Principal Engineer, Cryogenic Refrigeration Systems

Job Title

Principal Engineer, Cryogenic Refrigeration Systems

Role Summary

Lead the design, specification, integration, and validation of Snowcap's cryogenic refrigeration architecture that supports superconducting compute hardware. The role covers compressor systems, helium circuits, cold heads, heat rejection, mechanical interfaces, controls, and field serviceability.

This is a hands-on technical leadership position: set architecture, debug hardware, qualify suppliers, and establish engineering standards for product-grade cryogenic refrigeration.

Experience Level

Senior-level. The role expects significant industry experience — typically 10+ years designing, building, testing, or sustaining cryogenic refrigeration, compressor-based, vacuum, or other high-reliability mechanical systems.

Responsibilities

Primary responsibilities include defining system architecture, executing hardware trade studies, and validating designs through test and analysis.

• Own refrigeration architecture end-to-end: compressor package, helium circuit, cold head, thermal interfaces, heat rejection, controls, and service envelope.
• Define system-level requirements for cooling power, base temperature, cooldown time, pressure/flow, vibration, acoustic noise, power, heat rejection, uptime, redundancy, maintenance, and safety.
• Lead compressor- and system-level trade studies covering technologies, oil management, pressure ratios, cooling, duty cycle, efficiency, vibration, acoustics, and reliability.
• Specify, evaluate, and qualify cryocoolers, compressors, cold heads, vacuum components, gas-handling hardware, chillers, sensors, valves, fittings, and manifolds.
• Build analytical and empirical models: thermal budgets, cooldown curves, parasitic heat loads, pressure drop, flow distribution, compressor envelopes, and failure modes.
• Design and review mechanical subsystems: gas lines, manifolds, heat exchangers, cold plates, thermal straps, mounting hardware, vibration isolation, and vacuum interfaces.
• Develop and run cryogenic test strategies: cooldown testing, heat-load mapping, vibration characterization, compressor performance, leak testing, and reliability growth testing.
• Work cross-functionally with device, packaging, test, manufacturing, facilities, and controls teams to define mechanical and thermal interfaces.
• Drive vendor selection and supplier qualification including specifications, acceptance criteria, incoming inspection, and long-term reliability expectations.
• Translate lab-scale cryogenic systems into manufacturable, serviceable, and maintainable product infrastructure and establish engineering standards and documentation.
• Mentor and grow a team of mechanical, thermal, and systems engineers supporting cryogenic infrastructure.

Requirements

Must-have technical skills and experience required to perform this role.

• 10+ years designing, building, testing, or sustaining cryogenic refrigeration, thermal-fluid, compressor-based, vacuum, or high-reliability mechanical systems.
• Strong fundamentals in thermodynamics, heat transfer, fluid mechanics, pressure systems, mechanical design, vibration, reliability, and instrumentation.
• Direct, hands-on experience with helium refrigeration and cryocoolers (pulse tube, Gifford-McMahon, Stirling, or comparable systems).
• Compressor-level design or integration experience: oil-managed or oil-free compressors, water-cooled packages, pressure/flow control, heat rejection, duty cycles, service intervals, and failure modes.
• Ability to design and debug hardware using pressure, temperature, flow, vibration, acoustic, power, and leak-rate data.
• Mechanical design competence: CAD, drawings, GD&T, materials selection, sealing, vacuum-compatible design, weldments/brazing, and serviceable packaging.
• Experience with supplier specification, qualification, acceptance testing, cost and reliability trade-offs, and manufacturability constraints.
• Proven track record of making architecture-level decisions under incomplete information and validating them through analysis and testing.
• Ownership mindset: delivered systems that operated in real-world environments and required accountability for failures and reliability.

Education Requirements

BS, MS, or PhD in Mechanical Engineering, Aerospace Engineering, Cryogenic Engineering, Thermal Sciences, or equivalent demonstrated depth through industry work (explicitly accepts equivalent practical experience).

About the Company

Company: Snowcap Compute

Headquarters: San Francisco, CA, United States

Snowcap Compute develops commercial superconducting digital computers using Josephson junction–based PCL logic that operate at cryogenic temperatures, aiming for dramatically lower power than CMOS. The company combines expertise in quantum physics, cryogenic engineering, and semiconductor manufacturing to build production superconducting chips.