseWe are however out now from “panic” mode, we have an understanding of the most critical problemsg pWe are setting up a structure (R2E, RADWG) that will help groups to get out of the “tunnel”will help groups to get out of the tunnel


ConclusionsConclusions

W d bl 200923

We do not expect serious problems in 2009AL3 systems still under investigation

NNext problems :Power converters in RRs: solutions under study to implement “simple” modifications Shutdown 2010/11 ?simple modifications. Shutdown 2010/11 ?UJ14/UJ16/UJ23/UJ56/UJ87/US85…, RRs: several equipment concerned (access, collimation, BICs). Additional q p ( , , )shielding or relocation under study. Possible few problems in 2010, depending on luminosity and intensity.

Solutions to be found in 2009, implementation depending on operation experience and time.


ConclusionsConclusions24

For detailed information see presentation at LHC pPerformance workshop (Chamonix 2009) by Markus BRUGGER.


single event upset vulnerability - radiation...

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