Irene Joliot-curie | Encyclopedia.com
Joliot-Curie, Irène
(b. Paris, France, 12 September 1897; d. Paris, 17 March 1956)
radioactivity, nuclear physics.
Iréne Joliot-Curie’s fame stems principally from the discoveries she made with her husband, Frédéric Joliot, particularly that of artificial radioactivity, for which they shared the Nobel Prize in chemistry in 1935. Yet her own investigations on the radioelements produced by the irradiation of uranium with neutrons were sufficiently important to secure her a position among the great modern scientists.
Her father, Pierre Curie, married the brilliant Polish student Marie Sklodowska in July 1895. Their marriage marked the beginning of a close collabortion between two dedicated scientific researchers which culminated in the discovery of radium hardly more than a year after the birth of Irène, their first child. Marie Curie’s devotion to her laboratory work left her little time to spend with her daughter. Young Irène would have had scarcely any company other than her governesses had not her grandfather, Eugène Curie, come to live with Pierre and Marie Curie in 1898. Eugène Curie, a doctor, had distinguished himself by treating the wounded during the uprising in Paris of June 1848 and of the Commune of 1871. Until his death in 1910 he exerted a great influence on Irène’s personality, especially after her father’s death in 1906. It was to her grandfather, a convinced freethinker, that Irène owed her atheism, later politically expressed as anticlericalism. He was also the source of her attachment to the liberal socialism to which she remained faithful all her life.
Marie Curie did, however, very take charge of Irène scientific education. Irène did not attend school until the age of twelve, but for the two preceding years she studied at the teaching cooperative established by some of Marie’s colleagues and friends for their own children: Marie Curie taught physics; Paul Langevin, mathematics; and Jean Perrin, chemistry. Irène next went to the Collège Sévigné; she received her baccalauréat just before the outbreak of World War I. From then until 1920 she studied at the Sorbonne and took the examinations for a licence in physics and mathematics. During the war she served for many months as an army nurse, assisting her mother in setting up apparatus for the radiography of the wounded; at the age of eighteen she had sole responsibility for installing radiographic equipment in an Anglo-Canadian hospital a few miles from the front in Flanders.
In 1918 Iréne Curie became an assistant at the Radium Institute, of which her mother was the director, and in 1921 she began scientific research. Her first important investigation concerned the fluctuations in the range of αrays. She determined these variations by photographing the tracks that the rays formed in a Wilson cloud chamber. Presented in her doctoral thesis in 1925, this work was followed by a series of studies on classical radioactivity, some of which were in collaboration with Freédéric Joliot, whom she had married on 26 October 1926. Not until 1931, however, did they begin the constant collaboration, lasting several years, that brought them the Nobel Prize. It is worth noting that for their Nobel addresses Freédéric, considered to be the physicist, chose to deal with the chemical identification of the artificially created radioisotopes, while Iréne, the Chemist, recounted the discovery of a new type of radioactivity, the positive π decay. Marie Curie had died of acute leukemia in July 1934 and thus could not witness the triumph of her daughter and son-in-law, which duplicated her own accomplishment with Pierre Curie thirty-two years earlier.
Honors did not change Irène Joliot-Curie, who retained throughout her life a great simplicity and a thorough uprightness. Her pensive attitude made her appear somewhat slow and aloof, but she could be quite lively with her few close friends. She loved to be close to nature and enjoyed rowing, sailing, and especially swimming during vacations in Brittany. She was also fond of taking long walks in the mountains, where she was often obliged to go because of a tubercular condition. Although her interest in science was preeminent, she deeply loved the writings of certain French and English authors, especially Victor Hugo and Rudyard Kipling; she even translated some of Kipling’s poems. She found great joy in motherhood and, despite the hours spent in the laboratory, devoted much time to her children until their adolescence. Both Heélène and Pierre became brilliant researchers:the former, like her mother and grandmother, in nuclear physics; the latter, in biophysics.
After serving for four months in 1936 as secretary of state in Léon Blum’s Popular Front government, Irène Joliot-Curie was elected professor at the Sorbonne in 1937. She continued to work at the Radium Institute, while Freèdeèric Joliot transferred his research activities to the Colleége de France, where he had received a professorship.
