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Estimating Estimating “Damage 2 “Damage 2
Electronics” using Electronics” using FLUKAFLUKA
M. Brugger for the FLUKA Team
CERN FLUKA User MeetingJuly 31st 2008
MATERIAL CAUSE RADIATIONEFFECT
Semiconductors Electron-hole pair dose ionizationPhoton interaction photon
absorption Lattice displacement nucleon collision
Polymers Main and side chain rupture dose ionizationcross-linking degradation “ “gas evolution, radical productiondose rate
Ceramics Lattice displacements nucleon collisiontrapped charge carriers dose ionizationcolor centers “ “
Metals Lattice displacements nucleon collisionnuclear reactions producing clusters “
“voids and bubbles “
“
Radiation Effects – Rough Classification
© Lockheed MartinJuly 31st 2008 2CERN FLUKA User Meeting
Radiation Damage Effects
Total Dose DisplacementDamage
Single Event Error
hard SEE soft SEE
clock
data input line
data in register
expected data in register
© T. Wijnands
July 31st 2008 3CERN FLUKA User Meeting
Semiconductors
Polymers
Ceramics
Metals and alloys
10.0 1E2 1E3 1E4 1E5 1E6 1E7 1E8 1E9 1E10 1E11 Gy1E12 1E13 1E14 1E15 1E16 1E17 1E18 1E19 1E20 1E21 1E22 n/cm2
- no damage- mild to severe damage
- destruction
commercial COTS hardened electronics
accelerators
Radiation Damage to Materials/Electronics
!!! Assumption !!!(depends on particle energy spectra)
1 neutron (1MeV) /cm2 ~ 3.3E-11 Gy
Dose & Displacement Damage
© Lockheed MartinJuly 31st 2008 4CERN FLUKA User Meeting
!!! A Rough Overview Only !!!
High-Energy Hadron Fluences
104
e.g., LHC-Levels for Hadrons (E > 20 MeV) per cm2 per nominal year
105 106 107 108 109 1010 1011 1012
Aircraft Altitudes LHC Machine electronics equipment LHC Detectors
sea Level
(Lowest !!!)
Airbus A330
UAs(guess)
UJ76Under
ARC dipoleUnder
ARC quad
RE38
RR53RR77UX85
DS Q8UX45
UJ33
1013
TAN
© T. Wijnands
July 31st 2008 5CERN FLUKA User Meeting
CERN FLUKA User Meeting 6
Neutron flux (> 20 MeV) in the atmosphere
105 cm-2 y-1
3 105 cm-2 y-1
July 31st 2008
Radiation Physics/Effects/Monitoring
DoseDisplacemen
t
Single Events
EM cascade
h, e,.. > 100 KeV
h > 20 MeV
RadfetPIN
Diodes
SEU counter
nuclear cascade
radiation damage in semiconductors
Radiation Monitor
Radiation Field
Effect in the Device
Measurement
© partly T. Wijnands
July 31st 2008 7CERN FLUKA User Meeting
Dose in shielded aras (where the electronics is usually lcoated) is mainly due to neutrons (and associated photons)
Dose and neutron fluxes have a very close correlation Cumulative damage comes from
Energy deposition (dose) Lattice displacement (1-MeV n equivalent particle fluxes)
Stochastic failures can occur (SEU) and are mostly due to “high” energy hadrons (“E>20 MeV”)
No safe limit exists, only a risk level can be determined Risk level for commercial electronics is poorly known and varies
by orders of magnitude between different devices and series Only a combination of the following can assure safe operation:
Simulation studies of related radiation levels (Dose, 1MeV, 20MeV) Careful selection and testing of required electronics Shielding and displacement considerations
Important – Damage is Not Only Dose …
July 31st 2008 8CERN FLUKA User Meeting
July 31st 2008 CERN FLUKA User Meeting 10
FLUKA-Implementation – HistoryFrom 1995 up to now:
An linked user code (user defined fluscw.f and comscw.f) had to be used to score the following quantities:
- Dose: Energy deposition in the respective material) -> comscw.f
- SEE: high-energy hadron fluence (>20MeV) -> fluscw.f
- Displacement Damage: folding of fluences with damage functions -> fluscw.fFrom the last release up to now:
Energy dose can be scored directly in FLUKA with the ‘pseudo-particle-type’ DOSE. Please keep in mind that the unit is GeV/g, thus needs to be multiplied with the respective coefficient to get (Gy [J/kg]). The remaining quantities have still to be calculated through user routines.
