A picture drawn on a napkin won him the Nobel Prize and became the "Father of Big Science"

Lawrence invented and developed the cyclotron, created and expanded the radiation laboratory, and led to a large number of important discoveries, for which he won the Nobel Prize in Physics in 1939. The laboratory he led pushed physics research into what is known today as "big science", so Lawrence is also known as the "father of big science". During World War II, Lawrence's team was responsible for the uranium enrichment project and made a significant contribution to the manufacture of atomic bombs, so much so that Oppenheimer believed that Lawrence was the most influential scientist in many aspects of the field of atomic energy in the United States, and his importance exceeded his own.

Written by | Wang Shanqin

In 2012, the Large Hadron Collider (LHC), which cost more than $13 billion, discovered the Higgs particle. In 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO), which cost more than $1.1 billion, directly detected gravitational waves. Such projects are what we call “big science.”

Big science projects, with their large instruments, huge costs, and large numbers of people, are very different from "small science" projects that can be done on a bench or theoretical research using only pen, paper, and a regular computer. In the past few decades, big science projects have become the mainstream of experimental physics and astronomy.

In the process of moving towards big science, one person played a key role - Ernest Orlando Lawrence (1901-1958). Lawrence invented and vigorously developed the cyclotron, created and expanded the "radiation laboratory", and was therefore hailed as the "Father of Big Science".

Lawrence, 1939. Image source: Nobel foundation

As a pioneer of big science, the team led by Lawrence was responsible for the uranium enrichment project during World War II. Its position in the manufacture of the atomic bomb was no less than that of Oppenheimer (J. Robert Oppenheimer, 1904-1967). Oppenheimer even believed that Lawrence's position at the time surpassed his own.

This article introduces Lawrence's life, achievements and the scientific legacy he left behind.

Early academic activities

Lawrence was born on August 8, 1901 in Canton, a small town in South Dakota, USA. His father, Carl Lawrence (1871-1954) and his mother, Gunda Lawrence (1874-1959), were both teachers and descendants of Norwegian immigrants. Lawrence had a younger brother, John Lawrence (1904-1991).

After graduating from high school, Lawrence first studied at St. Olaf College in Minnesota for a year, then transferred to the University of South Dakota, where he received a bachelor's degree in chemistry in 1922. He then spent a year at the University of Minnesota to obtain a master's degree in physics, with a research topic of building an experimental device to rotate an ellipsoid in a magnetic field. Then, Lawrence went to the University of Chicago and then transferred to Yale University to study for a doctorate on the photoelectric effect in potassium vapor.

In 1925, Lawrence received a doctorate in physics and stayed at the university to continue his research on the photoelectric effect. Because he skipped the grade and became an assistant professor without becoming a lecturer first, Lawrence caused dissatisfaction among some colleagues. In 1928, the Department of Physics at the University of California, Berkeley (UCB) hired him as an associate professor, and Lawrence happily went there. The following year, Oppenheimer came to UCB, and Lawrence soon became his close friend.

In 1930, at the age of 29, Lawrence became the youngest full professor in the university. In 1932, he married his girlfriend Mary Blumer (1910-2003). Mary graduated from Vassar College and then completed graduate studies at Harvard Medical School; Mary's father, George Blumer (1872-1962), served as the dean of Yale University School of Medicine from 1910 to 1920.

In 1934, the Lawrences had their first child, John Eric Lawrence (1934-2010). They went on to have five more children: Margaret, Mary, Robert, Barbara, and Susan. [1]

Mary, Lawrence, daughter Margaret, and son Eric outside the UCB physics building in 1939. Image credit: Lawrence Berkeley National Laboratory

Cyclotron and Radiation Laboratory

One evening in April 1929, Lawrence was very excited when he saw a paper by Norwegian physicist Rolf Wilderøe (1902-1996). Wilderøe conceived an accelerator with a straight accelerating pipe that could continuously accelerate particles using alternating current. After calculations, Lawrence realized that if he wanted to use a straight pipe to accelerate charged particles to a high enough speed, a very long pipe would be needed.

