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Senior Diagnostics Mechanical Engineer
Commonwealth Fusion SystemsDevens, MA, United Statesfull_timeVerifiedPosted 8 Sept 2025
About the role
About Commonwealth Fusion Systems:
Commonwealth Fusion Systems is on a mission to deliver the urgent transition to fusion energy.
Combining decades of research, top talent, and new technologies, we’re designing and building commercially viable fusion power plants. And working with policymakers and suppliers to build the energy industry of the future.
We’re in the best position to make it happen. Since 2018, we’ve raised nearly $3 billion in capital, making us the largest and leading private fusion company in the world.
Now we’re looking for more thinkers, doers, builders, and makers to join us. People who’ll bring new perspectives, solve tough problems, and thrive as part of a team.
If that’s you and this role fits, we want to hear from you.
Join the power movement as a Senior Diagnostics Mechanical Engineer
The design of the SPARC facility is continually advancing, including the design of instrumentation that will be used to control the plasma and deliver the scientific data necessary to inform the design of ARC. The SPARC Diagnostic system is comprised of over forty sub-systems that use a variety of proven techniques to encode information from a tokamak plasma into measurable signals; active laser based measurements, passive and active analysis of microwave-band emission, spectroscopy of plasma emission from the x-ray to infrared, characterization of neutrons produced from fusion reactions, and a wide variety of wired sensors and probes integrated into the vacuum environment. Techniques have been demonstrated by decades of government-sponsored fusion research, and CFS is looking for multidisciplinary engineers who can contribute to innovative design and engineering solutions to endure these concepts can be integrated into the SPARC tokamak. Candidates that have design, build, or analysis skills in the mechanical, civil, or aerospace engineering disciplines are encouraged to apply. The SPARC diagnostic team welcomes engineers looking for a career transition who want to join a team with diverse backgrounds and can solve challenging problems in the growing fusion energy industry. Candidates will work alongside CFS staff, MIT-PSFC partners, and fusion community collaborators from around the world to design and build the tools that will control the SPARC plasma and measure net energy from a tokamak for the first time.
Commonwealth Fusion Systems is on a mission to deliver the urgent transition to fusion energy.
Combining decades of research, top talent, and new technologies, we’re designing and building commercially viable fusion power plants. And working with policymakers and suppliers to build the energy industry of the future.
We’re in the best position to make it happen. Since 2018, we’ve raised nearly $3 billion in capital, making us the largest and leading private fusion company in the world.
Now we’re looking for more thinkers, doers, builders, and makers to join us. People who’ll bring new perspectives, solve tough problems, and thrive as part of a team.
If that’s you and this role fits, we want to hear from you.
Join the power movement as a Senior Diagnostics Mechanical Engineer
The design of the SPARC facility is continually advancing, including the design of instrumentation that will be used to control the plasma and deliver the scientific data necessary to inform the design of ARC. The SPARC Diagnostic system is comprised of over forty sub-systems that use a variety of proven techniques to encode information from a tokamak plasma into measurable signals; active laser based measurements, passive and active analysis of microwave-band emission, spectroscopy of plasma emission from the x-ray to infrared, characterization of neutrons produced from fusion reactions, and a wide variety of wired sensors and probes integrated into the vacuum environment. Techniques have been demonstrated by decades of government-sponsored fusion research, and CFS is looking for multidisciplinary engineers who can contribute to innovative design and engineering solutions to endure these concepts can be integrated into the SPARC tokamak. Candidates that have design, build, or analysis skills in the mechanical, civil, or aerospace engineering disciplines are encouraged to apply. The SPARC diagnostic team welcomes engineers looking for a career transition who want to join a team with diverse backgrounds and can solve challenging problems in the growing fusion energy industry. Candidates will work alongside CFS staff, MIT-PSFC partners, and fusion community collaborators from around the world to design and build the tools that will control the SPARC plasma and measure net energy from a tokamak for the first time.
What you'll do:
- Support the diagnostic systems in the design of components by applying multi-disciplinary engineering and design skills to a variety of diagnostic systems
- Contribute to a strong safety culture while helping to commission and operate SPARC diagnostics
- Grow expertise that helps CFS build a core competency in fusion measurement tools that can deliver future tokamaks optimized for power production
- Project areas can range over multiple topics including design, analysis, and testing of:
- ➢ Large ~5m tall structures, towers, and weldments which provide support and precision locating features for 10’s - 1000’s of kg of diagnostic equipment
- ➢ Packaging and assembly constrained piping and wiring components that can interface from sensors and tokamak systems to signal processing equipment
- ➢ Radiation shielding to help increase the lifetime of sensitive equipment
- ➢ Support and interfacing structures for scientific measurement tools that use a ~375m^2 dedicated laboratory space next to the SPARC tokamak
- Scope and depth of required work is adjustable based on aptitude and experience, but can cover:
- ➢ Detailed component design and assembly layout in CAD
- ➢ Development of assembly and installation procedures for large assemblies
- ➢ Rapid prototyping and design of benchtop and rackmount parts that interface custom SPARC components to COTS equipment
- ➢ Structural, civil, and thermal analysis
- ➢ Collaboration with other CFS teams and external vendors to verify design functionality and manufacturability
- ➢ Developing and executing benchtop tests of prototypes
- ➢ Supporting the resolution of technical issues that arise during the manufacturing of SPARC diagnostic equipment
- ➢ Providing hands on support for diagnostic assembly and calibration, providing feedback on the impact of field changes during installation
What we're looking for:
- At least a bachelor’s degree in a relevant engineering field (manufacturing, mechanical or aerospace)
- 4+ years' experience as a manufacturing engineering manager in new manufacturing production launch / new facility startups
- Experience taking products from R&D into production
- Excellent time management and organizational skills and experience establishing guidelines in these areas for others
- Experience with ERP/MES software
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