Early in the spring of 1945 with my fellow SED Bud Lang, I went to Wendover, Utah, where the B-29 crews were in training. The trip from Kirkland [Kirtland] Field in Albuquerque to Wendover in a badly limping B-17 was, to understate the situation, hair-raising. At the Utah airbase we were engaged in a testing program involving practice bombs which were dropped on targets in the Salton Sea in southern California. Another part of our group was in the target area to receive the telemetry data. On the junket to Wendover, for security purposes, we traveled as civilians wearing clothes purchased in Santa Fe with army funds. We were instructed to play the role of civilian scientists from Washington. Apparently we played the role well.
We were setting up our little laboratory in a Pacific hutment on the edge of the airfield at Wendover assisted by the Air Force officer who was to supervise the continuation of the tests after our departure. Surrounded by crates of equipment, Lang and I sat down briefly to organize. The officer, who had been pushing some debris aside, finally put down the broom and announced he would have to get some enlisted men to do the sweeping, oblivious of the fact that enlisted men were right there sitting on their duffs. After the war was over that same officer visited us at Los Alamos and only then learned our true status. At Wendover he had been subservient to the apparent civilians. At Los Alamos, as enlisted army men, we saluted him.
Later in the spring of 1945, I made the first of many trips to Alamogordo in preparation for the test. Titterton’s group had three responsibilities: first, to make timing measurements on the bomb itself at the moment of detonation; second, to provide timing markers to other experimental groups during the last milliseconds before time zero; and third, to send out the signal which was to trigger the detonation at the proper moment. These latter two activities were conducted at the main control bunker 10,000 yards south of the tower, and they accounted for my presence there at the moment of the explosion. The timing measurements were made remotely with the recording equipment located in a bunker one-half mile west of the tower.
In May, 100 tons of TNT were exploded near the tower site as a calibration of some of the instrumentation. In view of what was to come later I doubt if the exercise was of any value but at the time I thought that 100 tons made an incredible explosion. Between May and the middle of July we made a number of trips between Los Alamos and Trinity, the test site at Alamogordo. As little time as possible was spent at Trinity because the working and living conditions there were highly uncomfortable. If we were driving sedans rather than panel trucks on the trip we normally carried other people along. A five hour nonstop discussion by Emilio Segrè and Titterton on the state of the war and international politics still rings in my ears.
At Trinity we occasionally had official visitors and Titterton had the pleasant habit of always introducing me. Thus I met, for the first time, R. C. Tolman, who was serving as scientific advisor to General Leslie R. Groves, and I. I. Rabi, then director of the Radiation Laboratory at MIT, who later was to become a mentor of mine.
We hooked our coaxial cables into the bomb at the top of the tower on the Friday before the test. We had the usual difficulties guaranteeing continuity in the cables leading to the equipment in the bunker one-half mile west. After several trips up and down the 100 foot tower we finally had our gear ready to go. Then Saturday morning a new check revealed the coaxial cable circuit between the tower and the bunker to be open. It developed that the ditch in which the cables were laid had been filled in by a bulldozer in the meantime. Unfortunately there had not been enough slack in the cables and the overburden of earth put too much tension on them.
We spent Saturday, July 14, 1945, in a broiling desert sun digging in the sand, finding the faults in the half mile of cable, and correcting them. By nightfall everything was again intact, all circuits were working. The gear was again tested on Sunday. We worked late Sunday night, went back to the base camp for a few hours rest, and then at about 3 A.M. I went to south 10,000, the main control. In the meantime Lowry and Titterton were retreating from the bunker half a mile west of the tower, having readied everything there. Titterton joined me at the main control and Lowry went on to the base camp.
Eventually those in authority, the high brass, began to appear. My reaction to their presence was mixed, pleased by their appearance on the scene but slightly resentful that they appeared only at the last moment. They really hadn’t bitten the desert sand.
It took about 30 millionths of a second for the flash of light from the explosion to reach us outside the bunker at south 10,000. It took the blast wave about 30 seconds. There was the initial loud report, the sharp gust of wind, and then the long period of reverberation as the sound waves echoed off the nearby mountains and came back to us.