Lawrence immediately envisioned a more compact device and drew its schematic on a napkin. Its core is two cavities with a cross-section shaped like the letter "D", namely "D-shaped boxes". Under the action of the electric field, the charged particles first start from one D-shaped box, enter the other D-shaped box, and then move half a circle under the action of the magnetic field; after the direction of the electric field changes, the particles are accelerated into the original D-shaped box, and the particles complete half a circle of movement under the action of the magnetic field and enter the other D-shaped box again. This process is repeated continuously, and particles can be accelerated to very high speeds without the need for long pipes.

Schematic diagram of a cyclotron. This diagram appears in Lawrence's 1934 patent application. The left is a "top view" and the right is a "side view". Image source: Ernest O. Lawrence - US Patent 1,948,384

Lawrence later called it a "cyclotron". This idea made Lawrence very excited. The next day, a family member of a colleague passed by him and heard him shouting, "I'm going to be famous!" [2] However, it was difficult to build such an accelerator in practice. Lawrence had to put it aside for a while. Once, he mentioned this idea to the visiting Nobel Prize winner Otto Stern (1888-1969), who was very excited and asked him to go to the laboratory to start working immediately. [2] So Lawrence asked his graduate student Niels Edlefsen (1893-1971) to help him build the cyclotron he envisioned.

In April 1930, Edfusson built a crude model of the machine. This was the world's first cyclotron accelerator. It was only 4 inches in diameter (10 cm, referring to the diameter of the magnet, the same below), could be held in one hand, and cost $25 (equivalent to $460 today). [3]

After Edfuson left UCB in September 1930, Lawrence asked his graduate student Milton Livingston (1905-1986) to build a larger cyclotron. In January 1931, Livingston built an 11-inch (28 cm) cyclotron that accelerated protons to 1.22 MeV, the first usable cyclotron. In 1932, Lawrence applied for a patent for the cyclotron.

Lawrence's invention of the cyclotron was also a matter of luck. In the same period, German physicist Max Steenbeck (1904-1981) first proposed the idea of ​​the cyclotron in 1927; Hungarian physicist Leo Szilard (1898-1964) also conceived the cyclotron in 1928, calculated the cyclotron frequency (resonance condition) for the first time, and applied for a patent in 1929. However, they did not publish relevant research or patents, let alone manufacture or find someone to help manufacture the cyclotron. Lawrence thus became the inventor of the cyclotron.

Lawrence foresaw the broad prospects of cyclotrons in the field of nuclear physics. On August 26, 1931, Lawrence founded the Radiation Laboratory in the UCB Department of Physics. In early 1932, Lawrence and Livingston designed a 27-inch (69 cm) cyclotron with a magnet weighing 80 tons. After that, Lawrence persuaded the wealthy people he knew to sponsor his team to build larger and larger cyclotrons.

Fruitful achievements, won the Nobel Prize

In 1934, Irène Joliot-Curie (1897-1956) and her husband Jean Joliot-Curie (1900-1958) discovered artificial radioactivity. Lawrence and his team used a 27-inch cyclotron to accelerate protons and bombard carbon 13 with them to produce nitrogen 13, an artificial radioactive isotope of nitrogen.

In July 1936, the Radiation Laboratory became a formal department, and Lawrence became the first director. In June 1937, Lawrence's team built a 37-inch (94 cm) cyclotron. In the same year, Italian physicist Emilio Segrè (1905-1989) and his colleagues confirmed element 43, technetium, in samples sent to them by Lawrence. These samples were produced by bombarding targets with particles accelerated by the cyclotron.

In May 1939, Lawrence's team built a 60-inch (152 cm) cyclotron. In June of the same year, Lawrence's team used it to accelerate protons to bombard iron and obtain a batch of new radioactive isotopes.

