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Preparation of the Gadget for Trinity Test, July 1945 (DOE)

Building the Bomb

Matt Wilce looks at the life and work of Manhattan Project physicist David Nicodemus ’33

At 5:10am on July 16, 1945, Sam Allison’s voice boomed out over the desert from a loudspeaker on the exterior control center, “It is now zero minus 20 minutes.” At 5:30am the world would change forever. The first atmospheric test of a nuclear weapon—the Trinity Test—was about to take place. Housed in bomb-proof shelters, less than six miles from the test site in New Mexico, over 425 observers waited. Along with Robert Oppenheimer, current and future Nobel Prize-winners and military personnel, one of those waiting was a promising, young physicist by the name of David Nicodemus ’33.

The thing that distinguished Nicodemus from his 250 colleagues in the Manhattan Project was his place of birth: Japan—the potential target of an atomic bomb, should the test prove successful.

Thunderstorms had swept across the site during the night, wracking up tension amongst the exhausted

scientists who had worked tirelessly for days readying the monitoring equipment and Gadget, as the test weapon was known. They threatened to delay the test, or worse. Gadget—a hodgepodge of electronics, high explosives, radioactive materials and an ionization chamber overseen by Nicodemus—sat on a wooden platform atop a spindly, hundred foot tall steel tower. A test version of its basic electrical system had been tripped by a passing storm, a potentially lethal failure that was not lost on those waiting for the weather to clear.

Hunkered down at the Alamogordo test site was every high-level member of the Manhattan Project, including its head General Leslie Groves. Groves, who had spent the days prior 120 miles away in Albuquerque at the Hilton Hotel enjoying spare ribs and mai tais at Trader Vic’s, was now kept waiting with the rest of the observers in the sparse, cramped conditions of the bunker.

With Trinity delayed by 90 minutes from its original 4am launch, the gathered scientists and military men were forced to wait with ever increasing tension. Hungarian-American theoretical physicist Edward Teller, who’d been instrumental in developing the implosion mechanism, took the time to slather sun cream on his face. Others toyed with their protective goggles, or took bets on the outcome of the test.

At 5:25am a rocket was launched from near the test site to indicate there were five minutes left. "Two minutes before the scheduled firing time all persons lay face down with their feet pointing towards the explosion. With a minute to go, another rocket pierced the desert air. Once the switch was thrown in the control center, a 45-second timer began counting down to the ignition of Gadget. The electrical charge triggered the bomb, setting off the 32 charges that surrounded the “solid pit” of hot pressed plutonium-gallium alloy that Teller, Nicodemus and the rest of the RaLa team had worked on. The sphere of plutonium compressed and Gadget exploded.

The sky fractured and a giant ball of fire rose, boiling from the desert floor. Orange at first and then purple.

Nicodemus later recalled simply being told, “Don’t look!” Teller later said that the atomic flash "was as if I had pulled open the curtain in a dark room and broad daylight streamed in." He had disobeyed order and stood during the test looking directly at the blast from behind a welder’s mask. Nicodemus had turned his back on the blast while the bulk of the observers had laid down as instructed. Just over two minutes after the flash of light, the shock wave from the blast hit—the crack continuing to reverberate off the surrounding mountains.

The world’s first nuclear weapon had just been detonated and mankind had entered the atomic age.


While over 110,000 Japanese Americans were interned in the United States as a potential threat to security following the Pearl Harbor attack and the United States entry into World War II, Nicodemus’ birth in Kobe, Japan proved no hindrance in him being selected for one of the war’s most secret projects. Born to missionary parents Frederick and Ella, Nicodemus spent his early years in Kansai before the family moved north to conduct missionary work in Sendai.

Nicodemus as a senior in the 1933 Chochin

Nicodemus and his older brother Fred ’30 were homeschooled using the Calvert Method until they were sent to Tokyo in 1929 to attend high school at ASIJ. As their parents were on a mission in Taihoku in Japanese-ruled Formosa (now the area in and around Taipei, Taiwan) at the time, the boys joined the small school dorm run by teachers Bernard and Persis Gladieux. Nicodemus quickly became a key member of the basketball team, where he was known for his quick passing and ability to cut through his opponents defense. He also found time to be the business manager of the Chochin his senior year, run track and play Algernon in the senior production of The Importance of Being Earnest.

