Helium Liquefier – Bluefors LHEP22 System

✅ Manufacturer: Bluefors Cryocooler Technologies, Inc. (formerly Cryomech)

✅ Core Functionality:

• Converts helium gas into liquid helium for MEG system cooling.
• Uses pulse-tube cryocooler technology for high efficiency with low vibration and noise.
• Daily Production: Over 22 liters of liquid helium per day.
• MEG Consumption: ~11 liters per day, allowing for excess capacity to manage losses.
• Compressor: CPA1110 powers the system.
• Cold Head: PT415 sits atop a 150-liter cryogenic Dewar for liquid helium storage.

Helium Recovery & Storage System

✅ Gas Collection & Storage

• Captures helium boil-off from the MEG system, particularly during refills or horizontal positioning for specific experiments.
• Uses a CPA286R compressor to transfer gas into two 1500-liter storage tanks at up to 100 psig.
• Collected helium is slowly reintroduced into the liquefier via a purification process.

✅ Custom MEG Interface

• Designed with non-magnetic components to prevent interference with MEG signals.
• Hoses, valves, pressure regulators, and heat exchange finned tubes warm helium gas to room temperature before reaching the recovery compressor.
• An electrical insulator at the recovery line entry point prevents electromagnetic noise contamination in the magnetically shielded MEG room.

Helium Purification System

✅ How It Works:

• Incoming helium gas passes through a liquid nitrogen-based purifier.
• Liquid nitrogen (−196 °C / −320 °F) traps contaminants such as:
• Oxygen (liquifies at −183 °C / −297 °F)
• Carbon dioxide (freezes at −78 °C / −109 °F)
• Purified helium is then reintroduced into the liquefier, ensuring high purity and efficiency.

Sustainability & Operational Benefits

✔ Significant cost savings by reducing the need for external helium refills.

✔ Minimizes environmental impact through helium recycling.

✔ Ensures continuous MEG operation without helium shortages.

✔ Low-maintenance, vibration-free system for stable and reliable MEG signal acquisition.