In nuclear science, the decay chain refers to a series of radioactive decays of different radioactive decay products as a sequential series of transformations. It is also known as a "radioactive cascade". Most radioisotopes do not decay directly to a stable state, but rather undergo a series of decays until eventually a stable isotope is reached. Decay stages are referred to by their relationship to previous or subsequent stages. A "parent isotope" is one that undergoes decay to form a "daughter isotope". One example of this is uranium (atomic number 92) decaying into thorium (atomic number 90). The daughter isotope may be stable or it may decay to form a daughter isotope of its own.
Introduction
Decay chain
Decay chain | Introduction
It refers to a series of radioactive decays of different radioactive decay products as a sequential series of transformations - a.k.a. "radioactive cascade". In nuclear science, the decay chain refers to a series of radioactive decays of different radioactive decay products as a sequential series of transformations. A series of radioactive decays of different radioactive decay products as a sequential series of transformations.  Most radioisotopes do not decay directly to a stable state, but rather undergo a series of decays until eventually a stable isotope is reached. It refers to a series of radioactive decays of different radioactive decay products as a sequential series of transformations.
who was lise meitner?
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She was an Austrian-Swedish physicist.
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in which country did she live in her early days?
user
In the Leopoldstadt district of Vienna
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any particular educational institution that she attended as a student?
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University of Vienna
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why did she have to flee from germany?
user
Because she lost her Austrian citizenship.
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why?
user
Sorry. I cannot find the answer based on the context.
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can you mention any of her contributions?
user
She completed the work on beta ray spectrum that she had begun with Hahn and Baeyer, and also her own study of the uranium decay chain.
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could you please elaborate the last reaction?
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This marked Wu's first work with beta decay, a subject on which she would become an authority. The second part of the thesis was about the production of radioactive isotopes of xenon produced by the nuclear fission of uranium with the 37-inch and 60-inch cyclotrons at the Radiation Laboratory.
Chien-Shiung Wu | Berkeley
In her post-war research, Wu continued to investigate beta decay. Enrico Fermi had published his theory of beta decay in 1934, but an experiment by Luis Walter Alvarez had produced results at variance with the theory. Wu set out to repeat the experiment and verify the result. She suspected that the problem was that a thick and uneven film of copper(II) sulfate () was being used as a copper-64 beta ray source, which was causing the emitted electrons to lose energy. To get around this, she adapted an older form of spectrometer, a solenoidal spectrometer. She added detergent to the copper sulphate to produce a thin and even film.
Chien-Shiung Wu | Beta decay and the conservation of parity
The first two reactions that the Berlin group had observed were light elements created by the breakup of uranium nuclei; the third, the 23-minute one, was a decay into the real element 93. On returning to Copenhagen, Frisch informed Bohr, who slapped his forehead and exclaimed "What idiots we have been!" Bohr promised not to say anything until they had a paper ready for publication. To speed the process, they decided to submit a one-page note to "Nature". At this point, the only evidence that they had was the barium. Logically, if barium was formed, the other element must be krypton, although Hahn mistakenly believed that the atomic masses had to add up to 239 rather than the atomic numbers adding up to 92, and thought it was masurium (technetium), and so did not check for it: Over a series of long-distance phone calls, Meitner and Frisch came up with a simple experiment to bolster their claim: to measure the recoil of the fission fragments, using a Geiger counter with the threshold set above that of the alpha particles.
Lise Meitner | Nuclear fission
The French scientists moved to Cambridge, where they conducted experiments that conclusively showed that a nuclear chain reaction could be produced in a mixture of uranium oxide and heavy water. In a paper written shortly after they arrived in England, Halban and Kowarski theorised that slow neutrons could be absorbed by uranium-238, forming uranium-239. A letter by Edwin McMillan and Philip Abelson published in the "Physical Review" on 15 June 1940 stated that this decayed to an element with an atomic number of 93, and then to one with an atomic number of 94 and mass of 239, which, while still radioactive, was fairly long-lived.
MAUD Committee | University of Cambridge
Meitner received the letter from Hahn describing his chemical proof that some of the product of the bombardment of uranium with neutrons was barium. Barium had an atomic mass 40% less than uranium, and no previously known methods of radioactive decay could account for such a large difference in the mass of the nucleus. Nonetheless, she had immediately written back to Hahn to say: "At the moment the assumption of such a thoroughgoing breakup seems very difficult to me, but in nuclear physics we have experienced so many surprises, that one cannot unconditionally say: 'It is impossible.'" Meitner felt that Hahn was too careful a chemist to make an elementary blunder, but found the results difficult to explain.
Discovery of nuclear fission | Eureka!
Fanny Cook Gates (26 April 1872 – 24 February 1931) was an American physicist, an American Physical Society fellow and American Mathematical Society member. She made contributions to the research of radioactive materials, determining that radioactivity could not be destroyed by heat or ionization due to chemical reactions, and that radioactive materials differ from phosphorescent materials both qualitatively and quantitatively. More specifically, Gates showed that the emission of blue light from quinine was temperature dependent, providing evidence that the emitted light is produced from phosphorescence rather than radioactive decay. She also served as head of the Physics department at Goucher, Professor of Physics and Dean of Women at Grinnell College, and the Dean of Women at the University of Illinois.
Fanny Gates | Introduction
Then there was the third reaction, an (n, γ) one, which occurred only with slow neutrons. Meitner therefore ended her report on a very different note to Hahn, reporting that: "The process must be neutron capture by uranium-238, which leads to three isomeric nuclei of uranium-239. This result is very difficult to reconcile with current concepts of the nucleus." After this, the Berlin group moved on to working with thorium, as Strassmann put it, "to recover from, the horror of the work with uranium". However, thorium was not easier to work with than uranium. For a start, it had a decay product, radiothorium () that overwhelmed weaker neutron-induced activity.
Discovery of nuclear fission | Research
The same attitude carried over to Noddack, who did not propose an alternative nuclear model, nor conduct experiments to support her claim. Although Noddack was a renowned analytical chemist, she lacked the background in physics to appreciate the enormity of what she was proposing. Noddack was not the only critic of Fermi's claim. Aristid von Grosse suggested that what Fermi had found was an isotope of protactinium. Meitner was eager to investigate Fermi's results, but she recognised that a highly skilled chemist was required, and she wanted the best one she knew: Hahn, although they had not collaborated for many years.
Discovery of nuclear fission | Objections
In 1942, Wheeler recruited Way to work on the Manhattan Project at the Metallurgical Laboratory in Chicago. Working with physicist Alvin Weinberg, Way analyzed neutron flux data from Enrico Fermi's early nuclear reactor designs to see whether it would be possible to create a self-sustaining nuclear chain reaction. These calculations were put to use in the construction of Chicago Pile-1. Afterwards, she examined the problem of nuclear poisoning of reactors by certain fission products. With physicist Eugene Wigner she developed the Way-Wigner approximation for fission product decay. Way also visited the Hanford Site and the Los Alamos Laboratory. In mid-1945 she moved to Oak Ridge, Tennessee, where she continued her research into nuclear decay.