“Bob Reischauer ’24 [who taught American and ancient history] was one of our very favorite teachers,” Nicodemus later recalled. “He was about the only one of the high school teachers who lectured in the manner you have classes conducted in university and he made them very interesting. He had us do lots of work on taking lecture notes and he was one of the few teachers who taught us how to take good notes.” Although at the time physics and chemistry were taught in alternating years due to the small faculty, the 1933 yearbook prophetically records that his future ambition was to become a professor.

It wasn’t all academics and sports though. “We had rather regular tea dances and class dances in the gym and would spend hours decorating the gym. Those were very much ‘stag’ affairs and there were very few dates. You might buy a ticket for a gal, but you’d meet her there,” Nicodemus recalled as an adult. “I do remember once that I wanted to take Peg Kriete who was a gal I liked very much then to a show down in Tokyo. I had to ride up to my folks in Sendai to get permission before Mrs Gladieux would let her out of the dorm,” he said. “I remember taking her by taxi and afterward we went to the Olympic Restaurant and had pancakes—that was the highpoint of my year.”

Trinity Test - Alamogordo, NM - July 16, 1945. Mushroom cloud after 10 seconds. Date 16 July 1945 (NARA/US Federal Govt)

One of the lasting legacies Nicodemus left his senior year was the new school seal—a modified version of which is still in use today. Harold Zaugg ’33 recalled that Hubbard Horn ’33 was the one that drew up the design and that Nicodemus and Bert Kriete ’33 had assisted in creating the concept. “Hubbie Horn was the class president and everyone seemed to like him very much,” Nicodemus remembered. Zaugg’s contribution was the Latin motto “Amicitia Per Scientiam”— Friendship through Learning. According to Zaugg, the design was supposedly inspired by the decorative border of the National Geographic magazines of the time and the doodles students would make on their homework in Violet Sweet’s geometry classes. The seal made its debut in the 1933 Commencement Program at a graduation ceremony presided over by the American Ambassador Joseph Grew.

Following graduation, the crew that created the school seal headed off on an adventure aboard the Kurama Maru. Nicodemus, Zaugg and Horn took the Kokusai Kisen steamship from Yokohama across the Pacific. Maintaining an average speed of 16 knots, the small ship made the crossing to Los Angeles in 12 days, with a further two-weeks of onward travel to New York its young passengers would have had plenty of time to enjoy the radio-gramophone and deck games—or

even “the luxury of sea water baths.” The three boys were all planning on attending Oberlin College in Ohio once they got Stateside, but as their ship passed through the Panama Canal, Nicodemus received a telegram saying he’d been awarded a scholarship to DePauw University in Indiana. Zaug and Horn stayed their course and attended Oberlin along with their classmate—and Nicodemus’ memorable date—Margaret [Peggy] Kriete ’33.

At DePauw, Nicodemus majored in math with the intent on becoming a teacher—even doing his teaching practice in the subject. He joined the Naperian Club, whose members explored complicated mathematical problems, becoming its vice president in his senior year. His college years also saw him join the science and education clubs, continue to run track and Nicodemus be inducted in Phi Beta Kappa. In his senior year an assistantship in the physics department became available, prompting Nicodemus to switch majors to enable him to take the position. “It gave me the chance to get involved in physics and do much more than I otherwise would have done,” he told The Oregon Stater in 1996. Following graduation in 1937, Nicodemus headed to Stanford to pursue advanced work in the subject.

It was at Stanford, where he took up a graduate teaching assistantship, that Nicodemus entered the big leagues. Nicodemus’ work in the lab focused on radiation physics, a growing field of research at the time. Felix Bloch—who would go on to receive the Nobel Prize for Physics in 1952—had joined the university a few years prior in 1934 and his arrival saw Stanford’s research program really take off. The Swiss scientist would go on to become professor for theoretical physics at Stanford and a year after Nicodemus joined the college Bloch began working with the 37-inch cyclotron at the University of California at Berkeley to determine the magnetic moment of the neutron, which would ultimately lead to them both being tapped for the Manhattan Project.

