An accelerator-based neutron microbeam system for studies of radiation effects

Area of Science:

• Radiation Biology
• Accelerator Physics
• Microdosimetry

Background:

• The Radiological Research Accelerator Facility (RARAF) has extensive experience with charged particle microbeams for studying radiation effects.
• Previous research has focused on radiation bystander effects in mammalian cells using established microbeam technologies.

Purpose of the Study:

• To develop a novel neutron microbeam facility at RARAF for advanced radiation biology studies.
• To adapt existing charged particle microbeam technology for neutron irradiation applications.

Main Methods:

• Utilizing a proton beam with a micrometre-sized diameter impinging on a lithium fluoride target to generate neutrons via the ⁷Li(p,n)⁷Be reaction.
• Designing the system based on the kinematics of the reaction near the 1.881 MeV threshold to confine the neutron beam to a narrow, forward solid angle.
• Employing Mg-doped luminescent aluminum oxide single crystals and confocal laser scanning fluorescent microscopy for neutron beam imaging.

Main Results:

• Calculations predict a neutron spot diameter of <20 µm for cells on a 3.8-µm propylene-bottomed dish backed by a 17-µm gold foil.
• The system is expected to achieve a neutron flux of approximately 2000 per second with a dose rate of about 200 mGy/min.
• Preliminary tests using a collimated proton beam validated the core principles of the neutron microbeam system.

Conclusions:

• A prototype neutron microbeam system is under development at RARAF, leveraging existing infrastructure and technology.
• This new facility holds significant potential for investigating radiation bystander effects and other radiobiological phenomena with high spatial precision.