In collaboration with Clifford G. Shull, who joined him at ORNL in 1946, he developed neutron diffraction methodology used for determining atomic resolution structure of substances. In 1994, Shull was awarded a share of the Nobel Prize in Physics for his work on neutron diffraction. The unusual delay in the Nobel award, which came more than four decades after the work that it recognized, may have resulted from negative views of the work’s relationship to nuclear power. Wollan was not eligible for the Nobel because he had died 10 years earlier. In his Nobel lecture Shull spoke of Wollan’s contributions and expressed regret that his colleague had not lived long enough to share in the prize.
Wollan remained a member of the ORNL research staff until retiring in 1967. For much of his 23-year service at ORNL, he was associate director of the Physics Division. He continued as a consultant to ORNL until 1977. In his final years, Wollan returned to Minnesota, the state of his birth, where he died in 1984. He is buried in the Oak Ridge Memorial Park.