Nicodemus (second from the left) with the residents of the boys’ dormitory, including Harold Zaugg (third from the right)

The bombing of Pearl Harbor by the Japanese in 1941, brought the realities of war home to Nicodemus quite literally. Fred Nicodemus, his brother, was in Honolulu at the time, but fortunately was not injured in the attack. Their mother Ella, who had returned to Japan following the death of their father, was in Sendai teaching at a women’s college when America entered the war. Along with 50 other missionaries, she was interned in northern Japan. Nicodemus had no contact with her, save for a Red Cross postcard to say she was alive and well, until she was repatriated to the United States the following year. The outbreak of war also had a direct and immediate effect on Nicodemus and his work at Stanford.

Bloch and fellow Swiss physicist Hans Staub, who come over from Caltech in 1938, had received a grant from the Office of Scientific Research and Development to measure the energy spectrum of fission neutrons. Their experiments required an assistant to help run the cyclotron and build

the associated apparatus and Nicodemus was chosen to support the project. “It was a classified program and clearly something aimed to help the war effort,” Nicodemus said in a later interview.

Early in 1943, Staub and Bloch approached Nicodemus and said, “We’ll be moving to a place we’ll call now Shangri-la. We can’t tell you where it is, but we’d like you to come. We’re going to continue work related to what we have been doing but we can’t tell you exactly what it is.” That was Nicodemus’ induction into the Manhattan Project. “I was free, single and looking for a job, so I said I would be interested,” he later recalled.

Instructed to go to Santa Fe, Nicodemus reported to the Army Corps of Engineers Office where he was give directions to Los Alamos about 25 miles away. He was instructed that he could tell friends and family that he was living near Santa Fe and that he was working with Army Corps of Engineers and not much more beyond that. On his arrival in Los Alamos, Nicodemus discovered that the program there had already been running for about a year and that he was assigned to a men’s dormitory. The first thing he did was go to the library and check out a primer. “For the first two days I sat and read the primer. It explained right away that the purpose of the project was to build an atomic bomb and sketched out what the problems were for the whole project. The philosophy applied to the technical and professional staff was that they should all know what it was all about,” Nicodemus told The Oregon Stater. “Oppenheimer and the others who ran the project felt it was important not to compartmentalize too much. You worked on a particular problem, but you should also know what the others were doing.”

The ’33 ASIJ seal, created by Nicodemus, Harold Zaugg ’33 and Hubbard Horn ’33

Nicodemus would become part of the RaLa (a contraction of Radioactive Lanthanum) experimental program, an interdisciplinary research program at the Los Alamos laboratory headed by Luis Alvarez. The group comprised of metallurgists, engineers, electronic specialists, chemists and physicist who were tasked with achieving the spherical implosion necessary for compression of the plutonium pit of the nuclear weapon. On April 26, 1944, Alvarez brought the RaLa committee together to coordinate their experiments and Nicodemus found himself in the company of heavyweights such as Oppenheimer himself, Bruno Rossi, Staub, Seth Neddermeyer and Teller.

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Nicodemus and the OSU cyclotron in 1954 (Courtesy of OSC Special Selections and Archive Research Center)

“I was just a young kid who had completed his PhD research. To even meet these people and hear them talk at weekly seminars was a priceless opportunity,” Nicodemus said in a 1996 interview. “I was also lucky that Hans Staub was good to me and had me join his family for various occasions. When he and his wife were invited to a party, they often dragged me along. I had a chance to get into social situations with some of the big shots, if you will.” Although the work on the atomic bomb was top secret, Nicodemus noted that the number of Nobel Prize winners and prominent scientists in and around Santa Fe could be enough to raise suspicions. “If a knowledgeable outsider knew they were all there, he could make a pretty good guess and to what Los Alamos was about,” he quipped.

Nicodemus worked closely with his mentor Staub and with Bruno Rossi, who jointly headed the detector group. Nicodemus was responsible for overseeing the production and testing of numerous fast, cylindrical ionization chambers. Large numbers of these chambers were blown up during the preliminary tests of the RaLa implosion process and Nicodemus constructed the chamber that would be used in the Trinity Test.

