Early Life

Being Called to MIT

Working at Los Alamos

Scientific Lectures and the First Atomic Bomb Detonation

Religious Services and Witnessing All Three Wartime Atomic Bomb Detonations

Time on Tinian then Back to the United States

Postwar Life and Career

Johnston OH Clip for PBS

Seeing All Three Wartime Atomic Bombs Detonated


Lawrence Johnston was born in February 1918 to parents who were Christian missionaries. He was born in China and spent his childhood there too. All Johnston knew about China during the time he lived there was the large house he lived in at the missionary compound and the Chinese servants the family hired. When Johnston was about six years old his father took a year's furlough to show the family the United States. The Johnston family left Shanghai on a ship to Canada then took the Trans-Canada Railroad to New Jersey, where his mother's family lived. Johnston met a number of his relatives. When the other kids asked him to say something in Chinese he would insult them. Johnston's father bought a Model T Ford in 1923 and the family set out across the country. It was a wonderful trip that ended in Los Angeles where Johnston's father's family lived. At the time, Los Angeles was just developing. The Johnston family had expected to return to China at the end of the year long furlough but his mother was diagnosed with having a thyroid problem which made it impossible for them to return. His father had to find another job. His father had graduated from Princeton Seminary and was well educated. The family lived in missionary cottages in Glendale, California. While there, Johnston's father learned that a pastor was needed for a church in La Jolla, California. Johnston loved it there. He and his sister would walk the beach and would catch moray eels and a type of small gold fish in tidal pools. It was not until later that Johnston learned that he fish he had been catching were protected. Johnston and his sister would pick shells up on the beach and would take them to a lady at the La Jolla Cove who sold sea shells and could tell them what kind of shells they were. During the depression, Johnston's father held several pastorates but they ended up in Los Angeles where his father had some family. Luckily for Johnston, the Los Angeles Junior College was within bicycle distance from where they were living. Johnston started taking classes there as a physics major. There were a number of wonderful teachers there from Cal Tech who Johnston had a wonderful time getting acquainted with. When Johnston's professor asked him what he could develop or show off to prospective students he developed the electronics that work with the Geiger counter. A professor suggested to Johnston that when he had completed his two years at the junior college he should go to Berkeley [Annotators Note: University of California at Berkeley]. Ernest Lawrence was there and he had just created the cyclotron and was smashing atoms. Johnston took the professor's advice and went to Berkeley.


Lawrence Johnston was already a junior by the time he got to Berkeley. One of his physics professors was Louis Alvarez, who is credited with discovering what killed off the dinosaurs. Johnston had built up a relationship with Alvarez and approached him one day with a problem. Alvarez asked Johnston what he wanted to do. Johnston replied that he liked to work with electronics and that he had heard of the cyclotron and wanted to see it. Alvarez invited Johnston to meet him at the radiation laboratory that night. Johnston did so and met Ernest Johnson, who had invented the cyclotron there. Lawrence put Johnston to work on electronics in the radiation lab. That was in 1940, and was the start of a career that would lead to Johnston working at Los Alamos. During the depression years student jobs were hard to come by, but Alvarez made sure that Johnston was hired to work in his lab. Alvarez left the school for a while. One day Johnston got a telegram from Alvarez informing him that he was needed at MIT [Annotator's Note: Massachusetts Institute of Technology]. Johnston drove Alvarez's car to MIT and joined the project to develop a radar set that would be used to aid in ground controlled approach. They were developing a set that enable them to talk planes in when the runways were invisible to the pilots. Their first big experience with the project was when a bunch of large flying boats got stuck in bad weather. The commander of the air field asked if they could talk the flying boats in and they did. This project was a top secret project. During this time Johnston got married. Alvarez really appreciated Johnston's wife Mildred, and when the radar crew went on a trip to the radar stations along the Atlantic coast Alvarez let Johnston take her along on the trip.


