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Salary
$128k – $150k per year
Location
In office (Denver)
Seniority
Middle · 3+ years exp
Employment
Full-Time

Confirmed on the employer's own hiring board on Oct 13, 2026. First seen by Alion on Oct 1, 2026. Xcimer Energy scores A on the Alion truth index.

Overview
Company
Impact
Profile match
Xcimer Energy is a Denver-based company developing laser-driven inertial fusion power and high-energy laser systems for air defense, built around large electron-beam-pumped excimer lasers. In 2024 it began building Phoenix, its first high-energy laser system, in its Denver laser bay, it has had a fusion power plant preconceptual design milestone approved by the US Department of Energy, and RTX has invested in it to develop directed energy technology. It hires optical, laser, pulsed power and nuclear engineers, physicists and materials scientists, scientific software and data engineers, technicians, quality and supply chain leaders, and summer interns.

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!

This is a full-time, onsite role based at our headquarters in Denver, CO.

As a Vacuum Systems Mechanical Engineer, you will lead the design, integration, and operation of vacuum systems for rare-gas/halide (excimer) lasers used in IFE power generation. Your work will begin with prototype systems and continue through the design and demonstration of power-producing IFE reactors. You will ensure that vacuum hardware meets flow and performance requirements throughout the product development lifecycle in a dynamic R&D environment. 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!

Responsibilities

  • Develop and specify pump-down and vent procedures to meet vacuum system flow requirements.
  • Perform analyses and calculations to predict and optimize flow architecture functionality, including pressure drop, flow budgeting, humidification, and gas purity.
  • Design equipment using NX CAD
  • Work with vendors for custom and OTS devices and instruments.
  • Select instruments for gas analysis such as RGAs and FTIR
  • Work with the controls team on device integration.
  • Ensure functional integration of vacuum architectures and subsystems through analysis, documentation, and machine testing.
  • Manage pressure and vacuum vessel certifications, proof-tests, and compliance with code standards.
  • Lead design efforts for prototype systems and subsystems, including Preliminary and Final Designs.
  • Troubleshoot escalations and derive practical recommendations for improvements.
  • Collaborate with mechanical, laser, pulsed power, and optical engineering teams throughout the design and development process.
  • Support procurement of vacuum-related hardware for laser amplifiers and optical conditioning equipment.
  • Oversee and assist with assembly, shakedown, and testing of vacuum systems on laser amplifiers and ancillary equipment.
  • Provide operational support for vacuum systems and equipment.
  • Contribute to scaling designs for power-producing IFE reactors and participate in concept studies for IFE applications and beyond.

Qualifications

  • Education:B.S. in Mechanical, Nuclear, Aerospace Engineering, or related field.
  • Experience:3+ years in mechanical engineering, with a focus on vacuum system design for complex hardware (preferred industries include semiconductor, solar, R+D, nuclear, fusion energy, lasers, defense).
  • Proficiency with 3D CAD software (NX preferred).
  • Working knowledge of high purity gas delivery components and standard equipment.
  • Working knowledge of Finite Element Analysis (FEA).
  • Experience with complex integrated system design (e.g., plasma source, gas delivery, pulsed power, lasers, opto-mechanical systems).
  • Strong problem-solving skills and a hands-on approach to troubleshooting and testing.
  • Interdisciplinary engineering experience is a plus.
  • 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 of granted asylum

Desired

    • Start-up experience preferred

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