Neutrons and JFK

Most Laboratory personnel learned of the assassination of President John Kennedy over the Laboratory's public address system on the afternoon of November 22, 1963. A week later, the Federal Bureau of Investigation (FBI) asked the Laboratory to study fragm ents of the bullets that struck the president and the paraffin casts taken of the hands and face of Lee Harvey Oswald, the accused assassin.

This request was made because the Laboratory had facilities and scientists available for performing neutron activation analysis. When neutrons from a reactor activate the atomic elements in a material, each element emits characteristic gamma rays, reveali ng its presence and concentration in the material.

About five years after John Kennedy had admired the Oak Ridge Research Reactor as a U.S. senator, evidence relating to his assassination came to the Laboratory, where William Lyon Jr., Frank Dyer, and Juel Emery, all of the Analytical Chemistry Division, test ed it in the High Flux Isotope Reactor's neutron flux. The FBI hoped Laboratory researchers could match gunpowder particles on the paraffin casts with gunpowder from a rifle found at the crime scene. The fact that Oswald had fired a pistol, killing a Dall as policeman, the day of the assassination, and earlier tests made on the paraffin casts complicated the research and made the Laboratory's results inconclusive.

The FBI hoped that ORNL's neutron activation analysis of the bullet fragments taken from the president's limousine could determine whether the bullets were fired from a single weapon. Lead bullets have traces of silver and antimony, and the Laboratory's a nalysis of these traces indicated that the bullets did indeed come from the same rifle. Later independent study by a University of California neutron activation specialist confirmed the Laboratory's conclusion. ORNL's Nuclear and Radiochemistry Analysis g roup complied with many requests for neutron activation analysis in connection with crimes until the 1970s when commercial laboratories entered the field.

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Neutron Scattering at the High Flux Isotope Reactor