Because of these achievements, Lawrence was awarded the Nobel Prize in Physics in November 1939, becoming the first Nobel Prize winner at UCB. He was awarded for "the invention and development of the cyclotron, and the results obtained therefrom, especially those concerning artificial radioactive elements". He did not go to Sweden to receive the award because ships traveling between Europe and the United States were attacked by Nazi German submarines at the time. The award ceremony was held on the UCB campus on February 29, 1940.

In 1938, before the 60-inch (1.52-meter) cyclotron was completed, scientists from the Radiation Laboratory took a group photo on the yoke of the magnet. The fourth from the left in the first row is Lawrence, and the one sticking his head out from the middle of the highest row, holding a pipe, is Oppenheimer. 丨Image source: Lawrence Berkeley National Laboratory

Winning the Nobel Prize dramatically increased the reputation of Lawrence and his laboratory. It was easier for them to obtain funding, and they soon produced more and more important results. In 1940, Martin Kamen (1913-2002) and Sam Ruben (1913-1943) of the Radiation Laboratory bombarded graphite with protons accelerated by a cyclotron to obtain carbon 14. This was the first discovery of carbon 14. In the same year, Dale Corson (1914-2012), Kenneth MacKenzie (1912-2002) and Segrè produced element 85, astatine.

Edwin McMillan (1907-1991) bombarded beryllium with deuterons accelerated by a 37-inch cyclotron. The neutrons released by the reaction were used to bombard uranium, and finally element 93 was confirmed from the product. It was soon named neptunium. This was the world's first "transuranium element" (an element with more protons than uranium) to be created. McMillan married Elsie Blumer (1913-1997), the sister of Lawrence's wife, in 1941 and became the brother-in-law of the Lawrence couple. In 1951, McMillan won the Nobel Prize in Chemistry for discovering neptunium.

Also in 1940, Lawrence began construction of the 184-inch cyclotron, which had a magnet weighing 4,500 tons and a budget of $2.65 million (equivalent to $58 million today). The laboratory in the UCB Physics Building could not accommodate such a large machine, so the Radiation Laboratory was moved to the hillside of the Berkeley Hills.

McMillan (left) and Lawrence (right). 丨Photo source: ENERGY.GOV

The achievements of the Radiation Laboratory that Lawrence founded and expanded in the production of new elements enabled the United States to catch up with the advanced level of Europe in the field of artificial radioactivity and rank among the top in the world. Lawrence is therefore recognized as one of the most outstanding scientific leaders in the United States.

Manhattan Project

In December 1938, the fission of uranium was discovered (see "This discovery that changed the fate of mankind embodies the hard work of many Nobel Prize winners"). Subsequent research confirmed that the fission of uranium 235 would trigger a chain reaction, which could be used to release nuclear energy and manufacture the core of an atomic bomb. These discoveries inadvertently opened the door to the era of nuclear energy and nuclear weapons.

The United States quickly launched research on the atomic bomb and established the Uranium Committee, which later became the S-1 Committee. Lawrence was one of the members of the committee and therefore one of the main decision makers of the atomic bomb manufacturing plan. At this time, Oppenheimer had not yet been included in the atomic bomb project.

On September 13, 1942, members of the S-1 Committee took a group photo. From left to right, they are Harold Urey (1893-1981), Lawrence, James Conant (1893-1978), Lyman Briggs (1874-1963), Eger Murphree (1898-1962) and Arthur Compton (1892-1962). Image source: LBL NEWS Magazine, Vol. 6, No. 3, Fall 1981, p. 32

In February 1941, Glenn Seaborg (1912-1999) and his collaborators used the cyclotron of the Radiation Laboratory to produce the first isotope of plutonium 94, plutonium 239 (for which Seaborg shared the 1951 Nobel Prize in Chemistry with MacMillan). They soon discovered that plutonium 239 would fission, and that its fission efficiency was higher than that of uranium 235, and that it could also be used to make atomic bombs.

