Low Radon Cleanroom for Underground Laboratories

Area of Science:

• Environmental Science
• Nuclear Physics
• Cleanroom Technology

Background:

• Minimizing radon and its decay products is crucial for sensitive research like radiobiology and nanoelectronics fabrication.
• Deep underground laboratories offer suppressed muon flux and shielding, creating ideal environments for ultra-low radiation studies.
• Existing cleanroom technologies require further development to achieve extremely low radon concentrations.

Purpose of the Study:

• To develop and test low radon cleanroom technology capable of achieving radon concentrations below 100 mBq·m³.
• To minimize radon decay product concentration and surface deposition rates within the cleanroom.
• To assess the feasibility of creating a
• zero dose
• space for specialized applications.

Main Methods:

• Construction and testing of two low radon cleanroom prototypes with enhanced leakproofness and advanced ventilation systems.
• Utilizing radon-free air supplied from a dedicated radon trapping facility.
• Implementing intensive filter-ventilation and monitoring radon concentration, decay products, and surface deposition rates.

Main Results:

• Achieved radon concentrations as low as 50 mBq·m^-3 in the first prototype with the ventilation system switched out.
• The second prototype, with a fully sealed ventilation system, demonstrated potential for further radon reduction.
• Preliminary tests showed an extremely low radon decay product equilibrium factor (0.002) and low surface deposition rates (0.05 mBq·m^-2·s^-1 per Bq·m^-3).

Conclusions:

• Low radon cleanroom technology is feasible for creating controlled environments for sensitive research and manufacturing.
• Advanced sealing and ventilation are critical for minimizing radon ingress and controlling decay products.
• Further research is needed to address factors like human radon exhalation into these controlled spaces.