[1] She was an international leader in photonuclear physics using beams of electrons, positrons and neutrons from high-energy accelerators to probe nuclear structure.
Over a period of over 5 decades her research interests included precision measurements of photo-neutron production cross sections; studies of the scattering and absorption of photons by deformed nuclei; the study of the nuclear photo-effect in oriented nuclei; and measurements of electron spectra and (e,p) and (e,α) reactions.
Evans' thesis research was on the ionization produced by high-energy cosmic-ray electrons with a cloud chamber in order to determine whether the probable ionization produced by a high velocity particle continues to rise logarithmically with energy.
At Berkeley she met her future husband Raymond Hayward and in 1950 they were both recruited to the National Bureau of Standards (NBS).
When NBS moved from Washington DC to Gaithersburg, MD and the 150 MeV linac became available, she could do more difficult experiments since the electron beam current was much more intense.
[6] They made measurements to determine the albedo of 1-MeV photons reflected from semi-infinite slabs of water, aluminum, copper, tin, and lead at various angles of incidence.
Particularly elegant was the theory of Arenhoevel and Hayward on scattering of plane-polarized photons by the giant resonances of nuclei.
The equally elegant experimental application of this theory was described in an article by Hayward, Barber, and Sazama in which “a beam of plane-polarized monochromatic photons” from a carbon target in a linac bremsstrahlung beam was “produced by the resonance fluorescence of the well-known 1+ state at 15.1 MeV in 12C.
These photons were scattered a second time from natural targets of Cd, Sn, Ta, W, Pt, Au, and Bi”.
Her collaboration with Wolynec, Martins and Dodge for photo- and electronuclear reactions led to publications that are well-known throughout the world.
She was selected by President Richard Nixon to serve on the General Advisory Committee to the Atomic Energy Commission.
After she was fully retired, she started taking evening classes at American University in areas such as politics and international relations, Spanish and Italian.
Her colleagues from around the world have expressed their condolences and their appreciation for the support and encouragement Evans offered for their research.