Posts Tagged ‘J. Robert Oppenheimer’

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Did Lawrence doubt the bomb?

Friday, September 4th, 2015

Ernest O. Lawrence was one of the giants of 20th-century physics. The inventor of the "cyclotron," a circular particle accelerator, Lawrence ushered in an era of big machines, big physics, big budgets — Big Science, in short. And that came with ups and downs. I've recently finished a review for Science of Michael Hiltzik's new Lawrence biography, Big Science: Ernest Lawrence and the Invention that Launched the Military-Industrial Complex. The full review is online but behind a paywall (if you want a copy, get in touch with me), but I am allowed to post the unedited version that I originally submitted, which in this case is about twice the size of the printed one, so maybe it's interesting as an essay in its own right (so I may flatter myself). I found it hard to cram the story of Lawrence, and this book, in a thousand words (and brevity has never been my strength), because there is just so much going on and worth commenting on.

My wonderful Stevens STS colleague Lee Vinsel had a review in last week's issue of Science as well.

My wonderful Stevens STS colleague Lee Vinsel had a review in last week's issue of Science as well.

Lawrence featured early into my education. I was an undergraduate at UC Berkeley, which means I was in Lawrence country. His laboratory literally perches above the campus, looking down on it. In various buildings on campus, it is not uncommon to come across a large portrait of the man. And any geeky child in northern California visits the Lawrence Hall of Science numerous times in the course of their education.

As a budding historian of science, what I found so incongruous about Lawrence was the way in which he embodied something of a paradox at the heart of particle physics. High-energy particle physics is for the most part a pretty "pure" looking form of science, trying to pull-off very elegant experiments with the most abstract of physical entities, and making the experimental evidence jibe with the theoretical understandings. When people want to point to evidence of objectivity in science, or to the places where theory gets vindicated in a very elegant way, they point to particle physics. And yet, to do these experiments, you often need big machines. Big machines require big money. Big money gets you into the realm of big politics. And so this very elegant, above-it-all form of science ends up getting tied to the hip of the military-industrial complex during and after World War II. How ironic is that?

The scientific staff of the University of California Radiation Laboratory with magnet of unfinished 60-inch cyclotron. Lawrence is front and center. Oppenheimer stands in back. Credit: Emilio Segrè Visual Archives.

The scientific staff of the University of California Radiation Laboratory with magnet of unfinished 60-inch cyclotron, 1938. Lawrence is front and center. Oppenheimer stands in back. Credit: Emilio Segrè Visual Archives.

As you can pick up from both the published and draft review, I had mixed feelings about Hiltzik's book. I think people who have never read anything about Lawrence before will find it interesting though potentially confusing, because it bounces around as a genre. One can't really tell what Hiltzik thinks about Lawrence. Half of the time Hiltzik seems to want to make him out to be the Great Hero of 20th century science. (Sometimes this gets hyperbolic — Lawrence was a big character, to be sure, but he was still of his time, and it does some historical injustice to claim that everything related to Big Science necessarily is laid at his door. To claim that Big Science was "a solitary effort," as Hiltzik does, is as self-contradictory as it is untrue.) The other half of the time, though, Hiltzik is pointing out what a huge jerk he could be, how bad of a scientist he could be, and how he sullied himself with some of the worst sorts of political engagements during the Cold War. Everyone gets on Edward Teller for being a far-right, pro-nuke, anti-Communist jerk, but even Teller thought Lawrence could be an extremist when it came to these things.

This ambivalent mix — Lawrence as great, Lawrence as terrible — never gets resolved. One could imagine it being talked about as two sides of the same coin, or some sort of synthetic whole emerging out of these two perspectives. But it just doesn't happen in the book. In my own mind, this is the somewhat Faustian result of Lawrence's "cult of the machine" (as I titled my review), where the Bigness required for his science ended up driving extremes in other parts of his life and politics as well.

The intense Ernest Lawrence. Credit: Emilio Segrè Visual Archives.

The intense Ernest Lawrence. Credit: Emilio Segrè Visual Archives.

Serious historians of 20th-century physics will find little new in Hiltzik's book, either in terms of documentation or analysis. He relies heavily on secondary sources and the archival sources he does consult are the standard ones for this topic (e.g. the Lawrence papers at UC Berkeley). The book also contains several avoidable errors of a mostly minor sort, but the kinds of misconceptions or misunderstandings that ought to have been caught before publication (some of which I would like to imagine would jump out to anyone who had read a few books on this subject already). I did not mention these in the formal review, because there was really not enough space to warrant it, and the book never hinged on any of these details, but still, it seems worth noting in this more informal space.1

That aside, the book reminded me of one of the strangest aspects of Lawrence's relationship with the bomb — whether he thought it was a good idea to drop one on Japan without a warning. As I've discussed before, the question of whether a "demonstration" should be made prior to shedding blood with the bomb was a controversial one on the project. A Scientific Panel composed of J. Robert Oppenheimer, Arthur H. Compton, Enrico Fermi, and Ernest Lawrence were asked to formally consider the question in the June of 1945. They formally recommended that the bomb be dropped on a city without warning: "we can propose no technical demonstration likely to bring an end to the war; we see no acceptable alternative to direct military use."

Lawrence and the Machine. (And M. Stanley Livingston, the one-time grad student who got the machines working.) I like the symbolism of this photo — Lawrence looking at the newest piece of hardware, Livingston with a hand on it, staring the camera down. They are with the 85-ton magnet of the 27" cyclotron, circa 1934. Credit: Emilio Segrè Visual Archives.

Lawrence and the Machine... and M. Stanley Livingston, the one-time grad student who got the machines working. I like the symbolism of this photo — Lawrence looking at the newest piece of hardware, Livingston with a hand on it, staring the camera down. They are with the 85-ton magnet of the 27" cyclotron, circa 1934. Credit: Emilio Segrè Visual Archives.

But there's potentially more to it than just this. Case in point: in the archives, one finds a letter from Karl K. Darrow to Ernest Lawrence, dated August 9th, 1945. Darrow was a friend of Lawrence's, and a fellow physicist, and a noted popularizer of science in his day. And this is an interesting time to be writing a letter: Hiroshima has already occurred and is known about, and Nagasaki has just happened (and Darrow may or may not have seen the news of it yet), but the war has not ended. This period, between the use of the bomb and the cessation of hostilities, is a very tricky one (a topic Michael Gordin has written a book on), because the meaning of the atomic bomb had not yet been cemented. That is, was the atomic bomb really a war-ending weapon? Or just a new way to inflict mass carnage? Nobody yet knew, though many had uncertain hopes and fears.

August 9th is also a tricky period because this is around the time in which the first casualty estimates from Hiroshima were being received, by way of the first Japanese news stories on the bombing. They were much higher than many of the scientists had thought; Oppenheimer had estimated them to be around 20,000, and they were hearing reports of 60,000 or higher. For some, including Oppenheimer, they saw this as a considerable difference with respects to how comfortable they felt with the attacks.

"Best Copy Available," the last excuse of the wicked. Click here for the original with a transcription appended.

"BEST COPY AVAILABLE" is the last excuse of the wicked. Click here for the original with a transcription appended.

This context is relevant to making sense of the Darrow letter. The archival document is hard to read, and in some places illegible, so I've included a transcription that I typed up from the best of my reading of it. The import of it is pretty easy to take away, though, even with a few phrases being hard to read. Here is an excerpt of the key parts:

Dear Ernest:

This is written to you to put on the record the fact that you told me, on August 9, 1945, that you had presented to the Secretary of War by word of mouth the view that the “atomic bomb” ought to be demonstrated to the Japanese in some innocuous but striking manner before it should be used in such a way as to kill many people. You made this presentation in the presence of Arthur Compton, Fermi, Oppenheimer and others, and spoke for about an hour. The plan was rejected by the Secretary of War on the grounds that (a) the number of people to be killed by the bomb would not be greater in order of magnitude than the number already killed in the fire raids, and (b) an innocuous demonstration would have no effect on the Japanese. [...]

I think that it is not far-fetched nor absurd to conjecture that in time to come, people will be saying “Those wicked physicists of the ‘Manhattan Project’ deliberately developed a bomb which they knew would be used for killing thousands of innocent people without any warning, and they either wanted this outcome or at least condoned it. Away with physicists!” It will not be accepted as an excuse that they may have disapproved in silence. We do not excuse the German civilians who accepted Buchenwald while possibility disapproving in silence.

I think that if the war ends today or tomorrow or next week, this sort of criticism will not be heard for a while, and yet it will be heard eventually -- and particularly it will be heard if at a time should come when some other power may be suspected of planning to use the same device on us. In other words, if the use of this weapon without forewarning has really brought quick victory, this fact will delay but will not indefinitely prevent the emergence of such an opinion as I have suggested. It may then be of great value to science, if some scientist of very great prominence has already said that he tried to arrange for a harmless exhibition of the powers of the weapon in advance of its lethal use.2

There is a lot going on in this letter. First, it makes it clear that Lawrence and Darrow had a discussion about the demonstration matter right around the time of the Nagasaki bombing. It is also clear that Darrow came away with the impression that Lawrence was deeply unsure about the logic of bombing without warning. Now the amount of pontificating by Darrow makes it seem like Darrow might be reading into what Lawrence told him more than Lawrence said — Darrow's concerns are not necessarily Lawrence's concerns. But it does seem clear that Darrow thinks he is setting something into the record that might be useful later, and that even if the war ended soon, there were going to be doubts to be contended with, and the fact that Lawrence was worried about using the bomb might somehow be exculpatory.

