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IntroductionIntroduction
The aim : to use TRAD experience in spatial applications and to apply existing literature to propose test recommendation for radiation characterization compliant with LHC environment search of radiation tests data on the different types
performed on public data base references chosen by CERN designers : radiation data
analysis & complementary radiation tests needed. Then we propose radiation characterization
recommendations and priority for the different component families : High, medium, low.
Irradiation facilities.
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LHC RADIATION ENVIRONMENTLHC RADIATION ENVIRONMENT
Maximum radiation level for 10 years LHC operation
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Total Ionizing DoseTotal Ionizing Dose 100 Gy for 10 years : level rather low but some devices
are excpected to show degradation
ELDRS has to be taken into account
Based on specifications for spatial application Margin
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TID Statistical approach TID Statistical approach
Delta XL = <delta x> +/- K(n,C,P) σ There is a probability P with a confidence limit C that a given
electrical parameter will not exceed the following limits Delta XL <delta x > is the mean shift among tested population of n
samples, σ is the standard deviation of the shift, K is the one sided tolerance limit factor.
A 3-sigma (K=3) approach is often used in spatial applications, with n=5 (samples) it will yield a probability of success P>0.9 with a confidence level C>0.9 90% of parts from a given lot have a failure level above the type
TIDS, with a confidence level of 90%.
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Displacement DamageDisplacement Damage
Tunnel : 3 e11 1MeV neutron/cm² for 10 years Devices concerned : Optocouplers, bipolar
transistors, operational amplifiers, comparators, voltage reference,…
shielded area : 6 e10 1MeV neutron/cm2 only a few high precision components may show a
significant degradation.
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Single Event Effects: Single Event Effects: Thermal neutrons
10B loacted near the sensitive nodes of the devices. The two recoils (Li and He) ions BPSG in CMOS devices for technology nodes of 0.15µm and older. P+ zones doped with boron give sensitivity to thermal neutrons.
So thermal neutrons effects need to be evaluated on digital devices (FPGA, SRAM,..)
in priority : technology node >150nm. The observed SEU sensitivity ratio is about two decades (typically 5E-14 cm2/bit with BPSG and
5E-16 cm2/bit without BPSG). Thermal neutron effects have been studied mostly on digital devices.
analog devices considered to be immune, to be checked for devices very sensitive to SET with High Energy neutrons
facilities,
ILL in Grenoble LLB in CEA/Saclay other reactors with a moderator to enhance the thermal/high energy ratio
can also be used.
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Single Event Effects: High Energy Hardrons Single Event Effects: High Energy Hardrons
The variation of sensitivity of the different devices to the energy of the incident hadrons is complex.
the cross-section is considered in a first approximation as constant for energy>20MeV
But for some particular effects such as SEL, SEB, MCU and ASET (Analog Single Event Transients) this assumption is probably not sufficient.
Both LET and range (related to energy) of the secondary recoils are important parameters to induce these SEEs.
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Heavy Ions testing approachHeavy Ions testing approach
Heavy ions testing is proposed to obtain the LET threshold to trigger SEL.
If LETth<15 MeV*cm2/g there is a high probability that SEL will be observed with HEH.
This approach will not give the SEL cross-section for the LHC environment but will indicate if SEL tests are needed in an environment representative of the LHC environment.
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OP27 : OP27 : bipolar technology, high precision bipolar technology, high precision operational amplifieroperational amplifier
Radiation data :
Testing recommendation OP27 operational amplifier can be used for LHC tunnel
environment. A proton test (both TID and DD) should be performed to
evaluate the degradation of the most sensitive parameter Ibias.
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LM139 : precision voltage comparators LM139 : precision voltage comparators
Radiation data : Total dose: Input bias current drift @ 20krad SET: cross-section and Threshold LET related to
the voltage difference between inputs. dV=12mV: sigma=4E-9 cm2
Testing recommendation A proton test (TID-DD) is needed to evaluate input
current, gain, output current. A high energy proton test to evaluate SET in
worst case condition (Input voltage difference=10mV) should be performed
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UC1842UC1842
Radiation data No SEL @ LETth >85 MeV.cm2/mg (Warren) TID:
Vref: 15 krad Other parameters >50krad
ASET Protons: Cross-section 5E-10 cm2
Testing recommendation UC1842 can probably be used in the application: Verify the
effect of a variation of Vref, on the output voltages in the application.
