Half-Life: The Divided Life of Bruno Pontecorvo, Physicist or Spy
Page 1
HALF-LIFE
ALSO BY FRANK CLOSE
The Infinity Puzzle
Neutrino
Nothing
Antimatter
The Cosmic Onion
Copyright © 2015 by Frank Close
Published by Basic Books
A Member of the Perseus Books Group
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Designed by Trish Wilkinson
Set in 11 point Minion Pro
Library of Congress Cataloging-in-Publication Data
Close, F. E.
Half life : the divided life of Bruno Pontecorvo, physicist or spy / Frank Close.
pages cm
Includes bibliographical references and index.
ISBN 978-0-465-06998-9 (ebook)1.Pontecorvo, B. (Bruno), 1913–1993.2.Nuclear physicists—Soviet Union—Biography.3.Nuclear physicists—Italy—Biography.4.Spies—Soviet Union—Biography.5.Spies—Italy—Biography.I.Title.
QC774.P66C56 2014
530.092—dc23
[B]
2014041019
10 9 8 7 6 5 4 3 2 1
To Abingdonians, present and past
Contents
Preface
Prologue: Midway on Life’s Journey
FIRST HALF
ONE From Pisa to Rome
TWO Slow Neutrons and Fast Reactions: 1934–1936
THREE Paris and Politics: 1936–1940
FOUR The First Escape: 1940
FIVE Neutrons for Oil and War: 1940–1941
SIX East and West: 1941–1942
SEVEN The Pile at Chalk River: 1943–1945
EIGHT Physics in the Open: 1945–1948
NINE Maneuvers: 1945–1950
INTERLUDE
West to East
HALF TIME
TEN Chain Reaction: 1949–1950
ELEVEN From Abingdon—to Where? 1950
TWELVE The Dear Departed: 1950
THIRTEEN The MI5 Letters
SECOND HALF
FOURTEEN In Dark Woods
FIFTEEN Exile
SIXTEEN Resurrection
SEVENTEEN Mr. Neutrino
EIGHTEEN Private Bruno
AFTERLIFE
NINETEEN The Right Road Lost
Afterword
Acknowledgments
Acronyms
Notes
Bibliography
Index
Preface
“DID MI5 GET BACK TO YOU AFTER I FORWARDED THEM YOUR LETTER?”
When I started to research the life of Bruno Pontecorvo, the nuclear physicist who disappeared through the Iron Curtain at the height of the Cold War in 1950, I didn’t anticipate receiving such an inquiry, let alone replying in the affirmative. Nevertheless, my correspondence with the British intelligence agency led me to solve a sixty-year-old enigma: Why did Pontecorvo flee so suddenly, just a few months after the conviction of his colleague, atomic spy Klaus Fuchs? The obvious answer—that Pontecorvo was “the second deadliest spy in history,” as the US Congress later described him—has hung around for decades, but no proof that he passed atomic secrets to the Soviets has ever been presented, nor has there been any suggestion of the information he might have disclosed. Contrary to popular wisdom, neither the FBI nor MI5 ever located evidence against him. So if Bruno Pontecorvo was a spy, he was most successful. Pontecorvo, a communist who had managed to evade detection and join the Manhattan Project, always insisted that he fled for idealistic reasons, having felt persecuted following Fuchs’s arrest.
Bruno Pontecorvo’s passage through the Iron Curtain split his life into two almost-equal halves. This chronological split defined his scientific life: great insights at the end of the first half were frustrated by his move to the Soviet Union and may have cost him his share of a Nobel Prize. His personality was also divided into two complementary halves. On one hand there was Bruno Pontecorvo, the extroverted, highly visible, brilliant scientist, and on the other was his alter ego: Bruno Maximovitch, the enigmatic, shadowy figure who was secretly committed to the communist dream.