I got up from the ground and watched the now famous mushroom cloud rise in the morning sky. Apparently no one had told the military policeman, stationed at the door of the bunker to control access, what to expect. He was absolutely pale and a look of incredible alarm was on his face as he came away from the bunker door to stand beside me and view the sight. I simply said what was on my mind, “The war will soon be over.”
Shortly after, Titterton and I drove the five miles back to the base camp. There was Rabi, always close to the action, breaking out a bottle of whiskey from the luggage in the trunk of a car. We joined the little party. I had a good shot from the bottle and then went to the barracks for some rest.
Two days later the radioactivity in the vicinity of where the tower had been had decreased sufficiently to permit Lowry to make a quick trip to the bunker at half-mile west to recover the film on which the timing data had been recorded. Subsequent development revealed the film to be so badly fogged by radiation that the data were completely obscured. There was little remorse over the failure. If the bomb had not been successful the data would have been invaluable for diagnostics and, of course, in that case the film would not have been fogged.
Linton and I remained at the Trinity site a few more days to collect equipment for transport back to Los Alamos. As we were finally leaving the test area, we made a detour up the road toward where the tower had once stood. We passed the remains of the bunker at half-mile west. Most of the earth which once covered the concrete structure had been blown away. Lengths of the cable we had so laboriously put together were flung incongruously back over the structure. Driving a bit further we entered the area where the sand of the desert had been turned to glass by the heat of the bomb. We stopped and I cautiously reached down from the panel truck and scooped some of the glassy material into a cardboard box. Not knowing the radiation level precisely we hastily retreated from the area and continued on to Los Alamos.
In the summer of 1948 I went back to Los Alamos to work for the summer. This was long after I had returned to civilian life, after I had returned to school. On one occasion, scrounging for some electronic equipment in a storage room, I encountered the apparatus which we had used to generate the signal which was transmitted on a cable the 10,000 yards to trigger the detonation of the first bomb. It was a circuit I had sketched, Titterton checked, and Linton constructed. I thought of its possible historical significance and idly toyed with calling it to the attention of someone at Los Alamos who was interested in the lares and penates of the laboratory. As usual, in matters of this kind, I did nothing about it. I suspect that by now that hydrogen thyratron circuit has been junked. In my recent research work I have used similar thyratron circuits to pulse spark chambers. The graduate students working with me could not possibly appreciate the déjà vu I have felt in using these circuits again.
This has been a highly personal report of some of the activities of one SED working on the Manhattan Project. I have not attempted to give a picture of the average SED. The background of each of us was different, we had different jobs, and the experience at Los Alamos had widely varying impacts on our lives. Many of us went on to get Ph.D.’s in physics. The bagel lover is now the chairman of the physics department in a well-known university, again comfortable i
n the environment of a big city.
None of us would claim that the Special Engineer Detachment played any pivotal role or made the project a success or failure. In scanning the account of the Manhattan Project by our commanding general (Leslie R. Groves, Now It Can Be Told) I had not found where the SEDs are even mentioned. Clearly we were not the low men on the totem pole. As carved by our commanding general, we were not on the totem at all.
What I will claim is that a number of young men like myself, very early in their lives and careers, were exposed to superb physicists who were remarkable people in many respects, and it had a profound influence upon us.
Eyewitness Accounts of the Trinity Test
General Groves asked many of the eyewitnesses to record their accounts of the Trinity test on July 16, 1945. The following are excerpts from these accounts, which were compiled and sent to Groves by Lieutenant Thomas O. Jones, head of security at Los Alamos at the time.
Edwin M. McMillan: The whole spectacle was so tremendous and one might almost say fantastic that the immediate reaction of the watchers was one of awe rather than excitement. After some minutes of silence, a few people made remarks like, “Well, it worked,” and then conversation and discussion became general. I am sure that all who witnessed this test went away with a profound feeling that they had seen one of the great events of history.
