R&D Medical Physicist; On-site, Palo Alto, CA)

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Varian Medical Systems, a Siemens Healthineers company is hiring an R&D Medical Physicist to strengthen our Engineering Physics team, developing next generation radiation therapy linear accelerators. This role focuses on dosimetry physics, radiation physics, and medical physics, ensuring accurate, defensible, and compliant beam performance through rigorous measurement, analysis, and verification.

• Own and execute dosimetry and radiation‑physics analyses supporting beam performance, safety, and compliance.
• Translate clinical medical‑physics principles into physics‑based requirements, acceptance criteria, and verification methods.
• Design and perform high‑accuracy radiation measurements (ion chambers, solid‑state detectors, films, arrays), with strong uncertainty discipline.
• Apply radiation transport modeling (analytical and/or Monte Carlo) to understand dose, collimation, scatter, leakage, and shielding.
• Produce clear, traceable, first‑time‑right physics conclusions suitable for QMS, IEC verification, and regulatory review.
• Collaborate closely with engineering, manufacturing, and regulatory partners to close physics risks early.

• PhD in Physics, Medical Physics, Nuclear Engineering, Biomedical Engineering, or closely related field (required).
• 2 + years of experience in radiation-therapy system R&D, beam dosimetry, accelerator physics, or related fields.
• Strong foundation in dosimetry physics, radiation physics, and medical physics.
• Demonstrated ability to perform high‑accuracy measurements, analyze data quantitatively, and assess uncertainties.
• Demonstrated experience performing Monte Carlo radiation‑transport calculations for hardware development, such as collimation, shielding, or leakage analysis (e.g., using Geant4, or equivalent).
• Technical rigor, critical thinking, and sound physics judgment, especially in safety‑ and compliance‑critical work.
• Clear written and verbal communication of complex physics concepts.

• Applied radiation‑transport expertise in shielding, collimation, and beam modeling (x‑ray, electron, and secondary radiation fields), with clear connections between simulation and measurement.
• Clinical medical‑physics intuition, such as LINAC commissioning, QA, or end‑to‑end dosimetric validation, and understanding of patient‑dose implications.
• Disciplined use of Monte Carlo and analytical methods, validating models against data rather than treating simulation as a black box.
• Strong quantitative analysis skills using Python, MATLAB, Excel, or similar tools, with emphasis on uncertainty evaluation and defensible conclusions.
• System‑level beam understanding, including familiarity with beam generation, monitoring/controlling, treatment‑planning systems, and source/beam modeling assumptions.
• Evidence of technical leadership or innovation, such as publications, patents, conference contributions, or impactful internal technical work demonstrating rigor and ownership.

• As an R&D Medical Physicist, you will drive the physics innovations that advance beam precision, safety, and efficiency in modern radiation therapy.
• You’ll join a collaborative team of physicists and engineers who combine conceptual research, hands‑on experimentation, and cross‑functional problem‑solving to transform scientific insight into…