Katharine Way | Manhattan Project
Meitner received the letter from Hahn describing his chemical proof that some of the product of the bombardment of uranium with neutrons was barium. Barium had an atomic mass 40% less than uranium, and no previously known methods of radioactive decay could account for such a large difference in the mass of the nucleus. Nonetheless, she had immediately written back to Hahn to say: "At the moment the assumption of such a thoroughgoing breakup seems very difficult to me, but in nuclear physics we have experienced so many surprises, that one cannot unconditionally say: 'It is impossible.'" According to Frisch: Meitner and Frisch had correctly interpreted Hahn's results to mean that the nucleus of uranium had split roughly in half.
Lise Meitner | Nuclear fission
On 19 December, Hahn wrote to Meitner, informing her that the radium isotopes behaved chemically like barium. Anxious to finish up before the Christmas break, Hahn and Strassmann submitted their findings to "Naturwissenschaften" on 22 December without waiting for Meitner to reply. Hahn concluded with: "As chemists... we should substitute the symbols Ba, La, Ce for Ra, Ac, Th. As 'nuclear chemists' fairly close to physics we cannot yet bring ourselves to take this step which contradicts all previous experience in physics." Frisch normally celebrated Christmas with Meitner in Berlin, but in 1938 she accepted an invitation from Eva von Bahr to spend it with her family at Kungälv, and Meitner asked Frisch to join her there.
Discovery of nuclear fission | Eureka!
Frisch also experimentally verified the fission reaction by means of a cloud chamber, confirming the energy release. Therefore, Noddack's original hypothesis was finally accepted.
Ida Noddack | Nuclear fission
Anxious to finish up before the Christmas break, Hahn and Strassmann submitted their findings to "Naturwissenschaften" on 22 December without waiting for Meitner to reply. Hahn concluded the paper with: "As chemists... we should substitute the symbols Ba, La, Ce for Ra, Ac, Th. As 'nuclear chemists' fairly close to physics we cannot yet bring ourselves to take this step which contradicts all previous experience in physics." Frisch normally celebrated Christmas with Meitner in Berlin, but in 1938 she accepted an invitation from Eva von Bahr to spend it with her family at Kungälv, and Meitner asked Frisch to join her there.
Lise Meitner | Nuclear fission
After graduating from University College London, Lieber became a doctoral student at the Kaiser-Wilhelm Institute in 1936. She studied barium and strontium extensively, discovered several isotopes of both elements, and used radiochemistry to investigate barium and strontium dehydration reactions. She also discovered that uranium could decay into strontium and xenon. With Otto Hahn and Fritz Strassmann, she conducted research that led to the discovery of fission and fission products. In 1939, she returned to the United States without a Ph.D. She became married after the war and served on the Committee for the Resettlement of Japanese-Americans. She was a member of Phi Beta Kappa.
Clara Lieber | Career and research
She considered the possibility that the reactions were from different isotopes of uranium; three were known: uranium-238, uranium-235 and uranium-234. However, when she calculated the neutron cross section, it was too large to be anything other than the most abundant isotope, uranium-238. She concluded that it must be another case of the nuclear isomerism that Hahn had discovered in protactinium. She therefore ended her report on a very different note to Hahn, reporting that: "The process must be neutron capture by uranium-238, which leads to three isomeric nuclei of uranium-239. This result is very difficult to reconcile with current concepts of the nucleus."
Otto Hahn | Discovery of nuclear fission
He finished his doctoral thesis in 1913, and by 1914 he was considered by Rutherford as a leading researcher into beta decay, but he did no further work. He enlisted in the French army in 1914 and was killed in action near Cormicy.
Jan Kazimierz Danysz | Introduction
During the question and answer period, she offered her opinions on the Fukushima Daiichi disaster: “Today we need nuclear power, and the challenge is to make it safe.”
Neutron trail | Public events
All four chains started with an alpha decay to Db; three chains ended there with spontaneous fission, as in the 113 chains observed at Riken, while the remaining one continued via another alpha decay to Lr, as in the Bh chains observed at LBNL.
Nihonium | 2004–2008
She lost these positions in the 1930s because of the anti-Jewish Nuremberg Laws of Nazi Germany, and in 1938 she fled to Sweden, where she lived for many years, ultimately becoming a Swedish citizen. In mid-1938, Meitner with chemists Otto Hahn and Fritz Strassmann at the Kaiser Wilhelm Institute found that bombarding thorium with neutrons produced different isotopes. Hahn and Strassmann later in the year showed that isotopes of barium could be formed by bombardment of uranium. In late December, Meitner and Frisch worked out the phenomenon of such splitting process. In their report in February issue of "Nature" in 1939, they gave the name "fission".
Lise Meitner | Introduction
She considered the possibility that the reactions were from different isotopes of uranium; three were known: uranium-238, uranium-235 and uranium-234. However, when she calculated the neutron cross section it was too large to be anything other than the most abundant isotope, uranium-238. She concluded that it must be a case of nuclear isomerism, which had been discovered in protactinium by Hahn in 1922. Nuclear isomerism had been given a physical explanation by von Weizsäcker, who had been Meitner's assistant in 1936, but had since taken a position at the Kaiser Wilhelm Institute for Physics. Different nuclear isomers of protactinium had different half-lives, and this could be the case for uranium too, but if so it was somehow being inherited by the daughter and granddaughter products, which seemed to be stretching the argument to breaking point.
Discovery of nuclear fission | Research
Over Christmas 1938, Meitner considered the problem of the uranium nucleus, which she reasoned, given its relative size, must be quite unstable. She decided to model the nucleus as a drop of water, ready to divide with the impact of a single neutron. She realised the nucleus had split in half, and both Fermi and Hahn had witnessed what is now known as nuclear fission. However, in doing the calculations for such an event, Meitner was unable to make the equations balance. She calculated that the products of the fission reaction were lighter than the initial uranium, by about one fifth of a proton.
Chemistry: A Volatile History | Lise Meitner explains Fermi's work
Sherr became an assistant professor of physics at Princeton University in 1946, an associate professor in 1949, and a full professor in 1955. In 1953, he provided experimental evidence of Fermi's interaction, a theoretical explanation for the beta decay phenomenon. Between 1955 and 1971, he headed an Atomic Energy Commission-contracted nuclear research project, and oversaw the development of Princeton's AVF cyclotron in 1970. Sherr retired from Princeton in 1982, but remained active in the research community for the rest of his life. He published over 100 articles in scientific journals during his career.
