Photo Gallery

Real-Time NAD Detector

Engineer Jaben Root installs a real-time neutron activation detector (NAD) assembly into a hole in the gunite that surrounds the NIF Target Chamber (gunite is a mixture of cement, sand, and water applied through a pressure hose, producing a dense hard layer of concrete used for lining tunnels and structural repairs; for NIF, it provides the first layer of shielding from neutrons produced from the fusion reactions in target experiments). Neutron activation diagnostics measure the neutron yield and flux of a target capsule during NIF experiments. Earlier NADs worked by activating a sample material, removing it from the chamber, and determining the activation level using nuclear counting techniques. The real-time NAD detectors are monitored remotely, providing a more accurate estimate of the angular distribution of the neutron yield, with much more rapid turnaround and at a significantly lower operating cost. They are installed at 48 locations on the Target Chamber, including 27 locations where gunite is drilled down the chamber wall.

Download hi-res image