The Tsar Bomba is the biggest man made explosive ever detonated on the face of the earth. It had an explosive yield equivalent to fifty million tons of TNT. When I read about the power of the weapons man has created I sometimes want to go hide, quivering, in a bunker somewhere. How would you feel if I told you that there is a place in the United States that is sitting on an explosive yield almost 20,000’s times that of the Tsar Bomba [4]. And that it’s on schedule to explode any day now.

Back in the 1960’s Bob Christiansen of the United States Geological Survey asked one of the most horrifying questions we’ve ever asked. It probably went something like this “All of Yellowstone’s geysers and hot springs are obviously volcanic, so where is the volcano?”.  Christiansen had the good luck to live in a time where NASA was starting to take satellite photos from space and so he was able to see what Yellowstone looks like from above. And what did it look like? One enormous caldera. The whole 35 by 45 mile crater was a single super volcano [2].

The last time it went off it’s explosion was estimated to have had a yield of almost nine hundred thousand Megatons with an ash-fall that covered most of the US west of the Mississippi. Now I’ve already tried to put that number in perspective by saying that it is almost twenty thousand times greater than the Tsar Bomba, but let me try again. The combined nuclear arsenals of all the powers in the world is about one and a half thousand megatons. This explosion was nearly six hundred times as powerful as the simultaneous explosion of ever nuke on earth.

Over the last eighteen million years this hot spot has had occasional explosions and intermittent slower lava flows. Over the last two million years it’s had a super eruption semi regularly every six hundred thousand years. That last eruption which I should mention was the smallest of the three super-explosions, was six hundred and thirty thousand years ago. We’re overdue for an eruption that would coat the US with ash, send us into a global winter, and level a solid chunk of the Midwest.

Now stop panicking, there’s a couple important things to keep in mind which all basically boil down to statistics. First off, I said that these explosions have a semi-regular schedule but that’s a vast oversimplification. Imagine rolling a 6 sided dice over and over again. How many times will you have to roll it before a 1 comes up? The answer is roughly 6 times, but you could roll a 1 your first time, or you might get a string of bad rolls and not get a 1 till the twentieth roll. The important thing to see here is that each roll of the dice isn’t effected by the rolls around it. My basic intuition around fault-lines, earthquakes, and volcanos, seems to say that pressure should build and build and build and then release all at once before waiting to “charge back up”. But most of the actual data we have seems to show something more like rolling dice, where as the power of the event goes up exponentially the likelihood of it happening goes down exponentially [3]. Yellowstone blowing up is more like rolling a 1 on a die with a simply enormous number of sides, than it is like a ticking time bomb waiting for it’s moment. In fact in any given year, scientists estimate Yellowstone has about a one in seven hundred thousand chance of going off. The number of Earthquakes, patients arriving in an emergency room, and meteorites falling in a given span of time all are closely approximated by what’s called a Poisson distribution. One of the core properties of a Poisson distributions is that they are “memoryless”, which means the expected time to an event doesn’t decrease as time goes by.

Every once in a while, I see an article talking about how we’re “on schedule” for another big earth quake in the San Fransisco Bay Area. Or how we’re “on schedule” for another mass extinction event, magnetic storm, reversal of the earths magnetic poles, or whatever. There are some cosmological events that take place on nice regular cycles, the earth going around the sun for instance. But most disasters are statistical events with a small chance of happening on any given year. And by and large the event not having happened in a while doesn’t make it more likely to occur now. So please get out of your bunker, it’s okay, Yellowstone is probably not going to blow up this year.

All that said, the world is a big place and unlikely things happen all the time. And, in February of 2018, Yellowstone was hit with a quake storm with over 200 measurable quakes over the course of a week and a half [1]. So maybe keep that bunker stocked anyway, just in case.

[1] Bartels, Meghan. “Yellowstone Supervolcano Earthquake Swarm Hits 200 Shakes in Less than Two Weeks.” Newsweek, Newsweek, 20 Feb. 2018, www.newsweek.com/yellowstone-supervolcano-earthquake-swarm-hits-200-shakes-less-two-weeks-812813.

[2] Bryson, Bill. A Short History of Nearly Everything. Black Swan, 2016.

[3] Silver, Nate. The Signal and the Noise: the Art and Science of Prediction. Penguin, 2013.

