Trinity Site History
Trinity Site is where the first atomic bomb was tested at 5:29:45 a.m. Mountain War Time on July 16, 1945. The 19-kiloton explosion not only led to a quick end to the war in the Pacific but also ushered the world into the atomic age. All life on Earth has been touched by the event which took place here.
The 51,500-acre area was declared a national historic landmark in 1975. The landmark includes base camp, where the scientists and support group lived, ground zero, where the bomb was placed for the explosion, and the McDonald ranch house, where the plutonium core to the bomb was assembled. Visitors to a Trinity Site Open House see ground zero and the McDonald ranch house. In addition, one of the old instrumentation bunkers is visible beside the road just west of ground zero.
The Manhattan Project
The story of Trinity Site begins with the formation of the Manhattan Project in June 1942. The project was given overall responsibility for designing and building an atomic bomb. At the time it was a race to beat the Germans who, according to intelligence reports, were building their own atomic bomb.
Under the Manhattan Project three large facilities were constructed. At Oak Ridge, Tenn., huge gas diffusion and electromagnetic process plants were built to separate uranium 235 from its more common form, uranium 238. Hanford, Wash. became the home for nuclear reactors which produced a new element called plutonium. Both uranium 235 and plutonium are fissionable and can be used to produce an atomic explosion.
Los Alamos was established in northern New Mexico to design and build the bomb. At Los Alamos many of the greatest scientific minds of the day labored over the theory and actual construction of the device. The group was led by Dr. J. Robert Oppenheimer who is credited with being the driving force behind building a workable bomb by the end of the war.
Two Bomb Designs
Los Alamos scientists devised two designs for an atomic bomb, one using uranium 235 and another using plutonium. The uranium bomb was a simple design and scientists were confident it would work without testing. The plutonium bomb was more complex and worked by compressing the plutonium into a critical mass which sustains a chain reaction. The compression of the plutonium ball was to be accomplished by surrounding it with lense-shaped charges of conventional explosives. They were designed to all explode at the same instant. The force is directed inward, thus smashing the plutonium from all sides.
In an atomic explosion, a chain reaction picks up speed as atoms split, releasing neutrons plus great amounts of energy. The escaping neutrons strike and split more atoms, thus releasing still more neutrons and energy. In a nuclear explosion this all occurs in a millionth of a second with billions of atoms being split.
Project leaders decided a test of the plutonium bomb was essential before it could be used as a weapon of war. From a list of eight sites in California,Texas, New Mexico and Colorado, Trinity Site was chosen as the test site. The area already was controlled by the government because it was part of the Alamogordo Bombing and Gunnery Range which was established in 1942. The secluded Jornada del Muerto was perfect as it provided isolation for secrecy and safety, but was still close to Los Alamos.
Beginnings of Trinity Site
In the fall of 1944 soldiers starting arriving at Trinity Site to prepare for the test. Marvin Davis and his military police unit arrived from Los Alamos at the site on Dec. 30, 1944. The unit set up security checkpoints around the area and had plans to use horses to ride patrol. According to Davis the distances were too great and they resorted to jeeps and trucks for transportation. The horses were sometimes used for polo, however. Davis said that Capt. Bush, basecamp commander, somehow got the soldiers real polo equipment to play with but they preferred brooms and a soccer ball.
Other recreation at the site included volleyball and hunting. Davis said Capt. Bush allowed the soldiers with experience to use the Army rifles to hunt deer and pronghorn. The meat was then cooked up in the mess hall. Leftovers went into soups which Davis said were excellent.
Of course, some of the soldiers were from cities and unfamiliar with being outdoors a lot. Davis said he went to relieve a guard at the Mockingbird Gap post and the soldier told Davis he was surprised by the number of "crawdads" in the area considering it was so dry. Davis gave the young man a quick lesson on scorpions and warned him not to touch.
Throughout 1945 other personnel arrived at Trinity Site to help prepare for the test. Carl Rudder was inducted into the Army on Jan. 26, 1945. He said he passed through four camps, took basic for two days and arrived at Trinity Site on Feb. 17. On arriving he was put in charge of what he called the "East Jesus and Socorro Light and Water Company." It was a one-man operation, himself. He was responsible for maintaining generators, wells, pumps and doing the power line work.
