1. Status overview of the radiation hardness assurance studies for FCC
Rubén García Alía, Markus Brugger, Giulio Borghello, Mar Capeans, Francesco Cerutti, Salvatore Danzeca, Federico Faccio,
Georgi Gorine, Simone Gilardoni, Angelo Infantino, Michael Moll, Federico Ravotti, Benjamin Todd, Slawosz Uznanski
R2E Project, task 11 of FCC Special Technologies WP

2. FCC week 2017 - Status of RHA studies
Outline
Radiation Hardness Assurance (RHA): approach and building blocks
Challenges for qualification in radiation facilities
Challenges at system level
Challenges at component/technology level
Conclusions and Outlook
May 31, 2017
FCC week Status of RHA studies

3. FCC week 2017 - Status of RHA studies
Outline
Radiation Hardness Assurance (RHA): approach and building blocks
Challenges for qualification in radiation facilities
Challenges at system level
Challenges at component/technology level
Conclusions and Outlook
May 31, 2017
FCC week Status of RHA studies

4. FCC week 2017 - Status of RHA studies
The RHA challenge
System level testing, common developments, monitoring and calculation
Optimal compromise between rad-tol design and qualification costs and impact on operation
Components not qualified for radiation
No radiation level criterion (monitoring, calculation)
Low system reliability/availability due to radiation
High costs associated to need of mitigating radiation effects once system is in operation
Worst-case condition testing at component level
Large margins
Rad-hard components
Very large system reliability at very high cost
May 31, 2017
FCC week Status of RHA studies

5. Key building-blocks Radiation Test Facilities Qualification Approach
Radiation Monitoring and Calculation
Rad-hard component design (experiments)
Rad-tol system development based on COTS
(accelerator)
Radiation Hardness Assurance
Qualification Approach
Radiation Test Facilities
May 31, 2017
FCC week Status of RHA studies

6. Radiation environment
In the detector (30 ab-1):
First layer of inner barrel: 6×1017 neq/cm2, 400 MGy
Forward calorimeter: 5×1018 neq/cm2, 10 GGy
Expected levels for HL-LHC: 1016 neq/cm2, 10 MGy
→ already extremely challenging, baseline is to change pixels at half-life (sensor + electronics); no solution available for FCC first layers today
In the accelerator arc section (annual):
Below the magnets: ~1011 HEH/cm2/yr, ~100 Gy/yr
In the optimized alcoves: below ~108 HEH/cm2/yr
Future work: radiation levels in LSS tunnel, alcoves near interaction region, dispersion suppressor, collimation…
I. Besana, FCC week 2017
~108 HEH/cm2/yr
~1011 HEH/cm2/yr
A. Infantino, FCC week 2017
May 31, 2017
FCC week Status of RHA studies

7. FCC availability requirements
FCC baseline: luminosity production targets can be reached with LHC like overall performance
Target availability budget similar to LHC values
For today’s machine, systems exposed to radiation and involving complex electronics, we can typically accept a 10% of the total failure budget to radiation
Example: FCC power converter budget would be 2.5 radiation failures/100 days (just as reference)
Additional constraints linked to short stable beam time:
Importance of injector availability
Importance of minimizing downtime for optimal turnaround
With input from
A. Apollonio (TE-MPE) and A. Niemi (BE-ICS)
May 31, 2017
FCC week Status of RHA studies

8. FCC week 2017 - Status of RHA studies
Outline
Radiation Hardness Assurance (RHA): approach and building blocks
Challenges for qualification in radiation facilities
Challenges at system level
Challenges at component/technology level
Conclusions and Outlook
CERN facility database ( and analysis on possible limitations for FCC (G. Gorine, FCC week 2017 poster)
May 31, 2017
FCC week Status of RHA studies

9. IRRAD for displacement damage
Shuttle System
IRRAD Proton Facility in 2016:
416 objects at RT, -25oC and 1.9K
>400 dosimetry measurements
28 user teams with 52 experiments
>1017 p/cm2 delivered  >30 MGy/year (HL-LHC ready; DD qualification for FCC remains a challenge)
Beam momentum: 24 GeV/c
Beam spot: 12×12 mm2 (FWHM)
Proton flux: ~1016 p/cm2 in 5 days
Several optics possible variants.
Cold Boxes
IRRAD Zone 1
May 31, 2017
FCC week Status of RHA studies

10. X-ray machines for total ionizing dose (TID)
Today, several X-ray generators are used in parallel and in their full capacity to provide 10 MGy in 5-7 days
Detector systems requiring tests for multi-100MGy levels will certainly need many more sources than those presently available today
May 31, 2017
FCC week Status of RHA studies

11. FCC week 2017 - Status of RHA studies
CHARM for SEEs
A unique facility for qualifying component batches and system in a high-energy accelerator environment
Lifetime (20+ yr) radiation levels for electronic equipment to be installed in the LHC and its injectors can be reached in ~1 week
May 31, 2017
FCC week Status of RHA studies

12. CHARM for HL-LHC SEE qualification
600A and kA power converters located in RRs of P1, 5 and 7
128 and 66 units respectively
Average expected annual fluence for HL-LHC: 1.4 and 2.7×109 HEH/cm2 respectively
HL-LHC R2E failure budget for power converters of one dump per year
Target upper limit cross sections of ~3×10-12 cm2/unit, close to CHARM limit
A. Tsinganis, 6th annual HL-LHC Collaboration Meeting, Paris, November 2016
May 31, 2017
FCC week Status of RHA studies

