Inaugural Meeting on the Opportunities at the SEEMS Facility

1. SEEMS: Facility Overview and SEE Testing Capabilities Inaugural Meeting on the Opportunities at the SEEMS Facility Bernie Riemer SNS Upgrades Office June 10-12, 2019

2. SEEMS Single Event Effects test capabilities are based on High Energy neutron Test Station (HETS) concept from 2014 study done for the FAA • Focus was on serving aerospace / avionics needs • Our goals were based on then-current practices and envisioned future needs • Reviewed existing JEDEC and IEC standards • SEE test publications and presentations • Meetings and communications with the FAA and AVSI committee member Laura Dominik • Visits to WNR ICE Houses and ISIS ChipIr • Some things have changed in regulation and standards • EASA CM-AS-004, SAE International AIR-6219 • FAA steps pending – (Advisory Circular or Policy Memo?)

3. Available testing hours must be high • SNS typically schedules neutron production for scattering science for ca. 4500 h/y • 90+ % availability track record • Whenever neutron production is on SEEMS can operate

4. We see it that aircraft avionics are only one user group of a high-energy neutron facility designed for SEE testing • Space-based systems • Ground-based systems, e.g. supercomputing, networking • Autonomous vehicles – ground and air • DoD • Other, non-SEE applications are possible

5. Systems testing is seen as essential for emergent need to evaluate large systems, while component testing remains a fundamental need • Significant differences in required flux and irradiation spot size • Concurrence with FAA and AVSI on this point

6. Components Systems • Equipment size: circuit board • Beam size: • from 1 mm2 to 0.2 x 0.2 m2 • Flux1,2: ≤ 107 n/cm2/s • Equipment size: 42U rack • Beam size: ≤ 1 x 2 m2 • Flux1,2: ≤ 104 n/cm2/s Common Spectrum: HE & thermal Spectrum tuning Flux intensity adjustability Protons / pions Environment DAQ infrastructure User amenities Secure storage Sum of neutrons ≥ 10 MeV Higher flux might be needed for solar flare events

7. Neutron spectrum • High-energy (HE) neutrons of energies 1 MeV and up are largely responsible for SEE • Current standards are based on 10 MeV and above

8. Thermal neutrons are recognized as an increasing contributor to SEE in avionics • Moderating materials in aircraft (fuel, people, carbon) can thermalize atmospheric HE neutrons • Absorption in neutron poisons inside integrated circuits can lead to energetic reactions causing SEE, e.g., • 10B + n 7Li +  (1.48 MeV, range ~ 5.2 µm) • Current research on thermal neutron flux (below 1 eV) in commercial airliners: • Thermal neutrons about 0.2–2 times the HE neutron flux (above 10 MeV) • IEC Technical Standard 62396-5 • Our goal was to provide ~ the same flux of neutrons below 1 eV as above 10 MeV • When desired by the user

9. Solar storms / extreme space weather can substantially increase atmospheric particle fields • Measured data are sparse, but 100x neutron flux increase over average was reported with a 1956 storm • Carrington Event (1859) was likely worse • The danger of solar events for SEE lies in increased neutron flux • Spectrum differences with “nominal” spectrum are of small consequence • Bottom line: Higher flux for solar event testing or live with lower acceleration for solar simulations Sources: Lei, Dyer

10. The impact of pions and muons on SEE seems to be an area of continued investigation • In the past, their contribution to SEE was considered negligible • Some test facility options could provide charged particle fluxes Angular neutron and particle emissions due to a proton beam of 1.0 GeV energy and 1 kW power incident on a 5 cm diameter tungsten target. Atmospheric particle spectra Source: Ziegler and Lanford • Dedicated proton irradiation capability in SEEMS is possible but was not included in the original HETS concept

11. ChipIr at ISIS • New SEE test facility in the UK provides generous features to aide SEE industries & researchers • Large systems testing capability • SEEMS intends to meet or exceed ChipIr irradiation capabilities and features

12. ChipIr features and amenities • Ease of access for users • Remotely operate equipment stages • Easy alignment with beam • Effective temperature and humidity control in test and DAQ areas • Convenient equipment loading area • Dedicated break area • Thorough characterization of irradiation conditions • Data cabling with patch panels • Quiet power supplies for DAQ equipment • EM shielded DAQ room • Quiet HVAC • Secure and private storage for users

13. ChipIr visit 2013 DAQ room with quiet power, EM shielded, data cable patch panels Chris Frost at component stage area; patch panel & cabling System test area & patch panel ChipIr is now operational

14. ICE House(s) at LANSCE-WNR • Two test areas; component testing dominates • Served from a 47 year old accelerator complex; NNSA funded • 2012 reported ~3000 h/y operation; ~25% industrial use Comparison of Los Alamos and TRIUMF neutron beam spectra with terrestrial spectrum. Source: JEDEC Standard No. 89A, Measurement and Reporting of Alpha Particle and Terrestrial Cosmic Ray-Induced Soft Errors in Semiconductor Devices, Arlington, Va., 2006. Circuit boards with components aligned for neutron irradiation at the ICE House. Source: L. Dominik, “Atmospheric Radiation Testing,” Presentation at 2012 National User Facility Organization meeting, Los Alamos, N.M., June 2012.