[4] “TNT Equivalent.” Wikipedia, 12 Mar. 2018, en.wikipedia.org/wiki/TNT_equivalent.

 

Emilio Gino Segrè was born in Tivoli, outskirts of Rome, Italy in a Sephardic Jewish Family in 1905. After completing his university preparatory schooling in Rome, he enrolled as an engineering student in the University of Rome, La Sapienza. This is where he would meet Franco Rasetti, who introduced him to Enrico Fermi, who was looking for talented students to work with. This led Emilio to switch to Physics for his laurea (PhD) and he became one of the Via Panisperna boys.

With instruction from Fermi and Rasetti, Segrè received his doctorate degree in his first year itself as a physics student. Segrè would serve his compulsory military service before becoming a professor of physics, a few years later. Segrè spoke several languages, and could quote classics at length. He led a very active lifestyle, which included hikes in the alps, foraging wild mushrooms and fly-fishing in America. Segrè’s first research revolved around studying the Raman effect and the Zeeman effect. The latter opened him up to an invitation from Pieter Zeeman to work in his laboratory. Segrè received the Rockefeller foundation fellowship multiple times, and worked with Otto Stern.

Segrè started working as a professor of physics at the University of Palermo in Rome. On a visit to the US, he convinced Lawrence Berkeley Radiation Laboratory to let him take back some discarded cyclotron parts to study slow acting radiation. Study of a discarded radioactive molybdenum strip led to him discovering a new element Technetium.  Segrè was frustrated by the lack of recognition to this discovery, which he considered worthy of a Nobel prize. Further, he was disappointed in the Italian government for their response. In 1938, on another visit to Lawrence Berkeley Radiation Lab, he learned that Benito Mussolini government in Italy had disallowed Jewish people from holding academic positions. This would lead Segrè to emigrate to the US with his family.

Segrè’s status as an alien would complicate his participation and collaboration on nuclear research, something that was considered high security. This meant he held the position of “Research Assistant” and was paid $300 a month. This pay was slashed to $116 when Lawrence learned that Segrè was trapped in California due to the circumstances. Due to second world war, a lot of Berkeley professors were kept busy by the war effort. Segrè supplemented his income by teaching physics as a professor at Berkeley in their absence. Later, Segrè accepted Oppenheimer’s invitation to join the Manhattan Project at Los Alamos.

While at Los Alamos, he led the group to identify U-235 and Pu-239 fission rates. His work would prove that the U-235 slow-cannon-design would still be too fast for spontaneous fission of Plutonium, and the contamination by Pu-240 isotope would result in pre-detonatiom of the bomb. This caused cancellation of the thin man atomic bomb.This would lead to a risky redesign, which proved successful in the detonation of Fat Man.

Segrè and his group were successful in measuring the gamma radiations from the Trinity test, even though intense radiation destroyed most of their apparatus. While at Los Alamos, Segrè served under the name Earl Seaman as to not raise suspicions about his alien status. In 1944 Segrè and his wife became citizens of United States. While working at Los Alamos, Segrè helped discover Astatine which would be useful in later atomic designs.

After the war, while he remained a professor at Berkeley, he would continue to pursue patent claims against the United States. The Italian scientist won the case leading to an award of $400,000 in damages.  After a brief stint at the University of Illinois Urbana-Champaign, Segrè returned to Berkeley as a professor and researcher in physics. With antimatter particles already discovered for Neutron and electron, Segrè started working on verifying the existence of anti-proton. Using Lawrence Berkeley’s Bevatron particle accelerator at 6 billion eV, Segrè and his team managed to prove conclusively the existence of antiproton. Segrè and Chamberlain received the Nobel Prize in physics for this discovery.

Segrè worked as a trustee of the Fermilab at Berkeley, and supported the successful bid to separate Lawrence Livermore National Laboratory and Lawrence Berkeley National Laboratory. He was an avid photographer and has taken a vast amount of photographs during his career. His photographs provide a great insight into the projects he worked on, the people he worked with and the history of his discoveries. He published a biography on Fermi and his autobiography titled “A Mind Always in Motion” which was published after his death.

Segrè died of a heart attack in 1989 at the age of 84 in Lafayette, California.