In August 1942, the Manhattan Project, which was dedicated to the development of the atomic bomb, was officially launched. The raw materials for making atomic bombs are uranium 235 and plutonium 239. The former must be separated from natural uranium, and the latter is obtained by neutron irradiation (bombardment) of uranium 238. The radiation laboratory headed by Lawrence was responsible for the production of enriched uranium, and the "metallurgical laboratory" headed by Compton was responsible for the production of plutonium.

In September 1942, Leslie Groves Jr. (1896-1970) was appointed director of the Manhattan Project. He wanted Compton, Lawrence, or Urey to be the director of the central laboratory responsible for designing and manufacturing the atomic bomb (later known as the Los Alamos Laboratory) because they were all Nobel Prize winners, had rich management experience, and posed no security risks. However, he believed that the tasks undertaken by these three people were too important to leave their respective positions, so he had to look for other candidates. [4] Finally, on the recommendation of Compton and others, Groves appointed Oppenheimer as the director of the laboratory.

Electromagnetic separation and the University of California cyclotron

Only 0.714% of natural uranium is uranium 235 (99.28% is uranium 238, and 0.006% is uranium 234). The process of obtaining enriched uranium is to separate most of the uranium 238. Uranium 235 and uranium 238 have the same chemical properties, so they cannot be separated by chemical methods and can only be separated by physical methods. The specific methods are: electromagnetic separation, gas diffusion, liquid thermal diffusion and centrifugal separation. At that time, the last two methods were too inefficient, and the most promising ones were electromagnetic separation and gas diffusion.

The principle of electromagnetic separation is that after the particles are driven into the vacuum chamber of the mass spectrometer, they are deflected by the magnetic field. Particles of different masses have different degrees of deflection. After circling half a circle in the vacuum chamber, they enter different collectors. This is the basic principle of the mass spectrometer.

On November 24, 1941, Lawrence and others removed the magnet of the 37-inch cyclotron and installed a mass spectrometer, which was called the "California University Cyclotron", abbreviated as Calutron. It is also translated as "electromagnetic isotope separator". Strictly speaking, this name applies to all isotope separators that use electromagnetic separation, and the "University of California Cyclotron" is just one of them. The two are not equivalent. However, for the sake of convenience, the following description will refer to this machine as "isotope separator".

On December 2, 1941, the UC accelerator was put into operation for the first time. On January 14, 1942, after working for 9 hours, the UC accelerator produced 18 micrograms of uranium 235 with a concentration of 25%. To improve efficiency, Lawrence dismantled the magnets of the 184-inch cyclotron under construction and built a larger isotope separator (XA), which was completed and put into operation on May 26, 1942.

However, these already terrifyingly large accelerators were only prototypes to test the feasibility and efficiency of electromagnetic separation. After the successful test, Lawrence suggested building multiple larger isotope separators to obtain enriched uranium in batches.

The electromagnetic separation method is simple in principle, but the operation requirements are very high, requiring equipment with high vacuum, high voltage and strong magnetic field. Its advantage is high feasibility. Yuri, the person in charge of the gas diffusion method, said that the difficulty of the electromagnetic separation method is like looking for a needle in a haystack with boxing gloves. Hans Bethe (1906-2005), a young master of nuclear physics, did not believe that any uranium enrichment plan could succeed, so he refused to join the Manhattan Project for a time, until he found that plutonium 239 could be used to make atomic bombs, and then he agreed to join.

However, Lawrence firmly believed that as long as there were enough large machines, usable enriched uranium could be accumulated in a short enough time. Groves later recalled that at the beginning, Lawrence was almost the only one who had confidence in the electromagnetic separation method, but Lawrence insisted on promoting the project. "If we did not have great confidence in Dr. Lawrence's ability and courage, we would not have tried this."

On June 25, 1942, the S-1 Committee, which was responsible for managing uranium raw materials, proposed building an electromagnetic separation plant and a gas diffusion plant at Oak Ridge, Tennessee. The Radiation Laboratory in Lawrence was responsible for the former, and Urey's laboratory was responsible for the latter.

