Marie & Pierre Curie's granddaughter, Hélène Langevin-Joliot, visits the United States
Hélène Langevin-Joliot comes from a family of distinguished scientists. Her grandparents won the Nobel Prize for physics in 1903 and her parents won a Nobel Prize for chemistry in 1935. Her grandmother won a second Nobel Prize for chemistry in 1911.
Note: Hélène Langevin-Joliot comes from a remarkable family of distinguished scientists. Her grandparents, Marie and Pierre Curie, won the Nobel Prize for physics with Henri Becquerel in 1903, for the discovery of radium. Marie Curie won a second Nobel Prize, for chemistry, in 1911. And Langevin-Joliot's parents, Irène and Frédéric Joliot-Curie, won a Nobel Prize for chemistry in 1935, for their discovery of artificial radioactivity.
Langevin-Joliot is a respected nuclear physicist from the Institute of Nuclear Physics at Orsay, the laboratory set up by her parents. JLab science writer, Melanie O'Byrne, spoke with Langevin-Joliot during the recent International Symposium for Spinal Radiography at Georgetown University An excerpt of the interview follows.
What do you do when you're not traveling around the world, speaking about your family?
I try to save part of my time for research. My fields of interest are exotic nuclei and highly excited hole states in medium and heavy nuclei.
I don't travel too much. I generally speak about the Curies and Joliot-Curies in lectures on radioactivity and its applications, on nuclear physics, science, research or women in science, either for the general public or students. Visits to high schools are occasions for meeting kids, telling them stories and answering questions.
I think that improving the public scientific culture is a major challenge of our time. Showing that science is a human adventure, not only equations and techniques, may help.
Important efforts are needed to preserve scientific archives. I am involved in those through my parents' archives.
What sparked your interest in science?
I was a very good student at mathematics and science. I had the feeling that science was something interesting when I heard my parents speaking about it. My mother, especially, gave me the feeling that you didn't need to be a genius to become a researcher. That was very encouraging. I would otherwise have chosen to do something completely different.
You completed your baccalaureate exams toward the end of World War II, in a small village...
My father was a Resistant against German occupation. In spring 1944, he went into hiding in Paris and decided that it was safer for my mother to leave France and try to reach Switzerland with my brother and me. I took my baccalaureate exam on the way. It happened that the exam was over on June 5. On the morning of June 6, we heard about the Allies landing in Normandy and we left to cross the border. It was the best day for this expedition, the Germans having other things in their mind!
Where did you conduct your Ph.D. research?
At the nuclear physics and chemistry lab at the Collège de France. My thesis was on internal Bremsstrahlung and auto-ionization phenomena. I worked alone for some 5 years, preparing the apparatuses, performing the experiments and discussing them with theoreticians. I started as a probationer at the CNRS (France's national scientific research center) and became a permanent researcher even before defending my thesis.
And what did you do next?
I continued working on beta-gamma spectroscopy, parity non-conservation experiments. Then our lab moved to the new nuclear physics Institute at Orsay and I turned to medium-energy nuclear reactions. My mother had discovered the Orsay site; she had obtained government funding for a new lab and ordered a synchrocyclotron. Such a machine could not be built inside Paris at the Radium Institute or the Collège de France. She died in March 1956 before the lab was built. My father spent the remaining two years of his life realizing the program they had decided together.
Are others in your family interested in science, too?
Yes, my husband, Michel Langevin, was a nuclear physicist at the Institute. My son, Yves, is an astrophysicist mainly interested in planetology and asteroids. My brother, Pierre, is a biophysicist working on photosynthesis.
Did Pierre keep the Curie name of your parents?
No, he is Pierre Joliot. Many people used to name my parents Joliot-Curie, but they signed their scientific papers Irène Curie and Frédéric Joliot. My father asked me to sign Langevin-Joliot, not just Langevin, as I would have done otherwise.
What do you remember about Marie Curie?