 

References :

1. Wikipedia : Emilio Segrè
2. EMILIO GINO SEGRÈ 1905–1989 A Biographical Memoir by J. DAVID JACKSON : National Academy of Sciences
3. Encyclopædia Britannica: Emilio Segrè
4. Atomic Heritage Foundation : Emilio Segrè
5. Jewish Virtual Library : Emilio Segrè

Additional Links

1. American Institute of Physics : Emilio Segrè Visual Archives
2. Flickr: Emilio Segrè Visual Archives

Robert Serber’s photo badge for Los Alamos National Laboratory.

Beginnings

On March 14, 1909, Dr. Robert Serber, an American physicist, was born. Dr. Serber was the protege of Dr. Robert Oppenheimer, widely known for his work as a director for the Los Alamos Project. Serber’s job entitled explaining the basic principles and goals of the Manhattan Project to incoming staff.

Education

In 1930, Serber earned his B.S. in Engineering Physics from Lehigh University and his Ph.D. from University of Wisconsin, Madison with John Van Vleck in 1934. After earning his doctorate, he began his postdoctoral work at University of California, Berkeley with Oppenheimer where the two became friends and also his mentor. 

Los Alamos

Shortly after, Serber was recruited by Oppenheimer for the Manhattan Project in 1941. As head of the laboratory, Oppenheimer decided to not separate the information among the different departments in order to give the departments a sense of unity and a common goal. This allowed them to work more efficiently and sparked a sense of urgency towards completion of the project. This decision also increased the partnerships and relationships between departments as it gave the scientists a clearer idea of the common goal they shared. In order to keep the departments on the same page, it fell on Serber to keep them up to date hence the creation of The Los Alamos Primer, which was based off of the conclusions from a conference held at the University of California, Berkeley by Oppenheimer. It has been declassified and is now available to the public.

Along with Serber’s amazing ability to illustrate complicated concepts, he had a knack for clever names.  He was responsible for the witty code-names for all three bomb designs — the “Little Boy” was the uranium gun, the “Thin Man” was the plutonium gun, and the “Fat Man” was the plutonium implosion. The code-names given were based on their design shapes. The “Little Boy” was named in contrast to the “Thin Man” which was a very long device and also inspired by the Dashiell Hammett detective novel The Thin Man. The “Fat Man” bomb was round and fat and inspired by a character in The Maltese Falcon.

Postwar

Serber’s hard work and efforts did not go unnoticed. In 1972, Serber was awarded the J. Robert Oppenheimer Memorial Prize for his work in theoretical physics and the Manhattan Project. The award included a medal, certificate and a $1000 reward. Unfortunately, Robert Serber died on June 1, 1997 due to complications after surgery for brain cancer. Serber’s legacy will be appreciated and remembered by many.  

 

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SOURCES

• “Robert Serber (1909 – 1997).” Robert Serber | Biography, 2015, www.atomicarchive.com/Bios/Serber.shtml.
• “Robert Serber.” Atomic Heritage Foundation, 14 Mar. 1909, www.atomicheritage.org/profile/robert-serber.
• “Robert Serber.” Wikipedia, Wikimedia Foundation, 23 Dec. 2017, en.wikipedia.org/wiki/Robert_Serber.
• Freeman, Karen. “Robert Serber, 88, Physicist Who Aided Birth of A-Bomb.” The New York Times, The New York Times, 1 June 1997, www.nytimes.com/1997/06/02/us/robert-serber-88-physicist-who-aided-birth-of-a-bomb.html?scp=1&sq=Robert%2BSerber&st=cse.

Written by Sabrina Au.

“I was an unusual theorist in that my greatest strength was… seeing how theory and experiment related.”

©Philosophy of Science Portal

Introduction

Born on May 14, 1916, the great Canadian-American Physicist Robert Frederick Christy was a major player in the development of the atomic bombs. His service as a theoretical physicist during the Manhattan Project would lead to the successful creation of a working plutonium-based atomic bomb.

Early Life

Robert Christy’s humble beginnings started as an orphan in Vancouver. However, his life would soon turn towards the better when he received the Governor General’s Gold Medal at age 16. This allowed him to skip the remainder of high school to attend the University of British Columbia as a sophomore. Within 3 years, he would complete his Bachelor’s degree in physics and additional 2 years, his Master’s in Physics and Mathematics. Afterwards, he traveled to the University of California at Berkeley, where he met Robert J Oppenheimer, the leading theoretical physicist at the time. Working under Oppenheimer as a graduate student, Christy would receive his doctorate’s degree in 1941 and be immediately hired as a physics professor at the Illinois Institute of Technology. During the fall of that year, he was invited to join the Manhattan Project and work with Enrico Fermi to build the first nuclear reactor. By the winter of 1942, they’d succeeded in creating Chicago Pile-1, the world’s first working nuclear reactor. And finally, in 1943, Oppenheimer would invite Robert to work at the Los Alamos research center for the development of the atomic bombs.