Darrow's letter was received on August 10th (so it is stamped), but it isn't clear when Lawrence read it. He did not reply until August 17th, 1945, by which point hostilities with Japan had ended. This is a big thing to point out: the Darrow-Lawrence conversation, and original letter, took place at a time when it wasn't clear whether the bombs would actually be credited with ending the war. By August 17th, Japan had already pressed for an end of the war and had credited the atomic bomb in part with their defeat.3 If Lawrence ever did have doubts, they were gone by August 17th:

Dear Karl:

In reply to your letter of August 9th, you have the facts essentially straight, excepting that I didn't believe I talked on the subject of the demonstration of the bomb as long as an hour. I made the proposal briefly in the morning session of the Secretary of War's committee, and during luncheon Justice Byrnes, now Secretary of State, asked me further about it, and it was discussed at some length, I judge perhaps ten minutes.

I am sure it was given serious consideration by the Secretary of War and his committee, and gather from the discussion that the proposal to put on a demonstration did not appear desirable [...] Oppenheimer felt, and that feeling was shared by Groves and others, that the only way to put on a demonstration would be to attack a real target of built-up structures. 

In view of the fact that two bombs ended the war, I am inclined to feel they made the right decision. Surely many more lives were saved by shortening the war than were sacrificed as a result of the bombs. [...]

As regards criticism of science and scientists, I think that is a cross we will have to bear, and I think in the long run the good sense of everyone the world over will realize that in instance, as in all scientific pursuits, the world is better as a result.4

To me, this letter reads as something of a kiss-off to Darrow's doubts — and maybe to doubts Lawrence himself might have once held. Darrow recalls Lawrence telling him it was an hour-long discussion, and a major conflict between the soulful Lawrence and the unfeeling others. In Lawrence's post-victory recollection, it becomes a 10-minute talk, duly taken seriously but not that hard of a question to answer, and in the end, the ends justified the means, neat and tidy.

Lawrence, Glenn T. Seaborg, and J. Robert Oppenheimer operate a cyclotron for the cameras in a postwar photograph. Small historical detail (literally): one can find this photograph sometimes flipped on its horizontal axis. Which is the correct orientation? One can take guesses based on rings, handedness, etc., but the copy of the scan that I have has sufficient resolution that you can read the dials, which I think resolves the question. Credit: Emilio Segrè Visual Archives.

Lawrence, Glenn T. Seaborg, and J. Robert Oppenheimer operate a cyclotron for the cameras in a postwar photograph. Small historical detail (literally): one can find this photograph sometimes flipped on its horizontal axis. Which is the correct orientation? One can take guesses based on rings, handedness, etc., but the copy of the scan that I have has sufficient resolution that you can read the dials, which I think resolves the question. Credit: Emilio Segrè Visual Archives.

So where lies the truth? Was Lawrence a doubter at the time of the Nagasaki bombing, only to lose all doubts after victory? Was Darrow projecting his own fears onto Lawrence at their meeting? I suspect something in between — with a second bomb so rapidly dropped after the first, Lawrence and Darrow might have both been wondering if these weapons would really end the war (much less all war), if they weren't just a new-means of old-fashioned mass incineration. Maybe Lawrence exaggerated, or gave an exaggerated impression, of his debate over the demonstration.

One interesting piece is that the story of "doubts" can, as Darrow implied, be made exculpatory without necessarily calling into question the wisdom of the bombing. That is, if the story is about how the scientists really didn't want to use the bomb, but couldn't see a better way around it, then you get (from the perspective of the scientists involved) the best of both worlds: they still have souls, but they also have justification. This is how Arthur Compton presents the meeting in his 1956 book, Atomic Quest, which takes more the Darrow perspective of a fraught Scientific Committee, Ernest Lawrence as the final hold-out, but with "heavy hearts" they recommend direct military use.5

Lawrence and the Machine (or, at least, one of them). I like the idea that Lawrence was doing his research wearing a full suit and tie. Credit: Emilio Segrè Visual Archives.

Lawrence and the Machine (or, at least, one of them). I like the idea that Lawrence was doing his research wearing a full suit and tie. Credit: Emilio Segrè Visual Archives.

J. Robert Oppenheimer, for his part, later said he had "terrible" moral scruples about the dropping of the bomb, of killing at least 70,000 people with the first one, though, notably, he never said he regretted doing it. He did, however, think that physicists had "known sin" and required an active role in future policy regarding these new weapons, if only to keep the world from blowing itself up. Lawrence parted ways with his former friend and colleague after World War II, remarking that "I am a physicist and I have no knowledge to lose in which physics has caused me to know sin" and chastising those scientists (like Oppenheimer) who thought that they ought to be getting involved with policymaking, as opposed to research — or bomb-building.

If Lawrence had doubts, he left by the wayside once the promise of victory was in the air, and he happily and seemingly without misgivings hitched himself permanently to the burgeoning military-industrial complex. He was part of the anti-Oppenheimer conspiracy that led to the 1954 security hearing, he worked closely with Edward Teller and Lewis Strauss to attempt to scuttle attempts at test bans and moratoriums, he pushed for greater quantities of bigger bombs, he sold out colleagues and friends, participating in McCarthyist purges with gusto. He was also the inventor of the cyclotron, a physicist of great importance, and one of the creators of the Big Science approach to doing research. These are not incompatible takes on a complex human being — but when we celebrate the scientific accomplishments, we do history poorly if we forget the parts that are arguably less savory.

Notes
  1. A short list of the serious errors that jumped out at me follows. Page 227: Hiltzik says that Hanford (as a site) could only produce half a pound of plutonium every 200 days. That this is a misunderstanding should be pretty obvious given that they managed to come up with 27 lbs of it (for Trinity and Fat Man) by late July 1945 despite starting B-Reactor in late 1944. I don't know where the 200 days figure comes from, but the Hanford reactors could get 225 grams (about half a pound) of plutonium for every ton of uranium they processed, and each reactor was designed to process 30 tons of uranium per month at full power (though it took several months for the plutonium to be extracted from any given ton of exposed uranium). Because there were three reactors, that means that optimally Hanford could produce about 20 kg (45 lbs) of plutonium per month. In practice they did less than that, but half a pound every 200 days is just wrong, and if true would have made two of the World War II bombs impossible. Page 292: The book gets the information about the Trinity core geometry wrong — it says it is a hollow shell that was "crushed into a supercritical ball." Rather, the Christy core was a mostly solid core (there was a small hole for the initiator) whose density was increased by the high explosives. Hollow shell designs were considered, and were later used in the postwar, but the wartime devices did not use them. This is one of those errors that won't die — often repeated despite a wealth of evidence to the contrary. Page 386: Hiltzik refers to the Soviet test Joe-4/RDS-6s as a "fizzle." This is incorrect terminology and implies that it did not achieve its target yield. It was not a staged thermonuclear weapon, but it was not a fizzle — it did what it was supposed to do, and was not a disappointment in any way. Page 405: Hiltzik, perhaps by reading too much Ralph Lapp (who was very smart but sometimes got things wrong), doesn't seem to understand how the so-called "clean bomb" would have worked. The higher the proportion of the weapon that comes from fusion reactions as opposed to fission reactions, the smaller the amount of fallout that would result. The contamination power of a weapon is not related to its total yield so much as its fission yield. The area of contamination does relate to the yield (so a 10 megaton weapon with only 1% of its yield from fission does spread those fission products over a wide area), but the intensity of the contamination does not (the level of radiation would be extremely low compared to a "dirty" hydrogen bomb that derived at least half of its power from fission). One can object that the "clean bomb" was at best a cleaner bomb, and doubt both its wisdom and the sincerity of its proponents, but the idea itself was not a hoax. Page 416: Hiltzik says that Hans Bethe "flatly refused" to join the hydrogen bomb work. This is not correct. Bethe initially refused, and then later joined the thermonuclear project at Los Alamos and made several important contributions (to the degree that he is sometimes referred to as the "midwife" of the hydrogen bomb). Bethe's wavering position on this is very aptly discussed in S.S. Schweber's In the Shadow of the Bomb: Oppenheimer, Bethe, and the Moral Responsibility of the Scientist. There are a few other nitpicks (e.g. saying that "the test ranges remained silent" from 1958-1961... only true if you ignore France), but those are the ones that really stood out as outright errors. The most irritating misrepresentation (not strictly a factual error so much as an omission) is the fact that while Lawrence's Calutrons were indeed an important part of the overall enrichment system used to make the fuel for the Hiroshima bomb (though not the only part), they were shut down in the early post war because they were not as efficient as the gaseous diffusion method. One would not get that impression from Hiltzik's book, and it is relevant inasmuch as evaluating the importance of Lawrence's method to the war — it was a useful stop-gap, but it was not a long-term solution. []
  2. Karl K. Darrow to Ernest O. Lawrence (9 August 1945), Ernest O. Lawrence papers, Bancroft Library, UC Berkeley. Copy in the Nuclear Testing Archive, Las Vegas, Nevada, accession number NV0724362. []
  3. Whether the bomb did or did not actually sway the Japanese high command is not a completely settled question, but does not matter for our purposes here — we are talking about what Lawrence et al., might have thought, not internal Japanese political machinations and motivations. []
  4. Ernest O. Lawrence to Karl K. Darrow (17 August 1945), Ernest O. Lawrence papers, Bancroft Library, UC Berkeley. Copy in the Nuclear Testing Archive, Las Vegas, Nevada, accession number NV0724363. []
  5. Arthur Compton, Atomic Quest: A Personal Narrative (New York: Oxford University Press, 1956), 239-241. []
Visions

Trinity at 70: “Now we are all sons of bitches.”

