The Berlin Project

by Gregory Benford

  Moe leaned forward, tenting his fingers. “This is more my line of work. When he’s in Switzerland, that’ll be the time to get to him—to see if he’s really running a big program.”

  Karl felt he had to say, “We’re assuming that the war won’t be over soon, after the gadget goes off.”

  Freeman said quietly, “One might quibble over the definition of soon.” The pealing laughter that followed revealed the unspoken tension in the cramped office.

  • • •

  When Dyson told him that the two of them had to go to a high-level meeting, Karl tried to get out of it. He had plenty to do.

  “Nobody will pay any attention to what we say.”

  Freeman nodded. “Undoubtedly. We will be there to answer questions on bombing and your ‘gadget’ device.” He liked the term, always gave a little smile as he used it.

  “We have reports, calculations—”

  “They want to get it from us. Most of your team is out at the airfield, doing their flight training and miscellaneous. Same on my side—I analyze data, I don’t have a hand in mission planning, really. Not much beyond simply saying some things we know about what works in bomber groups.”

  Karl shook his head. “I know nothing about that.”

  “I handle that, if anyone cares what analysis says.”

  Karl frowned skeptically. “So I discuss . . . what?”

  “The physics and engineering details, your judgment of them.”

  “I don’t know much. I’ve been running around for years now—getting spinners to work, mostly. Then Groves asked me to look at the bomb designs. Plus take part in figuring how to be sure they work.”

  “Very good. You know the estimated extent of damage?”

  Karl knew what various people thought, which varied by factors of two or three. “Some. I can relate our ideas. Not like we’re going to test them. Not with three or so months to get another warhead.”

  “Quite so.” Freeman sighed. “We are less useful to our groups for now, so we go. Efficient, you see.”

  Karl thought Freeman was the sort who proved quietly useful, and he recalled Luis Alvarez’s comment—Any successful team needs one rational guy who thinks this thing is sure as hell not gonna work. “Not willingly.”

  Freeman smiled wistfully. “Will does not come into it at all.”

  • • •

  The White Hart pub was jammed, of course. Yanks and Free French, Aussies, Brits of several persuasions—all thronged the noisy, smoky rooms and spilled into the street. A woman stood with her hip cocked against a windowsill and said with a leer, “On the stroll?”

  Karl stopped, not getting the meaning. She wore a tight skirt and sweater with a silver cross pointing the way to her breasts, in case he had somehow missed them. He edged away from her broad smile and stood outside to peer through the open windows. The pubs had just opened and the bar was a froth of shouted orders. Not his kind of spot, no.

  He did enjoy overhearing English terms like “codswallop” for “nonsense” and “tosser” for “idiot” while he waited. Then he saw Anton waving a hand and pointing to two beers he had already scored, sitting on a table. By the time Karl wedged himself into Anton’s vicinity, all possible chairs had been kidnapped. They pounded each other’s backs and Karl called, “Outside!”

  At last able to breathe, they leaned against the brick wall. Anton had hitchhiked up from a southern port in England to meet Karl. It was sheer luck they were in the same corner of the war at the same time. Now foot traffic brought more eager-eyed soldiers and the occasional woman in uniform toward the pub. The military owned these streets by sheer numbers.

  “How’s the navy treating you?” Karl asked, sipping his stout. It was the closest one could get to a real drink, in his opinion, given the horrible wine the locals called “plonk.”

  “Is fine! I sail on freighters. Plenty work, but no subs now.”

  Someone bumped Anton and some beer spattered on the pavement. “We seem to have sunk most of their navy.”

  “Yes! But am promise will get to Pacific once this invasion over.” Anton grinned with raised eyebrows at the prospect.

  “The invasion is the salad, not the dessert.” And wait until you see the appetizer we’re giving them. . . .

  Anton laughed heartily. “Always with food, you are. I applied for combat duty and was approved. No navy combat left, much, here.”

  “Maybe we should take a walk. . . .” So many of the pub crowd filled the street now; he looked around. To move quickly was to make enemies. Karl got pushed back. Jostling. Then an elbow jarred him. A fist flew by. Shouts rose. The anger came from nearby but had nothing to do with them.

