The Trinity Paradox (11 page)

Feeling suddenly reckless, Fox raised his glass and toasted the G-2 man.

The man looked away.

6

Berlin—the Virus House August 1943

“[Heisenberg] declared, to be sure, that the scientific solution had already been found and that theoretically nothing stood in the way of building such a .bomb.”

—
Albert Speer, Nazi Minister of Armaments

“German physicists had no desire to make atomic bombs, and were glad to be spared the decision by force of external circumstances.”

—
Werner Heisenberg

Gravel crunched under
the wheels of the staff car as the driver turned off of the cobblestoned streets. They proceeded to a less-traveled area of the Berlin suburb of Dahlem, then turned down the damp road to the Kaiser-Wilhelm Institute. The stolid construction of the Institute for Chemistry and the Institute for Physics was overbearing, designed at the turn of the century to please the rigid tastes of the Kaiser. Now, in the August rain, the trees and the flower boxes appeared subdued. Wet streaks ran down the stone walls as water splashed out of rusting gutters.

The driver of the staff car activated the windshield wiper, but it merely smeared a thin film of mud. Ahead of the car rode two motorcycle guards hunched over their handlebars. The motorcycle engines popped and puttered from the alcohol fuel.

Although he now held the upper hand, Professor Abraham Esau fidgeted in the back of the staff car, wondering if he would triumph as planned or if everything would backfire on him. The drive had not been long, but it was uncomfortable. Reichminister Albert Speer sat beside him, straight-backed and silent, staring ahead. The Minister of Armaments must be preoccupied with something other than the secret Nazi research center known as the Virus House.

Beside the driver sat Major Wilhelm Stadt of the Gestapo, dressed in a black uniform with SS armband. Major Stadt was rude, fast spoken, with an air of confidence that bordered on impatience. As did so many of the young officers, the major sported a small toothbrush moustache like Hitler’s and Himmler’s. He had his pale hair shaved severely up around his ears and the back of his neck, making him appear to be wearing an overlarge Jewish skullcap. Esau did not dare make such a comparison aloud; the SS major would not have found it amusing.

Major Stadt spoke to the driver, telling coarse stories and Jewish jokes, acting friendly toward the lower ranks—after all, wasn’t Gestapo head Himmler himself a former chicken farmer? But Stadt’s casual attitude seemed a ploy to Esau, a practiced interrogation technique. Every third or fourth comment, Major Stadt would turn around to look at Reichminister Speer, as if searching for some reaction. Occasionally Speer would nod, or smile if that seemed appropriate, but he said few words.

Esau knew that Speer had never wanted his position as Minister of Armaments—he was an architect who had served Hitler well, but he had been astonished when Hitler promoted him after the previous minister had been killed in an airplane crash. Speer had done his best in the position, but the German war effort seemed to be flagging. Mussolini had been overthrown in Italy, and a humiliating
and
disastrous Allied bombing raid had just turned the city of Hamburg into a firestorm.

No matter. From Esau’s work here at the Kaiser-Wilhelm Institute, both he and Reichminister Speer could become heroes. The firestorm of Hamburg would be nothing compared to the devastation a German atomic bomb could deliver. The other scientists would not be so smug and uncooperative with Speer standing beside him. Esau now had the crowbar he needed to consolidate the nuclear physics research firmly under his own custodianship.

Werner Heisenberg would not be expecting them; Esau wanted that as part of their surprise. Heisenberg lived in Leipzig with his family, but took the train to Berlin twice a week to continue work at the institute. Esau had taken great care to be sure they arrived on a day Heisenberg would be at the Virus House.

The motorcycles ground to a halt. The staff car pulled up in front of a complex of wooden buildings surrounded by a gate and a sagging barbed-wire fence. One guard, wrapped in a rain shawl with a machine gun over his shoulder, stepped forward to inspect the papers of the motorcycle riders, who gestured him toward the staff car. The driver wrestled with the crank to turn down the window.

“This is a restricted area. May I see your papers please?” the guard said, pushing his head in and dripping water on the driver’s shoulder.

When he saw Reichminister Speer and Major Stadt in their respective uniforms, the guard stiffened, but held his ground. For security reasons they had not marked the staff car to announce the ranks of its occupants.

Major Stadt remained silent, and Esau waited as the guard checked them through. Any other behavior by the guard would not have been tolerated. The guard returned the folded papers to the driver, then trudged off through the mud back to his windbreak shelter beside the barbed-wire gate. The two motorcycle riders kicked their engines into life again, then proceeded through the gate. The driver of the staff car kept the window cracked open, allowing damp air to purge the atmosphere inside. They drove into the grounds of the Virus House.

In July 1940 the researcher Karl Wirtz had built a small laboratory on the grounds of the Kaiser-Wilhelm Institute for Biology and Virus Research, adjacent to the Institute of Physics. All power and water for the new establishment came from the institute’s large virus growth laboratories. But Dr. Karl Wirtz was no biologist. The ominous name “Virus House” was prominently displayed only to keep the curious away, and to mislead any spies about the actual research conducted there.

At the beginning of the war, Reichminister Speer’s predecessor had been skeptical about the nuclear physics program, since it then appeared the Blitzkrieg would give Germany victory over Britain long before nuclear physicists could develop a new weapon. Nevertheless, a research program was set up. The head of the institute, the Dutch experimental physicist Paul Debye, was told that he must either become a German citizen or leave his post, because no foreign national could be allowed to work on a secret military project. Debye had chosen to leave, departing to go on a “lecture tour” to neutral America.

That was in January 1940. The Armaments Ministry tried to install Dr. Kurt Diebner from the military as Debye’s replacement, and this the rest of the Kaiser-Wilhelm Institute resoundingly opposed. But they had not yet realized how much times had changed. Finally the institute accepted Dr. Diebner as a provisional head, until such time as Paul Debye returned from his lecture tour.