Friday, July 17th, 2015

A quick dispatch from the road: I have been traveling this week, first to Washington, DC, and now in New Mexico, where I am posting this from. Highlights in Washington included giving a talk on nuclear history (what it was, why it was important) to a crowd of mostly-millennial, aspiring policy wonks at the State Department's 2015 "Generation Prague" conference. A few hours after that was completed, an article I wrote on the Trinity test went online on the New Yorker's "Elements" science blog: "The First Light of Trinity."

The First light of Trinity

Being able to write something for them has been a real capstone to the summer for me. It was a lot of work, in terms of the writing, the editing, and the fact-checking processes. But it is really a nice piece for it. I am incredibly grateful to the editor and fact-checker who worked with me on it, and gave me the opportunity to publish it. Something to check off the bucket list.

On the plane to New Mexico, I thought over what the 70th anniversary of Trinity really meant to me. I keep coming back to the post-detonation quote of Kenneth Bainbridge, the director of the Trinity project: "Now we are all sons of bitches." It is often put in contrast with J. Robert Oppenheimer's more grandiose, more cryptic, "Now I am become death, destroyer of worlds." Oppenheimer clearly didn't say this at the time of test explosion, and its meaning is often misunderstood. But Bainbridge's quote is somewhat cryptic and easy to misunderstand as well.

The badge photograph of Kenneth Bainbridge, director of the Trinity project. From a photo essay I wrote for the Bulletin of the Atomic Scientists two years ago.

The Los Alamos badge photograph of Kenneth Bainbridge, director of the Trinity project. From a photo essay I wrote for the Bulletin of the Atomic Scientists two years ago.

Bainbridge's quote first got a lot of exposure when it was published as part of Lansing Lamont's 1965 book, Day of Trinity, timed for the 20th anniversary of Trinity. Lamont interviewed many of the project participants who were still alive. The book contains many errors, which many of them lamented. (The best single book on Trinity, as an aside, is Ferenc Szasz's 1984, The Day the Sun Rose Twice, by a considerable margin.) A consequence of these errors is that a lot of the scientists interviewed wrote letters to each other to complain about them, which means they also clarified some quotes of theirs in the book. Bainbridge in particular has a number of letters related to mixed up quotes, mixed up content, and mixed up facts from the Lamont book in his personal papers kept at the Harvard University Archives, which I looked at several years back.

One of the people Bainbridge wrote to was Oppenheimer. He said he wanted to explain his "Now we are all sons of bitches" quote, to make sure Oppenheimer understood he was not trying to be offensive:

The reasons for my statement were complex but two predominated. I was saying in effect that we had all worked hard to complete a weapon which would shorten the war but posterity would not consider that phase of it and would judge the effort as the creation of an unspeakable weapon by unfeeling people. I was also saying that the weapon was terrible and those who contributed to its development must share in any condemnation of it. Those who object to the language certainly could not have lived at Trinity for any length of time.

Oppenheimer wrote back, in a letter dated 1966, just a year before his death, when he was pretty sick and in a lot of pain. It said:

When Lamont’s book on Trinity came, I first showed it to Kitty; and a moment later I heard her in the most unseemly laughter. She had found the preposterous piece about the ‘obscure lines from a sonnet of Baudelaire.’ But despite this, and all else that was wrong with it, the book was worth something to me because it recalled your words. I had not remembered them, but I did and do recall them. We do not have to explain them to anyone.1

I like Bainbridge's explanation, because it doubles back on itself: people will think we were unfeeling and terrible for making this weapon, which makes it sound like the people are not understanding, but, actually, yes, the weapon was terrible. I think you can get away with that kind of blanket condemnation if you're one of the people instrumental in its creation.

The original map of fallout from the Trinity test. There are several more "hot spots" to the South and West than are in the later more simplified drawings of it. Click to see the entire map at full resolution.

The original map of fallout from the Trinity test. There are several more "hot spots" to the South and West than are in the later more simplified drawings of it. Click the image to see the entire map at full resolution.

I have been thinking about how broadly one might want to expand the "we" in his quote. Just those at the Trinity test? Those scientists who made the bombs possible? All of the half-million involved in making the bomb, whether they knew their role or not? The United States government and population, from Roosevelt on down? The Germans, the fear of whom inspired its initial creation? The world as a whole in the 1940s? Humanity as a whole, ever?

Are we all sons of bitches, because we, as a species of sentient, intelligent, brilliant creatures have created such terrible means of doing violence to ourselves, to the extremes of potential extinction?

This is probably not what Bainbridge meant, but it is an interesting road to go down. It recalls the recent discussions about whether we live in a new era of time, the Anthropocene, and whether the Trinity test should be seen as the marker of its beginning,

Notes
  1. Regarding Baudelaire, supposedly, according to Lamont, this was going to be the code that Oppenheimer used to tell Kitty that the test was a success: "If the test succeeded, he would send her a brief message, an obscure line from a sonnet by Baudelaire: 'You can change the sheets.'" []
Redactions

What did Bohr do at Los Alamos?

Monday, May 11th, 2015

In the fall of 1943, the eminent quantum physicist Niels Bohr managed a dramatic escape from occupied Denmark, arriving first in Sweden, then going to the United Kingdom. He was quickly assimilated into the British part of the Manhattan Project, then well underway. Bohr's institute in Copenhagen had long been considered the world center of theoretical physics, and in the 1920s, young students from around the world flocked to work with him there. Now, in December 1943, Bohr and his son Aage made their pilgrimage to what was quickly becoming the new, stealth center of nuclear expertise: Los Alamos. At age 59, he would be the oldest scientist on "the Hill," a place where the average age was 29.

Bohr skiing at Los Alamos, January 1945, seemingly without a care in the world. Source: Emilio Segrè Visual Archives, Niels Bohr Library, American Institute of Physics.

Bohr skiing at Los Alamos, January 1945, seemingly without a care in the world. Source: Emilio Segrè Visual Archives, Niels Bohr Library, American Institute of Physics.

This much is a standard part of Manhattan Project lore. Bohr's contributions are usually spoken of primarily in psychological and moral terms. Bohr inspired the physicists to think about the consequences of their work, and laid the seeds of what would become the effort for postwar international control. He also spoke with both Churchill and Roosevelt, ineffectively, about the need to avoid an arms race. Bohr was a notoriously poor oral communicator, typically being barely audible. His deeply alienated and disturbed Churchill, who thought he might be proposing to tell the Soviets about the weapon. He probably just bored Roosevelt.

Some of the stories of his conduct at Los Alamos are adorably absent-minded. One of my favorite memos in the Manhattan Project archives is a February 1944 letter from Lt. Col. John Lansdale, head of MED security, to Richard Tolman, a physicist who was a good friend of the Bohrs. "Subject: Nicholas Baker," it starts out, using Bohr's wartime codename, and explains that in the process of following Bohr around, to make sure he was safe, some, well, deficiencies in his judgment were encountered:

"Both the father and son appear to be extremely absent-minded individuals, engrossed in themselves, and go about paying little attention to any external influences. As they did a great deal of walking, this Agent had occasion to spend considerable time behind them and observe that it was rare when either of them paid much attention to stop lights or signs, but proceeded on their way much the same as if they were walking in the wood. On one occasion, subjects proceeded across a busy intersection against the red light in a diagonal fashion, taking the longest route possible and one of greatest danger. The resourceful work of Agent Maiers in blocking out one half of the stream of automobile traffic with his car prevented their possible incurring serious injury in this instance."

... I understand that the Bakers will be in Washington in the near future, at which time you will unquestionably see them. If the opportunity should present itself, I would appreciate a tactful suggestion from you to them that they should be more careful in traffic.1

Nobel-Prize winning physicist nearly run over by a car, because he treats American streets like paths in a forest, saved from disaster only by a trailing secret agent blocking the road with his car? You can't make this stuff up. These kinds of stories reinforce the playful, harmless, "Uncle Nick" character that Bohr has come to represent in this period.

Bohr and General Groves' personal technical advisor, Richard Tolman, attending the opening of the Bicentennial Conference on "The Future of Nuclear Science," circa 1947. Source: Emilio Segrè Visual Archives, Niels Bohr Library, American Institute of Physics.

Bohr and General Groves' personal technical advisor, Richard Tolman, attending the opening of the Bicentennial Conference on "The Future of Nuclear Science," circa 1947. Source: Emilio Segrè Visual Archives, Niels Bohr Library, American Institute of Physics.

