Senior Cryostat Engineer at PsiQuantum in Milpitas, CA

PsiQuantum’s mission is to build the first useful quantum computers—machines capable of delivering the breakthroughs the field has long promised. Since our founding in 2016, our singular focus has been to build and deploy million-qubit, fault-tolerant quantum systems. Quantum computers harness the laws of quantum mechanics to solve problems that even the most advanced supercomputers or AI systems will never reach. Their impact will span energy, pharmaceuticals, finance, agriculture, transportation, materials, and other foundational industries. Our architecture and approach is based on silicon photonics. By leveraging the advanced semiconductor manufacturing industry—including partners like GlobalFoundries—we use the same high-volume processes that already produce billions of chips for telecom and consumer electronics. Photonics offers natural advantages for scale: photons don’t feel heat, are immune to electromagnetic interference, and integrate with existing cryogenic cooling and standard fiber-optic infrastructure. In 2024, PsiQuantum announced government-funded projects to support the build-out of our first utility-scale quantum computers in Brisbane, Australia, and Chicago, Illinois. These initiatives reflect a growing recognition that quantum computing will be strategically and economically defining—and that now is the time to scale. PsiQuantum also develops the algorithms and software needed to make these systems commercially valuable. Our application, software, and industry teams work directly with leading Fortune 500 companies—including Lockheed Martin, Mercedes-Benz, Boehringer Ingelheim, and Mitsubishi Chemical—to prepare quantum solutions for real-world impact. Quantum computing is not an extension of classical computing. It represents a fundamental shift—and a path to mastering challenges that cannot be solved any other way. The potential is enormous, and we have a clear path to make it real. Come join us. Job Summary: PsiQuantum is seeking a highly skilled Cryostat Engineer to lead the installation, commissioning, and ongoing operation of advanced cryogenic and ultra-high vacuum (UHV) systems supporting quantum computing hardware. This role is critical to ensuring reliable ultra-low-temperature and high-vacuum environments required for quantum device performance. Responsibilities: Lead installation and integration of cryostats and associated subsystems, including vacuum chambers, pumps, valves, and instrumentation. Execute commissioning procedures including vacuum pump-down, leak checking, bake-out processes, cooldown, and system qualification. Develop and maintain standard operating procedures (SOPs) for cryostat and vacuum system operation. Monitor and optimize vacuum performance (pressure levels, leak rates, outgassing) alongside cryogenic thermal stability. Troubleshoot and resolve issues related to vacuum integrity, cryogenics, and thermal interfaces. Perform helium leak detection, residual gas analysis (RGA), and vacuum diagnostics. Collaborate with cross-functional teams to integrate vacuum and cryogenic systems with quantum hardware. Perform preventive and corrective maintenance on cryostats, vacuum systems, and supporting infrastructure. Maintain detailed documentation, logs, and test reports for vacuum and cryogenic systems. Experience/Qualifications: Bachelor’s degree in Mechanical Engineering, Physics, or a related field (advanced degree preferred). 3+ years of hands-on experience with cryogenic and/or high or ultra-high vacuum systems. Strong understanding of vacuum technology (UHV practices, pumping systems, sealing methods, materials compatibility). Experience with vacuum pumps (turbo, cryo, roughing), gauges, and leak detection methods. Solid foundation in thermodynamics and heat transfer. Experience installing and commissioning complex mechanical and vacuum systems. Ability to read and interpret engineering drawings, vacuum schematics, and P&IDs. Strong troubleshooting and problem-solving skills in lab or manufacturing environments. PsiQuantum provides equal employment opportunity for all applicants and employees. PsiQuantum does not unlawfully discriminate on the basis of race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), gender identity, gender expression, national origin, ancestry, citizenship, age, physical or mental disability, military or veteran status, marital status, domestic partner status, sexual orientation, genetic information, or any other basis protected by applicable laws. Note: PsiQuantum will only reach out to you using an official PsiQuantum email address and will never ask you for bank account information as part of the interview process. Please report any suspicious activity to recruiting@psiquantum.com. We are not accepting unsolicited resumes from employment agencies. The ranges below reflect the target ranges for a new hire base salary. One is for the Bay Area (within 50 miles of HQ, Palo Alto), the second one (if applicable) is for elsewhere in the US (beyond 50 miles of HQ, Palo Alto). If there is only one range, it is for the specific location of where the position will be located.Actual compensation may vary outside of these ranges and is dependent on various factors including but not limited to a candidate's qualifications including relevant education and training, competencies, experience, geographic location, and business needs. Base pay is only one part of the total compensation package. Full time roles are eligible for equity and benefits. Base pay is subject to change and may be modified in the future. U.S. Base Pay Range $130,000—$145,000 USD Bay Area Pay Range $150,000—$165,000 USD