One day in October 1942, Groves visited Lawrence's radiation laboratory for the first time. He was very satisfied with the progress and decided to praise Lawrence as an encouragement. He said: "So, Mr. Lawrence, you'd better work hard. Your reputation depends on this work." [5]

The others present were stunned, because no one had ever dared to speak to Lawrence in such a way. Lawrence maintained his social grace and did not respond on the spot. Later, he invited Groves to lunch. At the restaurant, Lawrence looked Groves in the eye and said, "General Groves, in response to what you just said to me, I can say this: my reputation is already established, and it is your reputation that depends on this work." [5]

Oak Ridge Y-12 Plant

On February 18, 1943, the electromagnetic separation plant code-named "Y-12" began construction. Its mission was to obtain enriched uranium using more and larger isotope separators. All companies involved in the construction had people stationed in the radiation laboratory to communicate with the scientists there in a timely manner. Lawrence also appointed a special liaison officer to be responsible for the communication between the radiation laboratory and the Y-12 plant.

Theoretical studies have shown that the concentration of uranium 235 in weapons-grade uranium must exceed 80%, preferably 90%. This requirement cannot be achieved by a single separation, and two separations are required, using a primary separator and a secondary separator.

The first batch of first-stage separators were designed as a closed elliptical magnetic ring with a circumference of 37 meters, a width of 23 meters, and a height of 4.6 meters. There were 48 pairs of vacuum chambers placed back to back, totaling 96. Because they resembled a "racetrack", they were called "α racetracks". The second-stage separators were relatively small and had a straight configuration, which was called "β racetracks". The configuration of the second batch of "α racetracks" was changed to a straight line.

An "alpha runway" in the Y-12 factory, circa 1944 or 1945. Image source: Leslie R. Groves

On November 1, 1943, the first "α runway" was completed (due to a malfunction, it was dismantled for repair and restarted). In January 1944, the second "α runway" was put into use. After that, the "β runway" and other "α runways" were put into use one after another. Due to the shortage of copper during the war, the coils of these separators were all made of silver.

In March 1944, the "alpha runway" of the Y-12 plant separated the first few hundred grams of uranium with a concentration of 13%-15%. Although it did not reach weapon grade, it was very important for related experimental research, so the samples were shipped to Los Alamos. On June 7, 1944, Y-12 delivered its first batch of weapons-grade uranium with a uranium-235 content of up to 89%.

The K-25 plant, which used the gaseous diffusion method, and the S-50 plant, which used the thermal diffusion method, both started construction relatively late, and did not begin operation until March 1945. The low-enriched uranium obtained by the S-50 plant was further enriched by the K-25 plant, and then enriched to weapons grade by the Y-12 plant. In the spring and summer of 1945, the Y-12 plant could produce 30 kilograms of weapons-grade enriched uranium per month. A uranium atomic bomb (gun-type uranium bomb) detonated by the "gun method" required more than 60 kilograms of enriched uranium, which corresponded to two months of production at the time.

The control panel and operators of the Y-12 plant separator. Most of these operators were women, and they later became known as the "Calutron Girls". 丨Image source: unknown (probably Ed Westcott)

With the smooth progress of uranium enrichment, scientists in the Metallurgical Laboratory, which Compton was in charge of, could confidently advance the plutonium bomb program, which had a much greater risk of failure. Groves commented on the electromagnetic separation method: "It enabled us to obtain the uranium 235 samples needed in the early days of Los Alamos, and later the uranium 235 required for the bomb that bombed Hiroshima. Without it, our plutonium bomb design work would have been seriously delayed." [4] Groves believed that without Lawrence, the entire Manhattan Project could not have been successfully promoted. [4]

On July 16, 1945, Lawrence and others witnessed the world's first atomic bomb explosion at the test site - the "Trinity" nuclear test, which used an implosion-type plutonium bomb.

