Accelerator Physicist (United States)

Accelerator Physicist

Location: San Francisco Bay Area, CA | Newport News, VA | Naperville, IL | Remote

Reports To: Director, Accelerator Physics

About xLight

xLight is building the world's most powerful laser to revolutionize semiconductor lithography, metrology, and other critical applications. Our approach is to harness the power of free-electron lasers by building on accelerator technology currently used at scientific facilities around the world. In extending this technology, we are developing industrial-grade light sources, engineered for continuous operation to meet the sophisticated demands of next-generation patterning, metrology, and inspection applications. Join us in this new revolution!

At xLight, we hire exceptional talent and exceptional means more than a strong résumé. How we achieve results is just as important as the results themselves, which is why attitude and character matter as much as technical skill. We believe great talent is widely distributed and not confined to a particular school or background. We seek individuals who demonstrate ownership, a spirit of collaboration, technical curiosity, and a genuine willingness to learn and grow - guided by our core values of Respect, Integrity, Creativity, and Engineering Excellence. We don't just hire for what someone can do today; we hire for who they are and who they are becoming.

What We Need — and Why It Matters

xLight is seeking a highly motivated junior Accelerator Physicist to be on the ground floor during the development of a new free-electron laser light source for industry. The successful candidate will be comfortable working in a dynamic, start-up environment and will thrive working in a small group setting in close collaboration with the scientific and engineering team. Critical aspects of the work will focus on the accelerator system design, hardware specifications, and planning for commissioning and operations, including digital twin development. Relevant experience with an accelerator facility or a light source facility is advantageous to the successful candidate.

The ideal candidate will excel in the fast-paced nature of a start-up environment and demonstrate a proactive approach in a collaborative, interdisciplinary team. You will be instrumental in designing and implementing novel solutions to particle accelerator light sources.

This is a full-time appointment based in Palo Alto, California with remote and hybrid options supported.

What You’ll Do

• Develop high-fidelity, fast computational models of the accelerator and beamline components—including magnets, accelerating cavities, and diagnostics—to predict beam behavior, validate system requirements, and identify optimization opportunities.
• Build and validate virtual accelerator models that incorporate realistic machine and instrument behavior, including noise, drift, calibration, systematic errors, nonlinearities, latency, saturation, failure modes, and channel correlations.
• Perform large-scale particle beam simulations and end-to-end virtual commissioning studies to evaluate beam dynamics, operating limits, sensitivities, and system-level trade-offs. Validate models against vendor data, bench and first-article measurements, comparable-machine data, and first-principles analysis, while maintaining component-level uncertainty budgets.
• Translate simulation and virtual commissioning results into actionable engineering specifications and design decisions, collaborating closely with accelerator physics, controls, software, and multidisciplinary engineering teams.
• Develop physics-based optimization, machine learning, and computational tools to improve accelerator performance, stability, reliability, and enable predictive control and automated optimization.
• Grow into shared technical ownership of the accelerator digital twin , including the interfaces between the physical machine, models, diagnostics, and control systems; support diagnostics simulation and review control, analysis, and AI-enabled software developed by internal teams, vendors, and partners.

What We Are Looking For

• Ph.D. in Physics or related field, or equivalent experience
• 3+ years of experience with particle accelerators or other large-scale machines
• Strong understanding of particle accelerator design including theory, simulations and experimental efforts needed to commission and operate an accelerator
• Extensive experience with various particle accelerator simulation codes
• Experience with developing system specifications from physics models

And If You Bring This — Even Better

• Experience working at a large-scale accelerator or light source facility
• Knowledge of advanced particle simulation codes, like Bmad, Elegant or IMPACT
• Knowledge of beam diagnostics and diagnostic design and implementation
• Experience programming in Python

What You Can Expect from Us

• 100% Company-funded health insurance for employee
• Company funded Life Insurance and disability insurance
• 401k contribution. 100% up to 3% of compensation, plus 50% match between 3% and 5%. Immediately vested.
• Flexible Paid Time-Off, Sick leave and Company Holidays
• Company Paid Two-weeks Winter Break
• Flexible Hybrid Work Model

Pay transparency

The pay range for this position reflects the minimum and maximum target for new hire salaries at commencement of employment and is expected to be between USD 105,000/year-145,000/year. However, base pay offered may vary depending on multiple factors, including location, role, job-related knowledge, skills, relevant education and experience. The total compensation package for this position may also include other elements, including equity, and a full range of benefits. Details of all benefits will be provided if an employee receives an offer of employment.

EEO Statement

xLight Inc. is an Equal Opportunity Employer. Our policy is clear: there shall be no discrimination on the basis of age, disability, sex, race, religion or belief, gender reassignment, marriage/civil partnership, pregnancy/maternity, or sexual orientation. We are an inclusive organization and actively promote equality of opportunity for all with the right mix of talent, skills and potential. We welcome all applications from a wide range of candidates. Selection for roles will be based on individual merit alone.