Rubby Sherr | Academic career
The German chemist Ida Noddack notably suggested in print in 1934 that instead of creating a new, heavier element 93, that "it is conceivable that the nucleus breaks up into several large fragments." However, Noddack's conclusion was not pursued at the time. After the Fermi publication, Otto Hahn, Lise Meitner, and Fritz Strassmann began performing similar experiments in Berlin. Meitner, an Austrian Jew, lost her Austrian citizenship with the "Anschluss", the union of Austria with Germany in March 1938, but she fled in July 1938 to Sweden and started a correspondence by mail with Hahn in Berlin. By coincidence, her nephew Otto Robert Frisch, also a refugee, was also in Sweden when Meitner received a letter from Hahn dated 19 December describing his chemical proof that some of the product of the bombardment of uranium with neutrons was barium.
Nuclear fission | Discovery of nuclear fission
But he did not consider the reaction of two nuclei (Branch I) which we now know to be important. This was part of the body of work in stellar nucleosynthesis for which Bethe won the Nobel Prize in Physics in 1967.
Proton–proton chain reaction | History of the theory
As head of the physics section at the Kaiser Wilhelm Institute in Berlin she collaborated closely with the head of chemistry Otto Hahn on atomic physics until forced to flee Berlin in 1938. In 1939, in collaboration with her nephew Otto Frisch, Meitner derived the theoretical explanation for an experiment performed by Hahn and Fritz Strassman in Berlin, thereby demonstrating the occurrence of nuclear fission. The possibility that Fermi's bombardment of uranium with neutrons in 1934 had instead produced fission by breaking up the nucleus into lighter elements, had actually first been raised in print in 1934, by chemist Ida Noddack (co-discover of the element rhenium), but this suggestion had been ignored at the time, as no group made a concerted effort to find any of these light radioactive fission products.
Women in science | Europe before World War II
She completed her PhD in 1978 on "Coupled Channel Alpha Decay Theory for Even and Odd-Mass Light and Heavy Nuclei." She later held positions as professor of physics and general science at John F. Kennedy University, 1978–1984; research consultant to NASA, 1983–1985; and professor and graduate student adviser in the department of physics at the University of Nevada, Reno, 1990–1998.
Elizabeth Rauscher | Education and career
Meitner, and her nephew Otto Robert Frisch, correctly interpreted these results as being nuclear fission. Frisch confirmed this experimentally on 13 January 1939. Paul Harteck was director of the physical chemistry department at the University of Hamburg and an advisor to the "Heereswaffenamt" (HWA, Army Ordnance Office). On 24 April 1939, along with his teaching assistant Wilhelm Groth, Harteck made contact with the "Reichskriegsministerium" (RKM, Reich Ministry of War) to alert them to the potential of military applications of nuclear chain reactions. Two days earlier, on 22 April 1939, after hearing a colloquium paper by Wilhelm Hanle on the use of uranium fission in a "Uranmaschine" (uranium machine, i.e., nuclear reactor), Georg Joos, along with Hanle, notified Wilhelm Dames, at the "Reichserziehungsministerium" (REM, Reich Ministry of Education), of potential military applications of nuclear energy.
Gerhard Hoffmann | Career
But I believe that Frisch and I contributed something not insignificant to the clarification of the process of uranium fission—how it originates and that it produces so much energy and that was something very remote to Hahn." Hahn's receipt of a Nobel Prize was long expected. Both he and Meitner had been nominated for both the chemistry and the physics prizes several times even before the discovery of nuclear fission. According to the Nobel Prize archive, she was nominated 19 times for Nobel Prize in Chemistry between 1924 and 1948, and 29 times for Nobel Prize in Physics between 1937 and 1965.
Lise Meitner | Nobel Prize for nuclear fission
Yuan then applied for, and secured, a scholarship at Caltech. Wu made rapid progress in her education and her research. Although Lawrence was officially her supervisor, she also worked closely with Emilio Segrè. Her thesis had two separate parts. The first was on bremsstrahlung, the electromagnetic radiation produced by the deceleration of a charged particle when deflected by another charged particle, typically an electron by an atomic nucleus. She investigated this using beta-emitting phosphorus-32, a radioactive isotope easily produced in the cyclotron that Lawrence and his brother John H. Lawrence were evaluating for use in cancer treatment and as a radioactive tracer.
Chien-Shiung Wu | Berkeley
Her work with spontaneous nuclear fission was classified during the war, and was only published after the war ended in 1946.
Gertrude Scharff Goldhaber | Career
The possibility of creating a chain reaction in uranium became apparent in 1939 following the nuclear fission experiments of Otto Hahn and Fritz Strassman, and the interpretation of these results by Lise Meitner and Otto Frisch. The exciting possibilities that this presented rapidly spread throughout the world physics community. In order for the fission process to chain react, the neutrons created by uranium fission must be slowed down by interacting with a neutron moderator (an element with a low atomic weight, that will "bounce", when hit by a neutron) before they will be captured by other uranium atoms. It was well known in 1939 that the two most promising moderators were heavy water and graphite (a semi-crystalline form of pure carbon).
Herbert G. MacPherson | <a href="Nuclear%20graphite">Nuclear graphite</a> and the <a href="Manhattan%20Project">Manhattan Project</a>
Her nominators included Arthur Compton, Dirk Coster, Kasimir Fajans, James Franck, Otto Hahn, Oscar Klein, Niels Bohr, Max Planck and Max Born. Despite not having been awarded the Nobel Prize, Meitner was invited to attend the Lindau Nobel Laureate Meeting in 1962. Max Perutz, the 1962 Nobel prizewinner in chemistry, reached a similar conclusion: "Having been locked up in the Nobel Committee's files these fifty years, the documents leading to this unjust award now reveal that the protracted deliberations by the Nobel jury were hampered by lack of appreciation both of the joint work that had preceded the discovery and of Meitner's written and verbal contributions after her flight from Berlin."
Lise Meitner | Nobel Prize for nuclear fission
Hahn and Strassmann at the Kaiser Wilhelm Institute for Chemistry in Berlin bombarded uranium with slow neutrons, and discovered that barium had been produced. They reported their findings by mail to Meitner in Sweden, who a few months earlier had fled Nazi Germany. Meitner and her nephew Frisch theorised, and then proved, that the uranium nucleus had been split, and published their findings in "Nature". Meitner calculated that the energy released by each disintegration was approximately 200 megaelectronvolts, and Frisch observed this. By analogy with the division of biological cells, he named the process "fission". Hahn was awarded the 1944 Nobel Prize in Chemistry for the discovery.
