KEVION: An ion irradiation and sample analysis research facility for planetary science

Introduction:  KEVION, a KiloElectron Volt ION irradiation facility for space science – one of NASA’s new Planetary Science Enabling Facilities – will begin full operation this Fall (2026) as part of the Laboratory for Astrophysics and Surface Physics at the University of Virginia (LASP-UVa). This resource facility  is comprised of four major components: (1) a 25-300 keV Pelletron ion accelerator to provide positive atomic/molecular ions over a broad range of species, charges, and energies; (2) a novel, multi-technique analytical chamber (GRAINS) with low-energy ion gun built around an X-ray photoelectron spectrometer and in situ UV-Vis-NIR optical spectroscopy; (3) a specialized cryogenic chamber (ICE) for radiolytic astrochemistry studies of solid-state ices; and (4) a minimally-equipped chamber (TEST) for ion implantation, instrument performance testing, and user-customized experiments.

With the deployment of Juno, Juice and Europa Clipper to Solar System bodies with radiation-exposed surfaces, along with the anticipated Dragonfly and CNSA’s Tianwen-4 missions, and new galactic and interstellar science from the James Webb Telescope, the KEVION facility addresses an identifiable gap in available community tools for high-impact Planetary Science research. The KEVION high-energy linear accelerator, a Peabody Scientific light-ion accelerator, and low-energy (< 5 keV) ion guns will deliver positive ions appropriate for simulating magnetospheric, cosmic-ray, and solar wind interaction with surfaces to provide transformative research in studies of space weathering, radiolysis, radiosynthesis, sputtering, and surface charge. Meanwhile, the TEST chamber can be utilized to facilitate science instrument development and radiation damage.

Details: Investigators proposing across all NASA, ESA, JAXA, and other programs are invited to utilize the KEVION facility over the course of their research. A full-time facility instrument scientist (Dr. Adam Woodson) is available to assist with experiment planning, accelerator operation, instrument instruction, and analytical procedure. Specific details of the Pelletron accelerator and available analytical techniques associated with each end-chamber are outlined below and summarized on the KEVION website and at NASA’s science link, https://science.nasa.gov/wp-content/uploads/2024/01/kevion-2024.pdf.

Ion Accelerator: The National Electrostatics Corp. Pelletron ion implanter will generate isotopically pure ion beams with energies between 25 and 300 keV for simulated space weathering, radiolysis, materials characterization, measurement of fundamental parameters, and instrument prototyping applications. This range is sufficient to simulate a substantial cross section of energetic particles originating from the Sun, which vary in energy from ~300 eV/amu in the slow Solar Wind, to ~50 keV in transient Interplanetary Coronal Mass Ejection events, to > 1 MeV in the suprathermal tail. Similarly, magnetospheric ion energies generally range from a few keV to a few tens of keV as measured in Mercury’s and Titan's interaction regions, to MeV particle fluxes at the Moons of Jupiter [1-3]. The NEC instrument is designed to provide beam currents of 300 μA into the beamline Faraday Cup. Lower energy (0.2 – 4 keV) ions, appropriate for solar wind simulation, are available from a standard or m/q select-ed ion gun mounted on the GRAINS chamber.

GRAINS Chamber: The GRAINS chamber will enable comprehensive analytical measurement and monitoring of surface (1–3 monolayers, ML), near-surface (to ~10 nm depth) and bulk (to ~10 μm depth) material characteristics. In situ sample characterization can be done by: quadrupole secondary-ion mass spectroscopy (SIMS), X-ray photoelectron spectroscopy (XPS), Rutherford scattering (forward and RBS), and UV-Vis-NIR optical reflectance (or trans-mission). A low-energy ion gun for 3D compositional analysis by sputter depth profiling, charge neutralization, and irradiation can provide fluence dependent details over decades of energies/depths/time; and an electron flood gun for positive surface charge neutralization is available. Multiple, integrated analytical techniques on the same chamber eliminates the need to transfer samples between systems, thereby reducing the logistic complexity of such experiments as well as the risk of contamination due to atmospheric exposure.

ICE Chamber: Investigation into solid-phase radiochemistry is of high-importance, as icy bodies and granular surfaces act as substrates for simple and com-plex molecular species formation by gas-grain chemistry and photolytic / radiolytic reactions, and also serve as reservoirs for important reactive species in interstellar cold clouds. The ICE cryogenic end-chamber is equipped with an in-situ gas-dosing system, FT-IR spectrometer for Vis-IR reflectance / transmission, an in-situ quartz crystal microbalance system (QCM), a UV-Vis interferometer for coupled mass and density/porosity/thickness measurement, and a +/- ion-neutral mass spectrometer.

TEST Chamber: The TEST chamber is a large-diameter, mu-metal-lined UHV vacuum vessel, intended for instrument response testing over varied ion species/energies. In some instances, the TEST chamber may be outfitted with additional research tools from an investigator’s home institution for experiments beyond the capabilities of GRAINS or ICE.

Usage Information: The KEVION accelerator and analytical chambers are available at no cost for NASA awarded projects (~6 months/year), and we also welcome other ESA, JAXA, academic, governmental, and industrial clients as users at a nominal, tier-ed cost. Facility resources are available to clients “in person” with training, or analyses can be carried out “remotely” by facility personnel in consultation with users.

Contact Information: For more information on how to utilize the KEVION or to solicit information for proposals, please contact PI Dukes (cdukes@virginia.edu) or Instrument Scientist Woodson (akw8r@virginia.edu). Else, a “Request for Service” form can be submitted directly on the KEVION Website: https://engineering.virginia.edu/kevion.

Acknowledgments: We thank NASA for their support of the KEVION facility through the PSEF program (Award #80NSSC23K0200).

References: [1] Jasinski et al. 2020 [2] Connerney et al. 2017 [3] Bennett et al. Chem. Rev. 113, 12, 9086–9150 2013.