references:
"Inward Bound", by Abraham Pais, 1986, Clarendon Press
"Marie Curie - A Life", by Susan Quinn, 1995, Simon and Schuster

In 1906 when Rutherford was at McGill University he had been trying to measure the deflection of alpha particles in magnetic fields. In the course of these studies he noticed that alpha particles passing through thin sheets of mica would occasionally experience slight deflections from their straight line trajectories.

In Manchester, England, Rutherford and Hans Geiger were able to count alpha particles by letting them strike a zinc sulfide screen, which emitted a tiny scintillation of light at the point of impact. Geiger and Ernest Marsden, a young research assistant, used the zinc sulfide scintillator to investigate how the alpha particles were deflected by various materials. This was painstaking work. They had to let their eyes adjust to the darkness to see the scintillations, and then count the scattered alpha particles manually. In the course of their work they, at first, thought that there were stray alpha particles along with those actually passing through the sheets of material. Rutherford suggested that they try to determine if these were really alpha particles from their source which were being scattered through large angles, or even backwards, from the materials.
Data were collected in early 1909. By December 1910 it seems Rutherford had already made a model capable of explaining the data. On March 7, 1911 at the Manchester Literary and Philosophical Society meeting Rutherford proposed the nuclear model of the atom. Although J. Perrin had suggested a solar system model for the atoms in 1901, this model of Rutherford was the first able to explain the results of the alpha scattering experiments.

These experiments were pivotal. They served as prototypes for future investigations of the atomic nucleus and of elementary particles. Rutherford's analysis of the number of scattered alpha particles as a function of scattering angle showed that the atom consists of a tiny, very dense, core of positive charge. Based on elementary kinematics it is clear that alpha particles could only bounce back if they struck an object whose mass was greater than their own. Since the atom is electrically neutral the natural position of the electrons would be in orbits about the nucleus held in place by the electric force.

It is surprising in retrospect that Rutherford's atomic nucleus model drew so little interest at first. At the Solvay Conference in 1913 it seems that besides Rutherford himself, Marie Curie was the only person who paid any attention to the atomic nucleus hypothesis. J. J. Thompson presented a paper at the Solvay Conference and did not mention Rutherford's work, or that of Neils Bohr. Bohr made the first attempt in 1913 at extending quantum mechanics to atomic structure and he had to use the Rutherford nuclear model to explain the hydrogen atom's spectral lines. marie Curie referred to Rutherford's work on the atomic nuclear model during the conference and also in subsequent publications.