Kenneth Greisen: A group of us were lying on the ground just outside of base camp (10 miles from the charge), and received time signals over the radio, warning us when the shot would occur. I was personally nervous, for my group had prepared and installed the detonators, and if the shot turned out a dud, it might possibly be our fault. We were pretty sure we had done our job well, but there is always some chance of a slip.
U.S. Department of Energy
U.S. Department of Energy
The Trinity test took place near Alamogordo, New Mexico, on July 16, 1945.
Enrico Fermi: About 40 seconds after the explosion the air blast reached me. I tried to estimate its strength by dropping from about six feet small pieces of paper before, during, and after the passage of the blast wave. Since, at the time, there was no wind I could observe very distinctly and actually measure the displacement of the pieces of paper that were in the process of falling while the blast was passing. The shift was about 2½ meters, which, at the time, I estimated to correspond to the blast that would be produced by ten thousand tons of T.N.T.
Maurice Shapiro: The shock wave from the explosion arrived about one and a half minutes after the flash of light, and I heard it as a sharp report. Although I had expected it, the intensity of the blast startled me. My impression at the time was that an enemy observer stationed about 20 miles from the scene of delivery would be deeply impressed, to say the least.
Robert Serber: The grandeur and magnitude of the phenomena were completely breath-taking.
THE EDUCATION OF A JOURNALIST
Practically everybody at the Trinity test was a scientist except one person, a journalist with the New York Times by the name of William Laurence. We were quite far away, 20 kilometers on Compania Hill, so that long after the fire ball, the shock wave followed and made a tremendous rumble. Laurence was terribly afraid and cried out, “WHAT WAS THAT?” So I explained to him that sound takes some time to propagate as compared to light.
—HANS BETHE
“Violence without limit”
In this selection from his novel Los Alamos, Joseph Kanon helps us imagine the Trinity test, watching the unearthly and terrifying light and then the enormous mushroom cloud arise. The main character ponders what this new force, capable of complete annihilation, means.
From Los Alamos
BY JOSEPH KANON
By the time he got to Compania Hill, the wind had died down to the still hush before dawn. Busloads of scientists and visitors lined the sandy ridge, talking in groups around the jeeps and trucks like guests at a tailgate party. Some were looking southeast, toward the small tower in the distance, waiting for the signal flares. The rockets’ red glare, Connolly thought, the bombs bursting—a macabre new version of the song. Someone handed him a piece of welding glass and he held it up, the barely visible light disappearing completely behind the tinted square. Was it really necessary? Did anyone know? Some of the scientists had smeared their faces with suntan oil, so their skins gleamed. He recognized Teller, pulling on heavy gloves like a good boy bundling up for the storm. They were twenty miles from the gadget. Could it really burn the air, like the ball of fire over Hamburg, sucking breath out of lungs? Carpet bombing? But this was supposed to be something else.
Most of the men had been there all night and were stiff with cold and waiting. Now they grew quiet, fiddling with the squares of welding glass, stamping their feet warm. There was nothing left to say. Cameras had been set up at N 10,000. Here there were only people, knotting together on a sandy grandstand, anxious and expectant, like Romans at a blood sport. Connolly thought about the first time he’d seen the Tech Area—secretaries passing through the fence, men darting in and out of lab buildings as if they were late for class, everyone too busy to stop, an endless film loop. Now, finally, they were at an end, waiting to see their work, all those meetings and calculations, go up in smoke.
Mills handed him a Thermos cup of coffee. “They say you’re not supposed to look,” he said. “Even this far. What’s that?”
“The rocket. Five minutes.”
“Jesus, this stuff goes right through you, doesn’t it?” he said, agitated.
“Dark glass, everyone,” someone shouted down the line.
“The hell with that,” one of the scientists said, excited. “I’m going to see this. Even if it’s the last thing I see.”
“That’s a possibility, Howard.” A gruff Hungarian voice.