But the truth is a little more complicated. For his part, Bohr would later downplay his role in the actual creation of nuclear weapons. He told another physicist in 1950, for example, that he had spent most of his time while in the United States trying to forestall a nuclear arms race. "That is why I went to America… They didn't need my help in making the atom bomb," he later said.2

Did they need Bohr? Probably not — they probably would have managed well enough without him. But this is an odd standard for talking about one's role in making a weapon of mass destruction. They didn't need almost any individual who worked on the bomb, in the sense that they could have salvaged on without them.3

And not being "needed" does not really get one off the hook, does it? Which gets at what I think is a key point here: in the postwar, Bohr never relied on his contributions to the bomb as a means of claiming moral superiority, responsibility, or political leverage. He was active in attempts to promote international control and avoid an arms race, but he didn't do so in a way that ever owned up to his own role in making the bomb. As a result, a lot of people seem to believe that Bohr didn't really do that much at Los Alamos other than provide the aforementioned moral support and provocative questions.

In fact, Bohr did work on the bomb. And not just on esoteric aspects of the physics, either; one of his role was concerned with the very heart of the "Gadget."

Niels Bohr (r) conversing animatedly with his son Aage in front of a board full of equations. Source: Emilio Segrè Visual Archives, Niels Bohr Library, American Institute of Physics.

Niels Bohr (r) conversing animatedly with his son Aage in front of a board full of equations. Source: Emilio Segrè Visual Archives, Niels Bohr Library, American Institute of Physics.

One of the key parts of the implosion design for the atomic bomb (the same sort of bomb detonated at Trinity and over Nagasaki) is the neutron initiator that sits at the absolute center of the device. It is a deceptively tricky little contraption. At the instance of maximum compression, it needs to send out a small burst of neutrons, to get the whole chain reaction started. It's not even that many neutrons, objectively speaking — on the order of a hundred or so in the first bombs. But conjuring up a hundred neutrons, at the center of an imploding nuclear assembly, at just the right moment, was a tricky technical problem, apparently.

The details are still classified-enough that figuring out exactly what the nature of the problem is proves a little tough in retrospect. In an interview many years later, the physicist Robert Bacher, head of G (Gadget) Division during the war, recalled that for whatever reason, Enrico Fermi had become particularly focused on the initiator as the lynchpin of the bomb, and maybe his own conscience:

I think Fermi began to be very worried about the fact that this terrific thing that he'd sort of been the father of was going to turn into a great big weapon. I think he was terribly worried about it. … I think he [Fermi] was worried about the whole project, not just the initiator. But focusing on the initiator was the one thing that he thought he could look at. The thing really might not work.

And I think he also felt an obligation to take something that was as hare-brained as this was and try to find a way in which it really wouldn't work. So he did look into every sort of thing, and I think every second day or so for a period, I'd see him and he'd come up or he'd see Hans [Bethe] and come up with a new reason why the initiator wouldn't work. …4

Bacher got sick of Fermi's interference, and eventually went to Oppenheimer to complain. Bacher recalled:

I said, "What I'd like to do is, Uncle Nick is here now, and I'd like to go and explain to him about the initiator and say I'd like his advice and counsel on whether he thinks it will work or not. We'll answer any question that he puts to us, that we know the answer to." So we did and he agreed with us and I told him quite frankly, "One of the reasons that we want to do this is that Fermi has so many misgivings about initiators."

So I talked to him for a long while and then he spent about two days with his son Aage going over every single thing that had been done on this business. I saw him after this and he said, "My that's very impressive. I think that will work." I said, "Well now comes the test. Will you talk to Fermi about this? The two of you talk together and give me some counsel of what's up on this?" So he did. And it made a lot of difference to have Uncle Nick talk to Fermi, because he felt that this wasn't somebody you had working on some particular model and so on. It was sort of somebody from the outside, and I think it made Fermi feel a lot happier. And it certainly made it a lot easier for us.5

The initiator that "Uncle Nick" convinced Fermi of, the one that they ended up using in the Trinity and Nagasaki bombs, was the "Urchin."

A schematic of the "Urchin," as imagined by me, based on a postwar British account.

It was a hollow sphere of beryllium, a mere two centimeters in diameter. The inner side of the sphere was machined with grooves, facing inwards. At the center of these grooves was another sphere of beryllium, centered by pins embedded in the outer shell. On both the inner grooves of the outer shell, and the outer surface of the inner sphere were coated with nickel and gold. Onto the nickel of the inner sphere was a thin film of virulently radioactive polonium. Polonium emits alpha particles; in the non-detonated state of the "Urchin," these would be absorbed harmlessly by the gold and nickel. But when the bomb came imploding in around it, the beryllium and polonium would be violently mixed, producing a well-known reaction (beryllium + an alpha particle = carbon + neutron) that produced the necessary neutrons.6

Margrethe and Niels Bohr converse in Copenhagen, 1947, in this extremely rare color photo. Source: Emilio Segrè Visual Archives, Niels Bohr Library, American Institute of Physics.

Margrethe and Niels Bohr converse in Copenhagen, 1947, in this extremely rare color photo. Source: Emilio Segrè Visual Archives, Niels Bohr Library, American Institute of Physics.

"Urchin" wasn't the only initiator design on the table. Fermi apparently favored a design with the codename "Grape Nuts." What was "Grape Nuts"? I have no idea — it's still classified. Presumably these names meant something, since "Urchin" seems to reference the internal spikes. A topic listing for a May 1945 laboratory colloquium at Los Alamos discussed three initiator designs and their creators: "Urchin," attributed to James Tuck and Hans Bethe; "Melon-Seed," attributed to James Serduke; and, lastly, "Nichodemus," attributed to… Nicholas Baker, the codename for Niels Bohr.7

In the recently-declassified Manhattan District History, there are several paragraphs on Bohr. Most of them describe theoretical work he did on the physics of nuclear fission after arriving at the lab, which "cleared up many questions that were left unanswered before." His work affected their understanding the nuclear properties of tamper materials, and he apparently gave them ideas for "new and better methods… of alternative means of bomb assembly." (All of which apparently just pointed to the superiority of implosion, in the end, but still.)

MHD Bohr contributions to bomb

At least one sentence in the Manhattan District History is still completely blacked out. Maybe it refers to the initiator design (which the previous sentence refers to), maybe it refers to something else. It's interesting that seven decades later, something of what Bohr worked on was still considered too classified to reproduce — evidence that Bohr's influence on the bomb was less trivial than he would later make it out to be.8

Why does it matter? In Michael Frayn's Copenhagen, there is, towards the end of the play, an implied asymmetry between Bohr and Heisenberg. Heisenberg is criticized throughout the play for potentially making an atomic bomb for Hitler. The play ultimately says Heisenberg didn't make an atomic bomb in part because he wasn't trying to make a bomb. (It does so with perhaps a little bit too much credence to the "he didn't do it because he was sabotaging it thesis," which I think there is no evidence for and no reason to believe, but anyway.) Driven by his fears, Bohr goes to the United States and actually does work on the bomb, does contribute to the killing of over a hundred thousand people, and so on. And so there is some irony there, where Heisenberg, supposedly the one in a state of moral jeopardy, is the one who actually contributes to the death of no one, where Bohr, supposedly the moral authority, is the one who helps build the bomb.

Bohr with Elisabeth and Werner Heisenberg in Athens, Greece, 1956. Source: Emilio Segrè Visual Archives, Niels Bohr Library, American Institute of Physics.

Bohr with Elisabeth and Werner Heisenberg in Athens, Greece, 1956. Source: Emilio Segrè Visual Archives, Niels Bohr Library, American Institute of Physics.

Do Bohr's contributions to the atomic bomb, however major or minor, weaken his moral authority? I don't really think so. Bohr's strongest and most lasting contribution was putting the bug of international control into the heads of people like Oppenheimer. That bug might have come up on its own (when they learned about Bohr's scheme, Vannevar Bush and James Conant were surprised to find that they had been thinking along almost exactly the same lines, completely independently), but Bohr's influence on openness, candor, the moral obligation of scientists, and so on had a profound effect on postwar political discourse, even if his dreaded arms race was not avoided. In this light, I think Bohr still comes off pretty well, even if the bomb still does contain traces of his fingerprints.

