On May 2, James Hauver and William Henderson presented posters on their work from the summer of 2010 on photoneutron production with polarized gamma rays. Linearly polarized gamma rays provide a new window into these reactions and are particularly interesting for the student of fissile nuclides.
The targets Jimmy and William studied are Ta and Sn. The interesting observable is the ratio of the neutron yield in the plane of polarization divided by the yield at right angles to the beam polarization direction. This ratio, R, is a function of photon and neutron energy and provides a characteristic response for nuclei that is often enough different from other nuclei that some identification of the target can be made. This is particularly true for fissile material.
More targets will be studied this summer including La, Ce, Dy, and Hg.