At this time, the Y-12 plant had produced about 60 kilograms of enriched uranium. On July 24, 1945, this enriched uranium was transported to Los Alamos and then assembled into the first gun-type uranium bomb. The gun-type uranium bomb was sure to succeed, so there was no need for testing. The uranium bomb was transported to Tinian Island at the end of July, where American planes would load the atomic bomb and drop it on Japan.

Because of Lawrence’s leading role in the uranium enrichment project, Bruce Reed said in The Physics of the Manhattan Project: “Every uranium atom in the Hiroshima bomb passed through Lawrence’s hands.”[6]

However, in a secret meeting before the use of the atomic bomb, Lawrence opposed the use of the atomic bomb because his radiation laboratory had Japanese colleagues. Instead, it was Oppenheimer, who later claimed that he had "blood on his hands", who agreed to use the atomic bomb at the meeting.

By December 1945, the Y-12 plant had produced about 900 kg of 95% uranium 235, enough to make at least 15 more gun-type uranium bombs. If the implosion method was used, more uranium bombs could be made. The gaseous diffusion method could now independently produce weapons-grade enriched uranium, and this method was much more efficient than the electromagnetic separation method in producing enriched uranium, so the Y-12 plant was soon closed.

As early as the spring of 1940, when optician Robert Wood (1868-1955) wrote to congratulate Lawrence on his Nobel Prize, he said in the letter: "Since you are laying the foundation for the catastrophic explosion of uranium... I believe that old Nobel would agree."

In 1954, during Oppenheimer's hearing, a security committee lawyer asked Oppenheimer, "Doctor, from 1943 until recently, you were the most influential scientist in the field of atomic energy in this country, right?" Oppenheimer replied, "I think Lawrence was probably more influential in many ways."

The Father of Big Science

After the war, Lawrence's Radiation Laboratory began to refocus its efforts on research. In 1946, Lawrence applied for more than $2 million from the Manhattan Project. The XA magnets were dismantled and reused to build the 184-inch cyclotron, which was completed in November 1946.

In 1947, Lawrence applied for $15 million, part of which was used to build the Billions of eV Synchrotron (Bevatron). Bevatron is a proton accelerator that was built in 1954.

In 1950, Lawrence and others looked down at the Bevatron model. Image source: Lawrence Berkeley National Laboratory

Segrè and Chamberlain (Owen Chamberlain, 1920-2006) used the Bevatron to produce antiprotons in 1955, and Bruce Cork (1916-1994) and others used it to produce antineutrons in 1956. These achievements have made important contributions to human exploration of antiparticles and even antimatter. Segrè and Chamberlain were awarded the 1959 Nobel Prize in Physics for this.

Lawrence also won the second Enrico Fermi Award in 1957 for his contributions to nuclear physics. It is worth mentioning that Lawrence's brother John Lawrence also won the Fermi Award in 1983 for his work using cyclotron-produced radioactive isotopes to treat leukemia and polycythemia.

From the 1930s to the 1950s, Lawrence raised huge amounts of money from various channels, built increasingly powerful accelerators, organized and managed a large team in the laboratory, and established the "big science" model. Lawrence is a well-deserved "father of big science."

With Oppenheimer: From Brothers to Parting Ways

Of all Lawrence's friends, the one with whom he had the most complicated relationship was Oppenheimer. They once had a deep friendship. To express his love for Oppenheimer, Lawrence named his fourth child Robert (Oppenheimer's name was Robert).

However, their friendship was torn apart by their different political positions. At UCB, Oppenheimer had close contact with the left-wing figures in the United States at the time, and supported the scientists and graduate students at the school and even the radiation laboratory to participate in union activities. Lawrence was politically conservative; in addition, Lawrence was very close to the wealthy people who funded the radiation laboratory, and those wealthy people would not agree to some of the union's demands.

Therefore, Lawrence was angered by Oppenheimer more than once. Oppenheimer thought Lawrence was too overbearing and too sycophantic. During the Manhattan Project, Oppenheimer took the initiative to stay away from left-wing activities and actively participated in the construction of the University of California accelerator, solving some problems. The conflict between Lawrence and Oppenheimer was greatly eased for a time.

