Experimental Scientist​/Experimental Physicist

Austin, TX

Hexium

Hexium is building critical national infrastructure: an industrial isotope enrichment capability based on advanced laser science and precision engineering.

We're modernizing Atomic Vapor Laser Isotope Separation (AVLIS), combining advanced laser science, experimental physics, and precision engineering to develop a scalable industrial enrichment platform that supplies isotopes that fusion developers, advanced reactors, national labs, and defense programs depend on. We're moving from applied research to technology demonstration, and we need scientists who can make hard hardware measurably better.

As an Experimental Scientist on the technology development team, you'll investigate the physical processes that govern our lithium isotope separation systems and build the measurement capabilities needed to characterize and improve them.

This is a hands-on role with real technical ownership. You'll work directly with complex laboratory hardware, develop new diagnostics, and collaborate with scientists and engineers on hard questions in atomic physics, spectroscopy, and thermal and vapor dynamics. Your work will directly advance AVLIS from applied research toward industrial-scale operation.

• Plan and run experiments that characterize the performance of our laser isotope separation hardware, and use the results to validate models.
• Propose, design, and build new vapor, spectroscopic, and electromagnetic diagnostics, from concept through calibration and deployment.
• Develop physics-based models of lithium vapor behavior and lithium spectroscopy, and test them against experimental data.
• Identify performance limitations and turn findings into clear recommendations for hardware design and operation.
• Design test fixtures and experimental setups that enable new measurements.
• Support the design, operation, and troubleshooting of lithium-facing systems, working closely with engineers and technicians.
• Document experiments, methods, and results so others can reproduce and build on them.

• PhD in Physics, Applied Physics, Physical Chemistry, or a related field such as Aerospace, Mechanical, or Nuclear Engineering with an experimental diagnostics focus; or an MS in one of these fields plus 3+ years of hands-on experimental work
• 2+ years of hands-on optical diagnostics experience (graduate research counts), including building or substantially modifying the setup
• Demonstrated experience designing, building, and operating experimental hardware in a laboratory setting
• Strong foundation in physical understanding (e.g., heat transfer, fluid/gas dynamics, or electromagnetics) and the ability to build models to characterize a test article
• Proficiency in scientific programming (e.g., Python) for theoretical modeling, data analysis, and visualization
• Hands-on experience with instrumentation, sensors, and data acquisition, including calibration and troubleshooting
• Demonstrated track record of independently owning technical projects from concept through testing and reporting
• Clear written and verbal communication skills
• This role will be exposed to export-controlled information and technology and requires compliance with applicable export control laws and regulations

• Experience developing scientific hardware (e.g. a spectroscopy diagnostic, or magnetic sensor array)
• Experience designing, assembling, and operating high- or ultra-high-vacuum systems
• Background in thermal engineering, including heater design, thermal modeling, and material selection for extreme environments
• Experience with laser-based diagnostics development (e.g., scattering, absorption, or fluorescence techniques)
• Familiarity with handling reactive or alkali metals and the associated safety practices
• Background in atomic, plasma, or applied physics research environments

• You can share a portfolio that highlights your past relevant work (slides, pdf, link, etc.)
• Currently holds an active DOE Q clearance or active Top Secret clearance, or have held DOE Q / Top Secret clearance within the past 18 months

• Ability to work on-site in an active R&D lab with high-power (Class 3B/4) lasers, high-and ultra-high-vacuum systems, high-temperature equipment, and reactive alkali metals such as lithium.
• Ability to work safely in a compact lab with limited floor space, working in close quarters with equipment and teammates and maneuvering around tables, enclosures, and cabling.
• Ability to wear required PPE, including laser…