Lawrence Johnston had been working on the radar project at MIT [Annotator's Note: Massachusetts Institute of Technology] for three or four years when Alvarez [Annotator's Note: Louis Alvarez] was called to Los Alamos by Ernest Lawrence. Johnston was firmly attached to MIT and tried several times unsuccessfully to get a release to go to Los Alamos. Finally, Ernest Lawrence told Johnston to meet with Colonel Compton who was the president of MIT at the time. Colonel Compton asked Johnston if he had completed all of the projects he had been working on there. Johnston replied that he had so Compton told him he could go. Johnston was threatened and told that if he misbehaved he would be drafted into the Army as a regular soldier. What was keeping him from being drafted at that time was that he was doing essential war work. Johnston went to Los Alamos. Lawrence was there working on the Fat Man bomb, which was an implosion type bomb [Annotator's Note: Fat Man was the codename of the bomb dropped on Nagasaki on 9 August 1945]. Johnston was put to work developing detonators which could encircle the bomb and go off all within one microsecond of each other. Alvarez put Johnston to work on that, and within a couple weeks of Johnston's arrival at Los Alamos he had developed the exploding bridge wire detonator. The exploding bridge detonator made the use of plutonium possible. The Little Boy bomb [Annotator's Note: Little Boy was the codename of the atomic bomb dropped on Hiroshima, Japan on 6 August 1945], which used Uranium 235, had been developed in Oak Ridge, Tennessee. There was only enough uranium to make one bomb and that was the bomb dropped on Hiroshima, Japan. Plutonium was collected from reactors in Washington State, and was more readily available than uranium, but the plutonium required the use of a detonator like the one Johnston developed. Since Johnston developed the detonator used on the Nagasaki bomb he was aboard the aircraft that dropped the atomic bombs on both Hiroshima and Nagasaki. He feels very privileged to have been on both flights. Johnston had no idea what was going on at Los Alamos when he was called there by Alvarez but knew it had to be something essential to the war effort. When Johnston first started working on the project he knew he would be able to create the detonator needed for the plutonium-based bomb. Scientists at Los Alamos created explosive lenses that were placed at 32 points on the exterior of the bomb to create an implosion. The detonator Johnston developed was attached to those lenses. Johnston had had plenty of exposure to Oppenheimer [Annotator's Note: J. Robert Oppenheimer] when he was a student at Berkeley and took a class Oppenheimer taught. Oppenheimer was a chain smoker and lit one cigarette from another. Today smoking in the classroom is forbidden. At Los Alamos, Oppenheimer checked in on Johnston a time or two to see how his project was coming along, but that was about all the contact Johnston had with him there. Alvarez was Johnston's main point of contact.


To Lawrence Johnston, one of the great things at Los Alamos was that every Monday night a lecture was held with a different scientists speaking every week. Some of the scientists there were Oppenheimer and Philip Morrison. Oppenheimer and Morrison were suspected of being spies for the Soviet Union, and Johnston believes that information and materials being passed to the Russians made it possible for the Russians to develop their own atomic bomb shortly after the United States detonated its first bomb. The scientists were fairly sure that the atomic bomb which used the Uranium 235 would work but they were not so sure about the plutonium-fueled bomb, so they decided to test it. A plutonium-fueled bomb was placed on a 100 foot tower in the New Mexico desert along with sensor equipment that would measure the intensity of the blast. During the test all of the scientists would be in a bunker five miles away from the detonation site. Alvarez decided that the test would be a good time to practice dropping the bomb, but Oppenheimer insisted that Alvarez not get within 25 miles of the blast zone. Johnston was with Alvarez at 30,000 feet on the morning of the test. When the sun was starting to come up they heard the countdown. When the count got to zero they saw a bright flash and then saw the first mushroom cloud. Johnston and Alvarez were in a B-29 Alvarez had secured for use during the test. The aircraft towed a microphone on a parachute behind it. The information recorded by the sensors was telemetered into the airplane. When they got back to base they developed their film. Johnston had developed much of the equipment used to measure the effects of the blast. Early on, Germany was the big enemy but by the time Johnston was at Los Alamos it was clear that the bombs would be used on Japan. Alvarez developed the microphone that they would use, and Johnston developed all of the recording equipment. When the bomb detonated, Johnston and Alvarez were 25 miles away in the rear compartment of a B-29. After the detonation they began heading toward the blast sight. The B-29 they were using had been stripped of its defensive armament. When Johnston saw the atomic bomb detonate, his first thought, like that of many of the other scientists who took part in the creation of the bomb, was thank God it worked. Had the bomb not gone off every scientist would have thought it was their part that failed. The scientists were aware that Truman was meeting with Joseph Stalin somewhere on the East Coast and was waiting to hear the results of the test.


