Eos Atomics Senior Neutral Particle Beam (NPB) Scientist San Francisco, CA · Full time Company website

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Eos Atomics is a San Francisco-based startup building commercial fusion technology to solve humanity’s most pressing energy challenge. We are a lean, technical team built for speed, precision, and uncompromised execution. We design, build, test, and deploy novel systems at record pace. We expect full technical ownership, high scientific rigor, and the curiosity to tackle problems others deem impossible. We debate openly, test relentlessly, and value ideas over hierarchy. If you want to push the frontier of fusion energy, you belong at Eos Atomics.

The Role

You will lead the physics design, integration, and operational optimization of our Neutral Beam Injection (NBI) and Neutral Particle Beam (NPB) systems.

In this critical role, you will be the core subject matter expert responsible for the end-to-end physics design and performance of our neutral beam systems. You will work at the intersection of high-voltage accelerator physics, atomic and molecular physics, and plasma coupling.

You will bridge the gap between theoretical modeling and physical hardware—designing high-power beamlines, optimizing neutralization efficiency, and ensuring ideal energetic particle coupling with fusion plasmas and other targets.

You reach for whatever tool fits the problem best—whether that’s a quick first-principles calculation, a self-coded script, or a high-fidelity multiphysics suite. The method always serves the question. You treat fast, prototype testing as the primary engine of hardware design, rapidly incorporating real-world feedback into every design cycle. You take pride in full ownership, ensuring abstract concepts resolve into elegant, reliable, and high-performing physical systems.

Core Responsibilities

• System Design & Optimization: Lead the physics architecture for high-power, multi-megawatt neutral beam systems, including ion source (positive/negative ion systems), multi-aperture electrostatic extraction, gas cell, and photoneutralizer geometries. Design and develop neutral beam systems, including beam optics, vacuum system and beam dumps. Design high-voltage components (100 kV–1 MV class systems). Develop thermal management solutions for high-power-density components.
• Beam-Plasma Coupling & Transport: Model and analyze beam propagation, charge-exchange losses, ionized particle trajectories, and energy/momentum deposition profiles within magnetically confined plasmas and other targets.
• Modeling & Simulation: Utilize and develop numerical codes (e.g., Monte Carlo beam-tracing, NBI deposition codes, CAD-integrated particle tracking) to predict thermalization rates, fast-ion dynamics, and current drive.
• Hardware & Integration: Collaborate closely with mechanical, electrical, and vacuum engineers to specify requirements for high-voltage power supplies, cryogenic pumping, residual ion dumps, and calorimeter diagnostics.
• Experimental Testing & Operations: Prototype, test, and lead beamline commissioning, conditioning, and real-time operational tuning during plasma experimental campaigns.
• Cross-Functional Leadership: Mentor junior scientists and engineers, publish technical reports, and present progress to key internal and external stakeholders.

Required Qualifications

• Education: Ph.D. or M.S. in Applied Physics, Nuclear Engineering, Electrical Engineering, or a closely related quantitative field.
• Experience: You’ve earned your professional judgement with 5+ years of post-PhD experience (or 8+ years post-Master’s) working directly with high-power particle beams, ion sources, high-voltage engineering, UHV systems, or fusion NBI systems.
• Atomic & Beam Physics Expertise: Deep theoretical and practical knowledge of atomic collision cross-sections, multi-aperture electrostatic optics, and neutralization physics ( negative ion or high-energy positive ion regimes).
• Modeling Proficiency: Hands-on experience with beam deposition and fast-ion transport codes (e.g., TRANSP, NUBEAM, BBNBI, SIMION, or custom Monte Carlo beam-tracing scripts) and simulation tools (COMSOL Multiphysics, ANSYS, WarpX, IBSimu, or similar). Strong SolidWorks/CAD proficiency.
• Hardware Operations: Demonstrated track record working with ultra-high vacuum (UHV), high-voltage equipment (100+ kV), and advanced beam diagnostics.

Preferred Qualifications

• Experience with negative-ion-based neutral beam injectors (N-NBI) or high-energy (>100 keV) beam systems.
• Knowledge of RF ion sources, negative ion generation, high power beam dumps, fusion devices
• Familiarity with dynamic or real-time NBI/NPB power and voltage control for plasma instability management.
• Hands-on involvement in a major fusion facility (e.g., DIII-D, NSTX-U, JET, W7-X, or private fusion startup).
• Strong coding skills in Python, C++, or Julia for custom physics scripting and data analysis.

 

What We Offer

• Competitive Compensation & Equity. Success is shared. Competitive base and meaningful equity in the form of early-stage stock options.
• Benefits: Generous paid leave policy, paid holidays, and a company-wide December break
• Experience: Small team with low barriers to action, solving complex engineering challenges, building real hardware
• Impact: Direct ownership of first-of-a-kind systems without the red tape of traditional research facilities

 

This position may require access to information or technology that is subject to U.S. export control laws, such as ITAR or EAR. Under these regulations, we are required to ensure that such access is provided only to individuals who are classified as 'U.S. Persons.'