Manhattan Project

Under Hans Bethe, the head of the Theoretical Division in Los Alamos, Robert Christy’s first role was to aid in the development of an aqueous homogeneous reactor. This would test critical mass calculations and the effect of various tamper materials, with a strong emphasis on enriched uranium. Robert would help regain confidence within the Theoretical Division when his prediction of enriched uranium’s critical mass had a mere 1.7% error.

His key contribution, however, was the development of the Christy Pit. The previous design of the plutonium-based bomb could not deal with jets and spalling during the bomb’s drop as they would cause the hollow sphere of plutonium to change shape and prevent the nuclear blast. Robert Christy had an ingenious idea to use an ultraconservative design; he proposed using an almost solid sphere of plutonium slightly less than critical mass, with a small central cavity holding an “initiator” to supply neutrons to get the fission reaction started. When compressed hard enough, the atoms would be forced close enough to achieve critical mass, triggering the chain reaction and nuclear blast. His design would be used in “The Gadget” during the Trinity Bomb Test and in the “Fat Man” bomb during the Nagasaki bombing.

After the War

After the war, Christy would return to the University of Chicago where he became an assistant professor of physics. Soon after, however, he was invited to join the faculty at Caltech in 1946 by Oppenheimer. He turned his research towards astrophysics, where he assisted in creating some of the first computational models of stellar operation. Perhaps his most notable project was Project Orion, which investigated whether or not a spacecraft could be efficiently propelled by a series of controlled nuclear blasts behind the craft, a process known as nuclear pulse propulsion. For his work, he was awarded the Eddington Medal of the Royal Astronomical Society in 1967. Meanwhile, Christy would also be a large proponent of anti-nuclear warfare. In 1945, he became one of the founding members of the Association of Los Alamos Scientists to educate the public on the peaceful uses of atomic energy. He also aided in the studying of the radiation effects of the Hiroshima and Nagasaki bombs. Robert would be named the vice president and provost of Caltech in 1970, and in 1977, briefly become president of Caltech for a year. Unfortunately, he died on October 3, 2012, at the age of 96 in Pasadena, California. His work during the Manhattan Project will always be remembered for its importance in contributing invaluable information towards the development of the atom bomb.

-Timothy Lo

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Sources

1. Broad, William J. “Robert F. Christy, Atom Bomb Physicist, Dies at 96.” The New York Times, The New York Times, 4 Oct. 2012, www.nytimes.com/2012/10/05/science/robert-f-christy-atom-bomb-physicist-dies-at-96.html?ref=obituaries.
2. Christy, Juliana. “Robert F. Christy (1916 – 2012).” Robert F. Christy (1916 – 2012) | American Astronomical Society, American Astronomical Society, 2012, aas.org/obituaries/robert-f-christy-1916-2012.
3. Lippincott, Sara. “Robert F. Christy.” Caltech Oral Histories Library, Archives California Institute of Technology, 22 June 1994, oralhistories.library.caltech.edu/129/1/OH_Christy_R.pdf. Accessed 4 Jan. 2018.
4. Los Angeles Times Staff and Wire Reports. “Robert F. Christy Dies at 96; Manhattan Project Physicist – LA Times.” Los Angeles Times, Los Angeles Times, 5 Oct. 2012, www.latimes.com/local/obituaries/la-me-robert-christy-20121006-story.html.
5. Svitil, Kathy. “Noted Physicist Robert F. Christy Dies | Caltech.” The California Institute of Technology, The California Institute of Technology, 3 Oct. 2012, www.caltech.edu/news/noted-physicist-robert-f-christy-dies-36918.

An Introduction

From Stanford blackboards to raw nuclear power, Norris Bradbury has contributed (more than) his time to the world. Bradbury was not only a well-respected professor at Stanford, but also an exceptional physicist who contributed to the Manhattan Project during World War II. But these accomplishments were only the beginning for Bradbury, because in 1945 Bradbury was assigned as the director of Los Alamo’s Laboratory, where he oversaw research for the advancement of physics, chemistry, and various other fields.

