Making of the Atomic Bomb

by Richard Rhodes

  Mountain climbing had long been a Hans Bethe hobby. He and Fermi, among others, sometimes scaled Lake Peak across the Rio Grande in the Sangre de Cristos, one of Bethe’s admiring group leaders remembers, to “sit there in the sunshine” at 12,500 feet “discussing physics problems. This is how many discoveries were made.”2137 Leona Marshall, who moved with Fermi to Los Alamos, recalls less Olympian hours with “nothing to do but admire the view and gasp for breath.”2138

  Equally strenuous excursions went out to area landmarks. Genia Peierls and Bernice Brode determined to find the Stone Lions, prehistoric lifesized twin effigies of crouching mountain lions carved in tuff, reported beside a ruined pueblo on a distant mesa. They gathered up a carload of Navy ensigns and another of young bachelors from the British mission and drove within ten miles of their goal, then set out walking, Genia Peierls leading the way in tennis shoes without socks: “Best for stones, best for bunions.” Lunch at two in the afternoon by a cool canyon stream encouraged the weary ensigns to drop anchor, but Mrs. Peierls had cowed the young British mission men from similar protest. “OK, we proceed to Stone Lions without U. S. Navy. All aboard.” More hiking, crossing desert country from mesa to mesa, the Rio Grande below. The American woman was impressed with the Stone Lions; not so the Russian. “House cats only, my dear, not well made and maybe not even old.” “On the way back,” Bernice Brode recalls, “the young men . . . looked out over the wide expanse of the desert region and the ribbon of water shining in the setting sun. One of them, dark and slim, wearing tortoise shell rimmed glasses, spoke in his soft voice with a slight German accent. ‘I have not seen New York, nor Chicago, but I have seen the Stone Lions.’ He smiled pleasantly as we walked on. His name was Klaus Fuchs.” Penny-in-the-slot Fuchs, Genia Peierls nicknamed him, because the quiet, hardworking emigré theoretician only spoke when spoken to.2139

  On a hike through Frijoles Canyon with the Fermis, Niels Bohr stopped to admire a skunk, an animal unknown to Europeans, but it chose not to instruct the vigorous Dane in the pungency of its defenses. Bears sometimes appeared on the trails, prompting warnings in the daily bulletin: “Remember that these are not tame bears like those in Yellowstone Park.”2140 A family cat turned up with a suppurating jaw; the Hill’s Army veterinarian recognized the bone necrosis as a sign of radiation poisoning from Tech Area contamination and kept the animal alive to observe its unusual symptomatology, about which not much was yet known. Its tongue swelled and its hair fell out in patches; its heartsick owner eventually asked that the animal be destroyed.

  A low-power radio station began broadcasting to Hill residents on Christmas Eve, 1943, drawing on several fine collections of classical records, including Oppenheimer’s; the few New Mexicans beyond the Hill who could receive the station’s signals were puzzled that announcers never introduced live performers by their last names. The “Otto” who occasionally played classical piano selections was Otto Frisch. A golf course opened in June 1944. Men and women fielded baseball, softball and basketball teams. The Army divided up the old Ranch School truck garden east of Fuller Lodge into victory-gardening plots but had no water to spare for irrigation.

  Life was rougher for construction workers, machinists, soldiers and WAC’s: minimal barracks, jerrybuilt dormitories, muddy trailer courts. Hillbilly construction families invited once in the interest of authenticity to the square dancing at the mess hall arrived drunk and nearly caused a riot; thereafter a man in uniform guarded the door. Hans Bethe recalls that one wild machinist late in the war, when the laboratory took what help it could find, slit a fellow worker’s throat “from cover to cover.”2141 The Indians from San Ildefonso and other pueblos and ranches in the area lived better for their work on the Hill as cleaning women and maintenance men. The hand-coiled black pottery of Maria Martinez soon graced many Los Alamos apartments.