With the next release (and already in the current pre-release):
Displacement damage and high-energy hadron fluences can be directly scored in FLUKA using the respective ‘pseudo-particle-type’ (SI1MEVNE, HADGT20M)
July 31st 2008 CERN FLUKA User Meeting 11
FLUKA-Implementation – Main features
All important quantities to estimate risks of damage to electronics can be directly scored in FLUKA:Cumulative damage:
Energy deposition (dose) by scoring DOSE with any ‘energy deposition like estimator’ (e.g., USRBIN)
Lattice displacement (1-MeV n equivalent particle fluxes) with any ‘fluence like estimator’ (e.g., USRTRACK)
Stochastic failures (SEU): “high” energy hadron fluences (“E>20 MeV”) with
any ‘fluence like estimator’ (e.g., USRTRACK)
Respective levels can be illustrated through 3D meshes, as well as separately calculated for certain volumes (regions)
This, together with respective particle energy spectra efficient shielding options allows to select best possible locations or efficiently design shielding implementations
USRTRACK scores average d/dE (differential fluence) in a given region (SI1MEVNE, HADGT20M or any particle type)
USRBDX scores for the same quantities average d2/dEd (double-differential fluence or current) on a given surface (between two regions)
USRBIN scores the spatial distribution either of deposited dose, or fluence (1MeV or 20MeV) in a regular mesh (cylindrical or Cartesian) described by the user
USRBIN also scores the same quantites on a region basis
Electronic Damage - Related Scoring
* 1) high-energy hadron fluence spectrumUSRTRACK -1. HADGT20M -31. RADMON1 125. 170.Ust20MeVUSRTRACK 1D3 1D-14 &* 2) displacement damage spectrumUSRBDX 98. SI1MEVNE -41. TAIR RADMON1 150.Usx1MeVUSRBDX 1D3 1D-14 170. &* 3) dose distribution in a regular mesh through the geometryUSRBIN 10. DOSE -21. 100. 20. 200.UsbDoseUSRBIN -100. -20. -100. 100. 20. 150.&* 4) integrated high-energy hadron fluence on a region basisUSRBIN 18.0 HADGT20M -37.0 LSTREG 300.0 10000.0UsbReg20USRBIN FSTREG 0.0 -10000.0 1.0 1.0 1.0 &
July 31st 2008 12CERN FLUKA User Meeting
A full simulation for all quantities, HADGT20M, DOSE and SI1MEVNE require a full calculation including the electromagnetic cascade and high enough thresholds:
Simulation Settings
* Standard DefaultsDEFAULTS NEW-DEFA
The latter – depending on the complexity of the geometry – might lead to long computing times. If one is interested in SEUs mainly, one can then consider a separate simulation scoring HADGT20M only, switching off the electromagnetic cascade and adjust the thresholds accordingly (with care!): * Standard Defaults
DEFAULTS NEW-DEFA* Switching off the electromagnetic cascadeEMF EMF-OFF** 20 MeV for protons and neutrons ONLY (to be looked at more detail -> see later)!PART-THR -2.0E-2 PROTONPART-THR -2.0E-2 NEUTRON
In addition, if one is interested to get results in heavily shielded locations one will require respective biasing and possibly a Two-Step approach (BIASING, USRDUMP,…)
see some examples later and for more details please refer to the FUM presentations related to biasing as well as CNGS!