I do not have a good memory of my childhood, and my parents did not tell me that I had a very famous grandmother! I have some memories of Marie with me in the Luxembourg Garden in Paris. My few direct memories are mixed with photographs, home movies and my parents' memories.
Do you remember your parents winning their Nobel Prize?
It was at a time when we shifted from Paris to the new house my parents built in the suburbs. I can recall them saying they won the Nobel Prize but it did not mean much to me at the time!
Irène and Frédéric observed the neutron but did not know what it was. James Chadwick went on to get the Nobel Prize for that. Later Irène observed what turned out to be fission.
... how did that make your parents feel?
When fission was discovered at the end of 1938, I heard my parents comment, "maybe if we had worked together, we could have discovered fission!" From 1935 on, you see, my father had focused on building accelerators.
The Joliot-Curies were not the first to "observe" neutrons. At the end of 1930, Walther Bothe and Herbert Becker had discovered a mysterious radiation, which penetrated matter much more than usual ones, attributing it to very high-energy gamma rays. Note that physicists were much puzzled by cosmic rays; they did not know of the pair effect and of positrons. In mid-January 1931, my parents discovered that the Bothe and Becker radiation projected out energetic protons from hydrogenous matter. They published the result of this key experiment immediately, suggesting a kind of Compton effect. Their note (in French) was read in Cambridge, England, the next week. After confirming the surprising Paris results, James Chadwick started his decisive experiments to check if the radiation could be that neutral particle (a very tightly bound proton-electron system) suggested by Rutherford several years before. After the discovery at the end of February, the neutron finally turned out not to be the Rutherford particle but that is another story.
Your parents actually saw the first atomic bomb. What were their feelings and reactions?
They were stricken but not surprised with the power of the bomb dropped on Hiroshima and Nagasaki. Then, as with many nuclear physicists, they were eager with the hope of preventing a nuclear arms race. The Cold War, unfortunately, prevented any agreements for years. My parents were very much involved in the Peace Movement and the Stockholm appeal against atomic bombs.
Marie and Pierre Curie met through their research. Irène and Frédéric Joliot met through science. How did you meet your husband [Michel Langevin]?
We met at the School for Physics and Chemistry when we were both students.
Marie Curie and Irène Joliot-Curie were never accepted into the French Academy of Sciences yet Frédéric Joliot was. What do you think of that?
No women, or at most very few, belonged to scientific academies, whatever the countries, in those times. The situation has improved slightly now, but not enough. Marie was not elected when she tried in 1911, and she never tried again because of the vicious attacks she had suffered -- against her work, against women, against a woman of foreign origin. My mother presented her candidature after the Second World War, also without success. She found the situation comical and tried to be elected at every possible occasion, three times, but she died before succeeding. Marguerite Perey, who discovered francium, later became the first woman accepted into the French Academy of Sciences.
What is your advice to young students and physicists?
You need a love of the idea of physics and a love of doing physics -- and they are not the same thing. Try not only to read papers but also to visit labs to see what doing research means in the different fields. It is better not to choose the same thing as everyone else.
If you are becoming a physicist, try to resist the increasing tendency toward aggressive competition among individuals. Research is a very demanding activity, but perhaps the best success may be achieved by a right balance: between your involvement in personal as well as collective research efforts, personal and family life, and your responsibility as a scientist and a citizen in society.
What is your message to the public regarding fear of radiation?
Earth is naturally radioactive; otherwise it would already be a dead planet. We live in a bath of radiation from rocks, gas and space, with some 7000 becquerels (the number of nuclei that decay per second) inside our body. We get enormous benefits from the use of radiation, especially in medicine. Nuclear energy, whose wastes are hugely radioactive, has the advantage of producing no carbon dioxide.
I regret that the necessary efforts to handle nuclear wastes properly have been underestimated for many years. New programs are developing seriously now and I am convinced that safe answers could be found to the problem.