D.Ivanenko’s proton-neutron model of atomic nuclei of 1932

In 1932, Soviet physicist Dmitri Ivanenko proposed the proton-neutron model of atomic nuclei. One usually refers to Ivanenko's short letter [1] of April 21, 1932 in Nature, which was quoted by W. Heisenberg in his first work on the model of nuclei submitted to Zs. f. Phys on June 7, 1932 [7].

However, Ivanenko published five works on his model in 1932 [1-5].

In the above-mentioned first one, he proposed that atomic nuclei consist of alpha-particles and neutrons, and assumed the existence of beta-electrons in nuclei as constituents of these alpha-particles and neutrons. In the second and third works [2,3], Ivanenko stated that atomic nuclei contain only protons and neutrons, but electrons are created under beta-decay in accordance with the Ambarzumian - Ivanenko  hypothesis of creation of massive particles of 1930 [6].

In the next articles [4,5], D. Ivanenko and E. Gapon proposed the idea of the shell distribution of protons and neutrons in nuclei.

References:

[1]  Iwanenko D., The neutron hypothesis, Nature, 129, N 3265 (1932) 798.

[2] Iwanenko D., Neutronen und kernelektronen, Physikalische Zeitschrift der Sowjetunion 1 (1932) 820-822.

[3]  Iwanenko D., Sur la constitution des noyaux atomiques, Compt. Rend. Acad Sci. Paris, 195 (1932).439-441.

[4]  Gapon E., Iwanenko D., Zur Bestimmung der isotopenzahl, Die Naturwissenschaften 20 (1932) 792-793.

[5] Gapon E., Iwanenko D., Zur Bestimmung der isotopenzahl, Physikalische Zeitschrift der Sowjetunion 2 (1932) 99-100.

[6] Ambarzumian V., Iwanenko D., Les électrons inobservables et les rayons, Compt. Rend. Acad Sci. Paris 190 (1930) 582.

[7] Heisenberg W., Uber den Bau der Atomkerner I, Zeitschrift für Physik A  77 (1932) 1-11.