After World War II, Oppenheimer decided to resign as director of Los Alamos Laboratory. President Sproul (Robert Sproul, 1891-1975) invited Oppenheimer to return to UCB. Oppenheimer did not want to return to UCB because of his bad relationship with Sproul and the head of the physics department, Raymond Birge (Raymond Birge, 1887-1980).

Lawrence also persuaded Oppenheimer to return, but Oppenheimer declined on the grounds that Harvard University could offer him two or three times the salary. Lawrence asked Sproul to double Oppenheimer's salary, arguing that Oppenheimer's fame could bring in far more money than this salary. Sproul reluctantly agreed.

When Lawrence invited Oppenheimer back with a higher salary, Oppenheimer told the truth and said that Birch should leave the position of department head. Lawrence was very angry. Oppenheimer later wrote to Lawrence, saying that he had always been at a disadvantage in front of Lawrence for so many years, and his words were full of resentment. [7] However, the two had not yet broken up. After the 184-inch cyclotron was completed, the two happily took a photo in front of the accelerator.

Oppenheimer (left) and Lawrence (right) in front of the 184-inch cyclotron, circa 1946. Image source: University of California (Berkeley) Radiation Laboratory

In 1948, Richard Tolman (1881-1948), a mutual friend of Lawrence and Oppenheimer, died of a heart attack. Prior to this, Oppenheimer had been having an extramarital affair with Tolman's wife. Lawrence believed that Tolman had a heart attack after learning of his wife's affair, "and he died of a broken heart." Lawrence said that Tolman's death was the first time he became dissatisfied with Oppenheimer. [7]

In 1949, the Soviet Union successfully detonated an atomic bomb. Lawrence immediately began to actively promote the manufacture of hydrogen bombs and built a branch of the Radiation Laboratory in Livermore, which later became one of the important institutions for the manufacture of hydrogen bombs. Oppenheimer, however, strongly opposed the manufacture of hydrogen bombs. The rift between the two quickly widened.

In 1953, Lewis Strauss (1896-1974) became the chairman of the Atomic Energy Commission (AEC). Oppenheimer was previously the chairman of the General Advisory Committee (GAC) under the AEC. Strauss had a long-standing grudge against Oppenheimer and strongly supported the manufacture of hydrogen bombs, so he decided to expel Oppenheimer from the decision-making level of nuclear weapons and eliminate Oppenheimer's influence.

In 1954, Strauss organized a hearing against Oppenheimer to strip him of his Q-level security clearance (the highest level of security clearance, allowing access to nuclear secrets). He invited Lawrence to testify against Oppenheimer.

Lawrence was very angry about Oppenheimer's repeated obstruction of hydrogen bomb research and agreed to attend. However, the night before the hearing, he called Strauss and said that he had colitis and could not attend the hearing. In the movie "Oppenheimer", Lawrence was persuaded to leave by the gaze of the rabbi (Isidor Rabi, 1898-1988) outside the hearing room. This was a dramatic fiction in the movie because Lawrence did not go near the hearing site that day.

Strauss was furious and accused Lawrence of being a coward. Lawrence may indeed have feared that attending the accusation would worsen his relationship with some colleagues, so he backed out at the last minute (so-called "cowardice"). But he may have really had a colitis attack that day, because he did have severe colitis. Of course, he may have been out of consideration for old friendships at the last minute. His absence may have been the result of two or even three of the above reasons at the same time.

However, when AEC officials visited Lawrence, they left a written record of Lawrence criticizing Oppenheimer. Lawrence believed that Oppenheimer "should no longer have anything to do with decision-making." This was used as one of the testimonies against Oppenheimer. In the end, Oppenheimer's security clearance was terminated. However, Lawrence's interview record may not have played a decisive role in the final result.

This hearing also represented a complete break between Lawrence and Oppenheimer. However, Lawrence refused to appear in court, thus avoiding a face-to-face breakup with Oppenheimer and ending their friendship in a relatively decent way.

