In this post, we are going to review the feasibility of employing 200 MeV proton irradiation as a radiation testing technique at board level for spaceborne electronic systems. Rather than evaluating individual components separately, this approach enables the radiation response of an already assembled electronic unit to be investigated as a whole and/or alternative method to EEE parts testing mainly for quick debugging purposes.
It can therefore represent an attractive alternative when a conventional component-level irradiation campaign would require considerable financial resources and lead time.
The use of proton irradiation at board level is particularly relevant for NewSpace and CubeSat missions, for which the limited project budgets may prevent the implementation of extensive component-level proton testing. This testing strategy has also been considered for electronic systems supporting lower-criticality applications on board the International Space Station (ISS), where a simplified and more cost-effective approach to radiation assessment can be beneficial.
Environment Discussion
The method works best when the environment is dominated by particles with LET values below approximately 15 MeV·cm²/mg and by low- to moderate-energy protons. For example, the ISS environment contains low- to moderate-energy protons associated with the combination of galactic cosmic rays (GCR) and trapped particles in the Van Allen belts, together with a smaller contribution from high-energy GCR.
Consequently, proton board-level testing is considered particularly suitable for missions operating in LEO and MEO, where trapped proton populations represent a significant component of the radiation environment. Conversely, its applicability becomes increasingly limited in environments where heavy ions constitute a more substantial part of the radiation field.
200 MeV Proton Board-Level Testing Approach and Expected Benefits
Ground-based proton irradiation can reproduce the proton energy range encountered in LEO due to the presence of trapped particles within the radiation belts.
In this context, a 200 MeV proton campaign offers the possibility of rapidly assessing the radiation response of a complete electronic system under controlled terrestrial conditions. One of the main advantages of this approach is that radiation assurance can be performed directly on an already assembled unit without decapsulation nor major modifications to the existing design.
Figure 1. ISS orbit proton environment.
For instance, a COTS computer system can be exposed to the proton beam in its existing configuration, without requiring the manufacturer to produce a dedicated version of the equipment for radiation testing. For limited radiation assurance, proton fluences in the range of 1E10–1E11 protons/cm² are typically considered, offering a potentially significant reduction in cost compared with conventional component-level irradiation campaigns.
Limitations and Hazards
However, proton-only testing presents important limitations when the objective is to characterize the response of electronic devices to heavy ions.
For a proton fluence of 1E11 protons/cm², the resulting secondary heavy-ion fluence is approximately 1E5 ions/cm², whereas conventional heavy-ion testing typically employs fluences of around 1E7 ions/cm² at specific LET values. Consequently, the number of secondary heavy ions generated during a proton test is insufficient to obtain statistically robust cross-section measurements.
Furthermore, the secondary particles produced by 200 MeV proton interactions have limited energy-deposition capabilities and have been shown to be unable to produce energy-deposition events exceeding approximately 15 MeV.
Secondary heavy ions range is critical to estimate destructive SEE. Secondary range from 200MeV is limited to 10um.
Figure 2. Range versus LET for secondary heavy ions generated in proton interactions.
Cautions
The proton fluence should be kept below 1E12 protons/cm², as higher fluences may introduce TID effects that could interfere with the interpretation of the results. In addition, the test conditions should ensure that the accumulated dose does not exceed 2 krad(Si) at any device under test. Stacks of more than six boards should be avoided as well as irradiation through heat-sink material.
European Proton Irradiation Facilities
TIFPA – Trento Institute for Fundamental Physics Applications
The Trento Proton Therapy facility, operated by the Trentino Healthcare Agency, features a beam line divided into dedicated branches for medical physics, radiation-hardness studies, and space-related research. Its research beam line is accessible to external users through scientific collaborations and industrial activities. The facility is equipped with an IBA cyclotron capable of accelerating protons to energies of up to 228 MeV, with the beam energy adjustable down to approximately 70 MeV. Beam intensities ranging from 1 to 320 nA can be requested. In addition, the physics line provides a fixed, pseudo-monoenergetic pencil beam covering the energy range from 70 to 228 MeV.
More information available below.
Figure 3. TIFPA physics-line layout and experimental-room view.
Proton Irradiation Facility (PIF) – Paul Scherrer Institute
The Proton Irradiation Facility (PIF), located at the Paul Scherrer Institute (PSI) in Villigen, Switzerland, is dedicated to the irradiation testing of spacecraft components and operates under an ESA–PSI contract. The facility is also part of the ESA-supported European Component Irradiation Facility (ECIF) and provides capabilities for investigating radiation-induced effects in electronic components and devices. PIF is available for irradiation campaigns associated with ESA programmes, while external academic and industrial users can also access the facility. The facility offers proton energies ranging from 6 to 230 MeV and a maximum beam size of approximately 9.6 cm, corresponding to a square area of around 70 × 70 mm² for fluxes between 1E5 and 1E8 protons/s/cm². The achievable flux depends on the beam profile and proton energy and can reach approximately 1E9 protons/s/cm² at 200 MeV.
For more information on this facility, enter to the link at the button below
Figure 4. PIF proton beam assembly and setup.
Holland Protontherapy Center (HollandPTC)
HollandPTC, located in Delft, the Netherlands, operates a ProBeam superconducting cyclotron and provides several beamline configurations, including fixed beamlines, clinical treatment gantries, and a dedicated R&D room. The R&D facility offers proton pencil beams with energies ranging from 70 to 250 MeV. These beams exhibit Gaussian profiles, with adjustable intensities from 5 × 10^6 to 2 × 10^12 protons/s. The nominal pencil-beam current can be varied between 1 and 800 nA. These beam characteristics, together with the available configurations and diagnostic capabilities, make HollandPTC a potential candidate for conducting board-level proton irradiation campaigns.
More information is available in the following paper
Figure 5. HollandPTC R&D bunker
Conclusions
The review indicates that 200 MeV proton board-level testing can provide a cost-effective and rapid form of limited radiation assurance, particularly for LEO and MEO missions.
Benefits and drawbacks of this testing methodology are referenced in this article, providing some of the main sources in Europe, advising the limitations of this test methodology but also the significant cost-information benefit for certain NewSpace equipments, new developments (debugging or preliminary step to a dedicated Heavy ions test campaign) and cubesats.
As part of the radiation services provided by ALTER Technology, the performance of these 200 MeV Proton Board-Level Testing is gaining momentum, given the boost of NewSpace scenario and the need of basic performance/preliminary radiation data for LEO missions.
Should you consider this proton radiation or traditional (but necessary in most cases!) TID, TNID, SEE test campaigns, do not hesitate to contact radiation team at ALTER to provide you with further information.
Andrés García Herrera
Junior Radiation/Parts Engineer at ALTER with a Master’s degree in Space Science and Exploration. He has experience in radiation analysis and EEE parts for the space sector, focusing on radiation environment assessment, evaluation of its effects on electronic components, EEE parts selection, technical documentation, and participation in ERCB activities.