  That did not matter now. A strange guttural rage rippled outward. He realized they were in a vicious free-for-all for which Karl’s advanced degrees were no good. He ducked and dodged in Anton’s wake. Anton had a way of slipping punches and pushes so that he always moved toward the street. This proved to be not the optimal path. The fight spilled into traffic. Somebody clipped him lightly on the jaw. Karl emerged from a section of the fight with no more damage than could be racked up to shaving. Anton ran ahead and Karl followed, straight into another crowd. It took a moment of wary dodging to discover that this was a ring of spectators.

  A shrill whistle sounded.

  “MPs!” Anton shouted.

  They slipped between the hub and the bub and down a side street.

  They trotted away until Karl leaned against the half-collapsed wall of a bomb site, panting. I really must get more exercise. . . .

  “Well,” he said in a thin voice, “you wanted to see combat.”

  Anton’s eyes were bright. “Yeah, was fun!”

  “Not my idea of it.”

  “Didn’t you fight when young?”

  “Once, with an Italian kid in a school yard.”

  “How’d you do?”

  “Guess.”

  PART VIII

  * * *

  GROUND POUNDER

  Richard Feynman

  Nothing is worse than war? Dishonor is worse than war. Slavery is worse than war.

  —Winston Churchill

  1.

  May 2, 1944

  “Popcorn, that’s the model,” Richard Feynman said with a lopsided grin.

  This brought doubtful frowns. Feynman shrugged. “Say you pop a handful of kernels. Out comes a thimbleful of nice white corn to eat. Yum! The rest is some sizzled kernels, but not popped. Useless. That’s what this bomb will be like. A bang, sure—but you get maybe a few percent of what’s there, waiting in the uranium. So the rest is kernels.”

  “What efficiency?” Karl asked, sitting back from the old wooden conference table. Feynman’s Bronx accent was so thick, Karl wondered if he was putting it on. Talks like a bum!

  Feynman gave an eloquent shrug again. “One, two percent. Tops.”

  The trio of men fresh off the airplane from Los Alamos were a bit groggy but had wanted to deliver their estimates. Another one, Fred Reines, added, “We did a big critical mass calculation, months back. Said you could get by with maybe thirty kilograms, but didn’t recommend it.”

  Karl nodded. “Read your memo. We figured that too.” He nodded toward Luis Alvarez, who had served as checker on the calculation. “So this bomb is coming in at around a hundred kilograms.”

  Reines sat back and gave an evil chuckle. “That will work for damn sure. Ha!”

  Karl caught a tone that made him suspect Reines was a Jew. The man had a certain ironic delight. Karl had been thrown off when, coming into the big Admiralty Citadel plaza, Reines had burst into a Gilbert and Sullivan song in a big, booming voice. His first time in London, and he knew entire long verses. The tall man drew startled glances as he sang with a musical joy far from the severe, eastern European classical culture Karl knew.

  Karl stood, energy boiling up. “We just got in the last shipment of U-235 from Oak Ridge, all machined out. Ninety-four percent pure. In time for Luis here to add it into the cy
linder target and the disk bullet.” Karl paused. “Have any idea how dangerous it is to machine metal U-235? The guys had shifts, to lower the risk. They wore suits that wrapped them in. Plus oxygen fed into masks. They had to melt the damn stuff, shape it in molds accurate to a fraction of a millimeter, then machine it down to smooth it. Down to a tenth of a millimeter.”

  Karl stopped, feeling now that his voice had risen. “Everything’s been faster than it should be. We said we’d have the gadget for the invasion. But Eisenhower won’t wait for us, for a single bomb, no matter what. So we’re putting it all together now, out at the field.”

  He sat back, feeling the release of saying things, letting the pressure vent. The Los Alamos guys, three of them, just looked at him. He wished Dyson was here; that would help. But there were still barriers, classification regimes, things the Los Alamos team was not to know. God knows why, he thought, and realized he was more tired than he ever had been. Must be the pressure.

