warning.
It remained to carry the decision to the President for endorsement. Byrnes headed straight for the White House as soon as the Interim Committee adjourned:
I told the President of the final decision of his Interim Committee. Mr. Truman told me he had been giving serious thought to the subject for many days, having been informed as to the investigation of the committee and the consideration of alternative plans, and that with reluctance he had to agree that he could think of no alternative and found himself in accord with what I told him the Committee was going to recommend.
Truman saw his Secretary of War five days later. The President, Stim-son noted in his diary, “said that Byrnes had reported to him already about [the Interim Committee's decision] and that Byrnes seemed to be highly pleased with what had been done.”
Harry Truman did not give the order to drop the atomic bomb on June 1. But he appears to have made the decision then, with a little help from Jimmy Byrnes.
After the Interim Committee meeting on May 31 Robert Oppenheimer had sought out Niels Bohr. “I was very deeply impressed with General Marshall's wisdom,” he remembered in 1963, “and also that of Secretary Stimson; and I went over to the British mission and met Bohr and tried to comfort him; but he was too wise and too worldly to be comforted, and he left for England very soon after that, quite uncertain about what, if anything, would happen.”
Before Bohr left, late in June, he attempted one last tune to see a high official of the United States government — Stimson — Harvey Bundy sending in a message on June 18 to the Secretary: “Do you want to try and work in a meeting with Professor Bohr, the Dane, before you get away this week?”
At the side of the memorandum, in bold script, whether from exhaustion or impatience or because he understood that the matter had been taken out of his hands, Henry Stimson struck finally: “No.”
No one doubted that Little Boy would work if any design would. Otto Frisch's Dragon experiments had proven the efficacy of the fast-neutron chain reaction in uranium. The gun mechanism was wasteful and inefficient but U235 was forgiving. It remained to test implosion. While doing so the physicists could also compare their theory of the progress of such an exotic release of energy with the huge blinding fact. Trinity would be the largest physics experiment ever attempted up to that time.
The hard work of finding a proving ground sufficiently barren and remote and organizing it fell to a compact, close-cropped Harvard experimental physicist named Kenneth T. Bainbridge. His task, the Los Alamos technical history notes, “was one of establishing under conditions of extreme secrecy and great pressure a complex scientific laboratory in a barren desert.” Bainbridge was well qualified. From Cooperstown, New York, the son of a wholesale stationer, he had worked under Ernest Rutherford at the Cavendish and had designed and built the Harvard cyclotron that now served the Manhattan Project's purposes on the Hill. He had brought back word of the MAUD Committee report to Vannevar Bush in the summer of 1941 and had worked at MIT and in Great Britain on radar. Robert Bacher had recruited him for Los Alamos in the summer of 1943. Beginning in March 1944 he took charge of Trinity.
He needed a flat, desolate site with good weather, near enough to Los Alamos to make travel convenient but far enough away to obscure obvious connection. From map data he chose eight sites, including a desert training area in southern California, the Texas Gulf sandbar region now known as Padre Island and several barren dry valleys in southern New Mexico. Riding three-quarter-ton weapons carriers with Robert Oppenheimer and a team of Army officers in May 1944, Bainbridge led an exploration of the New Mexico sites through late snow; carrying along food and water and sleeping bags, he remembers, they “followed unmapped ranch trails past deserted areas of dry farming lands beaten by too many years of drought and high winds.” For Oppenheimer it was a rare escape from the daily burdens of directing Los Alamos, one he was not able to repeat. Several explorations later Bainbridge chose a flat scrub region some sixty miles northwest of Alamogordo between the Rio Grande and the Sierra Oscura, known ominously from Spanish times as the Jornada del Muerto — the dry and therefore dangerous Dead Man's Trail, the Journey of Death. Two hundred ten miles south of Los Alamos, the Jornada formed the northwest sector of the Alamogordo Bombing Range; with the permission of Second Air Force Commander Uzal Ent, Bainbridge staked out an eighteen-by-twenty-four-mile claim.