Prewar Life

Born on the May 30th, 1909 Norris Bradbury spent his early years studying natural sciences earning a bachelor’s degree in Chemistry and a PhD in physics, from Pomona College and UC Berkeley respectively. His PhD thesis, Studies on the mobility of gaseous ions, ultimately awarded Bradbury with fellowship from the National Research Council.

Upon completion of his studies, Bradbury applied for commission as a naval reservist in 1932. After his commission was signed, Bradbury commenced work at Stanford University as a Physics Professor from 1935 to 1944. It was also this that he was ordered by Commander Deak Parsons to head to Albuquerque, New Mexico to become a technical adviser for the E-5, the Implosion Experimentation Group.

The Manhattan Project

It was here that Bradbury’s command of physics proved useful. With Bradbury’s oversight, the E-5 group successfully carried out the implosion field test program. Following E-5, Bradbury was later moved to the Explosives Division of the Manhattan Project. Here Bradbury was placed in charge of the X-1 group which was responsible for implosion research. A critical part of this research was the Trinity Test, an implosion style weapon. On July 16, 1945 at exactly 5:29 am the plutonium-based implosion fission bomb went off.

Composed of a solid spherical core and plutonium-239, the nuclear bomb was hoisted 30 m above the Jornada del Muerto desert sand. Once dropped, it destroyed everything in its path including the McDonald Ranch House, the former testing place for “The Gadget” (the nickname for the bomb). With the success of the trial, Bradbury had ultimately become one of the most influential physicists that aided in the creation of nuclear weapons, the key component for the Allies’ victory in World War II.

Postwar Life

After the war, Bradbury was assigned as the Director of Los Alamos Laboratory in 1945. Although Bradbury initially feared that the laboratory would cease to exist (due to a lack of need of explosives), the cold war with the Soviet Union guaranteed the continuity of Bradbury’s lab. Having made advancements in nuclear weapons, Bradbury extended his range to general nuclear studies until he retired in 1970.

 

Sources:

1. Hoddeson, Lillian; Henriksen, Paul W.; Meade, Roger A.; Westfall, Catherine L. (1993). Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945. New York: Cambridge University Press.
2. Hewlett, Richard G.; Anderson, Oscar E. (1962). The New World, 1939–1946 (PDF). University Park: Pennsylvania State University Press.
3. “Norris Bradbury”. Atomic Heritage Foundation.Retrieved January 4, 2018.
4. “Robert F. Christy”. Atomic Heritage Foundation. Retrieved January 7, 2014.

Edward Teller

 

An early life marked by political instability

Edward Teller was born in Budapest, Hungary in 1908 into a Jewish family. His early ages were tainted with a lot of socio-political instability, but he was lucky enough to live in a loving, protecting and prosperous family. As a young boy, he lived through the difficult years of World War I. He also experienced the dismemberment of the Austria-Hungary (the Austro-Hungarian empire) which collapsed as a result of its defeat in World War I.  After the war, he also witnessed the short-lived socialist regime of Bela Kun together with the devastating currency inflation that followed and affected Hungary a great deal at the time. Amidst all these, he was anyways a joyful and friendly boy. Dyson, in his book about Teller would later confirm that “His memoirs are full of stories about his friends and the tragic fates that many of them encountered” [1]. Seeing his Jewish friends being killed, he has come to realize to a great degree that human life is very fragile and frail. He escaped the fate of the killings perpetrated on Jewish people by first moving from Hungary to Germany in 1926, from Germany to Denmark in 1933, from Denmark to England in 1934, and from England to America in 1935.

 

Research in quantum and nuclear physics

While a student in Germany, he joined a group of young people working at Leipzig and led by the 28 years old Heisenberg. The latter had just come up his leading-edge quantum mechanics paradigm in 1925. Quantum mechanics provided Teller with a thorough understanding of the working mechanism of atoms and how to better explain them. He used to his advantage of the promise of quantum mechanics to explain all that atoms do and explain their behavior. As a chemist in the group, Teller also decided to use chemistry to explain quantum mechanics. In 1930, Teller wrote a Ph.D. Thesis on the hydrogen molecule ion, the simplest of all molecules and made the subsequent years, significant contributions to molecular chemistry by applying quantum mechanics to it.