Notes
  1. John Lansdale to Richard Tolman, "Subject: Nicholas Baker," (5 February 1944), Manhattan Engineer District (MED) records, Records of the Army Corps of Engineers, RG 77, National Archives and Records Administration, College Park, MD, Box 64, "Security." []
  2. J. Rud Nielson, "Memories of Niels Bohr," Physics Today 16, no. 10 (Oct. 1963), 28-29. []
  3. I am occasionally drawn into a game of "who is so important that you absolutely couldn't remove them and still expect it to be successful?" I am inclined to think that almost everyone would be more or less replaceable, as individuals, though there are a few whose contributions were so pivotal that removing them would create serious issues. Someday I will post some concrete thoughts on this on this. []
  4. Robert Bacher interview with Lillian Hoddeson and Alison Kerr (30 July 1984), Robert Bacher papers, Caltech Institute Archives, Pasadena, CA, Box 48, Folder 5. []
  5. Ibid. []
  6. Accounts of the exact dimensions of the "Urchin" vary from source to source. John Coster-Mullen's book, Atom Bombs, gives what I find to be convincing evidence that it was 0.8 in./2 cm in diameter. There was 20 curies of polonium deposited in them, and they had to be replaced frequently because of polonium's low half-life. The inner core of the plutonium pit was about 1 in. in diameter, and apparently both the core and the initiator would be expected to expand slightly due to the heat generated by their radioactivity. Apparently James Tuck gave it the name "Urchin," on account of its inner ridges. There is some question as to how the grooves were machined, whether they were pyramids (as in the British account) or ridges (e.g. like a theatre in the round). It's always nice to be reminded that there are still a few secret details out there. []
  7. The list of wartime colloquia comes from the Klaus Fuchs FBI File, Part 49 of 111, available on the FBI's website, starting on page 49 of the PDF. The only other "Nicholas Baker" contribution mentioned in the document is a November 1944 talk on "nuclear reactions of heavy elements and particularly the various results obtained when a neutron comes in contact with heavy nuclei, such as Uranium 238." []
  8. Manhattan District History, Book 8 (Los Alamos Project), Volume 2 (Technical), pages II-2 to II-3. []
Redactions

To demonstrate, or not to demonstrate?

Friday, March 6th, 2015

As the atomic bomb was becoming a technological reality, there were many scientists on the Manhattan Project who found themselves wondering about both the ethics and politics of a surprise, unwarned nuclear attack on a city. Many of them, even at very high levels, wondered about whether the very threat of the bomb, properly displayed, might be enough, without the loss of life that would come with a military attack.

1945-06-12 - Franck Report

The Franck Report, written in June 1945 by scientists working at the University of Chicago Metallurgical laboratory, put it perhaps most eloquently:

...the way in which nuclear weapons, now secretly developed in this country, will first be revealed to the world appears of great, perhaps fateful importance. ... It will be very difficult to persuade the world that a nation which was capable of secretly preparing and suddenly releasing a weapon, as indiscriminate as the rocket bomb and a thousand times more destructive, is to be trusted in its proclaimed desire of having such weapons abolished by international agreement.... 

From this point of view a demonstration of the new weapon may best be made before the eyes of representatives of all United Nations, on the desert or a barren island. The best possible atmosphere for the achievement of an international agreement could be achieved if America would be able to say to the world, "You see what weapon we had but did not use. We are ready to renounce its use in the future and to join other nations in working out adequate supervision of the use of this nuclear weapon."

They even went so far as to suggest, in a line that was until recently totally etched out of the historical record by the Manhattan Project censors, that "We fear its early unannounced use might cause other nations to regard us as a nascent Germany." 

The evolution of the "Trinity" test fireball, at constant scale, with the Empire State Building for additional scale reference.

The evolution of the "Trinity" test fireball, at constant scale, with the Empire State Building for additional scale reference.

The idea of a "demonstration" was for many scientists a compelling one, and news of the idea spread to the various project sites. The idea would be to let the Japanese know what awaited them if they did not surrender. This would be more than just a verbal or textual warning, which could be disregarded as propaganda — they would set the bomb off somewhere where casualties would be low or minimal, but its nature easy to verify. If the demonstration did not work, if the Japanese were not receptive, then the bomb could be used as before. In the eyes of these scientists, there would be no serious loss to do it this way, and perhaps much to gain.

Of course, not all scientists saw it this way. In his cover letter forwarding the Franck Report to the Secretary of War, the physicist Arthur Compton, head of the Chicago laboratory, noted his own doubts: 1. if it didn't work, it would be prolonging the war, which would cost lives; and 2. "without a military demonstration it may be impossible to impress the world with the need for national sacrifices in order to gain lasting security." This last line is the more interesting one in my eyes: Compton saw dropping the bomb on a city as a form of "demonstration," a "military demonstration," and thought that taking a lot of life now would be necessary to scare the world into banning these weapons in the future. This view, that the bombs were something more than just weapons, but visual arguments, comes across in other scientists' discussions of targeting questions as well.

Truman was never asked or told about the demonstration option. It is clear that General Groves and the military never gave it much thought. But the Secretary of War did take it serious enough that he asked a small advisory committee of scientists to give him their thoughts on the matter. A Scientific Panel, composed of J. Robert Oppenheimer, Arthur Compton, Enrico Fermi, and Ernest Lawrence, weighed in on the matter formally, concluding that: "we can propose no technical demonstration likely to bring an end to the war; we see no acceptable alternative to direct military use."1

"Recommendations on the Immediate Use of Atomic Weapons," by the Scientific Panel of the Interim Committee, June 16, 1945. The full report (which also discusses the possibility of the H-bomb and many other things) is extremely interesting, as well — click here to read it in its entirety.

"Recommendations on the Immediate Use of Atomic Weapons," by the Scientific Panel of the Interim Committee, June 16, 1945. The full report (which also discusses the possibility of the H-bomb and many other things) is extremely interesting, as well — click here to read it in its entirety.

I find this a curious conclusion for a few reasons. For one thing, are these four scientists really the best experts to evaluate this question? No offense, they were smart guys, but they are not experts in psychological warfare, Japanese political thought, much less privy to intercepted intelligence about what the Japanese high command was thinking at this time. That four physicists saw no "acceptable alternative" could just be a reflective of their own narrowness, and their opinion sought in part just to have it on the record that while some scientists on the project were uncomfortable with the idea of a no-warning first use, others at the top were accepting of it.

But that aside, here's the other fun question to ponder: were they actually unanimous in their position? That is, did these four physicists actually agree on this question? There is evidence that they did not. The apparent dissenter was an unlikely one, the most conservative member of the group: Ernest Lawrence. After the bombing of Hiroshima, Lawrence apparently told his friend, the physicist Karl Darrow, that he had been in favor of demonstration. Darrow put this into writing on August 9, 1945, to preserve it for posterity should Lawrence come under criticism later. In Darrow's recollection, Lawrence debated it with the other scientists for "about an hour" — a long-enough time to make it seem contentious. On August 17, after the bomb had "worked" to secure the peace, Lawrence wrote back to Darrow, somewhat denying this account, saying that it was maybe only ten minutes of discussion. Lawrence, in this later account, credits Oppenheimer as being the hardest pusher for the argument that unless the demonstration took out a city, it wouldn't be compelling. I'm not sure I completely believe Lawrence's later recant, both because Darrow seemed awfully convinced of his recollection and because so much changed on how the bomb was perceived after the Japanese surrendered, but it is all an interesting hint as some of the subtleties of this disagreement that get lost from the final documents alone. In any case, I don't know which is more problematic: that they debated for an hour and after all that, concluded it was necessary, or that they spent no more than ten minutes on the question.2

1945-08-10 - Groves memo on next bombs

As an aside, one question that sometimes gets brought up at this point in the conversation is, well, didn't they only have two bombs to use? So wouldn't a demonstration have meant that they would have only had another bomb left, perhaps not enough? This is only an issue if you consider the timescale to be as it was played out — e.g., using both bombs as soon as possible, in early August. A third plutonium bomb would have been ready by August 17th or 18th (they originally thought the 24th, but it got pushed up), so one could imagine a situation in which things were delayed by a week or so and there would have been no real difference even if one bomb was expended on a demonstration. If they had been willing to wait a few more weeks, they could have turned the Little Boy bomb's fuel into several "composite" core implosion bombs, as Oppenheimer had suggested to Groves after Trinity. I only bring the above up because people sometimes get confused about their weapon availability and the timing issue. They made choices on this that constrained their options. They had reasons for doing it, but it was not as if the way things happened was set in stone. (The invasion of Japan was not scheduled until November 1st.)3

So, obviously, they didn't choose to demonstrate the bomb first. But what if they had? I find this an interesting counterfactual to ponder. Would dropping the bomb in Tokyo Bay have been militarily feasible? I suspect so. If they could drop the bombs on cities, they could probably drop them near cities. To put it another way: I have faith they could have figured out a way to do it operationally, because they were clever people.4

But would it have caused the Japanese high command to surrender? Personally, I doubt it. Why? Because it's not even clear that the actual atomic bombings were what caused the Japanese high command to surrender. There is a strong argument that it was the Soviet invasion of Manchuria that "shocked" them into their final capitulation. I don't know if I completely buy that argument (this is the subject of a future blog post), but I am convinced that the Soviet invasion was very important and disturbing to the Japanese with regards to their long-term political visions for the country. If an atomic bomb dropped on an actual city was not, by itself, entirely enough, what good would seeing a bomb detonated without destruction do? One cannot know, but I suspect it would not have done the trick.

The maximum size of a 20 kiloton mushroom cloud in Tokyo Bay, as viewed from the roof of the Imperial Palace today, as visualized by NUKEMAP3D. Firebombed Tokyo of 1945 would have afforded a less skyscraper-cluttered view, obviously.

The maximum size of the mushroom cloud of a 20 kiloton nuclear detonation in Tokyo Bay, as viewed from the roof of the Imperial Palace today, as visualized by NUKEMAP3D. Firebombed Tokyo of 1945 would have afforded a less skyscraper-cluttered view, obviously.

