Senior Cryogenic Engineer

Xcimer Energy • Denver, CO

3d

About The Position

Xcimer Energy leverages decades of research on Inertial Fusion Energy (IFE) combined with groundbreaking new laser architecture. Our mission is to deploy fusion power plants to meet global decarbonization goals as fast as possible. Xcimer has assembled a team of leaders in tough tech, fusion science, and manufacturing with a track record of rapid execution. Supported by leading investors, Xcimer is uniquely positioned to deliver limitless, clean, fusion power to combat climate change. Join us in powering a better world with inertial fusion! As a Senior Cryogenic Engineer , you will lead the development of deuterium–tritium (DT) fuel handling and target filling capabilities for the Vulcan and Athena programs at Xcimer. This role is critical to enabling reliable, repeatable cryogenic target production and supporting high-repetition-rate experimental campaigns. You will own the end-to-end design, integration, and operation of DT filling systems, working at the intersection of cryogenics, target fabrication, tritium handling, and experimental operations. We are looking for our engineers to apply their technical expertise, problem solving skills, and dedication to quality to positively impact the future of energy!

Requirements

• Degree in mechanical engineering, nuclear engineering or related field
• 8+ years of experience in cryogenic system design and operation
• Experience with 3D CAD (NX preferred), FEA, and CFD tools (ANSYS, Altair preferred) for detailed design and analysis
• Design experience with hydrogen isotope systems, cryogenic fluid handling systems, or ultra-low temperature systems
• Experience working with and around safely with hazardous materials (tritium, isotopes, chemically corrosive materials, etc.)
• Experience with precision systems, vacuum environments, and thermal control
• Ability to lead complex system development from concept through operation
• Creative problem-solver who thrives in fast-paced, dynamic environments
• Must be a U.S. citizen or national, U.S. permanent resident (current Green Card holder), or lawfully admitted into the U.S. as a refugee or granted asylum

Nice To Haves

• MS in Mechanical Engineering, Nuclear Engineering or related
• Familiarity with tritium handling, safety protocols, and regulatory frameworks strongly preferred
• Cryogenic target fabrication for inertial confinement fusion (ICF)
• DT layering and characterization techniques
• High-repetition-rate experimental systems

Responsibilities

• Lead the design and development of deuterium–tritium (DT) fuel filling and cryogenic layering systems for inertial fusion targets
• Define system architecture for tritium-compatible cryogenic infrastructure, including storage, transfer, and recovery
• Develop processes for repeatable, high-quality DT layer formation and characterization
• Integrate fueling systems with target fabrication, handling, and shot operations
• Establish procedures for safe handling of tritium in compliance with regulatory and facility requirements
• Drive commissioning, testing, and operation of cryogenic systems to support experimental campaigns
• Collaborate with target design, theory and computation, experimental teams, and external partnering institutions to define requirements and iterate on designs
• Identify and mitigate technical risks associated with cryogenic performance, reliability, and throughput

Benefits

• Xcimer offers a comprehensive benefits package designed to support employee health, well-being, and long-term success.
• Benefits include medical, dental, and vision coverage; basic and supplemental life insurance; short- and long-term disability; paid parental leave for employees at the time of birth or adoption; and a 401(k) with a company match of up to 6%.
• Eligible employees also receive equity, allowing them to share in the company’s long-term success.
• Xcimer operates under a flexible Paid Time Off (ATO) approach.
• Rather than a fixed number of vacation days, employees are trusted to take the time they need to rest and recharge while meeting the expectations of their role and team.
• In addition, employees receive paid sick time, 13 company-paid holidays, and an annual paid company shutdown.
• Benefits are available to regular employees, including part-time and fixed-term roles, as well as interns, with eligibility varying by benefit.

What This Job Offers

• Job Type: Full-time
• Career Level: Senior
• Number of Employees: 11-50 employees