Considering the risk of radiation contamination from the radioisoptope lanthanum-140 used in the experiments and to protect the experiment from shock, Alvarez moved the team’s work to a mobile laboratory located at Dugway Proving Ground in Utah. In his official history of the Los Alamos project, David Hawkins wrote: “RaLa became the most important single experiment affecting the final bomb design.”

Nicodemus remained in Los Alamos after the Trinity Test until 1946. He finished writing his thesis, titled The Average X-Ray Energy Expended in Forming an Ion Pair in Argon, and then returned to Stanford to take up a teaching position there. Staub also returned to Stanford as a full professor happy and eager to engage again in the peacetime pursuit of research. “By incorporating the results on the polarization of neutrons obtained before the war, he, with David Nicodemus and myself, succeeded in measuring the neutron magnetic moment with high accuracy,” Felix Bloch wrote in Physics Today. Nicodemus would teach there for the next four years while pursuing further research into neutrons, co-authoring scientific papers with both Staub in 1949 and Bloch in 1950. Two years later, Bloch would receive his Nobel Laureate, along with Edward Mills Purcell, for their development of new ways and methods for nuclear magnetic precision measurements.

While working at Stanford, Nicodemus had met a number of faculty members from Oregon State College (OSC) during their graduate work. When OSC began building a cyclotron they needed someone with expertise to join their physics program and Nicodemus was the perfect fit. Nicodemus and his new wife Janet Buck made the move to Corvalis, where he became an assistant professor of physics and began working on the cyclotron program. Within a year, he received the Carter Award for teaching from the College of Science in 1951.

Hans Staub (AIP Emilio Segrè Visual Archives, Physics Today Collection)

In the mid-fifties OSU expanded the cyclotron project, building a new 37-inch, 70-ton “atom smasher.” The device utilized 5.5 tons of copper strap and 50 tons of steel in the core magnet, which was salvaged from a magnet used by the Manhattan Project. Concrete walls up to 48 inches thick, salvaged from ship ballasts, surrounded the cyclotron to shield against radiation. Unlike commercial projects, which cost up to $500,000, the use of salvage materials, donated parts and having the device built by Nicodemus, other faculty members and students, meant the $175,000 Atomic Energy Commission grant was sufficient for the ambitious project.

Felix Bloch in the 1950s (The History Collection / Alamy Stock Photo)

Nicodemus went on to have a long and meaningful career at OSU becoming an associate professor in 1952 and a full professor in 1963. Honored for his teaching in 1956 with the university’s Outstanding Teaching Award, Nicodemus was made assistant dean of science in 1962. He headed the curricular and planning programs for the School of Sciences, the largest school on campus, and was made Dean of Faculty in 1966. In recognition of his commitment, Nicodemus won the Curtis Mumford Faculty Service Award in 1985 for the “quality and dedication” he brought to the job and for being the “conscience of Oregon State University.” Nicodemus held the role until his retirement in 1986.

Nicodemus’ lifelong connection to Japan continued when OSU began an exchange program. Nicodemus accompanied the first group of students to visit Waseda University. “To me it’s the most valuable experience a student can have. In one year of living as a member of a Japanese family, a student probably learns more about Japan and its people than I did in 17 years in Japan,” he said self-deprecatingly in 1996.


Gadget’s perch, the steel tower, was entirely vaporized in the blast. In its place was a huge sloping crater. The gathered scientists were initially dazed, but relieved that their years of work had paid off. Enrico Fermi, who’d won a Nobel Prize in 1938, was one of the first to venture out and examine the crater, using a specially designed tank to view the area. The enormity of what they had just witnessed began to sink in. Trinity had been successful—now the question became should the Allies use an atomic weapon against their enemy.

The scientists who had worked on the project were often circumspect on their role in creating the weapon and Bloch’s view was that if they hadn’t invented it, someone else would have. “I still believe that many lives were saved by the use of the bomb,” Nicodemus told The Oregon Stater. “Too many people were being killed on both sides. The determination of the Japanese to protect their country was so strong that an invasion was probably the only other way to get the job done, which would have been a very, very painful experience for both countries,” he reflected. “Whether it was a good or bad thing I can’t say. I just had the feeling it was a reasonable thing to do. War is dirty to begin with and the killing is terrible, particularly of civilians.”

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