It was during these years preceding World War II that Iréne Joliot-Curie did her most remarkable individual work. Aided by her great experience in radiochemistry, she sought to analyze the complex phenomena that result from bombarding uranium with neutrons. First brought to light by Enrico Fermi, these phenomena were subsequently studied by Otto Hahn and Lise Meitner, who demonstrated that in uranium submitted to a neutron flux there appear a rather large number of π radioactivities, displaying different periods associated with diverse chemical properties. This discovery led them to suppose the formation not only of several transuranic radioelements but also of new radioisotopes of elements preceding uranium (down to radium itself). Iréne Joliot-Curie, in collaboration with the Yugoslav physicist P. P. Savic, showed that, among the radioisotopes formed, a radioelement with a period of 3.5 hoursa could be carried away by adding actinium to the solution of irradiated uranium and then separating it out again through precipitation. But this radioelement was not an isotope of actinium, since by adding lanthanum to the actinium extract and then separating it out again though fractional precipitations, the new radioelement was shown to follow lanthanum, its chemical properties therefore being closer to those of lanthanum than to those of actinium.
Reproducing these experiments, the result of which he found surprising, Otto Hahn proved that the bombardment of uranium with neutrons produces not only radioactive atoms possessing chemical properties very similar to those of the lanthanides but also, undoubtedly, atoms of a radioactive isotope of barium. This was the proof that a neutron can induce the bipartition of a uranium atom into two atoms of a comparable mass—a phenomenon soon afterward termed “fission” Irène Joliot-Curie had instigated this important discovery—which she herself would probably have made had a fortuitous complication not concealed the formation of a true radioisotope of lanthanum in the uranium irradiated by neutrons. The former existed in association with a radioisotope of promethium with a similar period, which explains why the fractional precipitation of the lanthanum separated from the actinium results in the appearance in the top fractions of an increase in the 3.5-hour activity period.
At the time of the German invasion in 1940 Iréne Joliot-Curie decided to remain in France with the researchers in her laboratory. In 1944, a few months before the liberation of Paris, the Communist resistance organization, fearing that she might suffer reprisals for the resistance activities of her husband, who had gone underground, had her smuggled into Switzerland with her children. In 1946 she was named director of the Radium Institute, created for her mother some thirty years before, in which she conducted all her own research. From 1946 to 1950 she was also one of the directors of the French Atomic Energy Commission, of which Frédéric Joliot was the high commissioner.
Irène Joliot-Curie divided her efforts in the following years between the creation of the Radium Institute’s large, new laboratories at Orsay, a southern suburb of Paris, and working for women’s pacifist movements. She died at the age of fifty-eight, a victim, like her mother, of acute leukemia. The disease was undoubtedly a consequence of the X and γ radiations to which she had been exposed, first as an inadequately protected nurse-radiologist during World War I and then in the laboratory, when the dangers of radioactivity were still not fully realized.
BIBLIOGRAPHY
See Frédéric and Iréne Joliot-Curie, Oeuvres scientifiques complÈtes (Paris, 1961). Irène Joliot-Curie’s publications in collaboration with her husband are listed in the preceding article “Frédéric Joliot-Curie.” Her principal scientific publications include “Sur le poids atomique du chlore dans quelques minéraux,” in Comptes rendus hebdomadaires des séances de l‘ Académie des sciences, 172 (1921), 1025; “Sur la vitesse d‘émission des rayons α du polonium,” ibid., 175 (1922), 220; “Sur la distribution de longueur des rayons α,” in Journal de physique et le radium, 4 (1923), 170; “Sur le rayonnement γ du radium D et du radium E,” in Comptes rendus, 176 (1923), 1301; “Sur la constante radioactive du radon,” in Journal de physique et le radium, 5 (1924), 238, written with C. Chamié; “Sur la distribution de longueur des rayons α du polonium dans l‘oxygéne et dans l’azote,” in Comptes rendus, 179 (1924), 761, written with N. Yamada; “Sur l’homogénéité des vitesses initiales des rayons α du polonium,” ibid., 180 (1925), 831; “Recherches sur les rayons α du polonium. Oscillation de Parcours, vitesse d’émission, pouvoir ionisant,” in Annales de physique, 2 (1925), 403, diss.; “Sur les particules de long parcours émises par le polonium,” in Journal de physique et le radium, 6 (1925), 376, written with N. Yamada; “Sur le spectre magnétique des rayons α du radium E,” in Comptes rendus, 181 (1925), 31; “Extraction et purification du dépôt actif à évolution lente du radium,” in Journal de physique et le radium, 22 (1925), 471; “étude de la courbe de Bragg relative aux rayons du radium C’,” ibid., 7 (1926), 125, written with F. Béhounck; “Sur la distribution de longueur des rayons α du radium C et du radium A,” ibid., 289, written with F. Béhounck; “Sur l’oscillation de parcours des rayons α dans l’air,” ibid., 8 (1927), 25; Sla mesure du dépôt actif du radium par le rayonnement γ pénétrant,” in Comptes rendus, 188 (1929), 64; “Sur la quantité de polonium accumulée dans d’anciennes ampoules de radon et sur la période du radium D,” in Journal de physique et le radium, 10 (1929), 388; “Sur la décroissance du radium D,” ibid., 385, written with MarieCurie; “Sur la complexité du rayonnement α du radioactinium,” in Comptes rendus, 192 (1931), 1102; “Sur un nouveau composé gazeux du polonium,” ibid., 1453, written with M. Lecoin; and “Sur le rayonnement γ nucléaire excité dans le glucinium et dans le lithium par leas rayons α du polonium,” ibid., 193 (1931), 1412.