There are already two excellent books that provide extensive assessments of Bruno Pontecorvo: The Pontecorvo Affair, by Simone Turchetti, and Il lungo freddo, an Italian text by Miriam Mafai. Turchetti focuses on the first half of Pontecorvo’s life, the political implications of his defection, and how the British government in particular downplayed his significance at the time of his disappearance. I have profited on many occasions from discussions with Turchetti, not least in evaluating some of the new facts that have come to light during my own investigation. Mafai’s book is Bruno’s life story as he would wish it to appear, based on a series of interviews with Pontecorvo late in his life.
Half-Life takes a different approach. I am myself a physicist, and so I focused initially on Bruno Pontecorvo’s life as a scientist. Klaus Fuchs, Alan Nunn May, and other players in the atomic spy saga were quality scientists, but are known only because of their role in the passing of secrets; Pontecorvo is unique in that he could merit a biography for his scientific contributions alone. The fact that his name has long been associated with those of proven atomic spies simply adds to his interest. Thus I also sought to understand his value to the USSR once he arrived there, to assess what information he could have transmitted to the Soviets before 1950, and to filter truth from myth with regard to his real agenda. I do not examine in any detail the interactions between MI5, the FBI, and their respective governments, mainly because Turchetti in his book, and Timothy Gibbs in his Cambridge University PhD thesis, have already done so. Nor do I offer any sociopolitical commentary on his political beliefs or his reactions to the profound changes he experienced during the dissolution of the USSR; Mafai has covered this, although her personal communist perspective mingles with that of Pontecorvo, and it is not always clear whether her views or his are on display. In order to make the scientific concepts digestible, I have avoided technicalities in several places. Readers who want a more in-depth study of Pontecorvo’s work and its context can find it in the article “Bruno Pontecorvo: From Slow Neutrons to Oscillating Neutrinos” by Luisa Bonolis.
Frank Close
Abingdon, March 10, 2014
Prologue: Midway on Life’s Journey
1950: The Gathering Storm
NEW YEAR’S DAY 1950: THE FULCRUM OF THE TWENTIETH CENTURY. When the century began, no one knew that the atomic nucleus existed, let alone that it was the custodian of huge reserves of energy. By the century’s end, humanity had learned to live with the possibility of a thermonuclear holocaust. As 1950 dawned, however, less than five years had passed since the atomic bombs at Hiroshima and Nagasaki had ended World War II, and society was only beginning to realize the awful implications.
In a historic English market town near Oxford, one of the fathers of the atomic age celebrated the New Year with his family. Bruno Pontecorvo was thirty-six years old. Sixteen years earlier, as a student of physics, he had contributed to a discovery that would he
rald a new world of nuclear reactors and atomic weapons. That breakthrough would determine his destiny. By 1950, he had earned a reputation as one of the world’s leading nuclear physicists, had recently published two papers that would lead to Nobel Prizes, and was being courted by physics institutions in both Europe and North America. This brilliant Italian scientist appeared to have an idyllic life. He lived comfortably in a pleasant home near the River Thames. He had an attractive Swedish wife and three young sons.
All seemed perfect, carefree. But Bruno Pontecorvo had a secret.
For more than ten years he had been a member of the Communist Party. At first glance, this might hardly seem to merit comment. Many intellectuals who had grown up in the 1930s and witnessed the vicious effects of fascism had chosen to ally themselves with the communist movement. By 1950, however, anticommunist hysteria was growing in the West and many lives were being ruined. For Bruno it was imperative that his communist links remain secret. During World War II his work had related to the atomic bomb, and now he was again engaged in secret work, at Harwell in the heart of England, where the United Kingdom was building the first nuclear reactor in Europe.
As it happened, the British and American intelligence agencies were already interested in Dr. Pontecorvo, and during the next few months their files on him would grow rapidly. Before February 1950, when his colleague Klaus Fuchs was arrested for passing atomic secrets to the Soviet Union, Bruno Pontecorvo’s communist beliefs did not hinder his work or his life in general. Everyone involved in classified work had a security file; Pontecorvo was but one among many. But hysteria grew after Fuchs’s arrest and conviction. Events were about to move out of Pontecorvo’s control, leading ultimately to his midlife crisis.