Discovery of nuclear fission | Introduction
They identified ten different half lives, with varying degrees of certainty. To account for them, Meitner had to hypothesise a new class of reaction and the alpha decay of uranium, neither of which had ever been reported before, and for which physical evidence was lacking. Hahn and Strassmann refined their chemical procedures, while Meitner devised new experiments to shine more light on the reaction processes.
Lise Meitner | Transmutation
Meitner, and her nephew Otto Robert Frisch, correctly interpreted Hahn's and Strassmann's results as being nuclear fission. Frisch confirmed this experimentally on 13 January 1939.
Werner Heisenberg | Membership in the Uranverein
Hahn refused medical evaluation for radiation exposure. EPA scientists believe that Hahn's life expectancy may have been greatly shortened by his exposure to radioactivity, particularly since he spent long periods in the small, enclosed shed with large amounts of radioactive material and only minimal safety precautions, but he refused their recommendation that he be examined at the Enrico Fermi Nuclear Generating Station.
David Hahn | Creation of the neutron source
Rubens said that he would be happy for her to work in his laboratory. He also added that Otto Hahn at the chemistry institute was looking for a physicist to collaborate with. A few minutes later she was introduced to Hahn. He had studied radioactive substances under Sir William Ramsay, and in Montreal under Rutherford, and was already credited with the discovery of what were then thought to be several new radioactive elements. (In fact, they were isotopes of known elements, but the concept of an isotope, along with the term, was only propounded by Frederick Soddy in 1913.) Hahn was the same age as herself, and she noted his informal and approachable manner.
Lise Meitner | Friedrich Wilhelm University
Though others had failed to confirm the element, Rona was able to separate the Uranium-Y from interfering elements, proving it was a beta emitter (β-emission) with a half-life of 25 hours. The Hungarian Academy of Sciences published her findings. Rona first coined the terms "isotope labels" and "tracers" during this study, noting that the velocity of diffusion depended on the mass of the nuclides. Though contained in a footnote, this was the basis for the development of the mass spectrographic and heavy water studies later performed by other scientists. In addition to her scientific proficiency, Rona spoke English, French, German, and Hungarian.
Elizabeth Rona | Early career
It was soon noted by Hahn that if neutrons were released during fission, then a chain reaction was possible. French scientists, Pierre Joliot, Hans von Halban and Lew Kowarski, soon verified that more than one neutron was indeed emitted per fission. In a paper co-authored with the American physicist John Wheeler, Bohr theorised that fission was more likely to occur in the uranium-235 isotope, which made up only 0.7 percent of natural uranium. Chadwick did not believe that there was any likelihood of another war with Germany in 1939, and took his family for a holiday on a remote lake in northern Sweden.
James Chadwick | Tube Alloys and the MAUD Report
The importance of Harriet Brooks' contributions to physics became recognized in the 1980s as foundational work in the field of nuclear science. She was the first person to show that the radioactive substance emitted from thorium was a gas with molecular weight of 40-100, a discovery crucial to the determination that the elements undergo some transmutation in radioactive decay. Her research of radon and actinium was pioneering, and her brief research career was exceedingly accomplished. The Harriet Brooks Building, a nuclear research laboratory at Canadian Nuclear Laboratories was named for her. She was inducted into the Canadian Science and Engineering Hall of Fame in 2002.
Harriet Brooks | Legacy
Her postdoctoral advisor was Terrence J. Udovic. She researched the development and processing of novel metal hydride materials for hydrogen storage and hydrogen-storage materials using neutron scattering techniques.
Hui Wu | Education
Bohr's liquid drop model had not yet been formulated, so there was no theoretical way to calculate whether it was physically possible for the uranium atoms to break into large pieces. Noddack and her husband, Walter Noddack, were renowned chemists who had been nominated for the Nobel Prize in Chemistry for the discovery of rhenium, although at the time they were also embroiled in a controversy over the discovery of element 43, which they called "masurium". The discovery of technetium by Emilio Segrè and Carlo Perrier put an end to their claim, but did not occur until 1937. It is unlikely that Meitner or Curie had any prejudice against Noddack because of her sex, but Meitner was not afraid to tell Hahn "Hahnchen, von Physik verstehst Du Nichts" ("Hahn dear, of physics you understand nothing").
Discovery of nuclear fission | Objections
Progress was slow; the required equipment was not available, and the radar project had first call on the available resources. Francis Perrin had defined a critical mass of uranium to be the smallest amount that could sustain a chain reaction, and had calculated the critical mass of uranium oxide (not metal) to be about . He reckoned that if a neutron reflector were placed around it of materials such as iron or lead which did not greatly impede fast neutrons, this might be reduced to . Peierls also attempted to simplify the problem by using the fast neutrons produced by fission, thus omitting consideration of moderator.
Frisch–Peierls memorandum | Memorandum
Meitner, and her nephew Otto Robert Frisch, correctly interpreted these results as being nuclear fission. Frisch confirmed this experimentally on 13 January 1939. Paul Harteck was director of the physical chemistry department at the University of Hamburg and an advisor to the "Heereswaffenamt" (HWA, Army Ordnance Office). On 24 April 1939, along with his teaching assistant Wilhelm Groth, Harteck made contact with the "Reichskriegsministerium" (RKM, Reich Ministry of War) to alert them to the potential of military applications of nuclear chain reactions. Two days earlier, on 22 April 1939, after hearing a colloquium paper by Wilhelm Hanle on the use of uranium fission in a "Uranmaschine" (uranium machine, i.e., nuclear reactor), Georg Joos, along with Hanle, notified Wilhelm Dames, at the "Reichserziehungsministerium" (REM, Reich Ministry of Education), of potential military applications of nuclear energy.
Klaus Clusius | Career
Her research also showed that there was a steady rate of increase in the amount of radium in her uranium solutions, the first direct experimental evidence that radium was formed by the decay of uranium. Her results were published in 1915.
Ada Hitchins | Uranium and ionium
Frances Pleasonton (1912–1990) was a Particle Physicist at the Oak Ridge National Laboratory. She was an active teacher and researcher, and a member of the team who first demonstrated neutron decay in 1951.
Frances Pleasonton | Introduction
With enough uranium, and with pure-enough graphite, their "pile" could theoretically sustain a slow-neutron chain reaction. This would result in the production of heat, as well as the creation of radioactive fission products.
Nuclear fission | Fission chain reaction realized
With her thesis, titled "Contribution à l'étude du spectre continu des rayons β émis par les corps radioactifs artificiels" (Continuous beta-ray spectrum generated by artificial radioactivity), she earned a doctorate in science in 1943. In August 1944, Yuasa was forced to leave Paris for Berlin. She continued her research in a laboratory in the University of Berlin and developed her own beta-ray spectrometer. In 1945, she was ordered by Soviet officials to return to Japan; she travelled with her spectrometer carried on her back. Upon her return to Tokyo, she returned again to Tokyo Women's Higher Normal School as a professor.