Of course, the Chicago scientists suspected that as well, but said it was necessary from a moral point of view. Sure, the Japanese might not surrender, but then, at least, you can say you showed them what was coming first.  As it was, we gave no real warning whatsoever before dropping it on Hiroshima. But here's the question I come to next: could you demonstrate it, and then drop it on a city? That is, could the United States really say: "we have made this apocalyptic weapon, unleashed the atom, and many other peril/hope clichés — and we have chosen not to use it to take life... yet. But if you don't give in to our demands, we will unleash it on your people." How could that not look like pure blackmail, pure terrorism? Could they then turn around and start killing people by the tens of thousands, having announced their capability to do so? Somehow I suspect the public relations angle would be almost impossible. By demonstrating it first, they would be implying that they knew that it was perhaps not just another weapon, not just another way to wage war. And that acknowledgment would mean that they would definitely be seen as crossing a line if they then went on to use it.

As it was, that line, between the bomb as "just another weapon" and something "special," was negotiated over time. I think the demonstration option was, for this reason, never really going to be on the table: it would have forced the American policymakers to come to terms with whether the atomic bomb was a weapon suitable for warfare on an earlier schedule than they were prepared to. As it was, their imagery, language, and deliberations are full of ambiguity on this. Sometimes they thought it would have new implications for "man's position in the universe" (and other "special bomb" notions), sometimes they thought it was just an expedient form of firebombing with extra propaganda value because it would be very bright and colorful. Secrecy enabled them to hedge their bets on this question, for better or worse.

Without imagery like this, would the world fear nuclear weapons more, or less?

Without imagery like this, would the world fear nuclear weapons more, or less? When, if ever, would the first use of nuclear weapons in warfare have been?

So who was right? I don't know. We can't replay history to see what happened, obviously. I think the idea of a demonstration is an interesting expression of a certain type of ethical ideal, though it went so far against the practical desires of the military and political figures that it is hard to imagine any way it would have been pursued. I am not sure it would even have been successful, or resolved the moral bind of the atomic bomb.

I do find myself somewhat agreeing with those scientists who said that perhaps it was better to draw blood with the smaller, cruder bombs, before the really big ones came around — and they knew those were coming. If we didn't have Hiroshima and Nagasaki, what would we point to, to talk about why not to use nuclear weapons? Would people think the bombs were not that impressive, or even more impressive than they were? I don't know, but there is something to the notion that knowing the gritty, gruesome reality (and its limitations) is better than not. It took the Holocaust for the world to (mostly) renounce genocide, maybe it took Hiroshima and Nagasaki for the nuclear taboo to be established (arguably). That, perhaps, is the most hopeful argument here, the one that sees Hiroshima and Nagasaki as not just the first cities to be atomic bombed, but the last, but I am sure this is little solace to the people who were in those cities at the time.

Notes
  1. This was part of a larger set of recommendations these scientists made, including those which touched on the "Super" bomb, future governance of the atom, and other topics of great interest. Report of the Scientific Panel of the Interim Committee (16 June 1945), Harrison-Bundy Files Relating to the Development of the Atomic Bomb, 1942-1946, microfilm publication M1108 (Washington, D.C.: National Archives and Records Administration, 1980), Roll 6, Target 5, Folder 76, "Interim Comittee — Scientific Panel." []
  2. Karl Darrow to Ernest Lawrence (9 August 1945), copy in Nuclear Testing Archive, NV0724362 [note the NTA has the wrong name and date on this in their database]; Ernest Lawrence to Karl Darrow (17 August 1945), copy in Nuclear Testing Archive,NV0724363. []
  3. On the composite core question, see J. Robert Oppenheimer to Leslie Groves (19 July 1945), copy in Nuclear Testing Archive, NV0311426; Leslie Groves to J. Robert Oppenheimer (19 July 1945), Correspondence ("Top Secret") of the Manhattan Engineer District, Roll 1, Target 6, Folder 5B: "Directives, Memorandums, etc to and from Chief of Staff, Secretary of War, etc." []
  4. To answer one other question that comes up: would such a demonstration create deadly fallout? Not if it was set to detonate high in the air, like at Hiroshima and Nagasaki. If it was detonated underwater the fallout would be mostly limited to the area around the bomb detonation itself. It would be hard to actually create a lot of fallout with a bomb detonated over water and not land, in any case. "Local fallout," the acutely deadly kind, is caused in part by the mixing of heavier dirt and debris with the radioactive fireball, which causes the fission products to descend very rapidly, while they are still very "hot." []
Redactions

Oppenheimer, Unredacted: Part II – Reading the Lost Transcripts

Friday, January 16th, 2015

This is the second and final part (Part II) of my story about the lost Oppenheimer transcripts. Click here for Part I, which concerns the origin of the transcripts, the unintuitive aspects of their redaction, and the unorthodox archival practice that led me to find their location in 2009.


Oppenheimer photograph courtesy of the Emilio Segrè Visual Archive.

The Oppenheimer security hearing transcript is not exactly beach reading. Aside from its length (the redacted version alone is some 690,000 words, which makes it considerably longer than War and Peace), it is also a jumble of witnesses, testimonies, and distinct topics. It is also somewhat of a bore, as there is incredible repetition, and unless you know the context of the time very well, the specific arguments that are focused on can seem arbitrary, pedantic, and confusing, even without the additional burden of some of the content having been deleted by the censor.

The most damning problem for Oppenheimer at his 1954 hearing involved his conduct during the so-called “Chevalier incident,” in which a fellow-traveler colleague of his at Berkeley, Haakon Chevalier, approached Oppenheimer at a party in late 1942 or early 1943 at the behest of another scientist (a physicist named George Eltenton) who wanted to see if Oppenheimer was interested in passing on classified information to the Soviet Union. Oppenheimer, in his recollection, told Chevalier in no uncertain terms that this was a bad idea. Later, Oppenheimer went to a member of the Manhattan Project security team and told him about the incident, calling attention to Eltenton as a security risk, but also trying to not to make too big of a deal of the entire matter. Confronted with the idea of Soviet spying on the atomic bomb project, the security men of course did not take it so lightly, and pressed Oppenheimer for more details, such as the name of the intermediary, Chevalier, which Oppenheimer did not want to give since he claimed Chevalier had nothing truly to do with Soviet spying. Over the course of several years, the security agents re-interviewed Oppenheimer, trying to clarify exactly what had happened. Oppenheimer gave contradictory answers, seemingly to shield his friends from official scrutiny and its consequences. At his hearing, when asked whether he had lied to security officials, Oppenheimer admitted that he had. When asked why, Oppenheimer gave what was become the most damning testimony at a hearing about his character: “Because I was an idiot.” Not a good answer to have to give under any context, much less McCarthyism, much less when you are known to be brilliant.

I mention this only to highlight the difference between what is in the published transcript and what is not. The newly unredacted information does not touch on the Chevalier incident much at all. That is, it does not shed any new light on the central question of relevance towards Oppenheimer's security clearance. What does it shed light on? We can lump its topics into roughly three categories.

One of the censor's trickier redactions, in which he removed a trouble word, and substituted a different word in its place. "Principle" was too close to a secret, but"idea" was acceptable.

One of the censor's trickier redactions, in which he removed a trouble word, and substituted a different word in its place. "Principle" was too close to a secret, but"idea" was acceptable. (JB = James Beckerley.)

The first category concerns the creation of the hydrogen bomb. Oppenheimer had been on a committee that had opposed a “crash” program to build the H-bomb in 1949. This was at a time when it was unclear that such a weapon could be built at all. The then-favored design (later dubbed the “Classical Super”) had many problems with it, and didn’t seem like it was likely to work. It seemed to also require huge quantities of a rare isotope of hydrogen, tritium, the production of which could only be done in nuclear reactors at the expense of producing plutonium.For Oppenheimer and many others, there was a strong technical reason to not rush into an H-bomb program: it wasn’t clear that the bomb could be built, and preparing the materials for such a bomb would decrease the rate of producing regular fission bombs.

How much plutonium would be lost in pursuing the Super? This is an area the newly-reduced transcript does enlighten us. Gordon Dean, Chairman of the Atomic Energy Commission from 1950 to 1953, explained that:

You don't decide to manufacture something that has never been invented. Nothing had been invented. No one had any idea what the cost of this thing would be in terms of plutonium bombs. As the debate or discussions waged in the fall of 1949, we had so little information that it was very difficult to know whether this was the wise thing to do to go after a bomb that might cost us anywhere from 20 plutonium bombs up to 80 plutonium bombs, and then after 2 or 3 years effort find that ft didn't work. That was the kind of problem. So there were some economics in this thing.

The underlined section was removed from the published transcript. This does contribute to the debate at the time — if researching the Super meant depriving the US stockpile of 20-80 fission bombs, that is indeed a high price. We might ask: Why was it redacted? Because the censor wanted to undercut Oppenheimer's position? Probably not — if the censor had wanted to do that, he would have removed a lot more than just those numbers. More likely it is because you can work backwards from those numbers how much plutonium was in US nuclear weapons at that time, or, conversely, how much tritium they were talking about. Every atom of tritium you make is an atom of plutonium you don't make — and plutonium atoms are 80X heavier than tritium atoms. So for every gram of tritium you produce, you are missing out on 80 grams of plutonium. If you know that the bombs at the time had around 6 kg of plutonium in them, then you can see that they are talking about the expense of making just 1.5 to 6 kg of tritium. Should this have been classified? It seems benign at the moment, but this was still a period of a "race" for thermonuclear weapons, and nearly everything about these weapons was, rightly or wrongly, classified.

