This thesis describes the experimental work that finally led to a successful measurement of coherent elastic neutrino-nucleus scattering—a process proposed forty-three years ago. The experiment was performed at the Spallation Neutron Source facility, sited at Oak Ridge National Laboratory, in Tennessee. Of all known particles, neutrinos distinguish themselves for being the hardest to detect, typically requiring large multi-ton devices for the job. The process measured here involves the difficult detection of very weak signals arising from nuclear recoils (tiny neutrino-induced “kicks” to atomic nuclei), but leads to a much larger probability of neutrino interaction when compared to all other known mechanisms. As a result of this, “neutrino technologies” using miniaturized detectors (the author's was handheld and weighed only 14 kg) become a possibility. A large community of researchers plans to continue studying this process, facilitating an exploration of fundamental neutrino properties that is presently beyond the sensitivity of other methods.

The nucleon optical model is widely used to calculate the elastic scattering cross-sections and polarisations for the interaction of neutrons and protons with atomic nuclei. The optical model potentials not only describe the scattering but also provide the wave functions needed to analyse a wide range of nuclear reactions. They also unify many aspects of nuclear reactions and nuclear structure. This book consists of a comprehensive introduction to the subject and a selection of papers by the author describing the optical model in detail. It contains full references to the original literature with many examples of the application of the model to the analysis of experimental data.

An invaluable, up-to-date reference aid for investigators and researchers, this two-volume work develops the principles and concepts of statistical physics and quantum chemistry that are the basis for the interpretation of experimental data. These volumes build on the author's now standard text, Theory of Neutron Scattering (Oxford University Press, 1971), and include expanded coverage of nuclear scattering, with many sections completely rewritten and updated, and many previously unpublished experimental calculations. With a greatly expanded bibliography including 200 new references, this work will interest graduate students and researchers in physics.