Suddenly, there was a pinprick, whiter than magnesium, a photographer’s bulb, and he was blinded with light. It flashed through his body, filling all the space around them, so that even the air disappeared. Just the light. He closed his eyes for a second, but it was there anyway, this amazing light, as if it didn’t need sight to exist. Its center spread outward, eating air, turning everything into light. What if Fermi was right? What if it never stopped? And light was heat. Bodies would melt. Now a vast ball, still blinding, gathering up the desert at its base of light. The ball grew, glowing hotter, traces of yellow and then suddenly violet, eerie and terrifying, an unearthly violet Connolly knew instantly no one had ever seen before. Eisler’s light. His heart stopped. He wanted to turn away, but the hypnotic light froze him. He felt his mouth open in cartoon surprise. Then the light took on definition, pulling up the earth into its rolling bright cloud, a stem connecting it to the ground.
How long did it take for the sound to follow? The hours of light were only a blink of seconds and then the sound, bouncing between the mountains, roared up the valley toward them, tearing the air. He staggered, almost crying out. What was it like near the blast? A violence without limit, inescapable. No one would survive. Then he dropped the piece of welding glass, squinting, and watched the cloud climb higher, rolling over on itself, on and on, its stem widening until the cloud finally seemed too heavy and everything collapsed into the indeterminate smoke. He stared without thinking. Behind it now he could see the faint glimmer of dawn, shy behind the mountain, its old wonder reduced to background lighting.
He turned to Mills, but Mills had dropped to the ground as if he’d been knocked over by the blast, had lost whatever strength it took to stand. His eyes seemed fixed, mesmerized by their glimpse of the supernatural. Connolly heard shouts, loud whoops and spurts of spontaneous applause, and looked at the crowd. Scientists shook hands or hugged. Someone danced. But it was only a reflex, an expected thing, for then it grew quiet again, solemn, and people just stared at the cloud, wondering what they had seen. He felt an urge to swallow, to make some connection with his body. What had he thought it would be—a bigger explosion? A giant bonfire? All this time on the Hill they had talked in euphemisms.
What was it but a larger version of the terrible things they already knew? A sharper spear. A better bow and arrow. But now he had seen it. Not just a weapon. He felt himself shaking. Oppenheimer must have known. Maybe nobody knew. It didn’t have a name yet. Not death. People had ideas about death. Pyramids and indulgences and metaphors for journeys. Connolly saw, looking out at the cloud in the desert, that none of it was true, that all those ideas, everything we thought we knew, were nothing more than stories to rewrite insignificance. This was the real secret. Annihilation. Nothing else. A chemical pulse that dissolved finally in violet light. No stories. Now we would always be frightened.
Section Seven
Dropping the Bombs
Dropping the Bombs
On December 17, 1944, Lt. Col. Paul W. Tibbets Jr. was given command of the newly created 509th Composite Group of the Army Air Forces. Its top-secret mission was to drop the world’s first atomic bombs. The unique shapes of the Little Boy and Fat Man bombs required a great deal of testing with “pumpkin bombs” to ensure accurate flight after being dropped from specially modified B-29 planes. The 509th trained at a secluded base in Wendover, Utah before being sent to Tinian Island in the Marianas in May, June, and July 1945. At Tinian, the Manhattan Project recreated a little Manhattan, naming the roads after New York City streets.
The mission of the 509th was kept so secret that Admiral Chester W. Nimitz, Commander in Chief of the Pacific theater, did not know of the atomic bomb until February 1945. A Target Committee was convened in April and May 1945 to select a short list of Japanese cities to be removed from conventional bombing missions as possible atomic bomb candidates. By the end of July the list included Hiroshima, Kokura, Niigata, and Nagasaki. Earlier, Secretary of War Henry Stimson vetoed the ancient capital Kyoto with its magnificent shrines and temples. On July 25, 1945, official orders were issued to the 509th Composite Group to “deliver its first special bomb as soon as weather will permit visual bombing after about 3 August 1945 on one of the targets.… Additional bombs will be delivered on the above targets as soon as made ready by project staff.”
The Manhattan Project Page 31