A friend of Rudde, Loren Bourg, had a similar experience. He was a fireman in civilian life and ended up trained as a fireman for the Army. He worked as the station sergeant at Los Alamos before being sent to Trinity Site in April 1945. In a letter Bourg said, "I was sent down here to take over the fire prevention and fire department. Upon arrival I found I was the fire department, period."
As the soldiers at Trinity Site settled in they became familiar with Socorro. They tried to use the water out of the ranch wells but found it so alkaline they couldn't drink it. In fact, they used Navy salt-water soap for bathing. They hauled drinking water from the fire house in Socorro. Gasoline and diesel was purchased from the Standard bulk plant in Socorro.
According to Davis, they established a post office box, number 632, in Socorro so getting their mail was convenient. All the trips into town also offered them the chance to get their hair cut in the barbershop in town. If they didn't use the shop, SGT Greyshock used horse clippers to trim their hair.
100-Ton Test on May 7
Three observation points were established at 10,000 yards from ground zero.These were wooden shelters protected by concrete and earth. The south bunker served as the control center for the test. The automatic firing device was triggered from there as key men such as Dr. Robert Oppenheimer, head of Los Alamos, watched. None of the manned bunkers are left.
Many scientists and support personnel, including Gen. Leslie Groves, head of the Manhattan Project, watched the explosion from base camp which was ten miles southwest of ground zero. All the buildings at base camp were removed after the test. Most visiting VIPs watched from Compania Hill, 20 miles northwest of ground zero.
The test was scheduled for 4 a.m. July 16, but rain and lightning early that morning caused it to be postponed. The device could not be exploded under rainy conditions because rain and winds would increase the danger from radioactive fallout and interfere with observation of the test. At 4:45 a.m. the crucial weather report came through announcing calm to light winds with broken clouds for the following two hours.
At 5:10 the countdown started and at 5:29:45 the device exploded successfully. To most observers the brilliance of the light from the explosion, watched through dark glasses, overshadowed the shock wave and sound that arrived later.
What It Was Like
The McDonald Ranch House
A Quick End to the War
The First Visits
White Sands Missile Range
This is the text of the letter signed by Albert Einstein which was delivered to President Franklin Roosevelt by Alexander Sachs on October 11, 1939. The chief author is believed to be Leo Szilard.
Old Grove Rd.
Peconic, Long Island
August 2d, 1939
President of the United States
Some recent work by E. Fermi and L. Szilard, which has been communicated to me in manuscript, leads me to expect that the element uranium may be turned into a new and important source of energy in the immediate future. Certain aspects of the situation which has arisen seem to call for watchfulness and, if necessary, quick action on the part of the Administration. I believe therefore that it is my duty to bring to your attention the following facts and recommendations.
In the course of the last four months it has been made probable--through the work of Joliot in France as well as Fermi and Szilard in America--that it may become possible to set up a nuclear chain reaction in a large mass of uranium, by which vast amounts of power and large quantities of new radium-like elements would be generated. Now it appears almost certain that this could be achieved in the immediate future.
This new phenomenon would also lead to the construction of bombs, and it is conceivable--though much less certain--that extremely powerful bombs of a new type may thus be constructed. A single bomb of this type, carried by boat and exploded in a port, might very well destroy the whole port together with some of the surrounding territory. However, such bombs might very well prove to be too heavy for transportation by air.
The United States has only very poor ores of uranium in moderate quantities. There is good ore in Canada and the former Czechoslovakia, while the most important source of uranium is the Belgian Congo.
In view of this situation you may think it desirable to have some permanent contact maintained between the Administration and the group of physicists working on chain reactions in America. One possible way of achieving this might be for you to entrust with this task a person who has your confidence who could perhaps serve in an unofficial capacity. His task might comprise the following:
a) to approach Government Departments, keep them informed of the further development, and put forward recommendations for Government action, giving particular attention to the problems of securing a supply of uranium ore for the United States.
b) to speed up the experimental work, which is at present being carried on within the limits of the budgets of University laboratories, by providing funds, if such funds be required, through his contacts with private persons who are willing to make contributions for this cause, and perhaps also by obtaining the co-operation of industrial laboratories which have the necessary equipment.
