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Radiological Science and Engineering


On-Demand Neutron Source

PNNL staff are developing a neutron source with the unique capability to be able to start and stop the neutron emission at will. Such a device would be very useful for the nation's ports of entry, where neutron detectors are being installed in portal monitors to detect special nuclear material that may be smuggled into the country. These neutron detectors need to be source-checked periodically to ensure proper performance, but traditional neutron sources require a radiological safety program that is more intensive than these installations would typically accomodate. A neutron source with an "on/off" capability would provide the necessary functionality when needed but have a lower radiation emission during storage and, thus, lower safety and security requirements.

This project is implementing the well-known "alpha-n" nuclear interaction in which an alpha particle strikes a light-element nucleus to produce a neutron. Preliminary calculations show that a 1 cm2 disk coated with 241-Am could be placed next to a similar disk of beryllium to produce a neutron emission rate similar to the neutron sources recommended for source-checking at ports of entry.

Radiological Science and Engineering

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