GUY LIDDELL, DEPUTY DIRECTOR GENERAL OF THE BRITISH SECURITY service, MI5, sat down before his diary. A new year meant a new book, its blank pages soon to be filled with an insider’s personal record of international affairs. On New Year’s Day 1950, the implications of atomic weapons were at the top of his agenda.1
The scientists who had built these weapons were regarded as heroes. They had managed to unleash the immense forces contained within the atomic nucleus of a rare form of the element uranium, and also of a newly synthesized element, plutonium. It is hard today to fully appreciate the cataclysmic impact these developments had on the international scientific community. The war against fascism had been won, but with a Faustian pact: victory came with the release of the atomic genie. The explosions at Hiroshima and Nagasaki had shocked the world, but scientists already knew that even more devastating weapons were feasible. The fact that a major industrial city could be flattened by a single atomic bomb was bad enough; the next stage of nuclear technology, involving thermonuclear or “hydrogen” bombs, would have the potential to destroy life on earth.
The Western Allies briefly thought they had the power to rule the world, as they were the exclusive owners of these terrifying new weapons. The United Kingdom, especially, was proud that its scientists had first conceived of the new technology, and then played leading roles in its development. However, the illusion of Western omnipotence was shattered irrevocably in 1949. Liddell began his diary, “The event of [1949] has been the explosion of an atomic bomb in Russia, which has thrown everyone’s calculations out of date.” Although the USSR had been an ally in the war against the Nazis, it had not been party to the Manhattan Project, which built the atomic bomb. As the West’s relationship with the USSR grew increasingly tense in the years after the war, this fact provided some solace. Between 1945 and 1950, however, there were disquieting clues that some of those heroic Western scientists had been passing secret information about the weapon to Moscow. The Soviet Union had survived the war with large military reserves, capable of threatening American dominance. If Soviet espionage managed to neutralize the West’s trump card (exclusive possession of the atomic bomb), the USSR would be a formidable enemy.
The first hint of this duplicity had come as early as the fall of 1945. That was when Western intelligence agencies learned that British physicist Alan Nunn May had taken samples crucial to the atomic bomb project from his laboratory in Canada and passed them to the Soviet Union. By the start of 1950, Western counterespionage had discovered the treachery of Klaus Fuchs as well.
Fuchs had passed substantial information to the Soviets, both during the war (when he was working on the atomic bomb at Los Alamos) and later, following his move to Harwell. Indeed, he transmitted enough high-quality data to the USSR to threaten the balance of world power. Liddell concluded his diary entry for the first day of 1950 by writing, “It is clear that by 1957 the Russians should have sufficient atomic bombs to blot this country out entirely.”
He meant it. Two bombs had reduced the major Japanese cities of Hiroshima and Nagasaki to rubble. Given that a city could be destroyed by just a single atomic bomb, the Soviet Union could decimate the nerve centers of Great Britain with little more than a handful. If that wasn’t enough to worry him, thermonuclear hydrogen bombs were already being developed in the United States and, we now know, in the USSR. In 1957, when British prime minister Harold Macmillan asked his science adviser, Sir William Penney, how many H-bombs would render the United Kingdom useless, Penney (a gentle, peaceful man, who was no Dr. Strangelove) replied, “Five! Or let’s say eight to be on the safe side.”2
The atomic spies had given the USSR a fast track to this Promethean technology. Instead of a Western monopoly on nuclear weapons, the world now headed toward an unstable balance of mutually assured destruction.
