Mary Lucy Miller

Once her boyfriend enlisted, so did she

April 26, 2023

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Mary Lucy Miller travels under secret orders to New Mexico in 1943 and reports for duty at Project Y. A chemist in her late 30s with a doctorate from Columbia University, she’s leaving a well-developed career in medical research. She is highly motivated: her boyfriend is overseas fighting and she will do her part in the Women's Army Corps to bring him home safely. 

Many WACs, as they’re called, are dating and falling in love in the secret town of Los Alamos. Grace Rich Jarboe, who sleeps next to Sgt. Miller’s bed in the barracks, notices that she stays out quite often until 1 or 2 a.m. and suggests she must be dating some special guy. 

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Mary Lucy Miller

“No, I have been working,” explains Sgt. Miller, who spends long hours at the D-Building laboratory for a mission she cannot reveal. 

Many WACs are unaware of Project Y’s secret mission to mastermind the world’s most powerful weapon before the enemy does. World War II has been raging for five years, and the U.S. president and military need to know whether they can count on the new bomb concepts to work. 

Time is critical. There is no room for error. None of this has been done before.

Sacrificing career for service (and Bill Ransford)

The switch from being Dr. Miller to Sgt. Miller all happened so fast, interrupting the career and the romance she had dreamed of. Right after completing her doctorate in physical chemistry, in 1934, she had spent four years at the Rockefeller Institute for Medical Research in New York. The year the war broke out, in 1939, she was a new research associate in the Pathology Department at Washington University School of Medicine in St. Louis.

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Bill Ransford and Mary Lucy Miller. 

In 1941, her world turned upside down. Four months after the Japanese attacked the U.S. naval base at Pearl Harbor, her boyfriend, William Blackburn Ransford, enlisted in the U.S. Army.

“Speed them back, Join the WAAC” was among the slogans on posters recruiting women for the war effort, and she took the bait. Just after her 39th birthday, in 1943, she enlisted in the Women’s Army Auxiliary Corps (WAAC), leaving behind her post at Washington University. The terms: “Enlistment for the duration of the War or other emergency, plus six months, subject to the discretion of the President or otherwise according to law.” 

The WAAC was quickly replaced by the Women’s Army Corps (WAC) in 1943, becoming part of the regular U.S. Army. Of the more than 600 women who work at Project Y in Los Alamos, approximately 40% are members of the WAC. 

Although she was not a radiochemist by training (polymer chemistry was her emphasis), she’s assigned to the Radiochemistry group (CM-4) in the Chemistry and Metallurgy Division. She’s one of only a few women soldiers at Project Y with a doctorate, yet she begins her military career as a private first class.

She is among the more than 150,000 American women who will serve in the Army during World War II. She will be promoted to Sgt. Miller out of respect for her special technical knowledge. She will achieve the highest of the three technician ranks used during WWII: U.S. Army Staff Sergeant, Technician 3rd Grade (T/3).

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WACs in the crowded Women's Army Corps barracks. Sgt. Miller lived in T-228, a two-story building for 60 women with a dayroom and a sundeck. Courtesy Los Alamos Historical Society Photo Archive

The plutonium secret

Project Y is racing to design and build the first atomic bombs, which would be far more feared than ordinary TNT bombs. One uses uranium and the other uses a mysterious new element believed to be more destructive than uranium. 

The word “plutonium” is rarely said out loud, and as a matter of wartime security its existence is kept secret. Around Project Y, plutonium is called “49” for short. The “49” stands for 94Pu239, with the four taken from the last digit in plutonium’s atomic number and the nine taken from the last digit of the isotope.

In the Chemistry and Metallurgy Division, Sgt. Miller is getting a hands-on introduction to this mysterious new element. Her division leader, Joseph Kennedy, helped discover it in 1940 at the University of California, Berkeley. 

Manufactured in reactors at Site X in Oak Ridge, Tennessee, plutonium first arrives to Los Alamos in liquid solution in fall 1943. It’s in scarce supply, and each drop must be used wisely. 

Sgt. Miller makes samples for experiments in a lab, located on the edge of a canyon, that is designed for plutonium research, development and production. Once plutonium’s properties are better understood, metallurgists can fashion it into metal shapes and weapons designers can determine how to trigger its power.

