CURIE, IRÈNE & F. JOLIOT (AND P. SAVEL). - "THE NEUTRON IDENTIFIED"

Émission de protons de grande vitesse par la substances hydrogénées sous l'influence des rayons gamma très pénétrants. (+) Effet d'absorption de rayons gamma de très haute fréquence par projection de noyaux légers. (+) Projections d'atomes par rayons très pénétrants excités dans les noyaux légers. (+) Sur la nature du rayonnement pénétrant excité dans les noyaux légers par les particules alpha. (+ together with P. Savel) Quelques expériences sur les rayonnements excités par les rayons alpha dans les corps légers. (+) La complexité du proton et la masse du neutron. (In all 6 papers).

Paris, Gauthier-Villars, 1932-33. 4to. No wrappers. In: "Comptes Rendus Hebdomadaires des Séances de L'Academie des Sciences", Tome 194 and tome 197. - Tome 194: Nos 3,8,10,15 a. 25. - Tome 197: No 3. (6 entire issues offered). With titlepages to both volumes. The papers: pp. 273-275, 708-711, 876-877 a. 1 plate, 1229-1232, 2208-2211 a. 237-38 (tome 197). The issue no 25: pp. 2181-2248 lacks the first leaf, no affecting the paper. Titlepages with a faint stamp.

First printing of these papers of seminal importance to the evolution of particle physics - the results of these investigations immediately lead the way to the discovery of the neutron.
They found that the 'Beryllium radiation', discovered by Bothe and Becker, ejected protons from a paraffin target. This discovery was amazing because photons have no mass. However, the Joliot-Curies interpreted the results as the action of photons on the hydrogen atoms in paraffin. They used the analogy of the Compton Effect, in which photons impinging on a metal surface eject electrons. The trouble was that the electron was 1,836 times lighter than the proton and, therefore, recoiled much more easily than the heavier proton after a collision with a gamma photon. When James Chadwick reported to Lord Rutherford on the Joliot-Curies’ results, Lord Rutherford exclaimed, "I do not believe it!" Chadwick immediately repeated the experiments at the Cavendish Laboratory in Cambridge, England. He not only bombarded the hydrogen atoms in paraffin with the beryllium emissions, but also used helium, nitrogen, and other elements as targets. By comparing the energies of recoiling charged particles from different targets, he proved that the beryllium emissions contained a neutral component with a mass approximately equal to that of the proton. He called it the neutron.

Order-nr.: 49447