Redaction of a long section on the development of the Teller-Ulam design. Ulam's name was almost totally (but not entirely) removed from the transcript, sometimes very deliberately and specifically. The orange pencil shows the mark of the censor, as does the "Delete, JB" on the right.

Redaction of a long section on the development of the Teller-Ulam design. Ulam's name was almost totally (but not entirely) removed from the transcript, sometimes very deliberately and specifically. The orange pencil shows the mark of the censor, as does the "Delete, JB" on the right.

But the hydrogen bomb could be built. In the spring of 1951, physicists Edward Teller and Stanislaw Ulam hit upon a new way to build a hydrogen bomb. It was, from the point of view of the weapons physicists, a totally different approach. Whereas the “Classical Super” required using an atomic bomb to start a small amount of fusion reactions that would then propagate through a long tube of fusion fuel, the “Equilibrium Super,” as the so-called Teller-Ulam design was known at the time, involved using the radiation of an atomic bomb to compress a capsule of fusion fuel to very high densities before trying to ignite it. To a layman the distinction may seem minor, but the point is that many of the scientists involved with the work felt this was really quite a big conceptual leap, and that this had political consequences.

The differences between the redacted and un-redacted transcript shows a censor who tried, perhaps in vain, to dance around this topic. The censor clearly wanted to make sure the reader knew that the hydrogen bomb design developed in 1951 (the “Equilibrium Super”) was a very different thing than the one on the table in 1949 (the “Classical Super”), because this is a clear part of the argument in Oppenheimer’s favor. But the censor also evidently feared being too coy about what the differences between the 1949 and 1951 designs were, as such was the entire “secret” of the hydrogen bomb. For example, here is a section where Oppenheimer testified on this point, early on in the hearing:

In the spring of 1951, there were some inventions made. They were not discoveries, really; they were inventions, new ideas, and from then on it became clear that this was a program which was bound to succeed. It might not succeed at first shot; you might make mistakes, but for the first time it was solid. It was not on the end; it wasn’t so that every time you calculated it it was yes or not, but it came out that you knew that you could do not. It was just a question of how rapidly and how well and I am amazed at the speed at which this actually went after we learned what to do. Ulam and Teller had some very bright ideas; why none of us had them earlier, I cannot explain, except that invention is a somewhat erratic thing.

Again, what is underlined above was removed from the original. Read the sentences without them and they still have the same essential meaning: Oppenheimer is arguing that the 1951 design was very different than the 1949 one. Put them back in, and the meaning only deepens a little, adding a little more specifics and context, but does not change. One still understands Oppenheimer’s point, and much is left in to emphasize its import — Oppenheimer only opposed the H-bomb when it wasn’t clear that an H-bomb could be made.

Why remove such lines in the first place? A judgment call, perhaps, about not wanting to reveal that the “secret” H-bomb was not a new scientific fact, but a clever application of a new idea. The censor could have probably justified removing more under the security guidelines, but took pains to maintain coherency in the testimony. In one place, the physicist Hans Bethe referred to Teller and Ulam’s work as a new “principle,” and the censor re-worded this to “idea” instead. A subtle change, but certainly done in the name of security, to shift attention away from the nature of the H-bomb “secret.”

Early 1954 was a tricky time for hydrogen bomb classification. The US had detonated its first H-bomb in 1952, but not told anyone. In March 1954, a second hydrogen bomb was detonated as the “Bravo test.” Radioactive fallout rained down on inhabited atolls in the Marshall Islands, as well as a Japanese fishing boat, making the fact of it being a thermonuclear test undeniable. The Soviet Union had detonated a weapon that used fusion reactions in 1953, but did not appear to know about the Teller-Ulam design. As a result, US classification policy on the H-bomb was extremely conservative and sometimes contradictory; that the US had tested an H-bomb was admitted, but whether it was ready to drop any of them was not.

JRO redaction Rabi mermaids

In this category I would also attribute I.I. Rabi's "mermaids" redaction, mentioned earlier. As published, it was:

We have an A-bomb and a whole series of it, *** and what more do you want, mermaids?

Restored, it is:

We have an A-bomb and a whole series of it, and we have a whole series of Super bombs, and what more do you want, mermaids?

To the censor, the removed section implied, perhaps, that there was no single H-bomb design, but rather a generalized arrangement that could be applied to many different weapons (which were being tested during Operation Castle, which was taking place at the same time as these hearings). This is a tricky distinction for a layman, but important for a weapons designer — and it is the eyes of the weapon designer that the censor feared, in this instance.

The censor’s fear of foreign scientists scouring the Oppenheimer hearing transcripts for clues as to the H-bomb’s design was not, incidentally, unwarranted. In the United Kingdom, scientists compiled a secret file full of extracts from the (redacted) Oppenheimer transcript that reflected on the nature of the successful H-bomb design. So at least one country was watching. As for the Soviet Union, they detonated their first H-bomb in 1955, having figured out the essential aspects of the Teller-Ulam design by the spring of 1954 (there is still scholarly uncertainty as to the exact chronology of the Soviet H-bomb development, and whether it was an entirely indigenous creation).

Project Vista cover page

The second major category of deletions pertained to Oppenheimer’s role in advising on the use of tactical nuclear weapons in Europe. This involved his participation in Project Vista, a study conducted in 1951-1952 by Caltech for the US Army. Vista was about the defense of continental Europe against overwhelming Soviet ground forces, and Oppenheimer’s section concerned the use of atomic bombs towards this end. (It was named after the hotel that the summer study took place in.)

Oppenheimer’s chapter ("Chapter 5: Atomic Warfare") concluded that small, tactical fission bombs could be successfully used to repel Soviet forces. In doing so, it also argued against a reliance on weapons that could only be used against urban targets — like the H-bomb. The US Air Force attempted to suppress the Vista report, because it seemed to advocate that the Army into their turf and their budget. It was one of the many things that made the Air Force sour on Oppenheimer.1

In order to emphasize that Oppenheimer was not opposed to the hydrogen bomb on the basis of entirely moralistic reasons, a lot of the discussions at the hearing initiated by his counsel related to his stance on tactical nuclear weapons. They wanted it to be clear that Oppenheimer was not “soft” on Communism and the USSR. Arguably, Oppenheimer’s position was sometimes more hawkish than those of the H-bomb advocates. Oppenheimer wanted a nuclear arsenal that the US would feel capable of using, as opposed to a strategic arsenal that would only lead to a deterrence stalemate.

Another classic Cold War redaction: what we know about the enemy, even if we don't know anything.

Another classic Cold War redaction: what we know about the enemy, even if we don't know anything.

The debate of strategic arms versus tactical nukes is one that would become a common point of discussion from the 1960s onward, but in 1954 it was still confined largely to classified circles because they pertained to actual US nuclear war plans in place at the time and the future of the US nuclear arsenal. Much of this discussion is still visible in the redacted transcript, but with less emphasis and detail than in the un-redacted original. The essential point — that in the end, the US military pursued both of these strategies simultaneously, and that Oppenheimer was no peacenik — gets filled out a more clearly in the un-redacted version.

Among the sentences that got redacted are long portions that describe the Vista project, its importance, and the fact that it was taken very seriously. It is unfortunate that these were removed, because they would definitely have changed the perception that Oppenheimer was acting on purely "moral" reasons against the hydrogen bomb. Oppenheimer opposed the hydrogen bomb, but he did so, in part, because he advocated making hundreds of smaller fission bombs. Other statements removed is a remark by General Roscoe Charles Wilson about something he heard Curtis LeMay say: "I remember his saying most vigorously that they couldn't make them too big for him." One can appreciate why the censor might want to remove such a thing, as a rather unflattering bit of hearsay about the head of the Strategic Air Command. Lest one think that these removals would only help Oppenheimer's case, many of the other lines removed from Wilson's testimony concerned the fact that the Air Force did find that they had plenty of strategic targets for multi-megaton bombs — removed, no doubt, because it shed light on US targeting strategy, but the sort of thing that generally went against Oppenheimer's argument.

Similarly, John McCloy testified that Oppenheimer's views were fairly hawkish at the time:

I have the impression that he [Oppenheimer], with one or two others, was somewhat more, shall I say, militant than some of the other members of the group. I think I remember very well that he said, for example, that we would have to contemplate and keep our minds open for all sorts of eventualities in this thing even to the point of preventative war.

Did Oppenheimer really advocate preventative nuclear war with the Soviet Union? It's not impossible — his views in the 1950s could be all over the place, something that makes him a difficult figure to fit into neat boxes. In retrospect, we have made Oppenheimer into an all-knowing, all-rational sage of the nuclear age, but the historical record shows someone more complicated than that. Why would the censor remove the above? Probably because it would be seen as inflammatory to US policy, potentially because it might shed light on actual nuclear policy discussions. In this case, this line potentially could have had a strong impact on the post-hearing memory of Oppenheimer, had it been released, but probably not a positive one.