  In winter a pall of coal smoke hung over the mesa. The men the Army assigned to service the apartment furnaces stoked them so hot that apartment walls sometimes sizzled. Los Alamos sat high and dry surrounded by pine forests, and fire worried everyone. The main machine shop in the Tech Area caught fire one night early in 1945; Eleanor Jette remembers watching her husband Eric, Metal Reduction group leader in the Chemistry and Metallurgy Division, standing with Oppenheimer and the Hill commanding officer on the fire escape of the administration building grimly overseeing the firefighters. “Jesus,” she heard someone say, “let’s be thankful it isn’t D building. That place is as hot as seven million dollars. Every time it gets too hot for them to work, they slap on another coat of paint.” Her husband worked in D building; she did not know he worked with plutonium but understood that “hot” meant radioactive. “Damn,” he told her when she asked. “You mustn’t be upset. We’re so careful it’s fantastic.”2142 A fire in the plutonium-handling areas would be a major disaster; after the machine-shop fire Groves ordered a fireproof plutonium works built with steel walls and a steel roof and filtering systems for both incoming and outgoing air.

  Robert Oppenheimer oversaw all this activity with self-evident competence and an outward composure that almost everyone came to depend upon. “Oppenheimer was probably the best lab director I have ever seen,” Teller repeats, “because of the great mobility of his mind, because of his successful effort to know about practically everything important invented in the laboratory, and also because of his unusual psychological insight into other people which, in the company of physicists, was very much the exception.”2143 “He knew and understood everything that went on in the laboratory,” Bethe concurs, “whether it was chemistry or theoretical physics or machine shop. He could keep it all in his head and coordinate it. It was clear also at Los Alamos that he was intellectually superior to us.”2144 The Theoretical Division leader elaborates:

  He understood immediately when he heard anything, and fitted it into the general scheme of things and drew the right conclusions. There was just nobody else in that laboratory who came even close to him. In his knowledge. There was human warmth as well. Everybody certainly had the impression that Oppenheimer cared what each particular person was doing. In talking to someone he made it clear that that person’s work was important for the success of the whole project. I don’t remember any occasion at Los Alamos in which he was nasty to any person, whereas before and after the war he was often that way. At Los Alamos he didn’t make anybody feel inferior, not anybody.2145

  Yet Oppenheimer felt inferior himself, had always felt for the actions of his life, as he confessed many years afterward, “a very great sense of revulsion and of wrong.” At Los Alamos for the first time he seems to have found alleviation of that loathing. He may have discovered there a process of self-analysis anchored in complementarity that served him more comprehensively later in his life: “In an attempt to break out and be a reasonable man, I had to realize that my own worries about what I did were valid and were important, but that they were not the whole story, that there must be a complementary way of looking at them, because other people did not see them as I did.2146 And I needed what they saw, and needed them.” Certainly he found the more traditional alleviation of losing himself in work.

  Whatever his burden of morale and work in those years, Oppenheimer also carried his full share of private pain. He was kept under constant surveillance, his movements monitored and his rooms and telephones bugged; strangers observed his most intimate hours. His home life cannot have been happy. Kitty Oppenheimer responded to the stress of living at isolated Los Alamos by drinking heavily; eventually Martha Parsons, the admiral’s daughter, took over the duties of social leadership on the Hill. Army security officers hounded the director of the central laboratory of the nation’s most important secret war project mercilessly; at least one of them, Peer de Silva, was convinced Oppenheimer was a Soviet spy. They interrogated him frequently, fishing for the names of people he knew or believed to be members of the Communist Party, hoping to trip him up. He invented circumstances and volunteered the names of friends to protect his own, i
ndiscretions that would return in time to haunt him.2147

  During the first Los Alamos summer he heard from Jean Tatlock, the unhappy woman he had loved before he met his wife. Loyally, even though she had been and still might be a Communist and he knew himself to be spied upon, he went to her; an FBI document coldly summarizes a security man’s peepshow version of that meeting:

