Instrumentation Physicist: Digital Twin

xLight Inc.; San Francisco (CA); Hybrid; USD 100,000 - 145,000; Full time

Benefits offered by this job

Health insurance

Life Insurance

Disability Insurance

401k

Flexible Paid Time Off

Winter Break

Flexible Hybrid Work Model

Job summary

xLight Inc. is building digital twins for accelerator diagnostics in a hybrid work setting in the San Francisco area. The role focuses on physics-based instrument models, validation with real data, and turning models into reusable code used by the twin and real machine.

You will collaborate with Accelerator Physics, ML, and Controls teams to tune simulated machines and ensure measurements remain physically correct across the system. A strong physics and software background is essential.

Qualifications

• Ph.D. in Physics or related field, or equivalent experience.
• Strong Python software engineering including testing and packaging.
• Proficiency with Python scientific stack (NumPy, SciPy, Matplotlib).
• Experience with measurement instruments and data acquisition.
• Ability to collaborate with physicists and engineers on new devices.

Responsibilities

• Model diagnostics from physics to instrument reading including noise and calibration errors.
• Validate models against bench and machine data and report predictive accuracy.
• Develop reusable, tested software components from existing models.
• Simulate and calibrate diagnostic systems before beam, including tuning procedures.
• Integrate models with EPICS and connect readout to the digital twin.

Skills

Python engineering

Code testing

AI code review

NumPy/SciPy/Matplotlib

Beam dynamics understanding

Measurement instrumentation

Bench testing

Education

Ph.D. in Physics or related field

Tools

Bmad / Tao

Impact

Genesis

EPICS IOCs

Fortran or C++

Job description

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 what someone can do today; we hire for who they are and who they are becoming.

What We Need — and Why It Matters

The goal is to be a digital twin of the accelerator. The first step is virtual commissioning: tune a simulated machine to specification using only what its instruments can measure. This role makes each simulated instrument read what the real instrument would read, with the same noise, offsets and calibration errors.

The twin is a shared project. Accelerator Physics owns the beam dynamics and the error budget. The ML team owns surrogate models, fast solvers, and anomaly detection. This role is in the Diagnostics team and owns the instrument models.

What You'll Do

• - Model each diagnostic from physics, from the beam through the pickup, front-end electronics and digitizer to the processed reading. Include noise, offsets, nonlinearity and calibration errors.
• - Validate each model against bench and machine data, and report how well it predicts the real readings.
• - Turn models that others write into tested, reusable parts.
• - Commission the diagnostic systems in simulation before they meet beam: calibration, resolution, and the measurement procedures that use them.
• - With Accelerator Physics, develop the tuning procedures that depend on these measurements, and test them on simulated machines with unknown errors.

Integration

• - Serve each instrument model through EPICS with the same PVs as the real instrument, so that operator software runs the same against the twin and against the machine.
• - Connect instrument readout to the twin, with the team's Electrical, FPGA and Controls engineers.

Simulation software

• - Build and maintain the instrument models in the shared twin code base, and keep them correct and fast as the code base grows.
• - Review code from other contributors, including code written by AI agents.
• - Contribute to the beam dynamics codes the twin uses (Bmad / Tao, Impact, Genesis) where the instrument models need it.
• - With the ML team, infer beam properties that no single instrument measures, from several measurements and a model.

What We Are Looking For

• - Ph.D. in Physics or related field, or equivalent experience
• - Strong software engineering in Python: structure, testing (pytest), packaging, code review, including review of code written by AI agents.
• - The Python scientific stack: NumPy, SciPy, Matplotlib, etc.
• - Scientific or numerical computing where the result must be physically correct.
• - Physics depth, from a degree in physics or a related field or from demonstrated work.
• - Knowledge of how measurement instruments work, from physical signals through electronics to digitized data, including noise and calibration.
• - Hands-on measurement with real instruments: bench tests, data acquisition and calibration.
• - Ability to work closely with other physicists and engineers and learn about new devices quickly.

And If You Bring This — Even Better

Instruments and signals

• - Screens, cameras and optical imaging
• - Instrument and noise modeling
• - Signal processing and DSP
• - RF and analog front ends

Physics and simulation

• - Bmad / Tao
• - Impact
• - EM simulation of pickups and structures (CST, HFSS)

Controls

• - EPICS IOCs
• - Instrument control and DAQ

Software

• - Fortran or C++ in established simulation codes
• - GPU or HPC computing
• - Web front ends for scientific tools
• - Containers and CI

Domain

• - Accelerator, FEL or synchrotron facility experience
• - Detector, DAQ or diagnostic systems in particle, nuclear, plasma or fusion physics
• - Digital twins or hardware-in-the-loop simulation

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 100,000/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.