In 1933, when Hitler came to power, he moved to Copenhagen, Denmark where he met George Gamow, a young Russian who had been the first to apply quantum mechanics to nuclear physics. When Gamow moved to George Washington University in Washington, D.C., Teller decided to move to London. In 1935, he joined Gamow, at Gamow’s invitation, at George Washington University. Together, they came up with the Gamow-Teller theory, a nuclear physics theory that became twenty years later the basis for unified theory of weak interactions.

“In June 1939 Teller moved from Washington to Columbia University to help Fermi and Szilard with their project to build the first nuclear reactor” [1] While in New York and a few weeks before the outbreak of world war II, he received the visit of Heisenberg and tried to convince him to stay in America. Heisenberg politely declined the invitation but they will remain lifelong friends. A few days later, Szilard wrote a letter to President Roosevelt to inform him of the discovery of fission and the possibility of nuclear bombs. He got the letter signed by Einstein with the help of Teller as a driver since Szilard could not drive. “As a result, an official advisory committee on Uranium was established, and the bureaucratic machinery that later grew into the Manhattan Project slowly began to grind” [1].

 

The Manhattan Project and the Hydrogen Bomb

Teller worked two years (March 1943 – February 1946) at Los Alamos National Laboratory on the Manhattan Project which was an Allied effort to develop the first nuclear weapons. Even though Teller believed in the development of a nuclear weapon, he was reluctant to the idea of a weapon based on nuclear fission. Before the project began, he was invited to participate at Robert Oppenheimer’s summer planning seminar at the University of California, Berkeley to discuss the underlying scientific ideas of the Manhattan Project. “At the Berkeley session, Teller diverted discussion from the fission weapon to the possibility of a fusion weapon—what he called the Super, an early concept of what was later to be known as a hydrogen bomb” [3].

At Los Alamos, he first worked in the Theoretical Division that was led by Hans Bethe. But probably because of his interest in the Super and his repulsion for tedious calculations, he refused to do a massive calculation of the physics and hydrodynamics of an imploding bomb. He ran into some trouble with Hans because of that and was later moved out of the Theoretical Division by Oppenheimer whom he pretty much enjoyed working with. He was put in charge of a special group responsible of investigating his idea of the hydrogen bomb. Teller’s Super group became part of his friend Fermi’s F Division. “Despite an offer from Norris Bradbury, who had replaced Oppenheimer as the director of Los Alamos in November 1945, to become the head of the Theoretical (T) Division, Teller left Los Alamos on February 1, 1946, to return to the University of Chicago as a professor and close associate of Fermi and Goeppert-Mayer” [3]

After the war, in 1950, Teller would return to Los Alamos to work on the H-bomb project. With his Polish mathematician friend Stanislaw Ulam, Teller made a breakthrough invention that made possible the design of an H-bomb that was thought to be impracticable by some renowned physicists of his time. They came up with the Teller-Ulam design that is not, up to date, entirely accessible in the public domain. After the detonation of the first thermonuclear weapon to utilize the Teller–Ulam configuration, on November 1, 1952 in Ivy Mike, Teller became known to the media as the “father of the hydrogen bomb”

 

References

[1] F. J. Dyson, Edward Teller 1908-2003: A Biographical Memoir by Freeman J. Dyson, Washington: National Academy of Sciences, 2007.

[2] I. Hargittai, Judging Edward Teller: A closer look at one of the most influential scientists of the twentieth century, New York: Prometheus Books, 2010.

[3] https://en.wikipedia.org/wiki/Edward_Teller [Accessed: Jan. 17, 2018]

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Written by Bossou

 

Overview

Joseph W. Kennedy (May 30, 1916 – May 5, 1957) was an American chemist who co-discovered Plutonium and worked on weaponizing it as part of the Manhattan Project. He received his Bachelor’s degree at Stephen F. Austin State Teacher’s College, his Master’s degree from the University of Kansas, and his PhD from UC Berkeley.

Pre-War

Kennedy was one of the co-discoverers of plutonium, along with Glenn Seaborg, Edwin McMillan, and  Arthur C. Wahl in 1940. In particular, Kennedy built the instruments to verify the presence of the new element. They observed the creation of plutonium during experiments where uranium was bombarded with deuterons, creating neptunium (element 93), which, after beta-decay, created plutonium (element 94).