See also “Sur le rayonnement α du radioactinium, du radiothorium et de leurs dérivés. Complexité du rayonnement α du radioactinium,” in Journal de physique et le radium, 3 (1932), 52; “Sur la création artificielle d’éléments appartenant à une famille radioactive inconnue, lors de l’irradiation du thorium par les neutrons,” ibid., 6 (1935) 361, written with H. Von Halban and P. Preiswerk; “Remarquessur la stabilité nucléaire dans le domaine des radioéléments naturels,” ibid., 417; “Sur les radioélément de périod par l’uranium irradié par les neutrons,” ibid., 8 (1937), 385, written with P. Savic; “Sur le radioéléments pélriod 3, 5 h. forme dans l’uranium irradioe par les neutrons,” in Comptes rendus, 206 (1938), 1643, written with P. Savic; “Sur les radioéléments formés dans l’uranium irradié par les neutrons, II,” in Journal de physique et le radium, 9 (1938), 355, written with P. Savic; “Sur le rayonnement du corps de période 3, 5 h. formé par irradiation de l’uranium par les neutrons,” ibid., 440, written with P. Savic and A. Marqués da Silva; “Sur les radioéléments formés dans l’uranium et le thorium irradiés par les neutron,” in Computes rendus, 208 (1939), 343, written with P. Savic; “Comparaison des isotopes radioactifs des terres rares formés dans l’uranium at le theorium,” in Journal de physique et le radium, 10 (1939), 495, written with Tsien San-tsiang; “Détermination de la période de l’actinium,” in Cahiers de physique, nos 25 - 26 (1944), 25-67, written with G. BouissiÈres; “Parcours des rayons α de l’ionium,” in Journal de physique et le radium, 6 (1945), 162, written with Tsien San-tsiang; “Détermination empirique du nombre atomique Z, correspondant au maximum de stabilité des atomes de nombre de masse A,” ibid., 209; “Sur la possibilité d’étudier l’activite desa roches par l’observation des trajectoires des rayons alpha dans l’émulsion photographique,” ibid., 7 (1946), 313; Les radioéléments naturels. Propriétés chimiques. Préparation. Dosage (Paris, 1946); “Sur le rayonnement gamma de l’ionium,” in Journal de physique et le radium, 10 (1949), 381; “Autoradiographie par neutrons. Dosage séparé de l’uranium et du thorium,” in Comptes rendus, 232 (1951), 959, written with H. Faraggi; “Sélection et dosage du carbone dans l’acier par l’emploi de la radioactivité artificielle,” in Journal de physique et le radium, 13 (1952), 33, also in Bulletin. Société chimique de France, 20 (1954), 94; “Détermination de la proportion de mésothorium, radium, radiothorium dans une ampoule de mésothorium commercial,” in Journal de physique et le radium, 15 (1954), 1;and “Sur une nouvelle méthode pour la comparaison précise du rayonnement des ampouiles de radium,” ibid., 790.
Details on the biography of Irène Joliot-Curie can be found in Eugénie Cotton, Les Curie (Paris, 1963)
Francis Perrin