A planned test of the plutonium bomb at the Trinity site to calculate its destructive power is swiftly approaching. Sgt. Miller will be the one who establishes the methods for chemically separating, plating and counting fallout debris from the test site, with a particular focus on the impact of plutonium.

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Kennedy was Sgt. Miller’s division leader; Helmholz and Dodson were her group leaders. Sgt. Miller is eventually entrusted with responsibility as an alternate CM-4 group leader.

1944: Pivotal changes at work and at home

Plutonium displays a range of unusual characteristics, including unpredictability in a chemical environment. It makes a challenging metal, but its power is coveted for the new weapon. 

Larger gram amounts of plutonium start arriving at Los Alamos in early 1944. By March, the world’s first significant piece of plutonium metal (a 1-gram button) is produced at the D-Building lab where Sgt. Miller works. With that breakthrough, unanswered questions can be turned into research projects. 

For months, Sgt. Miller’s group is focused on producing foils and special materials for use by the experimental physicists, among other challenging assignments. CM-4 collaborates with the Radioactivity group and the Experimental Physics Division (and later the ordnance groups). Their emphasis is on the oxides of plutonium and uranium.

Sgt. Miller is tasked with making thin metal samples of plutonium oxide (a stable ceramic material with a high melting point) — a process she must develop and refine. In her June 12, 1944, preliminary two-page paper, “The Electrolytic Preparation of Thin Films of Plutonium Oxide," she says the process takes two to three hours. She gives shiny samples of plutonium oxide (on platinum) to the experimentalists. They need to understand the structure, properties and reactivity of plutonium oxides, so that plutonium can be properly used in a weapon.

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A plutonium oxide sample similar to the kind Sgt. Miller created. 

In time, CM-4 chemists successfully develop several new techniques for preparing foils, and they turn out large numbers of foils that accurately meet the physicists' specifications, including unusual geometries. 

Meanwhile, as the health risks of plutonium poisoning from dust are better understood at Project Y, those working with plutonium receive special training, their labs are outfitted with venting hoods and air monitors, they wear protective clothing and they undergo nose swabs and urine testing. Plutonium is extremely toxic due to its radioactivity, especially when inhaled.

Sgt. Miller is working with wet solutions, and once plated, the plutonium shouldn't flake off or create dust.

In the midst of this hectic time, Sgt. Miller feels a strong tug from home. In July 1944, her father — a banker and a farmer — dies suddenly in the family's Deansboro, New York, home at age 68. His obituary lists Sgt. Miller as a WAC member in service at Santa Fe, New Mexico. 

That same month, Project Y abandons work on the plutonium gun program. Experiments proved that plutonium (unlike uranium) could not be used in a gun-type fission weapon because residual impurities could not be completely removed and would interfere with weapon performance. An alternate method — implosion — must be developed if plutonium is to be used in a bomb. 

By August 1944, Project Y Director J. Robert Oppenheimer has reorganized all laboratory work around the plutonium implosion method. 

Project Y receives 51 grams of plutonium, which will be used in more than 2,500 different experiments. Sgt. Miller’s thin foils of purified plutonium support these efforts, allowing researchers to dissolve dirty foils and replate the plutonium. 

Her most daunting assignment is for the big test of this highly experimental weapon. By fall 1944, the Trinity site to test the world’s first atomic bomb is selected in southern New Mexico near Alamogordo. Many people fear the plutonium-based implosion device won't work. 

Even though the bomb's destructive power will be clearly visible in the desert, the weapons designers need to quantify the energy output of their invention. Calculations are being worked up on the behavior and effects of a nuclear explosion, including what will happen to plutonium and fission products in the ball of fire and smoke cloud. 

Physicist Herbert Anderson and his radiochemist colleagues make plans to collect fallout debris (radioactive samples) from the crater under the tower where the device will be detonated in the desert. To get reliable measurements, the debris must be separated into distinct parts (e.g., fission products, activation products and residual actinides) that can be studied individually, then all the data must be analyzed as a set. 

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A WAC Christmas party at Fuller Lodge in 1944. Sgt. Miller is partially visible in the very back row. Courtesy Los Alamos Historical Society Photo Archive

Plutonium, uranium and fission products — information about all of these is necessary to calculate explosive yield. That’s where Sgt. Miller comes in. 

To help experimentalists know how much plutonium is burned up in the blast, Sgt. Miller is developing laboratory techniques and procedures specific to plutonium. She is busy refining the methods to chemically separate out plutonium from the fission products. In her plan, a counting machine filled with nitrogen will measure the activity of the post-detonation plutonium. 