TID: Vref @ H4Irrad. ASET: protons
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LTC1595 16 bits DACLTC1595 16 bits DAC Radiation data
SEL LET threshold of about 10 MeV-cm2/mg cross section relatively small at low LETs, gradually increasing to
about 10e-4 at high LET factor of 1.5 to 2 increase in latchup cross section for the heated
device. Testing recommendation
SEL: static test Electrical conditions: Vdd= Vddmax Vref=Vref nom. Effects of input state on SEL sensitivity: LD, CLK, SRI will be put at 0 and then at 1. Out1 at Gnd,
Total dose: Bias under irradiation: Vdd nom, Vref nom :External high stable power supply , CLK (at
a given frequency), 0 is stored in the register (Power On Reset), Control: Power supply current, Output current (OUT1) Detail test at several steps.
SET test Room temperature test Codes input: all0 or all1 Observation of output with an Operational Amplifier. Measurement of SET amplitude and duration related to switches and register bits
upset.
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AD768 AD 16 bits DACAD768 AD 16 bits DAC Radiation data
TID : tested biased at high dose rate within specifications up to 50 krads.
SEU LETth of about 15 MeV-cm2/mg All of these SEU occur in the standby mode. A simple reclocking of the data reset the device. The device was tested at constant oscillation frequencies of 0.5, 1, and 12 MHz. No
SEUs were seen at these frequencies. The device is apparently immune to SEU effects at frequencies over 0.5 MHz.
Testing recommendation SEL test
The SEU rate is related to the refreshing frequency of the device. At high frequency (>0.5 MHz) the probability of upset can be neglected
TID and DD: The technology of AD768 is ABCMOS1 from Analog Devices. So ELDRS effects can exist.
Test to be performed at H4IRRAD in active mode. Bias: nominal on VDD and VEE.
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AD7846SQ ADAD7846SQ AD Radiation data
TID DNL exceeds specification limit at 10krads(Si). Functional failure at 15krads(Si), recovered after 168 hour annealing., parametric degradation
continues. Devices were taken to 20krads(Si) and no functional failure was observed. After 25krads(Si),
functional failures were again observed. SEL threshold > 110
Testing recommendation SEL test is not mandatory because SEL was not observed with heavy ions
at maximum LET.
SET: The output is a voltage output (A3 is the inside output amplifier). Output transients and outputs voltage variation will be monitored during irradiation.
Total Dose and DD Test performed at H4IRRAD Use of an external low noise high stability voltage reference Parameters monitored: output voltage, power supplies Vcc, VDD, Vss current Detailed linearity test before and after irradiation.
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LTC1609 16 bits ADCLTC1609 16 bits ADC
Radiation data 14 MeV neutrons
No SEL events were detected after a fluence of 2e10 neutrons per cm2. The limiting cross section 1.9 e-10 cm2
HI At room temperature, SEL LETth between 8.0 and 11.7 MeV-cm2/mg. For the heated device, SEL LETth between 5.3 and 8.0 MeV-cm2/mg.
Testing recommendation SEL to be performed at high temperature at maximum
values of Vdig and Vana. Total dose and DD:
Tests to be performed at H4IRRAD to study simultaneously DD and Total dose.
SET and SEU Output binary code modifications to analyze for a stable input condition. First the stability of the code values to evaluate without radiation in the
facility. A window of coding is defined that take into account of all sources of noise (Example + or -2bits around the code value). Only codes outside this window are considered as SET.
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Tests recommendations and prioritiesTests recommendations and priorities
Discrete devices
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ConclusionConclusion
radiation characterization recommendations can be used as a guideline for the test campaign phase.
The radiation effects on the different families have been identified in WP2 and the radiation test priorities are evaluated with three criteria: high, medium, low.
All the testing recommendations, derating rules are given as a guideline and have to be used with precaution.
In some particular cases (application, very sensitive parts…) this recommendation could be not applicable and radiation testing remains the only way to characterize the part sensitivity.