Compact shielding design of a portable ²⁴¹Am-Be source

Area of Science:

• Nuclear Engineering
• Radiation Shielding

Background:

• Americium-241 Beryllium (Am-Be) neutron sources are crucial for nuclear well logging.
• Existing shielding tanks pose challenges due to their size and weight.

Purpose of the Study:

• To design a compact and efficient shielding tank for portable Am-Be neutron sources.
• To evaluate the shielding performance of a novel dual-layer design.

Main Methods:

• Monte Carlo simulation was employed to design and analyze the shielding tank.
• Materials for neutron moderation (tungsten) and absorption (polyethylene with boron carbide) were evaluated.
• Shielding properties against high- and low-energy neutrons were assessed.

Main Results:

• A dual-layer shielding design significantly reduced tank volume by 86% and weight by 54%.
• Tungsten served as an effective inner-layer neutron moderator.
• Polyethylene with boron carbide effectively absorbed thermal neutrons in the outer layer.
• Simulated dose rates outside the tank remained below 0.025 mSv/h.
• Gamma flux intensity at the tank surface was reduced.

Conclusions:

• The developed compact shielding tank offers substantial size and weight reductions.
• The dual-layer shielding strategy effectively mitigates neutron and gamma radiation.
• This design enhances the portability and safety of Am-Be neutron sources for well logging applications.