Lawrence's Legacy

On August 27, 1958, Lawrence died of colitis at the age of 57. His early death was related to his long-term high-intensity management work. His frequent travels between the east and west of the United States during the Cold War had an impact on his health.

There is a heartwarming scene in the movie "Oppenheimer": In 1963, when Oppenheimer won the Fermi Prize, at the award ceremony, the gray-haired Lawrence went over and patted Oppenheimer on the shoulder to show reconciliation. However, this scene did not happen: in 1963, Lawrence had been dead for five years. (Of course, the movie is not a documentary, so it is also good to give the audience a beautiful imagination.)

To express gratitude to Lawrence for establishing and developing the Radiation Laboratory, the University of California Board of Regents renamed the Radiation Laboratory "Lawrence Radiation Laboratory" shortly after his death.

Later, the Lawrence Radiation Laboratory and its branch in Livermore were nationalized and renamed "Lawrence Berkeley National Laboratory" (LBNL) and "Lawrence Livermore National Laboratory" (LLNL), respectively, and were affiliated with the U.S. Department of Energy.

Aerial photo of LBNL's Buildings 62, 67 (Molecular Foundry), and 66. Image credit: US Department of Energy

In 1961, LBNL scientists announced the creation of element 103, which they named lawrencium in honor of Lawrence. This was a great honor, and when Seaborg later learned that his last name was used to name the new element (Seaborgium), he happily declared that this honor was better than the Nobel Prize in Chemistry he had won.

In fact, from 1949 to 1974, the Radiation Laboratory (LBNL) discovered element 97 berkelium (1949, the year of discovery, the same below), element 98 californium (1950), element 99 einsteinium (1952), element 100 fermium (1952), element 101 mendelevium (1955), element 102 nobelium (1958), element 103 lawrencium (1961), element 104 (1969) and element 106 (1974). Of the 27 transuranic elements discovered so far, 12 were first produced and confirmed in the Radiation Laboratory, accounting for as high as 44%.

Since its establishment, the Radiation Laboratory has been at the forefront of physics and chemistry, making many groundbreaking contributions to physics, chemistry, astronomy, cosmology, and other fields, as well as major contributions to biology, environmental research, energy, and other disciplines. So far, scientists at the Radiation Laboratory (LBNL) have won 15 Nobel Prizes, including 9 in Physics and 6 in Chemistry.

LBNL's city commuter bus, with "Bringing Science Solution to the World" written on the body | Image source: Wang Shanqin

Although LLNL is not as famous as LBNL, this organization enjoys a high reputation in the field of controlled nuclear fusion. The famous "National Ignition Facility" (NIF) is a laboratory managed by LLNL. It is the world's largest and most powerful laser system and the largest scientific project in the United States.

The building of the National Ignition Facility in the United States. The sign on it reads "National Ignition Facility Bringing Star Power to Earth". Image source: National Ignition Facility

In addition to physics research, cyclotrons have made important contributions to medicine. Some radioactive isotopes produced by cyclotrons have been used to treat cancer, thyroid disease, leukemia, polycythemia and other diseases, with certain therapeutic effects. To this day, cyclotrons are still widely used in many hospitals around the world.

Ernest Lawrence in the Cold War commented on Lawrence's contribution and influence:

"Lawrence left a great legacy. The development of the cyclotron transformed our understanding of nature, from the microstructure of matter to human metabolism, from the process of photosynthesis to the creation of new chemical elements. … Equally important, Lawrence created the model for the big science laboratory, which spread through the Manhattan Project to national laboratories in the United States and then to other countries. … Lawrence's laboratories advanced interdisciplinary approaches into fruitful new fields such as environmental research, alternative energy, astrophysics, and molecular biology. In the last area, Berkeley and Livermore laboratories were the two main centers for the Human Genome Project. Lawrence's laboratories helped build the first atomic bomb and then fueled a dangerous arms race with the Soviet Union, but they firmly believed that they had prevented nuclear war."[8]

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