13. CHARM for FCC SEE qualification
Let’s consider a distributed system with 4000 units
Located in the arc alcoves, with annual HEH fluence values of 108 HEH/cm2
Located in the arc tunnel below the magnets, with annual HEH fluence values of HEH/cm2
In order to comply with an R2E failure budget of 5 dumps per year, cross sections of cm2/unit to cm2/unit would need to respectively be qualified
Conclusion: for equipment located in the tunnel (or shielded areas with similar radiation levels, e.g. alcoves near interaction points or collimation) the FCC SEE requirements cannot be qualified with today’s CHARM facility performance
~108 HEH/cm2/yr
A. Infantino, FCC week 2017
~1011 HEH/cm2/yr
May 31, 2017
FCC week Status of RHA studies

14. FCC week 2017 - Status of RHA studies
Outline
Radiation Hardness Assurance (RHA): approach and building blocks
Challenges for qualification in radiation facilities
Challenges at system level
Challenges at component/technology level
Conclusions and Outlook
May 31, 2017
FCC week Status of RHA studies

15. FCC week 2017 - Status of RHA studies
System level testing
Efficiently combining top-down (from system to sub-system/component) and bottom-up (discrete testing of critical components) approaches
Importance of intelligent design of experiment in order to enhance failure observability (e.g. self-diagnose systems)
Importance of defining failure modes and associated criticality
Importance of common component qualification and sub-system development (e.g. versatile communication link)
FGClite system for LHC power converter controls (S. Uznanski, TE-EPC)
May 31, 2017
FCC week Status of RHA studies

16. Redundancies for enhanced radiation tolerance
From a radiation tolerance perspective:
Soft Error failure state (e.g. Single Event Functional Interrupt) can typically be removed with remote power-cycle/restart
Hard Errors (destructive) would need actual hardware replacement of component/board
Possible redundancy: failure detection, switch to redundant sub-system without impacting operation, minimize repair time (reset or online hot-swap, without interrupting operation) → comes at a very high cost, thus important to balance development investment and system availability
A well implemented redundancy can allow to retrieve operational SEE cross sections much lower than those experimentally qualified
May 31, 2017
FCC week Status of RHA studies

17. Links to other applications
High radiation levels, low number of systems, extremely high criticality
Space missions
High radiation levels, intermediate number of systems, high criticality
Low-cost space missions
Accelerators
Low radiation levels, very high number of systems, intermediate criticality
Ground-level
May 31, 2017
FCC week Status of RHA studies

18. The RADSAGA innovative training network
Marie Curie network coordinated by CERN (
Main objective: to deliver a handbook on guidelines for system level radiation testing for space, avionic, ground-level and accelerator applications
May 31, 2017
FCC week Status of RHA studies

19. FCC week 2017 - Status of RHA studies
Outline
Radiation Hardness Assurance (RHA) challenges and building blocks
Accelerated testing in mixed-field facilities: role in qualification procedure and limitations
Challenges at system level
Challenges at component/technology level
Conclusions and Outlook
May 31, 2017
FCC week Status of RHA studies

20. Technology scaling challenges
CMOS transistors in sub-250nm nodes have very thin gate oxides, almost insensitive to TID effects
However thick lateral (STI) and spacer oxides are still sensitive to TID, degrading the performance at large values
First measurements of 28nm transistors show larger TID tolerance than 65nm, studied for HL-LHC upgrades → still a huge challenge for FCC levels
Several 28nm and 40nm CMOS processes will be studied to extract possible trends and select best candidates for ASIC design
10 MGy
10 MGy
F. Faccio, G. Borghello
May 31, 2017
FCC week Status of RHA studies

21. Technology scaling challenges (II)
Example: thermal neutron SEU sensitivity as a function of transistor technological
As of 0.25 μm: no 10B used in passivation
R2E tests on state-of-the-art SRAM based FPGA show strong thermal neutron sensitivity, expected to dominate SEU rate in accelerator shielded environment
Possible origin: 10B as dopant or plug contamination
Similar challenge: direct ionization from singly charged particle,
Further example: SiC (solid-state switches for kicker applications) sensitivity to SEB, first tests at CHARM carried out in 2016
Infantino, ICRS13 (2016)
Yamazaki, JVSTB (2015)
R2E measurements
May 31, 2017
FCC week Status of RHA studies

22. FCC week 2017 - Status of RHA studies
Outline
Radiation Hardness Assurance (RHA) challenges and building blocks
Accelerated testing in mixed-field facilities: role in qualification procedure and limitations
Challenges at system level
Challenges at component/technology level
Conclusions and Outlook
May 31, 2017
FCC week Status of RHA studies

23. Conclusions and Outlook
Ingredients for FCC RHA approach:
Expected radiation levels
Availability/lifetime targets
FCC RHA considerations at system level
Development and qualification of common building blocks (e.g. FPGA processing units, communication links) is essential
Self-diagnose, redundancies and remote interventions can significantly reduce failure probability and impact on downtime
FCC RHA considerations at technology level
Micro-electronic technology evolves extremely rapidly, thus requiring a continuous study of related effects
Possible limitations related to TID degradation of deep sub-micron transistor technologies → radiation levels at least an order of magnitude larger than those expected for HL-LHC, therefore R&D in radiation hardness of sensor and front-end electronics is essential
Already beyond today’s performance and qualification limits (but margin from improvement)
May 31, 2017
FCC week Status of RHA studies

24. Thanks for your attention!
May 31, 2017
FCC week Status of RHA studies