  Feynman said kindly, his grin now gone, “We came with some of the shotgun assembly in our plane, but there was a whole backup setup on another. Both came through. We call ’em ‘pre-assemblies.’ Means partly assembled bombs without the fissile components. We got your measurements on the two 235 cores, adjusted the high explosives.”

  “What’s the gun like?” Karl looked at them, the guys who had actually built the final assembly, working with a naval gun team. Luis was rolling out and spreading the blueprints on the table, and the third Los Alamos guy, Bob Serber, helped weigh them down with staplers.

  Feynman said, “Gotta get out to that airfield and put it all together—Little Boy.”

  Karl now thought that Götterdämmerung would be more appropriate.

  Bob Serber’s mouth slid into an amused smile. “At Los Alamos we had movies shown on weekends in a big tent. I figured somebody named it after a short character in The Maltese Falcon movie. Bogart pushes him around.”

  Karl chuckled. “And nobody’s going to push this Little Boy around.”

  He went through it all with them—nitrocellulose propellant powder, the gun and breech made by the navy, the tail fairing and mounting brackets by the Expert Tool and Die Company, basic safety mechanisms, triggers. He showed a slide used in his innumerable talks to figures from the British government, their Royal Air Force, and various people he doubted had any idea what made the bomb work at all.

  Feynman said, “Y’know, everybody started out thinking that firing a small, solid bullet into the center of a hollow cylinder was the way to go. Not so! We’ve got to keep both parts below critical mass, so we don’t get a fizzle when they just touch. So we have to fire the cylinder onto the bullet. That hole in the center disperses the mass, increases the surface area, see? That lets more fission neutrons escape, preventing a premature chain reaction.”

  Karl knew this from the Columbia work, but it was good to hear that the Los Alamos guys had seen the basic physics, too. He handed over a printed illustration from an earlier Los Alamos report, signed by the Oppenheimer guy. “This cartoon, we got last year.”

  Little Boy

  “Yeah, slam the cylinder into the plug,” Feynman said. “Pretty, colors and all.”

  Luis Alvarez leaned forward on the table and said, “Guys, forget the mechanics. I want to know what it does to the target. I’ve got to calibrate the pressure meters we’re going to drop on ’chutes to measure the shock wave.”

  Feynman shrugged. “We had a team—hey, Bob, your guys—look into bomb impact. Depends on where it goes off.”

  Karl looked around the table. “Let’s say a ground impact.”

  Feynman screwed his mouth around skeptically. “I’d say the biggest effect will be from the flash of infrared. That’ll set fire to everything wood within maybe three, four miles.”

  Karl somehow didn’t think this young guy was taking the bomb seriously. He kept his tone light, casual. “There’s not much wooden around the center of Berlin.”

  “How do you know the target’s Berlin?” Reines asked in a resonant baritone voice.

  Karl said carefully, “I think it should be. We want to get Hitler. He’s underground all the time now, got to be—we bomb Berlin every night. I think we should go in at night. Catch the bastard in his bed.” He had let a vicious note of grating contempt into his voice. Well, so be it.

  Feynman brightened. “Now, this idea I like—a lot.”

  The man who had been silent, Bob Serber, said flatly, “I had time to think this through, on the planes coming over. A ground burst will be comparable to a Richter scale 5.0 earthquake. Big. But! Ordinary earthquakes occur scores or hundreds of miles underground. A surface explosion will have different seismic wavelengths and amplitudes. Periods of oscillation will be shorter, and the amplitudes will decay faster with distance from the site. The A-bomb target will suddenly become a superheated compressed gas, made from dirt and buildings. This gas expands, only to be slowed, stopped, and the expansion reversed.”

  Serber paused, as if he saw a movie running in his mind, a blossoming crimson blister on a dark city. “We estimate that twenty percent of the A-bomb energy will go into the ground wave. The rest goes into the air blast and cratering. The radiation in X-rays, gammas, and visible will convert into infrared and heat the surroundings. This will burn anything that can, within about two miles, instantly. The shock wave in ground and air will combine to flatten everything within at least two miles, probably more. It will yield ‘ground roll’ damage to any air-raid shelter or structures extending to at least several hundred yards underground. Steel-reinforced concrete will yield to the peak pressure. All deep structures will collapse within a second or two. I assumed the bomb will achieve an energy release equivalent to ten thousand tons of TNT. The more, the better.”

  “It’ll be more, I hope,” Karl said. “But we have to wait on our superiors, higher up, to decide if it’s Berlin, and at night.”

  Feynman sat back and yawned, now looking tired. “Always respect your superiors, if you have any.”

  • • •

  Marthe’s letter paper was so thin he could nearly see through it.

  510 W. 123rd Street

  April 21, 1944

  Tuesday evening

  My Dear Karl,

  I don’t know when or where or how you’ll get this letter, but I’m going to forge ahead anyway. New developments today—but not those we anticipated. First, the good news (?). Good thing I saved my $6 for a telegram; my fears of losing out on the new apartment dissipated this morning without a doubt: it’s still available. However, I’ll wait for you for the final decision.

  The other thing is less good. The bearer of bad news (Dr. Kugelmass) was right about Martine’s intestinal condition. I had to telephone him tonight at Saranac Lake—much more difficult than how it sounds! The phone lines are so overloaded that it took about two hours of repeated attempts before I got through. He said that the same condition she had last year is back, and that the strict diet and unpleasant treatments would be the same. Poor Fou! Amazingly, she is as happy and active as ever, her appetite is good, and she’s not suffering at all. It’s going to be hard to get her to drink all that stuff tomorrow morning, including the paraffin oil. Dr. K returns to town Sunday, and we can discuss treatments then. If you have a chance, buy her something interesting and new before you come home—she is interested in those little books again. Just seeing you again will give her great comfort.

  Elisabeth is doing well. She laughs out loud when Martine jumps on the bed—the two girls are beginning to get along like a house on fire—to use one of your odd English expressions.

  Anton is supposed to be posted to the Pacific somewhere, soon. He’s in England now for a few days, I hear. He seemed happy about being in the thick of it, but I worry about him sometimes—so far from home.

  The way the war is going enrages me. So slow!—when so many are dying. I particularly laughed at the American pounding of Kiska Island for two weeks, after the last Japanese had fled. Then ther
e’s France, where everyone is going to starve to death, and there won’t be two sticks standing, nor any soul surviving, at least in the towns, at the end of the day.

  I’m going to stop now, without lapsing further into grouchiness. I live in a desert when you are away, with no beauty for my eyes to behold, and no prose from you. I guess time is short and paper even scarcer.

  Good night,

  Marthe

  He could feel her in the words, hear the whisper of her voice. The little letter somehow filled him with a quiet joy. He knew he would sleep better now.

  2.

  May 4, 1944

  One of the infrequent German air raids, with a chorus of screaming sirens, sent Karl down into a subway, the “tube” as Londoners called it. Quite a few American soldiers sat together, chattering with Midwest accents for a while, the unspoken tension about the coming invasion skating in the air. That faded. The gloom and silence that followed, waiting through the booms and crashes dimly echoing down the rail lines, struck him as like a church. Our Temple of Self-Preservation, perhaps. There was little light, just enough from a gas lamp to make a gold tooth sparkle, or a teardrop glisten. From Bob Serber’s remarks, he saw that if the gadget were to explode on the cobblestone streets here, no one in the tube system would survive. The blast wave would slam through the tunnels for many kilometers.

  • • •

  The next day he gathered the Los Alamos guys and Freeman Dyson. In the short while since his meeting with Feynman’s gang, as he thought of them, Freeman had exercised what the dapper man called his best talent: Sitzfleisch. Freeman had explained that this German word had no equivalent in English, and literally translated as “Sitflesh.” It meant the ability to sit still and work quietly.

  “I did all your calculations over,” Freeman said mildly. “The critical mass problem as the uranium bullet-cylinder approaches the target, the timing, the lot. It will work. I also think, from Karl’s data on the ‘tickling the dragon’s tail’ experiments you fellows carried out, that the yield will be about fifteen kilotons of TNT.”