July 31st 2008 13CERN FLUKA User Meeting
Beam 1 – 20MeV Main Contributors
!!! Simulation over 600 meters !!!July 31st 2008 18CERN FLUKA User Meeting
Beam 1 – 20 MeV Main Contributors
Main Loss (Sampled)
Main ContributorsUJ76
Main ContributorsRR77
July 31st 2008 19CERN FLUKA User Meeting
UJ76 Results – Beam1 / Beam2 20 MeV
Downstairsopen Geometer Hole
closed Hole Upstairs
July 31st 2008 20CERN FLUKA User Meeting
IR7 Summary of Expected Levels 4.1 x 1016 as maxium loss assumption
Nominal (both beams): 2.3 x 1016
Ultimate (both beams): 3.7 x 1016
July 31st 2008 21CERN FLUKA User Meeting
IR6 – UA67 – FLUKA TCDQ, TCDS,…
TCDQ/TCDS/etc… loss assumptions
Tunnel simulation only
Effect of lateral holes estimated by empirical formulas
90cm hole, 8m long, attenuation factorof ~100
!!! tunnel only !!!
!!! tunnel only !!!
July 31st 2008 23CERN FLUKA User Meeting
© calculations by S. Roesler
IR6 – UA67 – TCDQ, TCDS,… Fire detection almost in line of
sight of the hole in line with TCS ‘Ducts’ and fully open passage ~8 x 108 for 20MeV ~8 x 109 for 1MeV conservative loss-assumptions
X
July 31st 2008 24CERN FLUKA User Meeting
IR6 – UA67 – TCDQ, TCDS,… Ethernet switch and power
converters behind hole pointing to TCDM
‘Ducts’ and fully open passage ~4 x 108 for 20MeV ~4 x 109 for 1MeV conservative loss-assumptions
X
July 31st 2008 25CERN FLUKA User Meeting
2 3 4 5 6 7 8
2
4
6
8
10
12x 10
9
Time[Hrs]
Had
ron fl
uen
ce [cm
-2]
RADMON1.2x1010 cm-2
FLUKA0.96 x 1010 cm-2 ± 3.2%
protons: 9.8% neutrons: 34.1% pos. pions: 21.9% neg.pions: 22.4% others: 11.8%
8RM08S, 26.5cm behind dump 2cm off beam axis
High energy hadron fluence
(scoring in a volume of 2 x 2 x 2cm3)
[1.03 x 1010 cm-2 ± 3.2%] (scoring in a volume of 5 x 5 x
5cm3) July 31st 2008 28CERN FLUKA User Meeting
© calculations by S. Roesler
FLUKA5.0 Gy (air) ± 10%
Dose
RADMON 4.73 Gy (Si)
FLUKA2.1 x 1010 cm-2 ± 2.5%
protons: 4.6% neutrons: 81.6% pos. pions: 5.3% neg.pions: 5.6% others: 2.9%
RADMON 2 x 1010 cm-2
July 31st 2008 29CERN FLUKA User Meeting
1MeV and Dose Levels1MeV
© calculations by S. Roesler
CNGS Target Chamber
Temperature Probes
Ventilation Units
Target Chamber
ServiceGallery
Proton Beam Linetarget
horn He tube 1 reflector
He tube 2 decay tube
Single event upsets in ventilation electronics: caused ventilation control failure and interruption of communication
Electronics
Racks
July 31st 2008 31CERN FLUKA User Meeting
ElectronicsRacks
Ventilation Units
CV, crane,fire detection
Dose Distribution – Electronics Dose Distribution – Electronics FailuresFailures
Gy/yr for a nominal CNGS year of 4.5 1019 pot
July 31st 2008 32CERN FLUKA User Meeting
Thermal neutron dominated
“Soft” spectrum: ‘Shadowed’ Part
CERN FLUKA User Meeting 35 July 31st 2008
CNGS: RPL and Alanine Dosimeter Positions
Gy/yr for a nominal CNGS year of 4.5 1019 pot
TCV4 TSG4
CERN FLUKA User Meeting 36 July 31st 2008
FLUKA Comparison: Alanine and RPL dosimeters
Detector type / position description
Exp. Value(Gy/p)
Simulation(Gy/p)
RPL: perp. horn strip lines 1.7·10-15
1.2·10-15Alanine: perp. horn strip lines
9.0·10-16
RPL: perp. refl. strip lines 8.2·10-16
5.4·10-16
Alanine: perp. refl. strip lines 3.8·10-16
RPL: perp. to the target 1.7·10-15
3.7·10-16
Alanine: perp. to the target 3.4·10-16
RPL: top of PMI404 9.4·10-18
7.2·10-18
Alanine: top of PMI404 4.3·10-18
Hole in shielding
not included
in simulatio
n
Alanine and RPL dosimeters are in principle sensitive to both rays and neutrons, RPL are more sensitive to n due to some
Boron content`
CERN FLUKA User Meeting 37 July 31st 2008
Good Agreement
Detector readings thanks to H. Vincke et. al.
