1. Colmar Setember 2002 M. Dentan, Ph. Farthouat 1 out of 38 Radiation Assurance in the LHC experiments Martin Dentan CEA Saclay Philippe Farthouat CERN With the help of Francis Anghinolfi Jorgen Christiansen Mika Huhtinen Peter Sharp Giorgio Stefanini

2. Colmar Setember 2002 M. Dentan, Ph. Farthouat 2 out of 38 Outline u Radiation Issues u Radiation constraints in the experiments u Radiation hardness assurance in the experiments u A few examples of difficulties u Conclusions

3. Colmar Setember 2002 M. Dentan, Ph. Farthouat 3 out of 38 Radiation Issues (1) u Cumulative effects –Total Ionising Dose (TID) »Energy deposited in the electronics by radiation in the form of ionization. »Unit:Gray (Gy), 1 Gy = 100 rad »Affects all electronics devices –Non Ionising Energy Loss (NIEL) »Displacement damage »Unit: particles/cm2 »Complex radiation  1 MeV neutrons equivalent »CMOS devices are not affected

4. Colmar Setember 2002 M. Dentan, Ph. Farthouat 4 out of 38 Radiation Issues (2) u Single Event Effect (SEE) –Destructive effects: SEL, SEB, SEGR, … –Upsets: SEU (logic), SET (linear) –Instantaneous effect: may occur just after the beam is switched on.

5. Colmar Setember 2002 M. Dentan, Ph. Farthouat 5 out of 38 Radiation Issues: TID u Charge trapping in oxides and interfaces u Vt shift, change gm, leakage current, noise, … u Cumulated damage => delayed effect u Dose rate and temperature dependence u Effects on MOSFETs, BJTs, diodes, … u May appear after only few krads

6. Colmar Setember 2002 M. Dentan, Ph. Farthouat 6 out of 38 Radiation Issues: NIEL u Bulk defects in semiconductors u , noise, … u Cumulated damage => delayed effect u Effects on bipolar devices u No effect on MOSFETs

7. Colmar Setember 2002 M. Dentan, Ph. Farthouat 7 out of 38 Radiation Issues: SEE u Energy deposition in the component u Can change the state of logic node (SEU) or generate transients in linear circuitry (SET) u Can trigger parasitic components and generate latch-up (SEL), burn-out (SEB),.. u A work done by M. Huhtinen, F. Faccio has shown that only the hadrons of E > 20 MeV have to be considered

8. Colmar Setember 2002 M. Dentan, Ph. Farthouat 8 out of 38 Radiation constraints: ALICE u TID (10 years) –2.5kGy (pixels inner layer @ 3.9cm radius) –1 Gy (in the experimental hall) u NIEL (10 years) –2.10 12 n.cm -2 (pixels inner layer @ 3.9cm radius) –10 8 n.cm -2 (in the experimental hall) u Radiation levels: internal note with updated calculations –A. Morsch, B. Pastircak (to become available end Sept 02)

9. Colmar Setember 2002 M. Dentan, Ph. Farthouat 9 out of 38 Radiation constraints: ATLAS u TID (10 years) –3 MGy (Pixels) –5 Gy (Cavern) u NIEL (10 years) –2 10 15 n.cm -2 (Pixels) –2 10 10 n.cm -2 (Cavern) u SEE (10 years) –3 10 13 h.cm -2 (Pixels) –2 10 9 h.cm -2 (Cavern) –h > 20 MeV

10. Colmar Setember 2002 M. Dentan, Ph. Farthouat 10 out of 38 Radiation constraints: CMS u TID (10 years) –8 MGy (Pixels) –5 Gy (Cavern) u NIEL (10 years) –2.5 10 15 n.cm -2 (Pixels) –2 10 10 n.cm -2 (Cavern) u SEE (10 years) –3 10 13 h.cm -2 (Pixels) –2 10 9 h.cm -2 (Cavern) –h > 20 MeV

11. Colmar Setember 2002 M. Dentan, Ph. Farthouat 11 out of 38 Radiation constraints: LHCb u TID (10 years) –0.1 MGy (vertex) –< 100 Gy (cavern) u NIEL (10 years) –10 15 n.cm -2 (vertex) –2 10 12 n.cm -2 (cavern)