15. SEE Beamline capabilities of SEEMS • Two neutron beamlines for SEE testing with large shielded areas • Placed at ±30º off incident proton beam direction • Best position for neutron spectrum • Component neutron test beams from 1 x 1 to 20 x 20 mm2 High energy flux (above 10 MeV) reaching 107 n/cm2/s • Large systems test beams from 0.5 x 0.5 to 1 x 2 m2 High energy flux from 1.3 x106 to 1 x104 n/cm2/s, respectively • New capabilities: • Selectable moderators when thermal neutrons additionally desired • Largest beam size for systems testing – can irradiate a tall computer rack • Opportunities for proton and muon irradiation – potential spacecraft SEE testing • Longest available hours per year, with substantial fast-access time for urgent industry needs

16. SEEMS facility layout • SEE and µSR missions are very compatible, and can share a building and target • This produces a dual-purpose facility, which will produce significant cost savings compared to building separate facilities Target monolith µSR 1 & 2 µSR 3 & 4 SEE Testing 1 & 2 Proton irradiation option

17. Irradiation Capabilities at each neutron test area: • Components and systems irradiation capabilities • Minimum beam size: 1 x 1 mm2 • Maximum beam size: 1 x 2 m2 • Atmospheric HE neutron spectrum • On demand thermal neutrons • Scattered protons to normally be deflected away from test area • Can be disabled if desired, on demand

18. Testing amenities • Controlled temperature and humidity environment • Electromagnetically shielded testing areas • Low-noise power through independent grounding grids for each of the testing areas • Translation stages at the component testing areas • Remote control over beam optics components • collimators, filters, and shutters • DAQ patch panels for flexible and short electronic connections between the control room and testing areas • Cable feed-through options for direct electric connections between testing areas and the control room • Crane access to the systems irradiation area through a hatch in the testing area enclosure and the building crane

19. Local infrastructure • Local secured equipment storage and cooldown areas • Truck bays for loading and unloading • Network • Building and jib cranes • Break and rest rooms

20. SEEMS does not employ a parasitic target as in other muon / spallation neutron sources • Instead, kW-level proton beam is extracted by laser stripping of SNS H- beam upstream of accumulator ring • Proton beam intensity is tunable by laser beam intensity and duty factor • No impact to the primary target station operation H+ • Laser strips electron from H- beam to H0 • H0 and H- beam components are separated by transverse magnetic field • H0 beam is stripped to protons by a foil H+ H-

21. Target station requirements, size, beam power • Flux at component test position: • 107 n/cm2/s • Dose rate at monolith edge = 1 mrem/h • Tungsten target • Proton Energy 1.0 GeV (1.3 GeV) • Ideal neutron beam angle for matching atmospheric energy spectrum: • 30 degrees Shielding Target Proton beam Θ R Neutron test area Goal: Minimize Shielding and Beam Power

22. neutrons Neutron Beam Optics Components Target monolith test area protons Target reflector moderator Neutron optics

23. Thermal Beam Generation (on demand) • 2.5 cm thick water moderator surrounded by 30 cm radius beryllium reflector needed to achieve thermal-to-HE flux ratio of 1.0 ber target n-beam water beryllium

24. Enclosure • Irradiation positions at • 5 m – components • 14 m for systems • Beam attenuation for systems irradiation by: • Laser power & duty cycle • Intensity dialer (100) • Filter (10) • Distance (8)

25. Enclosure shielding Target Beam line Slit Target monolith shielding, 90% steel, 10% 5% borated poly Target monolith shielding, tungsten Enclosure shielding Sample position 2 • Walls and ceiling of 195 cm HD concrete or 145 cm steel & polyethylene • A massive beam stop is also needed Sample position 1

26. Enclosure with DAQ Room and Labyrinth Access • All experiment controls for one test area are brought together in the respective DAQ room • The experimental area is controlled by a Personnel Protection System (PPS) system much like at main target station • Beam-on target control will be managed through the SNS Central Control Room

27. SEEMS can provide world leading SEE test capabilities for aerospace, space, and other applications – for decades • We need to hear from the user communities • Are the neutron parameters right? • Is the systems test beam size appropriate? • Are the available hours sufficient, or excessive? • Is there strong interest in direct proton irradiation for space applications? • ORNL/SNS has the expertise to design and operate SEEMS, and to provide user program support • Later discussion: • What will you need in 10, 20, or 30 years from now?

28. Backup slides

29. Chopper system makes gaps 945 ns mini-pulse (700 ns) Current Current 1 ms macropulse 1ms Ring injection stripping foil The SNS Accelerator Complex Accumulator Ring: Compress 1 msec long pulse to 700 nsecprotons Accumulator Ring Collimators Front-End: Produce a 1-msec long, chopped, H- beam Extraction RF • Liquid Hg Target • 1.4 MW, 60 Hz 1000 MeV RTBT 2.5 MeV 1 GeV 1.3 GeV upgrade HEBT Front-End LINAC 1 ms macropulse 1 ms

30. HETS Floor area: ca. 3x9 m2

31. Intensity Dialer and Charged Particle Filter • The intensity dialer is a tungsten slit of 20 cm thickness • allows a factor of 100 variation in intensity by closing the view • The charged particle filter is a dipole magnet of 80 cm length steering charged particles into the surrounding shielding by a 1 Tesla transverse magnetic field • Deflects protons, pions, muons away from neutron test area • Can be disabled if charge particles also desired with neutron beam

32. Shutter and Coarse Collimator A guillotine steel structure integrates the function of shutter ( 1m thick tungsten block), and three coarse collimator options with several of different openings

33. Neutron Beam Monitoring • Neutron Flux and Fluence measurements • Spectral Measurements • Beam homogeneity

34. Fine Collimator • Fine tuning beam sizes from 1x1 mm2 to 20x20 cm2 • Reduce backgrounds and protect equipment • Two pairs of jaws acting in the horizontal and vertical ChipIr Fine Collimator

35. Spectrum Modifier • The spectrum modifier consists of various material plates that can be inserted into the beam to tweak the spectral shape and/or attenuate the beam intensity