Analysts will combine the plutonium readings with information about different fission products to determine the yield of the Trinity device and the residual plutonium in the debris.

1945: Test anxiety

As the need for chemists escalates, the Chemistry and Metallurgy Division grows to 400 people by 1945. Their radiochemistry work is critical to the development of the metal plutonium core of the implosion bomb.

Within the division, many women are working on nuclear chemistry projects, supporting fundamental research. Some are civilian scientists with Project Y and others are military. 

In March 1945, Sgt. Miller is the alternate group leader for CM-4. 

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Sgt. Miller signs her Project Y exit paperwork on June 30, 1945 — 16 days before the Trinity test. It is stamped SECRET in red. But she doesn’t leave until July 31.

Nobody can know for sure the plutonium implosion device will work, and the months leading up to test day are fraught with doubt and angst. Finally, on July 16, 1945, the truth is displayed in the New Mexico desert. 

The Trinity test is a success, and the new weapon’s performance far exceeds Oppenheimer's yield calculations. The power from its detonation is equivalent to around 21,000 tons of TNT. Its mushroom cloud grew to about 3,280 feet wide, then rose in a column of smoke higher than 40,000 feet.

The post-detonation work goes on. Sgt. Miller’s methodology calls for drying small amounts of recovered plutonium solutions on platinum disks and screening the results for the yield calculations.

Sgt. Miller’s final payroll states she was honorably discharged Aug. 3, 1945, departing through Santa Fe on July 31, 1945. It lists “40 years of age or older” as the discharge reason. Under Army regulations, she had an option to exit early if she was 40 or older and had provided at least one year of service. She would have fit those requirements. (Sgt. Miller’s military personnel file, which may have offered more insight, burned in a St. Louis fire along with other military archives.)

On Aug. 6, 1945, the gun model uranium bomb, called Little Boy, is dropped on Hiroshima, Japan. 

On Aug. 9, the implosion model plutonium bomb, called Fat Man, is dropped on Nagasaki.

An estimated 200,000 people are killed in the bombings. By early September, Japan officially surrenders to the Allied Powers, ending WWII.

1946: Mission accomplished, life goes on

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Mary Lucy and Bill Ransford.

After the war ends, Sgt. Miller is awarded the typical WWII Victory Medal and Honorable Service Lapel Button, but no higher honors. Joseph Kennedy, her division leader, receives the Medal for Merit in 1946 from President Harry Truman for his “important part in solving all phases of the many chemical problems involved in the development and production of the bomb.” Kennedy also receives $400,000 from the Atomic Energy Commission for his role in the discovery of plutonium. 

The Manhattan Project behind her, Mary Lucy Miller marries Bill Ransford in 1946. She re-launches her career, taking a position as a research fellow at Stamford Research Laboratories in Connecticut.

She goes on to have a big career in polymer chemistry and publishes important papers. By the time she retires from the American Cyanamid Company in 1969, her credits include numerous articles in peer-reviewed journals, several patents and a 704-page book on the structure of polymers.

In 1990, she dies at age 86 of leukemia, in Tallahassee, Florida. Nine years after her death, she’s remembered as "probably the most accomplished scientist among the WACs stationed at Los Alamos” in a book about Manhattan Project women.

Long-lived legacy shows up in Los Alamos scientific methods 

Sgt. Miller’s contributions are alive and well at Los Alamos National Laboratory, with applications far different from testing new bombs. But her name isn’t well-known.

Her foundational work in plutonium can be seen today in the scientific methods used to detect clandestine nuclear tests and investigate suspicious materials. It informs the work of those who create targets for experiments and protect the health of plutonium workers.

"The chemistry Mary Lucy developed for the yield analysis of the first plutonium bomb led to significant advances in analytical radiochemistry and nuclear instrumentation," said Lisa Hudston of the Nuclear and Radiochemistry group (C-NR).

The plating method Sgt. Miller described in her 1944 paper has been refined and is a standard procedure. “It’s a significant part of what we do today,” said Hudston, a chemist who specializes in alpha spectrometry.

For instance, when the Lab's plutonium workers provide urine samples, TA-48 scientists plate the plutonium out of the urine samples and count the atoms to determine the workers' radiation exposure, Hudston said. 