12. Colmar Setember 2002 M. Dentan, Ph. Farthouat 12 out of 38 Radiation constraints: summary u ATLAS and CMS are very similar –10’s of MRad in the trackers –100 – 1000 kRad in the calorimeters (Em) –A few kRad in the muon spectrometers and the caverns u LHCb –A few Mrad in the vertex –A few kRad in the calorimeter and muon »Although the muon electronics has more u ALICE has lower levels –250 kRad in the pixel –Less than a kRad in the cavern –SEE have still to be taken into account

13. Colmar Setember 2002 M. Dentan, Ph. Farthouat 13 out of 38 Radiation Hardness Assurance u Goal: reliability of the experiment with respect to radiation u The radiation hardness assurance methods must be applied to each sub-system of the experiments –Particular attention should be paid to the identification of critical elements and to the possible failure modes u Should be coherent –Same rules for every system u Apart for the tracker electronics, there are differences between the experiments

14. Colmar Setember 2002 M. Dentan, Ph. Farthouat 14 out of 38 Radiation hardness for inner trackers u Very uniform policy within the four experiments –Use of radiation hard technology (DMILL) –Use of DSM technology with a rad-hard lay-out –Very strict qualification for other components »e.g the optical links components u Status of design and production

15. Colmar Setember 2002 M. Dentan, Ph. Farthouat 15 out of 38 Radiation Hardness Assurance: Constraints u Basis for the tests to be done u Needed: –TID (Gy), NIEL (1 MeV equiv. N.cm -2 ), “SEE” h.cm -2 (E > 20 MeV) u Very desirable to have tools to get these constraints in small elementary domains –Averaging may lead to optimism

16. Colmar Setember 2002 M. Dentan, Ph. Farthouat 16 out of 38 Radiation Hardness Assurance: Constraints ATLAS MDT readout ASIC Leakage current versus TID Average constraint Hot points (a few 10’s of ASICs)

17. Colmar Setember 2002 M. Dentan, Ph. Farthouat 17 out of 38 Radiation Hardness Assurance: Constraints u Constraints from simulation tools (Fluka, Gcalor, Mars) –There are uncertainties due to the physics models, to the detector model, … –There are uncertainties with the electronics  Safety Factors

18. Colmar Setember 2002 M. Dentan, Ph. Farthouat 18 out of 38 Safety Factors u Simulation uncertainties (location and type dependent) –ALICE proposes from 2 to 3 –ATLAS ranges from 1.5 to 6 –LHCb uses 2 –CMS quotes from 1.3 to 3 u Electronics effects –Low dose rate effects »ATLAS ranges from 1 to 5 depending on radiation type, technology and tests procedures (e.g. annealing at high temperature) –Lot to lot variation for the COTS »ATLAS ranges from 1 to 5 »LHCb ranges from 2 to 100 –Safety factors are there to flag possible problems u Dosimetry uncertainties –LHCb applies a factor 2 –Others trust the dosimetry

19. Colmar Setember 2002 M. Dentan, Ph. Farthouat 19 out of 38 Testing Procedures u Testing electronics against radiation is complex –Tests conditions –Type of radiation –Biasing conditions –Annealing conditions u Better to base the tests on standard methods –ESA or MIL u Tests to be done several times –Pre-selection –Qualification of production lots u Experiments policy –ATLAS has defined some testing procedures –LHCb is pointing to them

20. Colmar Setember 2002 M. Dentan, Ph. Farthouat 20 out of 38 Results book keeping u Very desirable to have a standard radiation test report –To be sure that nothing is forgotten –To be easily reviewed and shared u A central place to store them is also desirable –To share the results between different groups u A data base accessible through the WEB is available –Developed by Chris Parkman for ATLAS –Adopted by RD49 i.e available for all experiments –Not sufficiently used