Toshiko Yuasa | Career
Meitner, and her nephew Otto Robert Frisch, correctly interpreted these results as being nuclear fission. Frisch confirmed this experimentally on 13 January 1939. Flügge and Gottfried von Droste, an assistant to Meitner, independently also predicted a large energy release from nuclear fission.
Siegfried Flügge | Career
In 1990, she habilitated with the work "Zintlphasen mit komplexen Anionen". She later became an extraordinary professor. She was the first woman professor for Chemistry at the Technische Universität Darmstadt. She also contributed to the Landolt–Börnstein.
Brigitte Eisenmann | Life
In 1953, she habilitated on the basics of fluorescence application in medicine at the Karl Marx University Leipzig. She was thus the third woman in the GDR, and the seventh, who habilitated in Germany since the Weimar Republic in the traditionally male dominated subject physics. After her habilitation, Herforth received a lecturer position for radiation physics at the University of Leipzig. From 1955 to 1960, Herforth was a research associate at the Institute for Applied Radioactivity in Leipzig. At the same time Herforth worked from 1957 to 1960 as a professor with a teaching assignment for applied radioactivity at the Technical University of Leuna-Merseburg and followed in 1960 a call to the Dresden Technical University, where she taught as a professor in the same field and from 1962 as a professor for the application of radioactive isotopes.
Lieselott Herforth | Life
Her thesis focused on research concerning unknown material and was titled “A Mechanism for the Alpha Radiolysis of Gaseous Hydrogen Sulfide”. On the 50th anniversary of her graduation, her achievement was commemorated with a plaque dedication ceremony at the University of Syracuse.
Rubye Prigmore Torrey | Early life and education
Since Maurice's lab was only set up for nuclear physics research, Gertrude Goldhaber took up research in that field as well. During this time Gertrude and Maurice Goldhaber had two sons: Alfred and Michael. Goldhaber was eventually given a soft-money line by the department to help support her research. Goldhaber studied neutron-proton and neutron-nucleus reaction cross sections in 1941, and gamma radiation emission and absorption by nuclei in 1942. Around this time she also observed that spontaneous nuclear fission is accompanied by the release of neutrons — a result that had been theorized earlier but had yet to be shown.
Gertrude Scharff Goldhaber | Career
At this time, the rarity and importance of Bachelder's achievements as a woman in science were also acknowledged.
Myrtle Bachelder | Contribution to post-war developments in nuclear energy
They identified ten different half lives, with varying degrees of certainty. To account for them, Meitner had to hypothesise a new class of reaction and the alpha decay of uranium, neither of which had ever been reported before, and for which physical evidence was lacking. Hahn and Strassmann refined their chemical procedures, while Meitner devised new experiments to shine more light on the reaction processes. In May 1937, they issued parallel reports, one in "Zeitschrift für Physik" with Meitner as the principal author, and one in "Chemische Berichte" with Hahn as the principal author. Hahn concluded his by stating emphatically: "Vor allem steht ihre chemische Verschiedenheit von allen bisher bekannten Elementen außerhalb jeder Diskussion" ("Above all, their chemical distinction from all previously known elements needs no further discussion"); Meitner was increasingly uncertain.
Otto Hahn | Discovery of nuclear fission
Frisch and Meitner calculated that the energy released by each disintegration was approximately . By analogy with the division of biological cells, they named the process "fission". Niels Bohr and John A. Wheeler applied the liquid drop model developed by Bohr and Fritz Kalckar to explain the mechanism of nuclear fission. Bohr had an epiphany that the fission at low energies was principally due to the uranium-235 isotope, while at high energies it was mainly due to the more abundant uranium-238 isotope. The former makes up just 0.7% of natural uranium, while the latter accounts for 99.3%. Frédéric Joliot-Curie and his Paris colleagues Hans von Halban and Lew Kowarski raised the possibility of a nuclear chain reaction in a paper published in "Nature" in April 1939.
MAUD Committee | The discovery of fission
Originally from New Jersey, Weimer received a scholarship to Purdue University and got her B.Sc. in chemistry in 1939. Then she continued her education at the Ohio State University, switching her area of interest from chemistry to physics, and received her Ph.D. in physics in 1943. Her thesis was entitled "Artificial Radioactivity of Barium and Lanthanum" and supervised by Marion Llewellyn Pool. Katherine Weimer was the first woman Ph.D in physics at the Ohio State University.
Katherine Weimer | Education
There was disagreement about whether fission was produced by uranium-235, which made up less than one percent of natural uranium, or the more abundant uranium-238 isotope, as Fermi maintained. Fermi and Szilárd conducted a series of experiments and concluded that a chain reaction in natural uranium could be possible if they could find a suitable neutron moderator. They found that the hydrogen atoms in water slowed neutrons but tended to capture them. Szilárd then suggested using carbon as a moderator. They then needed large quantities of carbon and uranium to create a reactor. Szilárd was convinced that they would succeed if they could get the materials.
Einstein–Szilárd letter | Origin
Harteck believed that if Hertz had had a leading position "the first working reactor in the world would have been built in Germany, and perhaps the thermal diffusion process would have been achieved".
German nuclear weapons program | Missing generation of physicists
With her assistant Kurt Philipp she later used it to take the first images of positron traces from gamma radiation. She proved Chadwick's assertion that the spectral lines were entirely the result of secondary electrons, and the spectra were therefore indeed entirely caused by the primary ones. In 1927, Charles Drummond Ellis and William Alfred Wooster measured the energy of the continuous spectrum produced by the beta decay of bismuth-210 at 0.34 MeV where the energy of each disintegration was 0.35 MeV. Thus, the spectrum accounted for nearly all of the energy. Meitner was so stunned by this result that she repeated the experiment with Wilhelm Orthmann using an improved method, and verified Ellis and Wooster's results.
Lise Meitner | Beta radiation
His 1932 doctoral thesis, written under the supervision of Rutherford and Charles Drummond Ellis, on "The Disintegration Electrons", subsequently published in the "Proceedings of the Royal Society", described relationship between the radioactive disintegration constants of beta particle-emitting radioisotopes and corresponding logarithms of their maximum beta particle energies. These plots are today known as "Sargent curves" or "Sargent diagrams". This was used by Enrico Fermi in developing his theory of beta decay. Sargent returned to Canada, where he became a lecturer and then an assistant professor at Queen's University. In 1941, he joined George Laurence of the National Research Council (NRC) in Ottawa to investigate nuclear energy, writing a report on "Uranium Fission in a Bulk of Carbon and Uranium Oxide".