While Lawrence Johnston was working as a scientists at Los Alamos, religious services were held every Sunday. A group of the scientists who were independent Christians approached the chaplain and asked if he planned to hold a sunrise service. The chaplain said no, but if the scientists wanted to host the service the chaplain would publicize it. They all did so and had a sunrise service on Easter [Annotator's Note: 1 April 1945]. Two or three months after the test detonation of the atomic bomb in New Mexico Johnston shipped out overseas. They were initially looking forward to using their weapons on Germany, but when it became clear that Germany was about to surrender they knew that they would be going to Japan. Johnston was selected to go on the mission to drop the atomic bomb on Hiroshima because he had developed the recording equipment that would be used to record the blast. During the missions to both Hiroshima and Nagasaki Johnston flew aboard a B-29 named the Great Artiste. All of their recording equipment was installed in that plane. Alvarez only went on the mission to Hiroshima. Johnston went on both missions and is the only person to see all three wartime atomic bomb detonations. That made Johnston happy. Johnston prayed for all of the people who would be killed by the weapon he was helping to develop. He also prayed for all of the people who were dying every day during the war. The number of people killed by the atomic bombs was small compared to the number of people killed by the fire bombing missions. The blast was spectacular enough to end the war though. The decision was made to drop the first bomb then wait a day then drop the second bomb. This was to give the Japanese the impression that the United States had a stockpile of the bombs. Johnston does not know if there were any plans in place to develop any additional atomic bombs during the war but does know that there was a large explosives area at Los Alamos where castings of the explosive components of the Fat Man bomb were being made. Liquid explosives were being poured into a mold, and then when they cooled they were machined down and fitted into a bomb. When Johnston gives atom bomb talks he always pays tribute to the explosives people because they did such a wonderful job.


Lawrence Johnston never had a chance to talk to any of the German scientists who had come to the United States, although he would have liked to. After the Nagasaki mission they thought they would be heading home, but General Groves [Annotator's Note: Lieutenant General Leslie R. Groves] told them that they would be staying until Japan surrendered. Johnston spent several weeks on Tinian after the bomb was dropped on Nagasaki. Johnston liked to look around in the tide pools. He borrowed a diving mask from a Red Cross nurse and would go snorkeling. He liked to look at and collect crustaceans. He picked up 20 or 30 of one type of crustacean and placed them on the beach near a sugar cane field that had been planted by the Japanese. The hermit crabs that were living in the sugar cane field ate the organisms out of the shells. Johnston recalls being very thankful when he learned of the Japanese surrender but cannot recall any details of when he heard about it. Johnston was anxious to get back to the United States so he could go back to Berkeley. Quite a few of the people from Los Alamos went to Japan after the war to study the effects of the bombs on Hiroshima and Nagasaki. Johnston returned to Berkeley and completed his graduate studies there. He was prepared to teach physic,but another opportunity came up for him. Alvarez had developed a linear accelerator for protons and Johnston developed some of the electronic equipment that would be needed for that process. Alvarez helped Johnston get a job at the University of Minnesota. Alvarez went along too. It took them a couple of years, but Johnston and Alvarez built the linear accelerator. After that everywhere Johnston went he was able to do proton scattering which gained him some publicity. Johnston was invited to a big to-do in London and asked to speak at the event. He was honored to do so.


Lawrence Johnston was at Stanford University helping to build a two mile long linear accelerator. A guy named Pinofsky [Annotator's Note: unsure of spelling] had promised to complete the job on time and on budget. He had a hardnosed guy running the project. Johnston was in charge of developing the instrumentation and controls. Johnston was wearing out under the pressure, so when the opportunity came up for him to go to a nice place in the back woods where he could do some physics he took it. Johnston developed a very good program involving infrared radiation. He was given free rein to do whatever he wanted so he built a large laser. The laser was about 12 feet long. The laser enabled him to do some good physics so that is where he finished his career. While he was there he had six graduate students who worked with him who got their PhDs under his direction. Some of them still visit him at his home. Johnston still holds the patent on the exploding bridge wire detonator for the Fat Man bomb [Annotator's Note: the atomic bomb dropped on Nagasaki, Japan on 9 August 1945]. His detonator is still used today in automobile airbags. Johnston had very little contact with Paul Tibbets [Annotator's Note: Brigadier General Paul W. Tibbets] but Alvarez did. At later conferences, Johnston got to know Tibbets and the other crewmen who flew the missions to drop the atomic bombs. Johnston is concerned with Iran building the components to create an atomic bomb. Years ago the Israelis dropped a bomb on a building in Iran where they were building bombs. It will be interesting to see if they do it again. The most criticism Johnston got as a result of his work came from his daughter, but the family issues that came about have since been smoothed out. Johnston enjoys talking about the things he was a part of years ago.

All oral histories featured on this site are available to license. The videos will be delivered via mail as Hi Definition video on DVD/DVDs or via file transfer. You may receive the oral history in its entirety but will be free to use only the specific clips that you requested. Please contact the Museum at digitalcollections@nationalww2museum.org if you are interested in licensing this content. Please allow up to four weeks for file delivery or delivery of the DVD to your postal address.