A similar plating method is used for making targets for cross-section measurements of plutonium and other actinides at the Los Alamos Neutron Science Center. 

"We're using similar separation chemistry and we're using similar plating techniques as developed in the Manhattan Project," said Gus Keksis (C-NR). 

At Los Alamos and internationally, Sgt. Miller’s work is clearly recognizable in applications relevant to nuclear forensic evidence examinations. "This analytical capability is a very important aspect of nuclear nonproliferation," Keksis said. 

If a suspicious material is interdicted by the United States or another country, for instance, a chemical process similar to what Sgt. Miller developed is used to separate plutonium and electrodeposit the sample for counting. 

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In her 1944 preliminary paper, Sgt. Miller said the plutonium oxide process takes two to three hours.

Legacy unearthed 

Until 2018, the folks in C-NR hadn’t heard of Sgt. Miller, who had achieved so much in the Lab’s first Radiochemistry group. Although her name is mentioned in many books about the Manhattan Project, her technical contributions were lost to history until retired Chemistry Division Leader Alex Gancarz and Keksis dug into her legacy at the request of a Los Alamos employee.

They found two declassified papers — in one, Sgt. Miller describes the method she developed for plutonium oxide. In the other, she shows a sketch of the counting machine she used to do her work. 

“It’s pretty exciting that she was setting up the plutonium chemistry for the analysis of the Trinity test,” Gancarz said. “It’s pretty remarkable.”

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This counting machine dates to the Trinity test period and is still located at Los Alamos National Laboratory, in the counting room at TA-48.

Sgt. Miller’s foundational work in plutonium was essential to yield analysis for nuclear tests carried out by the U.S. until 1992, he noted.

Keksis ponders what it must have been like to be entrusted with the plutonium secret, under extreme pressure. “She was doing research and development on a new element, so I’m sure there were setbacks along the way. But she kept researching and developed a procedure to separate and electrodeposit plutonium in a uniform manner," he said. “In providing plutonium samples, she helped enable the numerous tests that led to an understanding of its physical properties.”

The Los Alamos Lab invented radiochemistry, and its collection of modern radiochemical procedures is widely consulted today. Sgt. Miller’s procedures to separate and electrodeposit plutonium provided the foundation on which modern procedures were built, he noted. 

Chemist Darleane Hoffman, who joined the Laboratory in 1951, may have built upon Sgt. Miller’s processes when she developed the electrodeposition of plutonium procedure for fission counting, according to Keksis. Hoffman’s contributions provided a basis for scientific methods used today in the national security community.

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Mary Lucy Miller Ransford (far right) with Diana Del Mauro’s grandparents, Walter and Mary Rist of St. Louis. 

The Manhattan Project solved an unfathomable technical challenge in an extremely compressed amount of time, and its success made possible a swift end to the war. 

Roger Meade, Laboratory archivist-historian emeritus, offered this perspective: "During World War II, the Laboratory had one mission: to produce an atomic bomb. To that end, the Laboratory operated as one team. The individual work of everyone, including that of Oppenheimer and Mary Lucy Miller, contributed to that mission. Like most who worked at Los Alamos during the war, she remains relatively unknown.”

Editor’s note: Diana Del Mauro (CEA-PA) had heard stories about her great-aunt but never had an opportunity to meet her. The quest to uncover Mary Lucy Miller’s accomplishments began in 2011 with a photo in the Lab’s Bradbury Science Museum and a book at the Los Alamos History Museum.

What the books say about Mary Lucy Miller

  • 1993: “Los Alamos WAACs/WACs: World War II, 1943-1946,” by Iris Y. Bell. Sgt. Miller’s barracks mate, Grace Rich Jarboe, helped with the book. “At Los Alamos, Mary became an Alternate Group Leader in the Chemical and Metallurgical Division of the Technical Area. It has been said of her that when she spoke at the seminars, people listened.”
  • 1999: “Their Day in the Sun: Women of the Manhattan Project,” by Caroline Herzenberg and Ruth Howes. “Probably the most accomplished scientist among the WACs stationed at Los Alamos was Mary Lucy Miller, a physical and polymer chemist.”
  • 2010: “The Madame Curie Complex: The Hidden History of Women in Science,” by Julie Des Jardins. “Mary Miller would likely have received more credit as a group leader at Los Alamos had her Ph.D. in physical chemistry not been obscured by her low military rank as a WAC.”