Bernice Weldon Sargent | Biography
In Germany, Otto Hahn and Fritz Strassmann bombarded uranium with neutrons, and noted that barium, a lighter element, was among the products produced. Hitherto, only the same or heavier elements had been produced by the process. In January 1939, Meitner and her nephew Otto Frisch astounded the physics community with a paper that explained this result. They theorised that uranium atoms bombarded with neutrons can break into two roughly equal fragments, a process they called fission. They calculated that this would result in the release of about 200 MeV, implying an energy release orders of magnitude greater than chemical reactions, and Frisch confirmed their theory experimentally.
James Chadwick | Tube Alloys and the MAUD Report
Elizabeth Rona (20 March 1890 – 27 July 1981) was a Hungarian nuclear chemist, known for her work with radioactive isotopes. After developing an enhanced method of preparing polonium samples, she was recognized internationally as the leading expert in isotope separation and polonium preparation. Between 1914 and 1918, during her postdoctoral study with George de Hevesy, she developed a theory that the velocity of diffusion depended on the mass of the nuclides. As only a few atomic elements had been identified, her confirmation of the existence of "Uranium-Y" (now known as thorium-231) was a major contribution to nuclear chemistry. She was awarded the Haitinger Prize by the Austrian Academy of Sciences in 1933.
Elizabeth Rona | Introduction
Based on the radioactive displacement law of Fajans and Soddy, this was an isotope of the missing element, which they named "brevium" after its short half life. However, it was a beta emitter, and therefore could not be the mother isotope of actinium. This had to be another isotope of the same element. Hahn and Meitner set out to find the missing mother isotope. They developed a new technique for separating the tantalum group from pitchblende, which they hoped would speed the isolation of the new isotope. The work was interrupted by the First World War. Meitner became an X-ray nurse, working in Austrian Army hospitals, but she returned to the Kaiser Wilhelm Institute in October 1916.
Otto Hahn | Discovery of protactinium
This neutron capture causes beta particle decay that enables U-238 to transform into Pu-239. Plutonium was once found naturally in the earth's crust but only trace amounts remain. The only way it is accessible in large quantities for energy production is through the neutron capture method.
Nuclear chain reaction | Nuclear fission fuel
Rona began her postdoctoral training in 1912 at the Animal Physiology Institute in Berlin and the Kaiser Wilhelm Institute, studying yeast as a reagent. In 1913 she transferred to Karlsruhe University, working under the direction of Kasimir Fajans, the discoverer of isotopes, for the next eight months. During the summer of 1914, she studied at University College London, but returned to Budapest at the outbreak of World War I. Taking a position at Budapest's Chemical Institute, she completed a scientific paper on the "diffusion constant of radon in water". Working with George de Hevesy, she was asked to verify a new element at the time was termed Uranium-Y, now known as Th-231.
Elizabeth Rona | Early career
A team led by Enrico Fermi in 1934 observed that bombarding uranium with neutrons produces the emission of beta rays (electrons or positrons from the elements produced; see beta particle). The fission products were at first mistaken for new elements with atomic numbers 93 and 94, which the Dean of the Faculty of Rome, Orso Mario Corbino, christened "ausonium" and "hesperium", respectively. The experiments leading to the discovery of uranium's ability to fission (break apart) into lighter elements and release binding energy were conducted by Otto Hahn and Fritz Strassmann in Hahn's laboratory in Berlin. Lise Meitner and her nephew, the physicist Otto Robert Frisch, published the physical explanation in February 1939 and named the process "nuclear fission".
Uranium | Fission research
Sarah Ratner (June 9, 1903 – July 28, 1999) was an American biochemist. Her contributions to the study of nitrogen metabolism led to a better understanding of human disorders in urea synthesis. In 1961, Ratner was awarded the Garvan–Olin Medal from the American Chemical Society and was elected to the National Academy of Sciences in 1974.
Sarah Ratner | Introduction
During the Christmas holiday in 1938, Frisch visited his aunt Lise Meitner in Kungälv in Sweden, where she had relocated after Germany's annexation of Austria. While there she received the news that her former colleagues Otto Hahn and Fritz Strassmann in Berlin had discovered that the collision of a neutron with a uranium nucleus produced barium as one of its byproducts. Frisch and Meitner hypothesized that the uranium nucleus had split in two. They estimated the energy released at around 200 MeV, and Frisch appropriated the term fission from biology to describe it. Hahn's paper described the experiment and the finding of the barium byproduct.
Frisch–Peierls memorandum | Nuclear fission
Her recent efforts have been focused on the chemistry of uranium and thorium compounds with nitrogen-rich ligands. For example, experimental and theoretical work from her group revealed that tetrazolate ligands of these complexes act as sigma donors.
Jaqueline Kiplinger | Career
Dorothy Anna Hahn (1876–1950) was a lifelong educator and American professor of organic chemistry at Mount Holyoke College. Her research utilized the then newly developed technique of ultraviolet spectroscopy to study hydantoins.
Dorothy Hahn | Introduction
She entered the University of Munich in 1929, where she listened to lectures by Arnold Sommerfeld. For her doctorate, she was accepted into the Kaiser Wilhelm Institute for Physical Chemistry and Electrochemistry at Berlin-Dahlem, where she wrote her thesis on the spectra of alkali metal halides, under the supervision of Peter Pringsheim and Fritz Haber.
Hilde Levi | Early life
But Hahn and Meitner had a sample from which they had regularly removed its mother isotope, mesothorium (), over a period of several years, allowing the radiothorium to decay away. Even then, it was still more difficult to work with because its induced decay products from neutron irradiation were isotopes of the same elements produced by thorium's own radioactive decay. What they found was three different decay series, all alpha emitters—a form of decay not found in any other heavy element, and for which Meitner once again had to postulate multiple isomers. They did find an interesting result: these (n, α) decay series occurred simultaneously when the energy of the incident neutrons was less than 2.5 MeV; when they had more, an (n, γ) reaction that formed was favoured.
Discovery of nuclear fission | Research
During the Christmas holiday in 1938 he visited his aunt Lise Meitner in Kungälv. While there she received the news that Otto Hahn and Fritz Strassmann in Berlin had discovered that the collision of a neutron with a uranium nucleus produced the element barium as one of its byproducts. Hahn, in a letter to Meitner, called this new reaction a "bursting" of the uranium nucleus. Frisch and Meitner hypothesized that the uranium nucleus had split in two, explained the process, and estimated the energy released, and Frisch coined the term fission to describe it. Political restraints of the Nazi era forced the team of Hahn and that of Frisch and Meitner (both of whom were Jewish) to publish separately.
Otto Robert Frisch | Nuclear fission
These included Arnold Flammersfeld, Kan-Chang Wang and Nikolaus Riehl. In 1926, she became an "außerordentlicher Professor" (extraordinary professor), the first woman university physics professor in Germany. Her physics section became larger, and she acquired a permanent assistant. Scientists from Germany and around the world came to the KWI for Chemistry to conduct research under her supervision. In 1930, Meitner taught a seminar on "Questions of Atomic Physics and Atomic Chemistry" with Leó Szilárd. Meitner had a Wilson cloud chamber constructed at the KWI for Chemistry, the first one in Berlin, and with her student Kurt Freitag studied the tracks of alpha particles that did not collide with a nucleus.