A paper about the discovery was submitted to the Physical Review, but was withdrawn after Seaborg, Emilio Segrè, and Kennedy discovered in 1941 that plutonium-239 was fissile, or able to sustain a fission chain reaction. After that, the patent was sold to the government, who made the existence of the element secret.

During the War

In March 1943, Kennedy was recruited for the Manhattan Project (started in 1942). Upon arrival, he became Acting Head of the Chemistry and Metallurgy (CM) Division at the Los Alamos lab, which was responsible for “purification and fabrication of active, tamper, and initiator materials of the bomb”.  In layman’s terms, they attempted to discover reliable methods to manufacture and shape plutonium. Despite initial concerns over Kennedy’s young age of 26, he did well in the position.

Kennedy was one of the few scientists who attended the Trinity test.

Safety Concerns

Kennedy became concerned with the safety of his work early on. Initially, he agreed to hide the discovery of plutonium from the public (and even managed to keep it secret from his wife, until she came across references to “PU” while in Los Alamos), and, during his time with the Manhattan Project, acted as part of a committee which attempted to develop better plutonium exposure tests.

In his book, as revealed by his wife Adrienne Lowry, Kennedy devoted a whole chapter to peaceful uses of atomic energy. He wondered about how they could possibly control the terrible thing they had let loose, and questioned the decision to drop a second bomb.

Post-War

After the war, Kennedy was bombarded with solicitations offering professorship from multiple colleges, including Harvard and Stanford. He ultimately accepted a position at Washington University in St. Louis.

He died of hereditary stomach cancer (from his mother’s side) on May 5, 1957 at the age of 40.

References

Atomic Heritage Foundation. (2018). Joseph W. Kennedy. [online] Available at: https://www.atomicheritage.org/profile/joseph-w-kennedy [Accessed 4 Jan. 2018].

Atomic Heritage Foundation. (2018). Plutonium. [online] Available at: https://www.atomicheritage.org/history/plutonium [Accessed 4 Jan. 2018].

En.wikipedia.org. (2018). Joseph W. Kennedy. [online] Available at: https://en.wikipedia.org/wiki/Joseph_W._Kennedy [Accessed 4 Jan. 2018].

Lowry, A. (2014). .

MANHATTAN DISTRICT HISTORY PROJECT Y THE LOS ALAMOS PROJECT. (1961). Los Alamos.

 

Victor Weisskopf

By Isaak Cherdak

Origins

As a man that began his career by advancing nuclear weapons research and later campaigning against their proliferation, “Viki” was a unique and influential character. Although Austrian born to a Jewish family in Vienna, Victor went to Germany to receive his doctorate in physics at the University of Göttingen. He was also recognized by and had the opportunity to work with some of the greatest physicists at the time. Victor died silently at his home on the 24th of April in 2002 at the age of 93.

Contributions, Positions, and Awards

Victor’s earliest contribution is in the field of Quantum Electrodynamics through his work on the structure of the atomic nucleus. Victor also managed to produce results demonstrating a phenomenon called Lamb Shift, named after Willis Lamb who published the results instead. However, Victor’s most notable contribution was perhaps his involvement as group leader in the theoretical division of the Manhattan project. By the end of World War 2, Victor joined MIT as the head of the Physics department. He was considered a memorable teacher that emphasized learning the mindset behind being a physicist over learning physics concepts. Victor soon made an important historical milestone for MIT where he co-founded the Union of Concerned Scientists (UCS), an organization focused on directing efforts of the scientific community away from the military and toward “pressing environmental and social problems” (En.wikipedia.org, 2018). Victor joined and served as Director General of CERN around the same time. He was also a member of the National Academy of Sciences, and president of the American Physical Society as well as the American Academy of Arts and Sciences. Over the course of his life, Victor received numerous awards including the Max Planck Medal, the Prix mondial Cino Del Duca, the National Medal of Science, the Wolf Prize, and National Academy of Science Public Welfare Medal. Victor even was appointed to a group chosen by the pope to dissuade at-the-time U.S. President Ronald Reagan from the use of nuclear weapons.