21. Colmar Setember 2002 M. Dentan, Ph. Farthouat 21 out of 38 Management u Two main types u Radiation Hardness treated centrally –One responsible for the experiment, One per sub-system, one per electronics entity (boards) –Common rules for everybody –Common rules for the reviews –Preselection and qualification processes u Radiation Hardness treated by each sub-system –As an extra specification –No specified rules u ATLAS is using the first model, CMS the second one

22. Colmar Setember 2002 M. Dentan, Ph. Farthouat 22 out of 38 Interpretation of the results u Assuming a perfect procedure has been applied we should know when launching the production –How the electronics will behave in time with respect to cumulative effects –What is the cross-section of SEE u The agreement for starting the production still needs some extra thinking –Can we have some maintenance for cumulative effects »Physical access and financial capability –Can we overcome the effects of SEE »In the design in implementing special techniques (e.g redundancy) »In the system in implementing reset sequences or continuous monitoring of the key data »In the power supplies for latch-up detection and automatic switch off »In just living with them (e.g data corruption)

23. Colmar Setember 2002 M. Dentan, Ph. Farthouat 23 out of 38 Interpretation of the results –cont.- u The most difficult point concerns the SEE as this is a statistical process and that it is not needed to have high doses to be disturbed u The experience that we have got in ATLAS is that there has not been a single SEE test not leading to problems  u FPGA are particularly sensitive –LHCb has issued a rule for using only antifuse FPGA and triple redundancy –Several systems are going to use ASICs or Gate Arrays instead of FPGA (ATLAS Liquid Argon and Muon trigger) or are moving the complexity at safer places (ATLAS Muon tracking, LHC machine) 

24. Colmar Setember 2002 M. Dentan, Ph. Farthouat 24 out of 38 A few examples of difficulties u ATLAS Liquid Argon electronics and power supplies u ELMB u Low voltage regulators

25. Colmar Setember 2002 M. Dentan, Ph. Farthouat 25 out of 38 Liquid Argon Electronics u Radiation Tolerance Criteria for LAr –TID = 525–3500 Gy/10yr –NIEL = 1.6–3.2 10 13 N/cm 2 /10yr –SEE = 7.7-15 10 12 h/cm 2 /10yr u Electronics in crates around the detector G’damm I am good!

26. Colmar Setember 2002 M. Dentan, Ph. Farthouat 26 out of 38 Liquid Argon Electronics u 1 responsible per board –FEB (1600 boards) : J. Parsons –Calib (120 boards) : N seguin –Controller (120 boards) : B. Laforge –Tower builder (120 boards) : J. Pascual –Tower driver board (23 boards) : E.Ladyguin –LV distrib ( ) : H. Brettel –Purity (?) : C. Zeitnitz –Temperature : ? u 1 representant for power supplies –Helio Takai u 1 representant for optical links –Jingbo Yee

27. Colmar Setember 2002 M. Dentan, Ph. Farthouat 27 out of 38 Liquid Argon Electronics u First tests made with COTS were very disappointing… u Decision to avoid them as much as possible  A lot of extra design work

28. Colmar Setember 2002 M. Dentan, Ph. Farthouat 28 out of 38 Liquid Argon Electronics: FEB u 10 different custom rad-tol ASICs, relatively few COTs DMILL DSM AMS COTS 32 SCA16 ADC8 GainSel 1 GLink1 Config.2 SCAC 1 SPAC 1 MUX 32 Shaper 1 TTCRx 7 CLKFO 14 pos. Vregs +6 neg. Vregs 2 LSB 32 0T 128 input signals 1 fiber to ROD Analog sums to TBB 2 DCU TTC, SPAC signals

29. Colmar Setember 2002 M. Dentan, Ph. Farthouat 29 out of 38 Liquid Argon Electronics: ASICs

30. Colmar Setember 2002 M. Dentan, Ph. Farthouat 30 out of 38 Liquid Argon Electronics u Tracking of the status of radiation hardness of components u Still possible to forget a component –E.g opto-receiver of the TTC u Complete crate with radiation tolerant electronics to be ready in 2003