In February 1950, Klaus Fuchs was arrested in London. The interrogation of Fuchs soon led to the arrest of Harry Gold, his courier in the United States, where Fuchs had worked (and spied) during the war. Gold’s arrest and confession led the FBI to a Soviet spy ring, which included David Greenglass as well as Julius and Ethel Rosenberg, who were destined for execution by electric chair. In the US, Senator Joseph McCarthy started a witch hunt with his claim to have a list of 205 communists working at the heart of the American government. Today we know that this was fantasy, but in the ensuing hysteria it became risky for Americans to express views that were even slightly left-of-center. One chemist who worked at the University of Wisconsin, in McCarthy’s home state, later recalled, “We would not talk about anything if a third person might be listening.”3
Until 1950, Bruno Pontecorvo had successfully hidden his life as a communist, but now his well-kept secret was threatened. A sister and a brother were also communists, as was a cousin, Emilio Sereni, who worked for the Italian government. It would be easy for Western intelligence agencies to discover this, should they choose to investigate. Bruno felt certain that they would do so. For, with the exposure of Klaus Fuchs, his colleague at Harwell, lightning had struck twice in his vicinity: four years earlier, Bruno Pontecorvo had been working in Canada alongside Alan Nunn May.
The British security services interviewed Pontecorvo in March, and again in April. His security clearance was withdrawn, and the authorities prepared to transfer him to a university, away from classified work at Harwell. In the feverish atmosphere of the times, Pontecorvo’s communist associations were enough to foster suspicions that he too had passed secrets to the USSR. The intelligence agencies had no proof, but Pontecorvo was in the dark as to the contents of MI5’s files. Klaus Fuchs and Alan Nunn May were prosecuted because they had confessed, and offered the intelligence agencies critical information that would condemn them. The atomic spy Ted Hall, by contrast, admitted nothing, was never arrested, and only came to public attention decades later. In Pontecorvo’s case, there was one crucial question: Who would blink first in the game of cat and mouse? Suddenly, Pontecorvo disappeared, along with his wife and their three sons—Antonio (age five), Tito (age six), and Gil (the eldest at twelve). They went on vacation to Italy, flew to Stockholm and Helsinki, and then disappeared completely, only resurfacing five years later—in the USSR.
THE BRITISH GOVERNMENT DIDN’T HAVE A CLUE WHAT HAD HAPPENED. Bruno
’s brother Guido, who lived in Glasgow, didn’t either. As of September 1, 1950, Bruno Pontecorvo had officially vanished. Even several years later, Pontecorvo’s former teacher and mentor Enrico Fermi remained ignorant of his whereabouts, as Fermi’s biography, written by his wife, Laura, in 1954, makes clear:
Over three years have now passed since the Pontecorvos’ disappearance. No word has been heard from them. Nobody has seen them. Their relatives deny knowing anything about them. Enrico and I have come to accept that Bruno and his family have probably passed to the other side of the Iron Curtain.
The British Government has made no charge against Bruno. If anything at all has been found in England that could be construed as evidence against him, the existence of this evidence has never been revealed. And all this happened in the twentieth century!4
I read Laura Fermi’s book in the 1960s, when I was a physics student at Oxford. Her tale of the unsolved mystery of Bruno Pontecorvo was the first time I had heard his name. So it was a shock when, a few weeks later, I saw a new article in the scientific journal Physics Letters written by none other than Bruno Pontecorvo. His professional address was given as the Joint Institute for Nuclear Research (JINR), in Dubna, near Moscow. “Did anyone realize?” I wondered. My interest in Pontecorvo began at that moment.
Fortunately, the head of my group at Oxford was Rudolf Peierls, a man whose knowledge of the atomic bomb and the spy sagas it had spawned was second to none. In 1940, Peierls had calculated that an atomic explosion would require no more than a few kilograms of a rare form of uranium, a calculation that would prove crucial to the Allies’ Manhattan Project, which culminated in the explosions over Japan. He went on to play a central role in the project at Los Alamos, where he had worked actively with Klaus Fuchs and been his closest friend. After the war, they both returned to the UK, and when Fuchs was exposed as an atomic spy, Peierls came under suspicion himself. Peierls had also known Pontecorvo, and told me that Pontecorvo’s defection had been hardly less of a shock to him than Fuchs’s exposure. Many colleagues dismissed the idea that Pontecorvo, extroverted and superficially naive, could have been a spy. However, in Peierls’s opinion Fuchs had also given no hints of his secret life, so one could never be sure.