Lise Meitner | Beta radiation
She was also a member of the American Chemical Society and the American Association for the Advancement of Science.
Helen Blair Barlett | Introduction
In November 1938, Szilard moved to New York City, taking a room at the King's Crown Hotel near Columbia University. He encountered John R. Dunning, who invited him to speak about his research at an afternoon seminar in January 1939. That month, Niels Bohr brought news to New York of the discovery of nuclear fission in Germany by Otto Hahn and Fritz Strassmann, and its theoretical explanation by Lise Meitner, and Otto Frisch. When Szilard found out about it on a visit to Wigner at Princeton University, he immediately realized that uranium might be the element capable of sustaining a chain reaction.
Leo Szilard | Columbia University
Kemmler-Sack did her doctorate on "Untersuchungen an ternären Uran (V)oxiden" (Investigations on ternary uranium (V)oxides) in 1962. She habilitated in 1968 and the title of her habilitation thesis was "Über spektroskopische und magnetische Untersuchungen an Oxidfluoriden es fünfwertien Urans" (About spectroscopic and magnetic investigations on oxide fluorides it five-valent uranium). She became a university lecturer in 1968, an extraordinary professor in 1973, a university professor in 1978.
Sibylle Kemmler-Sack | Life
Using her husband's electrometer, she discovered that uranium rays caused the air around a sample to conduct electricity. Using this technique, her first result was the finding that the activity of the uranium compounds depended only on the quantity of uranium present. She hypothesized that the radiation was not the outcome of some interaction of molecules but must come from the atom itself. This hypothesis was an important step in disproving the assumption that atoms were indivisible. In 1897, her daughter Irène was born. To support her family, Curie began teaching at the École Normale Supérieure. The Curies did not have a dedicated laboratory; most of their research was carried out in a converted shed next to ESPCI.
Marie Curie | New elements
At the reception for this award, she sat next to the President of the United States, Harry S. Truman. But Meitner did not enjoy public speaking, especially in English, nor did she relish the role of a celebrity, and she declined the offer of a visiting professorship at Wellesley College. In 1966, the United States Atomic Energy Commission jointly awarded the Enrico Fermi Prize to Hahn, Strassmann and Meitner for their discovery of fission. The ceremony was held in the Hofburg palace in Vienna. It was the first time that the Enrico Fermi Prize had been awarded to non-Americans, and the first time it was presented to a woman.
Discovery of nuclear fission | In history and memory
In preparation for the first nuclear device test on July 16, 1945, which was codenamed Trinity, Anderson, with his radiochemist colleagues, developed a method of determining the nuclear yield by collecting fission products at the detonation site. This technique was later perfected for nuclear yield determinations through the analysis of airborne fission products. After the conclusion of World War II, Fermi and Anderson returned to the University of Chicago. There, they established the Institute for Nuclear Studies (today, the Enrico Fermi Institute). At the University, Anderson was assistant professor of physics 1946 to 1947, associate professor 1947 to 1950, professor 1950 to 1977, and distinguished service professor 1977 to 1982.
Herbert L. Anderson | Chain reaction
She subsequently returned to Columbia, studying under Harold Urey, who had just won the Nobel Prize. Originally, Cohn was working to study the different isotopes of carbon. However, her equipment failed her, and she could not finish this project. She went on to write her dissertation on oxygen isotopes and earned her PhD in physical chemistry in 1938.
Mildred Cohn | Education
Clara Flora Lieber (July 10, 1902 – December 14, 1982) was an American chemist known for her work with Otto Hahn on discovering fission, and her discovery of several isotopes of strontium and barium.
Clara Lieber | Introduction
The main finding of Haber and Weiss was that hydrogen peroxide (HO) is decomposed by a chain reaction. The Haber-Weiss reaction chain proceeds by successive steps: (i) initiation, (ii) propagation and (iii) termination. The chain is initiated by the Fenton reaction:
Haber–Weiss reaction | Haber-Weiss chain reaction
On returning to Copenhagen, Frisch informed Bohr, who slapped his forehead and exclaimed "What idiots we have been!" Bohr promised not to say anything until they had a paper ready for publication. To speed the process, they decided to submit a one-page note to "Nature". At this point, the only evidence that they had was the barium. Logically, if barium was formed, the other element must be krypton, although Hahn mistakenly believed that the atomic masses had to add up to 239 rather than the atomic numbers adding up to 92, and thought it was masurium (technetium), and so did not check for it: Over a series of long-distance phone calls, Meitner and Frisch came up with a simple experiment to bolster their claim: to measure the recoil of the fission fragments, using a Geiger counter with the threshold set above that of the alpha particles.
Discovery of nuclear fission | Eureka!
Noddack correctly criticized Enrico Fermi's chemical proofs in his 1934 neutron bombardment experiments, from which he postulated that transuranic elements might have been produced. This theory was widely accepted for a few years. However, Noddack's paper "On Element 93" suggested a number of possibilities, but centered on Fermi's failure to chemically eliminate "all" lighter than uranium elements in his proofs, rather than only down to lead. The paper is considered historically significant today not simply because she correctly pointed out the flaw in Fermi's chemical proof but because she suggested the possibility that "it is conceivable that the nucleus breaks up into several large fragments, which would of course be isotopes of known elements but would not be neighbors of the irradiated element." In doing so she presaged what would become known a few years later as nuclear fission.
Ida Noddack | Nuclear fission
Enrico Fermi and his colleagues in Rome picked up on this idea, and began irradiating elements with neutrons. The radioactive displacement law of Fajans and Soddy said that beta decay causes isotopes to move one element up on the periodic table, and alpha decay causes them to move two down. When Fermi's group bombarded uranium atoms with neutrons, they found a complex mix of half lives. Fermi therefore concluded that the new elements with atomic numbers greater than 92 (known as transuranium elements) had been created. Meitner and Hahn had not collaborated for many years, but Meitner was eager to investigate Fermi's results.
Otto Hahn | Discovery of nuclear fission
In 1962-63, as part of his PhD thesis, Rajaraman demonstrated that the prevalent calculations of the energy of nuclear matter in powers of the Brueckner reaction matrix would not yield a convergent result. He suggested instead summing, in closed form, interactions to all orders among any given number of nucleons, thereby generating a density expansion. He also outlined a method for doing so. Subsequently, Hans Bethe converted Rajaraman's outline into a substantive theory for the three-nucleon problem in nuclear matter. These developments, summarized in the 1967 review article by Rajaraman with Bethe, eventually led to the Coupled Cluster method in Many Body theory.