  On June 14, 1943, Oppenheimer traveled via Key Railway from Berkeley to San Francisco on the evening of June 14, 1943, where he was met by Jean Tatlock who kissed him. They dined at the Xochimilcho Cafe, 787 Broadway, San Francisco, then proceeded at 10:50 P.M. to 1405 Montgomery Street and entered a top floor apartment. Subsequently, the lights were extinguished and Oppenheimer was not observed until 8:30 A.M. next day when he and Jean Tatlock left the building together.2148

  In January 1944 Jean Tatlock committed suicide. “I wanted to live and to give and I got paralyzed somehow,” her suicide note said.2149 It was a paralysis of the spirit Oppenheimer seemingly had to resist in himself.

  Planning began in March 1944 for a full-scale test of an implosion weapon. Sometime between March and October Oppenheimer proposed a code name for that test.2150 The first man-made nuclear explosion would be a historic event and its designation therefore a name that history might remember. Oppenheimer coded the test and the test site Trinity. Groves wrote him in 1962 to find out why, speculating that he chose the name because it is common to rivers and peaks in the American West and would be inconspicuous.

  “I did suggest it,” Oppenheimer responded, “but not on [that] ground. . . .2151 Why I chose the name is not clear, but I know what thoughts were in my mind. There is a poem of John Donne, written just before his death, which I know and love. From it a quotation:

  As West and East

  In all flatt Maps—and I am one—are one,

  So death doth touch the Resurrection.”

  The poem was Donne’s “Hymne to God My God, in My Sicknesse,” and among its subtleties it construes a complementarity that parallels the complementarity of the bomb that Bohr had recently revealed to Oppenheimer. (“Bohr was deeply in this,” Bethe testifies, “and this was his real interest, and Bohr had long conversations with Oppenheimer which brought Oppenheimer into this at a very early stage. Oppenheimer was very much indoctrinated by Bohr’s ideas of international control.”2152) That dying leads to death but might also lead to resurrection—as the bomb for Bohr and Oppenheimer was a weapon of death that might also end war and redeem mankind—is one way the poem expresses the paradox.

  “That still does not make a Trinity,” Oppenheimer’s letter to Groves goes on, “but in another, better known devotional poem Donne opens, ‘Batter my heart, three person’d God;—.’ Beyond this, I have no clues whatever.”2153 Nor must Groves have had; but the fourteenth of Donne’s Holy Sonnets equally explores the theme of a destruction that might also redeem:

  Batter my heart, three person’d God; for you

  As yet but knocke, breathe, shine, and seeke to mend;

  That I may rise, and stand, o’erthrow mee, and bend

  Your force to breake, blowe, burn and make me new.

  I, like an usurpt towne, to another due,

  Labour to admit you, but Oh, to no end;

  Reason, your viceroy in mee, mee should defend,

  But is captiv’d, and proves weake or untrue.

  Yet dearly I love you, and would be loved faine,

  But am betroth’d unto your enemie:

  Divorce me, untie, or breake that knot againe,

  Take mee to you, imprison me, for I

  Except you enthrall me, never shall be free,

  Nor ever chaste, except you ravish me.

  That is poetry perhaps martial enough, ardent enough and sufficiently fraught with paradox to supply a code name for the first secret test of a millennial force newly visited upon the world.

  Oppenheimer did not doubt that he would be remembered to some degree, and reviled, as the man who led the work of bringing to mankind for the first time in its history the means of its own destruction.2154 He cherished the complementary compensation of knowing that the hard riddle the bomb would pose had two answers, two outcomes, one of them transcendent. Such understanding justified the work at Los Alamos if anything did, and the work in turn healed the split between self and overweening conscience that hurt him.2155 He had long recognized the possibility of such a convalescence and evoked it explicitly in the epistle on discipline he wrote his brother Frank in 1932 that concluded in Pauline measure: “Therefore I think that all things which evoke discipline: study, and our duties to men and to the commonwealth, war, and personal hardship, and even the need for subsistence, ought to be greeted by us with profound gratitude; for only through them can we attain to the least detachment; and only so can we know peace.”2156 At Los Alamos, if only for a time, he located that detachment in duties to men and to the commonwealth that Bohr was teaching him to believe might be worthy, not macabre. He was not the first man to find himself in war.