CNGS: PMI ioniz. Chambers – Only Qualitative
Saturated (correction in red)!!
0.19(x0.8)
0.14(x0.6)
0.32
0.79(x1.2)
0.50(x1.3)
Numbers are exp/FLUKA ratiosafter (rough) correction of PMI data for
saturation , background
0.77(x1.1)0.67
(x24)1.1
(x11)5.2
(x52)2.4
(x12)
July 31st 2008 39CERN FLUKA User Meeting
Detector readings thanks to H. Vincke et. al.
TLD’s: Dose Equivalent
Absorbed dose (Gy) for an exposure of 7.2 1016 potJuly 31st 2008 40CERN FLUKA User Meeting
TLD dosimeters
TLD / position descriptionExp. Value
(Sv/p)Simulation
(Sv/p)
n dose: UA232/TSG4 2.3·10-17
1.3·10-17
γ dose: UA232/TSG4 4.3·10-18
n dose: UA231/TSG4 8.1·10-18
2.6·10-18
γ dose: UA231/TSG4 2.5·10-18
n dose: fire detector (TCV4) 4.0·10-18
2.4·10-18
γ dose: fire detector (TCV4) 1.2·10-19
n dose: pump cupboard (TCV4)
1.3·10-18
6.9·10-19
γ dose: pump cupboard (TCV4)
5.0·10-20
Sim. dose equivalent values (Sv) has been obtained out of calculated absorbed dose in air (Gy), correcting for air tissue and weighting for the neutron quality factors with a couple of representative spectra. The related uncertainty is +/- 30% on top of the (large) statistical one
July 31st 2008 41CERN FLUKA User Meeting
Detector readings thanks to H. Vincke et. al.
Simulation ApproachBiasing Region importance biasing for
hadrons and neutrons Leading Particle biasing for
electromagnetic showers (inside the target chamber shielding)
“blackhole” where possible
Two-Step Approach First simulation to collect the
spectrum of particles (mainly neutrons) moving towards the additional shielding locations
Separate simulations to evaluate the attenuation due to each plug configuration
July 31st 2008 43CERN FLUKA User Meeting
The final configuration is a “fake chicane” for one of the ventilation pipes in the movable shielding part and two (real) chicanes in the upper fix shielding part.