The demands of the implosion crisis in the autumn of 1944 reduced Trinity's priority, says Bainbridge, “almost to zero… until the end of February 1945.” With bomb physics well in hand by then Oppenheimer set the test shot's target date at July 4 and Bainbridge got busy. His staff of twenty-five increased across the next five months to more than 250. Herbert Anderson, P. B. Moon, Emilio Segre and Robert Wilson carried major responsibilities; William G. Penney, Enrico Fermi and especially Victor Weisskopf served as consultants.
The Army leased the David McDonald ranch in the middle of the Jornada site and renovated it for a field laboratory and Military Police station. About 3,400 yards northwest of McDonald Ranch Bainbridge marked out Ground Zero. From that center, at compass points roughly north, west and south at 10,000-yard distances, Corps of Engineers contractors built earth-sheltered bunkers with concrete slab roofs supported by oak beams thicker than railroad ties. N-10000, 5.7 miles from Zero, would house recording instruments and searchlights; W-10000 would house searchlights and banks of high-speed cameras; S-10000 would serve as the control bunker for the test. Another five miles south beyond S-10000 a Base Camp of tents and barracks took shape.
A hill named Compania twenty miles northwest of Zero on the edge of the Jornada would serve as a VIP scenic overlook. The Oscuras to the east rose more than 4,000 feet above the high alkaline plain.
The Jornada was host to gray hard mesquite, to yucca sharp as the swords of samurai, to scorpions and centipedes men shook in the morning from their boots, to rattlesnakes and fire ants and tarantulas. The MP's hunted antelope with machine guns for fresh meat and for sport. Groves authorized only cold showers for his troops; their isolated duty would win them eventual award for the lowest VD rate in the entire U.S. Army. The well water, fouled with gypsum, made a sovereign purgative. It also stiffened the hair.
Contractors built two towers. One, 800 yards south of Zero, they bolted together 20 feet high in trestles of heavy beams like those that framed the bunkers. It supported a wide platform like an outdoor dance floor and one day in early May the builders returned from a mandated layoff to find it had vanished. Bainbridge had seen it stacked with 100 tons of high explosives in wooden boxes, had packed canisters of dissolved hot Hanford slugs at the center and before dawn on May 7 had blown the entire stack, the largest chemical explosion ever deliberately set off, merely to practice routines and try out instruments. The dirt roads had caused delays; he demanded twenty-five miles of paved roads from Groves as a result and got them, and tightened up procedures for the one and only nuclear test to come.
The tower went up at Zero. It had been prefabricated of steel and shipped to the site in sections. Concrete footings poured through the hard desert caliche 20 feet into the earth supported its four legs, which were spaced 35 feet apart; braced with crossed struts it rose 100 feet into the air, culminating in an oak platform roofed and sheltered on three sides with sheets of corrugated iron. The iron shack's open side faced toward the camera bunker to the west. A removable section at the center of the platform gave access to the ground below. The high-iron workers who finished the tower installed bracing at the top for a $20,000 electrically driven heavy-duty winch.
Frank Oppenheimer, a Berkeley physics Ph.D. working for his brother now troubleshooting the test, remembers that when he arrived at Trinity in late May “people were feverishly setting up wires all over the desert, building the tower, building little huts in which to put cameras and house people at the time of the explosion.” The reinforced concrete camera bunkers had portholes of thick bulletproof glass. Hundreds of 6-foot wooden T-poles strung thick as a loom frame with 500 miles of wire walked away from Zero to the instrument bunkers safe miles beyond; other wires buried underground ran protected inside miles of premium garden hose.
Besides photographic studies three kinds of experiments concerned Bainbridge and his team. One set, by far the most extensive, would measure blast, optical and nuclear effects with seismographs, geophones, ionization chambers, spectrographs, films and a variety of gauges. A second would study the implosion in detail and check the operation of the new exploding-wire detonators Luis Alvarez had invented. Experiments planned by Herbert Anderson to reveal the explosive yield radiochemically made up the third category. Harvard physicist David Anderson (no relation) arranged to acquire two Army tanks for that work and to pressurize them and line them with lead; Herbert Anderson and Fermi meant to ride them close to the crater at Zero immediately after the shot, scoop up some of the radioactive debris with a tethered cup hitched to a rocket fired into the crater and retrieve the material for laboratory measurement. Its ratio of fission products to unfissioned plutonium would reveal the