  * * *

  To develop implosion Los Alamos had to develop diagnostics, ways to see and to measure events that began and ended in considerably less time than the blink of an eye. The iron pipes Seth Neddermeyer imploded could be studied by aiming a high-speed flash camera down their bores, but how could the physicists of G Division observe the shaping of a detonation wave as it passed through solid blocks of high explosives, or the compression of the metal sphere which those explosives completely surrounded? They were competent research scientists who had been working within narrow technological constraints for a year and a half; diagnostics demanded imagination and they brought all their frustrated creativity to the task.

  X-raying was a reliable approach; the Ordnance Division had already used X rays to study the behavior of small spherical arrangements of explosives. X rays reveal differences in density—dense bone casts a darker shadow than lighter flesh—and since the detonation wave of a developing implosion changed the density of the explosive material as it burned its way through, X rays could make that wave visible. But adapting X-ray diagnostics to implosion studies on an increasing scale meant protecting fragile X-ray equipment from the repeated blasts of as much as two hundred pounds of high explosives at a time. That challenge the physicists met by the unorthodox expedient of mounting their implosion tests between two closely spaced blockhouses with the X-ray unit in one building and the radiography equipment in the other, accessible to the test event through protected ports. Ultimately flash X-ray equipment—high-current X-ray tubes that pulsed as rapidly as every ten-millionth of a second—proved most useful for detonation-wave studies.

  The behavior of a test unit’s HE shell was easier to study with X rays and high-speed photography than was the compression of its denser metal core. For following the metal core as it squeezed to less than half its previous volume Los Alamos developed several different diagnostic methods and used them in complement.

  One method set the test unit within a magnetic field and measured changes in field configuration as the metal sphere compressed. Since HE is essentially transparent to magnetism, this method allowed the physicists eventually to study full-scale assemblies. It gave reliable measure of shock waves reflected from the core and of the troublesome detonation-wave intersections that caused jets and spalling.

  Carefully spaced prearranged wires contacted by the metal sphere as it imploded supplied information not only about the timing of the implosion but also about material velocities at various depths within the core. That provided direct, quantitative data which the Theoretical Division could use to check how well its hydrodynamic theory fit the facts. The Electric Method group began by measuring the high-explosive acceleration of flat metal plates. Early in 1945 it adapted its techniques to partial spheres and eventually to spheres surrounded by HE lens systems with only one lens removed to access the necessary wires.

  Duplicated at another test site, the blockhouse arrangement that served to protect ordinary X-ray equi
pment also served to shield the most unusual diagnostic method the scientists devised: firing pulsed X rays from a betatron through scale-model implosion units into a cloud chamber and photographing the resulting ionization tracks with a stereoscopic camera.1 The betatron method needed an ingenious timing circuit to trigger in quick but precise sequence the explosive charge, the betratron X-ray pulse, the expansion of the diaphragm of the cloud chamber that made the ionization tracks visible as droplets in the fog and the camera shutters that photographed them.

  The fifth successful method G Division developed varied the betatron method by incorporating an intense source of gamma radiation within the core itself. The source, radioactive lanthanum extracted from among fission products of the Oak Ridge air-cooled pile, gave the method its name: RaLa. Not a cloud chamber but alignments of rugged ionization chambers served to register the changing patterns of radiation from the RaLa cores as they compressed. Since no one knew at first how extensively the radiolanthanum would contaminate the test site, Luis Alvarez, who coordinated the first experiment, borrowed two tanks from the Army’s Dugway Proving Ground in Utah to use as temporary blockhouses. He recalls spectacular results: