NEW YORK — Benjamin Bederson turned past the page in the diary from long ago, the page he had burned a hole through, and mentioned things he had done since that summer of 1945.
“Was an experimental atomic physicist,” he said. “Worked as a professor at New York University, taught almost every course in physics, was editor-in-chief of the American Physical Society and helped usher physics journals into the electronic age.”
He left out the part about helping to usher in the atomic age — the part about testing the ignition switches for the atomic bomb that was dropped on Nagasaki, Japan, on Aug. 9, 1945. The part about having been one of the lowest-ranking soldiers assigned to the Manhattan Project, the huge research-and-development effort that delivered the first atomic devices, and as a corporal or a private in his early 20s, one of the youngest. The part about having been one of the few soldiers sent to key spots at key moments as the work progressed.
“That makes it sound a little grandiose,” Bederson, now 93, said modestly.
He did not even have his bachelor’s degree then, having suspended his undergraduate work at City College of New York to join the Army Signal Corps as a civilian. Before long, he was drafted, and after three days of basic training in Atlantic City, N.J., the Army sent him to Illinois and Ohio — and then canceled the program it had put him in to learn electrical engineering. His commanding officer had heard that something called the Manhattan Project was looking for soldiers, and told him to apply.
“He knew I was a loudmouthed New Yorker,” said Bederson, who grew up in the Bronx. “He said, ‘Here’s your chance to get back to New York.’ ”
But it turned out that was not the case. “The next thing I knew,” Bederson said, “I was in Oak Ridge, Tennessee. I was nonplused.”
Oak Ridge was booming, with as many as 45,000 people living and working there, and — according to the Atomic Heritage Foundation — consuming just over 14 percent of all the electricity generated in the United States.
Why they were such power hogs was a mystery, but Bederson noticed what appeared to be distillation plants. “I thought they were making sour mash to drop on the Germans, get them all drunk,” he said. He guessed wrong, of course: “I found out later those were distillation plants. They were distilling U-235 from U-238.” U-235 is the isotope that can be used to fuel reactors and make bombs.
Bederson was assigned to a unit called the Special Engineering Detachment and transferred again, this time to Los Alamos. There, he worked on developing ignition switches for the bombs. In the spring of 1945, there were more orders and more travel, first to the base in Utah where bomber pilots were trained, then to Tinian, the Pacific island from which the B-29s known as Enola Gay and Bockscar took off. His assignment was to test the switches for the bomb that was dropped on Nagasaki.
So there he was, 7,800 miles from home, on an island about the size of Manhattan that had its Broadway, its numbered avenues, its 42nd Street, its Riverside Drive, even its Central Park.
“It is ironic,” he said dryly.
Tinian had been laid out that way in 1944, after the Allied forces seized it in the invasion of Saipan, but the Seabees who did the construction work had had no idea the Manhattan Project was coming.
Of the thousands of people who worked on the Manhattan Project during the war, Bederson was apparently one of the few soldiers who were privy to its overall scope — that it involved enriched fuel for a bomb and, with the war in Europe over by mid-1945, that the first target would be Japan. “He was like the special student who was picked out from among the other students,” said Owen Pagano, program manager at the Atomic Heritage Foundation in Washington. “There were other SEDs who were involved in other aspects of the project but did nowhere near the significant work that he did,” he said, referring to members of the Special Engineering Detachment.
Bederson’s work was singled out by no one less than J. Robert Oppenheimer, who was the scientific head of the Manhattan Project and is often called the father of the atomic bomb.
“The final successful operation of the Nagasaki bomb was testimony to the fact that your work had been well done,” Oppenheimer wrote in a letter of recommendation.
Pagano said Bederson was one of 15 to 20 Manhattan Project veterans who attended a recent reunion. “He’s almost this — I don’t want to say Forrest Gump character,” Pagano said. “He wasn’t going around like Forrest Gump was, having all these different jobs and experiences, but there were very few Manhattan Project veterans who knew about the other sites that were involved, knew the overall scope, not only worked at Los Alamos but got to go to Tinian and help prepare the actual bomb itself.”
Bederson spent his childhood in the Bronx — and eight months, around the time he turned 11, in Russia. “I hated it,” he said. On returning to the Bronx, “a relative put us up in the Coops,” a housing complex formally known as the United Workers Cooperative Colony. It was, he said, “a Communist neighborhood, or at least a Communist-sympathizing neighborhood — anything from pink to red.”
“But that’s another story,” he said.
So is his account of David Greenglass, whose sister, Ethel Rosenberg, was executed as a spy. Greenglass testified in 1945 that he delivered atomic secrets to his brother-in-law, Julius Rosenberg.
Bederson remembers Greenglass as “a machinist making molds for lenses” on the bombs. “I knew he was pretty radical,” he said. “He made no bones about it. He was in the next bunk to mine at Los Alamos. We had arguments.” Things became so heated and Bederson and another bunkmate became “so disgusted” with Greenglass that they asked for a transfer.
Bederson had a security clearance, which is why he burned the hole through that page in the diary. It was the entry for Aug. 6, 1945, the day of the Hiroshima bombing. When he reread it a couple of weeks later — after the world had changed — he felt he had written more than he should have written about the bomb itself.
Even now, he will not say exactly what was in the sentence he deleted. Secrets are secrets.
Bederson said he believed in the atomic bomb. “It must have saved far more lives than it cost,” he said. “The military in Japan didn’t want to end the war.” But he said he had written in his diary that “there should be total nuclear disarmament and countries would be smart enough to do it.”
The diary’s place these days is in a blue binder marked “Army” in his apartment in a Greenwich Village high-rise. He skipped over a letter that began “Dear Mother and Dad” and was signed “Love, Benny.”
Also in the binder was that letter of recommendation from Oppenheimer, who praised Bederson’s “cleverness and ingenuity” in devising simple solutions to unexpected technical problems.
Bederson turned a page in the binder and paused at a photograph on Tinian of perhaps 30 people, lined up as if for a class picture. “There are two Nobel Prize winners and two or three admirals in that photograph,” he said.
“And,” he said, “there’s me. Third row, fifth from the left.”