Final Shielding Design
July 31st 2008 44CERN FLUKA User Meeting
Annual Dose (Gy)
Without Shielding
With New Shielding
4.5 x 1019 protons / year
July 31st 2008 45CERN FLUKA User Meeting
1 MeV Equivalent Neutrons
Without Shielding
With New Shielding
4.5 x 1019 protons / year
July 31st 2008 46CERN FLUKA User Meeting
> 20 MeV Hadron Fluence
Without Shielding
With New Shielding
4.5 x 1019 protons / year
July 31st 2008 47CERN FLUKA User Meeting
49
SEU Sources & Brief History of SEE Research Cosmic Rays - On ground: neutrons (MeV – GeV) - High altitudes: neutrons, protons, pions (MeV – GeV) - Space programs: high-energy protons & heavy ions (GeV) - Cosmic ray-induced soft fails predicted in 1979 (IBM) Observed in space programs (early 1980s) Neutron-induced SEUs experimentally verified in mainframes (mid-1980s,
IBM) 1st Monte Carlo SEU simulation tool for product designs, SEMM-1 (1986,
IBM) SEMM-2: full BEOL+FEOL analysis & linkage to high-level tools (2001-
present,IBM)
Man-Made Radiation Environments SEUs & other SEE-related problems discovered in high-energy & nuclear
physics experiments in 1990s at BNL, FNL, CERN, …..
Thermal Neutrons BPSG (heavily doped w/ 10B): n(th) + 10B 4He (1.74 MeV) + 7Li (0.84 MeV) Predicted by Fleishman (1980); reported by TI (1995)
Alphas in IC Materials: eg. 206Pb 4He (5.3 MeV) (Bell Labs. & Intel, 1979).
© H. Tang/CERN Talk/20-Sep-2007
July 31st 2008 CERN FLUKA User Meeting
50
Metallization layer 1
Layer 2
Th Foil (Alpha Source)
Alpha particle
Diffusion
Depletion Layer
Funneling Region
Alpha particle
Recoil Ion
Cosmic RayNeutron
++
+
++
+
++
+++
+
++ + +
+ +
+ +
+
--
--
--
--
-
-- - -
--
- --
--
Layer 3
Collision Nucleus
Particle Origin of SEU – Nuclear Physics
SEUs are noise problems triggered by intruding charged particles.
In bulk devices, charge collection in an SEU event is due to a field-assisted funneling mechanism.
In SOIs, SEU can be caused by source-to-drain shunting, or parasitic bipolar gain effect, triggered by charge deposited by an ionizing particle.
Cosmic ray particles like p, n, interact w/ IC materials via spallation reactions. These reactions produce secondary nuclear fragments (light ions, heavy recoils). A charged secondary w/ sufficiently large LET causes a soft fail.
© H. Tang/CERN Talk/20-Sep-2007
July 31st 2008 CERN FLUKA User Meeting
51
Internal Radiation Sources: Alpha particles
Package (Th, U)
Wiring
Silicon
Solder Ball210Pb, 210Po
neutron
Devices
• Alpha particles emitted from radioactive impurities have energies up to 9 MeV and travel distances up to 50 m.
• Alpha particles deposit ~ 1 – 10 fC/um along their path.• Flux = 10-2 alpha / chip / Hr
© H. Tang/CERN Talk/20-Sep-2007
July 31st 2008 CERN FLUKA User Meeting
CERN FLUKA User Meeting 53
28Si(n,xα) cross section below 20 MeV:
Incident neutron data / ENDF/B-VII.0 / Si28 / /
Incident Energy
Cros
s-se
ctio
n
10.000.000 eV5.000.000 eV4.000.000 eV 6.000.000 eV 8.000.000 eV 20.000.000 eV
0,01 b
0,1 b
0,005 b
0,05 b
0,5 b
MT=22 : (z,na) TotalAlphaMT=107 : (z,a) Cross sectionMT=22 : (z,na) Cross section
A possible guess about the (relative) response to neutrons at E<20 MeV? And if so what is the impact of using this curve below 20 MeV (normalized @ 20 MeV)
and 1 above?
Thresh.: 2.7 MeV
July 31st 2008
54
RP PMI CERF Studies – Inside Positions
© H. Vincke, EDMS 456017July 31st 2008 CERN FLUKA User Meeting
55
CERF
Spectra Inside
Positions (PMI)
© H. Vincke, EDMS 456017July 31st 2008 CERN FLUKA User Meeting