He described to Tibbets one of the experimental machines they had built to test the theory of critical mass. It had been nicknamed “The Guillotine.” A piece of doughnut-shaped uranium was placed in the machine. Then another piece of uranium was dropped through the hole in the doughnut. For a split second, the extra uranium plunging through the gap brought both pieces close to critical mass. It was a dangerous game to play. They called it “twisting the dragon’s tail.”
Parsons explained more about the bomb’s mechanism to Tibbets. “It is designed to ensure that the bringing together of the two ‘subcritical’ pieces occurs for the first time at the moment of planned detonation over the target. The pieces will then combine in a critical mass, causing the chain-reaction explosion. That’s the theory. Until that moment, we cannot know for sure whether the bomb will work.”
Parsons described how the heart of the bomb was really just “a good old gun, a five-inch cannon with a six-foot-long barrel. After the bomb has left the plane and is on its way, a piece of uranium two-three-five about the size of a soup can will be fired down the barrel into a second piece of uranium fixed to the muzzle.”
“And if it doesn’t work?” persisted Tibbets.
“We will just make a nice big dent in the target area and go back to the drawing board,” said Parsons.
To avoid that dismal prospect, explained Oppenheimer, in the coming months Tibbets’s unit would drop test bombs. These would help the scientists develop the final shape of the atomic-bomb casing as well as prove the proximity fuzes, which governed the height at which the bomb would explode.
So far, the proximity fuzes were proving troublesome.
Tibbets continued to be astonished by Oppenheimer during his conducted tour of Los Alamos. Late in the afternoon, they were walking down another corridor, past identical rooms whose inner walls were lined with blackboards covered with formulas and whose occupants pored over slide rules and logarithm tables.
Suddenly, Oppenheimer halted in midstride. His head was cocked like a dog scenting game. He turned and stalked back to an office.
Inside, a man sat slumped on a straight-backed wooden chair, staring fixedly at a blackboard. He was unshaven and disheveled.
Tibbets wondered if he “might be the building janitor taking an unauthorized rest after a night out.”
Oppenheimer stood silently behind the man. Together they stared at the blackboard with its jumble of equations.
Oppenheimer moved to the blackboard and rubbed out part of an equation. Still, the man on the chair did not move.
Oppenheimer quickly wrote a new set of symbols in the space he had erased.
The man remained transfixed.
Oppenheimer added a final symbol.
The man rose from his chair, galvanized, shouting, “I’ve been looking for that mistake for two days!”
Oppenheimer smiled and walked out of Enrico Fermi’s office, leaving one of the founders and greatest geniuses of nuclear physics happily restarting work.
Beser was enjoying “the most fantastic day in my life.” He had met and talked to a dozen renowned scientists who were his teenage heroes.
Hans Bethe and Ernest O. Lawrence were among those who gave Beser a glimpse of their work. The scientists told him about the strange kinds of guns they had devised that used atomic bullets. When fired at each other, on impact the bullets devoured one another. They described how they hoped this phenomenon would be used to produce an atomic explosion. They spoke of temperatures they hoped to create which would make a light “brighter than a thousand suns.”
Ramsey outlined the role the radar officer would play on the mission. Beser would be taught how to monitor enemy radar to see if it was trying to jam or detonate the intricate mechanism of the bomb. To understand how this could happen, Beser must learn what few of the scientists involved knew—the minute details of the bomb’s firing mechanism, including its built-in mini-radar system.
On this first day, nobody seemed concerned about how much they should tell Beser. They poured information over him, “leaving me sinking in a scientific whirlpool.”
Late in the evening, Beser was introduced to a dour young technician, David Greenglass. Nobody yet suspected Greenglass had just stolen the first of many blueprints. His haul would eventually include schematic drawings of a special lens crucial to detonating the plutonium bomb which was being developed in parallel with the uranium bomb. The drawings would be spirited to Russia through the highly professional espionage ring the Soviets had been able to set up from inside Los Alamos. Greenglass would receive a few hundred dollars for his treachery.
Later, Beser would believe that, on this very evening, he had interrupted Greenglass in his espionage activities.
When the radar officer left Greenglass, it was dark. With difficulty, he reached the small guesthouse assigned to visitors. He opened the front door and stopped dead in his tracks. Sprawled on a couch, sipping a drink, was an attractive brunette, stark naked. She carefully lowered her glass and rose to her feet.
“Can I help you?” The voice had just a trace of a German accent.
It was Katherine Oppenheimer, wife of the scientific director. She had left Germany when fourteen; her relatives included Nazi Field Marshal Wilhelm Keitel.
“Ma’am, I’m sorry….”
Blushing furiously, Beser stammered into silence. He had never seen a naked woman before.
“Are you looking for someone?”
“Yes, ma’am… No, ma’am… My… bed… I mean, the guest quarters, ma’am.”
“They are in the back of the house. You have come in the wrong door, but you can go through here.” Mrs. Oppenheimer sat down and resumed sipping her cocktail.
Averting his eyes, the bashful Beser stumbled past the languid first lady of Los Alamos.
Her husband was startling Paul Tibbets. The two men were alone in Oppenheimer’s office, reviewing what Tibbets had been shown. The flier felt that in a few hours he had received “a better scientific education than all my years in school.”
Now Oppenheimer began to question him. Apart from enemy interference, the scientist wanted to know what other risks were involved in a bombing mission. Tibbets explained there was always the chance of bombs jamming in their bays, or a faulty mechanism detonating them prematurely. Oppenheimer was confident such risks could be eliminated in the atomic bomb.
Then he stared intently at Tibbets. “Colonel, your biggest problem may be after the bomb has left your aircraft. The shock waves from the detonation could crush your plane. I am afraid that I can give you no guarantee that you will survive.”
8
The scraping against the stone floor of his geta, the Japanese wooden clogs he favored, was the only sound in the Osaka University laboratory of Dr. Tsunesaburo Asada, possibly Japan’s most imaginative scientist. His staff had come to recognize that this habit of shuffling his feet was a signal that Asada was content.
Putting his weight first on one foot, and then on the other, the white-coated scientist studied his latest creation, a proximity fuze. It was similar in design and purpose to those being perfected at Los Alamos.
Months of work had gone into the fuze’s development in Asada’s well-equipped laboratory. He rarely left the campus now, working well into the night, catnapping on a couch in a corner of the laboratory, impatient of any interruptions.
He was still, as he had been when the war began, chairman of the physics department. But since late 1941, he had done no teaching. His brilliance made him one of the scientists crucial to Japan’s war effort.
Since 1937, Asada had regularly lectured at the Naval Technical Research Institute in Tokyo and at the Naval Aeronautical Research Institute in Yokosuka. Besides lecturing, Asada had worked closely with the military authorities before Japan entered the war. And on December 17, 1941, he was one of the scientists selected to work on Project A.