But Diebner’s career had not survived political machinations in the following years. Other scientists, such as Karl Wirtz and Carl-Friedrich von Weizsacker had schemed to draw Werner Heisenberg into the institute, where he became titular head of nuclear physics work-subordinate to the Plenipotentiary for Nuclear Physics, of course, Esau reminded himself.

Esau had been to the Virus House on official visits, but he had accomplished nothing. The program remained as scattered and uninspired as ever, the scientists more concerned with maintaining their reputations than with winning the war.

Now, though, Esau was bringing them sufficient inspiration, thanks to Graham Fox.

He allowed himself to smile as they drove into the muddy courtyard outside the wooden barracks. Dark stains showed where rain had soaked through the plank walls. All around, the city of Berlin pressed close, too close perhaps for such dangerous research as this, but it did make a perfect hiding place.

A dim shadow behind one of the windows watched the staff car pull up, then ducked back. Esau hoped the observer would inform the rest of the physicists exactly who had arrived for a visit.

They had come to accuse Professor Werner Heisenberg of treason.

A week before, when the Reich post had delivered a letter with Belgian postmark, Professor Esau took notice. He held up the stained envelope and frowned; it looked like cheap stationery inside. He did not recognize the bold handwriting on the address with its excessive loops and flourishes. With a letter opener he slashed open the edge.

He recognized the handwriting on the letter inside immediately. Graham Fox! It was impossible, but he could not stop himself from a smile such as he had not worn since his student days at Cambridge. He wondered how Fox had managed to get a letter through the postal blockades to Germany. But none of Esau’s initial astonishment compared to what he felt upon reading the terse but profound message.

... So, my dear friend, Fermi has achieved a self-sustaining neutron reaction moderated by graphite blocks. By virtue of Germany’s superior physicists, Heisenberg’s group should have come to this discovery on their own—could he perhaps be leading you down the wrong path? After all, no one would question Heisenberg’s claims. I will do what I can here because we must maintain parity. All humanity is at risk. Must count on you, Abraham.

At that moment Esau’s secretary—the same one who had bungled his invitation to the physics conference, and then bungled his subsequent apology letter—appeared at the door with some inane question. Esau’s shouting fit sent her scurrying back into the hall. Her heels echoed on the tile floor like gunshots.

Esau clutched the letter with sweaty fingers. A nuclear reaction moderated by graphite! Esau was astounded. According to all their careful studies—no, he corrected himself, not careful enough—they had thought heavy water was the only substance that could appropriately moderate a reacting pile. How could they have missed something as simple and common as graphite?

A nuclear reactor could produce a different element, a new element beyond uranium on the periodic table, that could be used as a substitute for the rare isotope uranium-235 in an atomic bomb. In 1940 the American Edwin McMillan, working at the University of California at Berkeley, had artificially created “element 93” by bombarding uranium with neutrons. Since uranium had been named after the planet Uranus, McMillan had decided to call his new element “neptunium” after the planet Neptune.

But physical theory predicted that the
next
artificial element in the series, element 94, would be a candidate for fission, just like uranium-235. Element 94 did not exist in nature, but in all likelihood could be made in the laboratory. But only if they could keep a nuclear chain reaction going. Continuing the scheme of using planetary names, this element should be named after the newly discovered ninth planet Pluto. Plutonium?

If they could produce enough of this new plutonium, Esau would not need to worry about the incredible difficulties of separating uranium-235 from the rest of the ore. They could have a German bomb sooner than expected.

But for that they needed a working reactor to “cook” the uranium until it became plutonium ... and to achieve a functioning reactor, Esau had thought he needed enormous quantities of heavy water, which was exceedingly rare and precious. Even then it remained a matter for conjecture, because they had never been able to obtain enough heavy water to test the theory.

The difficulties continued to tangle worse and worse as the war went on.

Germany’s only source of heavy water had been the Norwegian Hydro Works at Vemork—and the Allies had recently destroyed the plant, bringing all heavy water production to a halt. Allied saboteurs had even sunk the ferry carrying the last few drums of dilute heavy water rescued from the ruined factory.

Esau had seen no future for the possibility of reactor research. It had left them with nothing to try but the impossible isotope separation.

Now, though, Fox’s letter implied that perhaps graphite—simple carbon—could be used instead of heavy water. Esau could not comprehend why his own researchers had ignored the possibility. Especially with the great Heisenberg at the helm.

Feeling his cheeks flush with a growing anger, Esau dug through the files and progress reports describing aspects of his disjointed program. He loathed this clerical work—he could never find anything. Progress reports had been falsified, or not submitted on time, or written in such terse, vague language that he couldn’t understand what the physicists were talking about. He had not unpacked and organized the files completely, and he did not dare risk asking his inept secretary to help him. Some of the files were from Diebner’s tenure over the Kaiser-Wilhelm Institute; others had been culled from the Armaments Ministry itself, or even von Ardenne’s work for the post office.

Surely someone must have tested graphite.

He found the records after an hour of searching. He snapped the thin file away from the stack with a brisk gesture that betrayed his own impatience. Outside, an automobile horn blasted three times, and Esau made an annoyed comment to himself. He took the papers back to his desk and spread them out, piling everything else on top of his unopened mail.

Professor Walther Bothe had made the analysis. At Heidelberg, Bothe had used a sphere of high-quality graphite larger than a meter in diameter, submerging it in a tank of water to measure its neutron absorption cross-section. According to Bothe’s test results, graphite was indeed a poor choice, swallowing far too many of the available neutrons. For the nuclear reaction to be successful, the moderator needed to
slow down
the neutrons to the proper speed so they could cause fissions in the uranium—slow them down, not take them out of the reaction entirely.