I understand that Germany has actually stopped the sale of uranium from the Czechoslovakian mines which she has taken over. That she should have taken such early action might perhaps be understood on the ground that the son of the German Under-Secretary of State, von Weizaecker, is attached to the Kaiser-Wilhelm-Institut in Berlin where some of the American work on uranium is now being repeated.
Yours very truly
(signed) A. Einstein
SOURCE: U.S. Army in World War II Special Studies Manhattan: The Army and the Atomic Bomb
by Vincent C. Jones
Center of Military History
United States Army
This is a report filed by Major Palmer on July 18, 1945. It deals with the plans to evacuate civilians around the Trinity Site area if high concentrations of radioactive fallout drifted off the Alamogordo Bombing Range.
Evacuation Detachment at Trinity
Detachment, Equipment, Personnel, Organization, Base Operations.
A. Equipment and Personnel.
This detachment consisted of 140 enlisted men, 4 officers, 140 vehicles, including one 500 gallon improvised water tank for drinking purposes, 2 lister bags, latrine flies, 30 pyramidal tents, 1000 type "C" and "K" rations, coffee, sugar, milk, and three field ranges.
The detachment was formed into four platoons of nine vehicles each. The first and second platoons made up the first section under the Command of Captain Huene. The third and fourth platoons made up the second section under the Command of First Lieutenant M. Miller. Each vehicle had a driver and two men; three jeeps, under the direct supervision of the detachment Commander to act as messengers; one two-way radio vehicle.
C. Operating Base.
The detachment moved into its bivouac area 14 July. For security reasons this area was 4O miles from Trinity; the detachment remained there until the morning of 15 July, then moved to a semi-permanent Base Camp, with an alternate base site Selected. The Base Camp was set-up as a company; latrine dry flies put up; lister bags hung, and field ranges set up. The rest of the day and night was spent in briefing the men and having the section leaders and drivers familiarize themselves with the roads and dwellings in their assigned sections, and visiting Trinity headquarters for instructions. The Base Camp was approximately nine miles from Zero. The detachment Commander returned to Base Camp from Trinity around Mid night 15 July with last minute instructions. Major Miller was assigned the radio vehicle and put in Command of the Base Camp. The detachment was alerted in case the wind shifted in that direction, so it could move quickly to the alternate site.
The orders received by the detachment Commander from General Farrell were generally as follows:
1. The two prepared press releases were made known to the detachment Commander. One in case of no evacuation, which stated briefly that an ammunition dump had blown up; and one in case of evacuation, which stated that an ammunition dump had blown up which contained gas shells and the people would be evacuated for 24 hours to protect them from the gas.
2. The detachment Commander would work with Mr. Hoffman and Mr. Herschfelter, with their crew of monitors, and was to evacuate upon Mr. Hoffman´s request.
The detachment Commander planned, in case of evacuation, to set-up the Base Camp as a shelter for the people; tents and shelters would be provided to cover and feed 450 people for two days. This was ample shelter for the small population centers that were close enough to be in immediate danger. The larger centers were some distance away and there was ample time to transport them to Alamogordo Air Field and house them in barracks. In cases of one or two families, it was planned to send them to a hotel in a near-by town.
The area in the vicinity of the shot was divided into sections and each section leader was responsible for his section, with additional help if needed.
A jeep was assigned to Trinity headquarters, Major Miller at Base Camp, and to the detachment Commander during the operation, to supplement radio communications.
Immediately after the shot, the wind drift was ascertained to be sure the Base Camp was not in danger. Monitors were immediately sent out in the direction of the cloud drift to check the approximate width and degree of contamination of the area under the cloud. A small headquarters was set-up at Bingham, near the center of the area in the most immediate danger. The monitors worked in a wide area from this base reporting in to Mr. Hoffman or Mr. Herschfelter. One re-enforced platoon, under Captain Huene, was held at Bingham; the rest of the detachment was held in reserve at Base Camp. Fortunately no evacuations had to be made.
Mr. Hoffman released the detachment about 1300 hours 16 July; by that time, any danger of serious contamination had passed.
The detachment Commander would like to take this time to say that the Officers and men of the detachment were alert, obedient, and conducted themselves in a superior manner throughout the experiment.
T.O. PALMER, JR.
((Smith watched from Compania Hill near present-day Stallion Range Center))
DATE: 5 September 1945
FROM: Ralph Carlisle Smith
SUBJECT: Comments on Trinity Test Shot Trip.
At about 1945 MWT, 15 July 1945, the coordinating council started from the Los Alamos Technical Area, riding in a three bus convoy with three G.I. sedans driven by Convoy Commander Captain George Turner, Mr. David Dow, and Dr. Earl Long and with a G.I. truck carrying spare equipment. The first stop was at the Camel on the Santa Fe Road. Then through back roads of Santa Fe to outskirts of Albuquerque where we stopped twenty minutes for convoy to be reassembled. The truck had broken down and the sedans stopped to get passengers at Santa Fe (Dr. C.A. Thomas).
We then proceeded to Wilson´s garage to get gas, remaining in Albuquerque for about 45 minutes -- the passengers wandering about town. At the Hilton, Sir James Chadwick, William Laurence, William Fouler, Tom Lauritsen, Charles Lauritsen, Major Ackerman, and an Army Captain (S-2) awaited to convoy. 2nd Lt. Dazzo (S-2) was there but was returning to Los Alamos.
We proceeded to Trinity (just beyond San Antonio, N. Mex) on Route U.S. 385 at a turn off marked Harriets Ranch. We were first stopped at the bivouac of Major T.O. Palmer´s Special Detachment of Engineers, who were stationed there for any emergency such as evacuation of personnel. After a brief check we proceeded to the Military Police Post No. 2 which was about 20 miles from zero point and about ten miles from the Trinity Base Camp. This was approximately 0200 to 0230 16 July 1945. About 0500 the searchlights allegedly at 6 miles from zero point started playing about, apparently fixing cloud elevation. At about 0520, the warning came by radio that the test was about to take place in 10 minutes. 1st Lt. Schaeffer, a civilian, and I stretched out on a blanket facing south to the spot where the several searchlights seemed to be focusing on the ground. A glow was appearing in the sky toward the East so that the mountain range stood out quite distinctly. The road was to our right and the buses to the rear of us. It was bright enough that you could identify people several hundred feet away. 1st Lt. Huene fired a rocket at minus six minutes and again at minus three. The latter did not explode in the air, hence another rocket went up about minus one minute. About then you could hear the warning siren at the bivouac area. I was staring straight ahead with my open left eye covered by a welders glass and my right eye remaining open and uncovered. Suddenly, my right eye was blinded by a light which appeared instantaneously all about without any build up of intensity. My left eye could see the ball of fire start up like a tremendous bubble or nob-like mushroom. I Dropped the glass from my left eye almost immediately and watched the light climb upward. The light intensity fell rapidly hence did not blind my left eye but it was still amazingly bright. It turned yellow, then red, and then beautiful purple. At first it had a translucent character but shortly turned to a tinted or colored white smoke appearance. The ball of fire seemed to rise in something of toadstool effect. Later the column proceeded as a cylinder of white smoke; it seemed to move ponderously. A hole was punched through the clouds but two fog rings appeared well above the white smoke column. There was a spontaneous cheer from the observers. Dr. von Neumann said "that was at least 5,000 tons and probably a lot more." My estimate of the width of the ball of fire was guessed to be 1 to 2 miles at that time. Someone said keep your mouth open and just then, about 1 1/2 to 2 minutes after the light flash, a sharp loud crack swept over us -- it reverberated through the mountain like thunder. Several small flashes took place some distance from and after the big flash, apparently part of a measuring system. Commander Bradbury said that the cloud was up over 20,000 feet and still rising. The top of the cloud was moving slightly northeast and was being sheared off. At about 0555, we were aboard the buses and started home again. We stopped for relief on the road between Albuquerque and Santa Fe, we gassed at Santa Fe (Closson and Closson) but did not dismount. We arrived at the Hill at about 1300 16 July 1945.
Signed by Ralph Carlisle Smith
((Ralph Smith was a lawyer at Los Alamos))