Ramamurti Rajaraman | Nuclear many-body theory
With the news of fission neutrons from uranium fission, Szilárd immediately understood the possibility of a nuclear chain reaction using uranium. In the summer, Fermi and Szilard proposed the idea of a nuclear reactor (pile) to mediate this process. The pile would use natural uranium as fuel. Fermi had shown much earlier that neutrons were far more effectively captured by atoms if they were of low energy (so-called "slow" or "thermal" neutrons), because for quantum reasons it made the atoms look like much larger targets to the neutrons. Thus to slow down the secondary neutrons released by the fissioning uranium nuclei, Fermi and Szilard proposed a graphite "moderator", against which the fast, high-energy secondary neutrons would collide, effectively slowing them down.
Nuclear fission | Fission chain reaction realized
The new laboratories offered new opportunities, as the old ones had become too contaminated with radioactive substances to investigate feebly radioactive substances. They developed a new technique for separating the tantalum group from pitchblende, which they hoped would speed the isolation of the new isotope. The work was interrupted by the outbreak of the First World War in 1914. Hahn was called up into the German Army, and Meitner became a volunteer radiographer in Austrian Army hospitals. She returned to the Kaiser Wilhelm Institute in October 1916, when not only Hahn, but most of the students, laboratory assistants and technicians had been called up.
Discovery of nuclear fission | Protactinium
In Sweden, Meitner continued her research as best she could. She measured the neutron cross sections of thorium, lead and uranium using dysprosium as a neutron detector, an assay technique pioneered by George de Hevesy and Hilde Levi. She was able to arrange for Hedwig Kohn, who faced deportation Poland, to come Sweden, and eventually to emigrate to the United States, travelling via the Soviet Union. She was unsuccessful in bringing Stefen Meyer out, but he managed to survive the war. She declined an offer to join Frisch on the British mission to the Manhattan Project at the Los Alamos Laboratory, declaring "I will have nothing to do with a bomb!" She later said that the atomic bombings of Hiroshima and Nagasaki had come as a surprise to her, and that she was "sorry that the bomb had to be invented".
Lise Meitner | Later life
This would require more than one neutron to be emitted per fission on average in order to keep the chain reaction going. By March 1939, they established that about two were being emitted per fission on average. The delay between an atom absorbing a neutron and fission occurring would be the key to controlling a chain reaction. At this point Zinn began working for Fermi, constructing experimental uranium lattices. To slow neutrons down requires a neutron moderator. Water was Fermi's first choice, but it tended to absorb neutrons as well as slow them. In July, Szilard suggested using carbon, in the form of graphite.
Walter Zinn | Manhattan Project
Initially nothing registered on the oscilloscope, but then Zinn realized that it was not plugged in. On doing so, they discovered significant neutron multiplication in natural uranium, proving that a chain reaction might be possible. Szilard later described the event: "We turned the switch and saw the flashes. We watched them for a little while and then we switched everything off and went home." He understood the implications and consequences of this discovery, though. "That night, there was very little doubt in my mind that the world was headed for grief".
Leo Szilard | Columbia University
Berta Karlik was an Austrian physicist. She worked for the University of Vienna, eventually becoming the first female professor at the institution. While working with Ernst Foyn she published a paper on the radioactivity of seawater. She discovered that the element 85 astatine is a product of the natural decay processes. The element was first synthesized in 1940 by Dale R. Corson, K. R. MacKenzie, and Emilio Segrè, after several scientists in vain searched for it in radioactive minerals.
Berta Karlik | Introduction
In mid-1936, Heisenberg presented his theory of cosmic-ray showers in two papers. Four more papers appeared in the next two years. In December 1938, the German chemists Otto Hahn and Fritz Strassmann sent a manuscript to "The Natural Sciences" reporting they had detected the element barium after bombarding uranium with neutrons and Otto Hahn concluded a "bursting" of the uranium nucleus; simultaneously, Hahn communicated these results to his friend Lise Meitner, who had in July of that year fled to the Netherlands and then went to Sweden. Meitner, and her nephew Otto Robert Frisch, correctly interpreted Hahn's and Strassmann's results as being nuclear fission.
Werner Heisenberg | Pre-war work on physics
In the 1980s, she moved to Columbia University where she taught from 1983 to 1989. She became a full professor in 1986 and was the first woman to receive tenure in the Chemistry department at Columbia. Her research focused on the use of organo-ruthenium complexes to examine the physical structure of DNA. With Nicholas Turro and Vijay Kumar she studied the interactions of ruthenium phenanthroline complexes and DNA and was able to design binding molecules targeted to specific DNA sequences. Photosensitive ruthenium complexes would glow brightly when they attached to the DNA double helix. When rhodium complexes were attached to the DNA, they would attract the electron causing the glow, and "turn off" the effect.
Jacqueline Barton | Career and research
She developed leukemia later in life due to inhaling an exploded capsule from her lab. Lastly, Kean mentions the injustice done to Lise Meitner and her tremendous work with Otto Hahn. They both found element 91 known as brevium, but then it was changed to protactinium. Owing to the fact that Lise was a woman and the advent of World War II, she was not awarded then or later. Otto Hahn received a Nobel Prize and did not mention her.
The Disappearing Spoon | Chapter 12. Political elements
A Christian Scientist, as well as a member of the League of Women Voters, the American Association of University Women, the National Education Association, Phi Beta Kappa, and the American Historical Association, she died in August 1976.
Con-Con Eleven | Background
Cremer's father moved to a new position in Berlin and Cremer had trouble adjusting to the new Prussian school system. Cremer graduated high school in Berlin in 1921 and matriculated to the University of Berlin to study chemistry. At the University of Berlin, she attended lectures by Fritz Haber, Walther Nernst, Max Planck, Max von Laue, and Albert Einstein. Cremer received her Ph.D. "magna cum laude" six years later in 1927 under Max Bodenstein. Her dissertation was on the kinetics of the hydrogen-chlorine reaction. The paper was published under her name only because it concluded that the hydrogen-chlorine reaction was a chain reaction, which was still considered an extremely original concept for that time.
Erika Cremer | Education and early career
Bohr had an epiphany that the fission at low energies was due to the uranium-235 isotope, while at high energies it was due mainly to the more abundant uranium-238 isotope. The former makes up just 0.7% of natural uranium; while the latter accounts for 99.3%. On 16 April, Bohr, Placzek, Wheeler, Eugene Wigner and Leon Rosenfeld discussed whether it would be possible to use a nuclear chain reaction to make an atomic bomb, and concluded that it was not. Bohr observed that "It would take the entire efforts of a country to make a bomb."
Frisch–Peierls memorandum | Nuclear fission