31. Colmar Setember 2002 M. Dentan, Ph. Farthouat 31 out of 38 Liquid Argon Power Supplies u Each crate requires 3 kW u 4 kW DC-DC based power supply has been designed –To be located inside the detector –300 V DC input u 2-3 years of measurement and development to understand and solve radiation problems u Most severe problem was SEB (Single Event Burn-out) –SEB destroys the MOSFET. –SEB depends on how the MOSFET is biased and therefore on the topology of the power supply. Resonant circuits for example are particularly bad for SEB because VDS depends on the load –The second effect that one has to be aware is the asymmetric nature of the SEB cross section. When particles hit from the drain side it can be significantly larger than from the gate side. This has been determined for ~6 different power MOSFET. TestGoalAchieved Ionizing Radiation 10kRad300kRad NIEL1.15x10 12 5.0x10 13 Hadrons E>20MeV 5x10 11  SEB <1x10 -16 cm 2  SEL <7x10 -13 cm 2 Magnetic Field 20 G120 G

32. Colmar Setember 2002 M. Dentan, Ph. Farthouat 32 out of 38 Liquid Argon Power Supplies –cont- u NOT because of loss of power supplies! u SEB and SEGR are potential hazards that can short converters and failure in protection systems could lead to instant fire hazard. Power supplies are rated to 4kW. u Note that they are located in places that are inaccessible in case of emergency. u Ionizing radiation damage leads to loss of regulation and potentially loss of electronics. u Magnetic Field saturates transformers and supplies ceases to work with possible short in the input stage. u Unknown background is the one that will do the job. Currently SEB for pions, kaons are unknown but we know that SEE induced by pions can be 5x larger than neutrons. Production of fragments in packaging, etc have not been considered. Still a Lot of Concerns !!

33. Colmar Setember 2002 M. Dentan, Ph. Farthouat 33 out of 38 Embedded Local Monitor Box (ELMB) u Basic element for the slow control of the ATLAS muon chambers u Radiation constraints (including safety factors) –TID : 8.4 Gy in 10 years; –NIEL: 5.7E11 n/cm2 (1 MeV eq.) in 10 years; –SEE: 9.5E10 h/cm2 (>20 MeV) in 10 years. CAN SAE81C91 3.3 to 5.4V option? VSup 50 mm 67 mm DIP-SW ID BAUD ISP OPTOs Voltage regulators ATMEL micros CAN Tranceiver ADC Analog MUX REF Logic Latch

34. Colmar Setember 2002 M. Dentan, Ph. Farthouat 34 out of 38 ELMB –cont- u TID results: one of the processors is sensitive (although well within the requirements)

35. Colmar Setember 2002 M. Dentan, Ph. Farthouat 35 out of 38 ELMB –cont- u SEE results: requirement for an automatic power on-off u Care being taken for the use of the RAM –“SEE resistant” software

36. Colmar Setember 2002 M. Dentan, Ph. Farthouat 36 out of 38 ELMB –cont- u Additional work going on –Current design has two processors. Next will have one only. Improved TID response –Software to counteract the SEE being improved u Production organisation –Qualification of batches of components u Safe definition of where the ELMB can be used: –TID > 40 Gy for protons –NIEL > 5*1012 neutrons/cm2 – SEE >> MDT requirements

37. Colmar Setember 2002 M. Dentan, Ph. Farthouat 37 out of 38 Low Voltage Regulators u Radiation tolerant low voltage regulators (a few krad and a few 10 12 n.cm -2 ) almost impossible to find –One from Intersil may be OK for ATLAS calorimeter but costs too much u RD49 has initiated a development with ST Electronics –Positive and negative adjustable regulators –Very hard (several Mrad) u Positive version available u Negative version had a bug –Has been corrected –A few 100’s available in November (not lifetime qualified) –Quantities in January-February 2002

38. Colmar Setember 2002 M. Dentan, Ph. Farthouat 38 out of 38 Summary-Conclusions u Radiation Hardness is still an issue in the experiments –SEE is a major concern u The knowledge of the problems has reached a reasonably good level in the community thanks to tutorials organised either in the experiments or by RD49 u The radiation hardness assurance approaches are not identical in the experiments (or in the machine) u Book keeping is a key issue if one wants to benefit from the work done –The existing data base should be more widely used –It requires a effort of documentation from all of us »Tests descriptions »Results