Challenges

Victor faced a number of challenges both due to his background and the nature of ethical concerns that arise from working with biological weapons. Victor had trouble in Europe, particularly because he was Jewish. This kind of discrimination was not uncommon, especially at the time. Luckily, Niels Bohr helped Victor find an appropriate position in the United States. Victor also was very insecure about his mathematical abilities; He once lost the opportunity for a Nobel Prize when somebody else published results that he was not completely sure of but turned out to be correct.  After Victor’s work on the Manhattan project, his focus had shifted to campaigning against the use of nuclear weapons. His contributions to the development of nuclear weapons must have had a tremendous effect on him as he has since taken to dissuading their use.

Sources Cited

En.wikipedia.org. (2018). Victor Weisskopf. [online] Available at: https://en.wikipedia.org/wiki/Victor_Weisskopf [Accessed 9 Jan. 2018].

MIT News. (2018). Weisskopf dies at 93; was protégé of physicist Niels Bohr. [online] Available at: http://news.mit.edu/2002/weisskopf-0424 [Accessed 9 Jan. 2018].

 

Side Note: I know about discrimination against the Jews in these areas mostly from personal experience since this is the major reason my parents, and a large number of other people in areas formerly under control of the USSR, immigrated to the United States.

Early Life

The “atom smasher”, Ernest Orlando Lawrence was born to Norwegian immigrants in Canton South Dakota on August 8, 1901. He attended public schools in South Dakota going on to receive BS from the University of South Dakota and a Masters from the University of Minnesota. Lawrence finished his formal education with a Ph.D in physics from Yale in 1922. After much courting, he moved to Berkeley in 1928 as an associate professor, and was made the then youngest ever, full professor in 1930. In 1936 Founded the Radiation “Rad” Lab at UC Berkeley. Novel in both the research being conducted but also the interdisciplinary collaboration between physicists, biologists, engineers, and chemists. This broke from the traditional silos of academic research of the past, and encouraged regular interdisciplinary collaboration.

Cyclotron

When Lawrence took up particle bombardment, the field had seen little success. There had been work done, Rutherford at Cambridge, but there were too few radioactive materials with a significant lack of the voltage necessary to penetrate the nucleus. Lawrence, familiar with previous work of high voltage particle acceleration, read a concept sketch by Rolf Wideröe detailing the reuse of electric potential. Lawrence realized the design was flawed, but altered the design to include such advanced technologies such as high vacuum electric fields and single plane particle control. In 1931, Lawrence, with the help of a grad student, created the first cyclotron. It used 1,800 volts to accelerate hydrogen ions to 80,000 volts. Lawrence won the Nobel Prize in 1939 for his creation of the cyclotron.

Manhattan Project

Of the many great challenges in building a nuclear weapon is creation of fissile material. One of these methods is to separate uranium-235, an isotope from uranium-238, which is comparatively abundant. The Rad Lab took up the challenge. Lawrence took his largest cyclotron, 37 inches, and magnet, 184 inches, and altered them into mass spectrographs. This would separate 235 and 235 electromagnetically in a process called uranium enrichment. In 1942, the calutron was born. The U.S. Army, under the codename Manhattan Engineer District, built 15 racetracks consisting of 96 calutrons in Oak Ridge, TN. Lawrence was tasked with organizing the staff and combat any technical problems that occurred.

Post War and Legacy

With the first nuclear detonation by the Soviet Union in 1949, the nuclear scientific community was split. Lawrence sided with the proponents for the development and use of fusion based weaponry. This led to his proposal of the creation of a second nuclear weapons lab, Livermore National Lab. Though he supported the design of thermonuclear weapons, Lawrence worked on a test ban treaty with the USSR until his untimely end. Ernest Lawrence died August 27^th, 1958 from complications of Ulcerative Colitis. Twenty-three days after his death, The UC Board of Regents named both Berkeley and Livermore Labs after him. Lawrence left a legacy as not only the father of nuclear science , but as the first to explore multidisciplinary scientific organizations and the first promoter of large scale, “Big Science.“

References

American Institute of Physics. (2018). Ernest Lawrence.[online]Available at: https://history.aip.org/exhibits/lawrence/bomb.htm [Accessed 1/2/2018]

Lawrence Berkley Lab. (2018). Ernest Lawrence. [online]Available at: http://www2.lbl.gov/Science-Articles/Archive/lawrence-legacy.html [Accessed 1/3/2018]

Wikipedia.[2018]. Ernest Lawrence.[online]Available at: https://en.wikipedia.org/wiki/Ernest_Lawrence [Accessed 1/3/2018]