JRO redaction Groves on Rosenbergs

Lastly, there are a few removals for miscellaneous reasons relating to the conduct of the hearings themselves. As I pointed out at the beginning, when the witnesses at the security hearing took the stand, they were told that their responses would be “strictly confidential,” and not published. This was to encourage maximum candor on their part. When the decision was made to publish the transcript, each of the witnesses were contacted individually to be told this and were asked if there was anything they would not want made public. There is evidence of a few removals for this reason.

General Leslie Groves, the head of the Manhattan Project during World War II, said a number of things that were not classified but would have been embarrassing or controversial if they appeared in print. For example, he was emphatic that “the British Government deliberately lied about [Klaus] Fuchs,” the German physicist who had been part of the British delegation to Los Alamos and was, as it later became known, a Soviet spy. Groves also opined on the importance of Fuchs’ espionage versus that of the Rosenbergs:

I think the data that went out in the case of the Rosenbergs was of minor value. I would never say that publicly. Again that is something while it is not secret, I think should be kept very quiet, because irrespective of the value of that in the overall picture, the Rosenbergs deserved to hang, and I would not like to see anything that would make people say General Groves thinks they didn't do much damage after all.

Even Groves’ comment at the time made it clear that this was not something he wanted circulated publicly. Should this information have been removed? It is a tricky question. If Groves had known what he said would be printed, he never would have said any of it. Ultimately this becomes not an issue of classification, but one of propriety. Its inclusion does not affect issues relating to Oppenheimer’s clearance. It is part of a much longer rant on Groves' part about the British, something he was prone to do when confronted with the fact that the worst cases of nuclear secrets being lost occurred on his watch.

In one slightly smaller category, there is at least evidence of one erroneous, accidental removal. There is a line, on page 129 of the GPO version, which, when restored, looks like this: "Having that assumption in mind at the time Lomanitz joined the secret project, did you tell the security officers anything that you knew about Lomanitz’s background?" The restored material contains nothing classified, or even interesting, and its removal is not noted in the official "concordance" of deleted material produced by the Atomic Energy Commission censor. So why was it removed? Looking at the originals, we find that the entire contents of the deleted material comprise the last line of the page. It looks like it got cut off on accident, and marked as a redaction. Such is perhaps further evidence of the rushed effort that resulted in the transcript being published.

* * *

Does the newly released material give historians new insight into J. Robert Oppenheimer? In my view: not really. At best, they may address some persistent public misconceptions about Oppenheimer, but ones that have long since been redressed by historians, and ones that even the redacted transcript makes clear, if one takes the time to read it carefully and deeply. The general public has long perceived Oppenheimer to be a dovish martyr, but even a cursory reading of the actual transcripts makes it clear that this is not quite right — he was something more complex, more duplicitous, more self-serving.

Oppenheimer's two TIME magazine covers: as ascendent atomic expert (1948), and casualty of the security state (1954).

Oppenheimer's two TIME magazine covers: as ascendent atomic expert (1948), and casualty of the security state (1954).

If the redacted sentences had been released in 1954, they would have fleshed out a little more of the story behind the H-bomb and behind Oppenheimer’s advocacy for tactical nuclear weapons. They would have emphasized more strongly that Oppenheimer opposed the H-bomb not just for moral reasons, but for technical reasons, and that rather than opposing the development of atomic armaments, Oppenheimer supported them vigorously — and even supported using them in future conflicts. The latter aspect, in particular, might have changed a bit the public’s perception of Oppenheimer at the time. Oppenheimer was not a dove, he was just a different sort of hawk, which somewhat reduces the idea of Oppenheimer as a martyr against the warmongers. This latter notion (Oppenheimer as anti-nuke) is a common perception of Oppenheimer, even today, though much scholarly work has tried to go against this notion for several decades.

The recent declassification of the transcript does not tell us anything we essentially did not already know from other sources, including the many of the wonderfully-researched histories of this period published in recent years by scholars such as Jeremy BernsteinKai Bird, David Cassidy, Gregg Herken, Priscilla McMillan, Richard Polenberg, Richard Rhodes, Sam SchweberMartin Sherwin, and Charles Thorpe, among others. These new revelations do not drastically revise our understanding of Oppenheimer or his security clearing. He looks no more nor less of a “security risk” than he did in the redacted version of the transcripts.

At the same conference where I initially was inspired to search for the hearing transcripts, Polenberg asked the group assembled: how would we remember Oppenheimer today, if he had not had his security clearance stripped after the hearing? His own answer is that we would probably have longer focused on the more negative aspects of Oppenheimer's personality and perspectives. We'd see him not as a dove, but as a different flavor of hawk. He'd see him as someone who was willing to turn in his friends to the FBI, if it served his interests. We'd see him as someone who, again and again, wanted to be accepted by the politicians and the generals. We would see more of his role as an enabler of the Cold War arms race, not just his attempts at tamping it down. By revoking the clearance, Oppenheimer's enemies may have crushed his soul, but they made him a martyr in the process.

Headlines from 1954 regarding Beckerley and his split with the Atomic Energy Commission — and his turn as a secrecy critic.

Headlines from 1954 regarding Beckerley and his split with the Atomic Energy Commission — and his turn as a secrecy critic.

But just because these transcripts don't give us much of a revision on Oppenheimer, or the conduct of his security hearing, doesn't mean they are not  instructive. For one thing, they shed a good deal of light on the process of secrecy itself — and it is only by getting the full story, the record of deletions, that one can pass judgment on whether the secrecy was used responsibility or inappropriately.

In my view, the erasures appear to have been done responsibly. They do not greatly obscure the ultimate arguments for or against Oppenheimer’s character, and primarily hew to legitimate security concerns for early 1954. The choice of what to remove and what to keep was done not by one of Oppenheimer’s enemies, but by Dr. James G. Beckerley, a physicist who was at the time the Director of the Atomic Energy Commission’s Division of Classification. His initials (“JB”) can be found next to many of the specific deletions in some of the volumes. Beckerley was no rabid anti-Communist or promoter of secrecy. He was a moderate, one who often felt that the AEC’s security rules were highly problematic, and believed that only careful and sane application of classification rules (as opposed to zealous or haphazard) would lead to a stronger nation. As it was, he resigned his job in May 1954, not long after the Oppenheimer hearing, and became an outspoken critic of nuclear secrecy. We do not know Beckerley’s personal opinions on Oppenheimer, but in every other aspect of his work he seems not to be the classification villain that one expects of a Cold War drama.

So it is perhaps not surprising that his deletions from the Oppenheimer transcript are, in retrospect, pretty reasonable, if viewed in context. They do not seem overtly politicized, especially in the way that Beckerley carefully carved up some of the problematic statements so that their ultimate argument still came out, even if the classified details did not. Most were plausibly done in the name of security, according to the security concerns of early 1954. In fact, the amount of discussion of the H-bomb’s development allowed in the final transcript is rather remarkable — very little has in fact been removed on this key topic. A few of the removals, were done in the name of propriety, removed because of the changing status of the transcript from “confidential” to public record. None of the comments removed for non-security reasons seem to have had any bearing on the question of Oppenheimer’s character and loyalty, though they are certainly interesting. Groves’ comments on the Rosenbergs, for example, is completely fascinating — but not relevant to Oppenheimer’s case.

Two frames from a 1961 photo session with Oppenheimer by Ulli Steltzer. "He was shy of the camera and I never got more than 12 shots. It is hard to say which expression is most typical." More on this image, here.

Two frames from a 1961 photo session with Oppenheimer by Ulli Steltzer. "He was shy of the camera and I never got more than 12 shots. It is hard to say which expression is most typical." More on this image, here.

In this case, I disagree with the conclusions given by the other historians in the New York Times article about the release. I don't think the removals bolster Oppenheimer's case, and I don't think there is any evidence to suggest that the redactions were made to aid the government's case. We are accustomed to a story about classification that involves bad guys hiding the truth. Sometimes that is a narrative that works well with the facts — classification can, and has often been, abused. But in my (someday) forthcoming book, I argue that part of this impression of "the censor" as a shadowy, faceless, draconian "enemy" is just what happens when we, on the outside, are not privy to the logic on the "inside."

It is somewhat tautological to say that secrecy regimes hide their own logic by the very secrecy they impose, but it is actually a somewhat subtle point for thinking about how they work. When you are outside of a secrecy regime, you can't always see why it acts the way it does, and it is easy to see it as an oppositional entity designed to thwart you. Peeling back the layers, which is what historians can do many years after the fact, often reveals a more subtle and complex organizational discussion going on. In the case of these transcripts, it is clear, I think, that Beckerley was trying his best to satisfy both the security requirements of the day regarding the key features of the newly-invented hydrogen bomb, as well as avoid saying too much about US nuclear force postures in Europe. And, just as key, he was juggling the problem of witnesses who had been told their original testimony would be confidential. There is no evil intent in these actions, that I can see.

Did these redacted sentences need to be kept classified for 60 years? Of course not. And by releasing them in full, the Department of Energy explicitly agrees that these transcripts contain nothing classified as of today. But they weren’t being hoarded for decades because of their lasting security relevance — they were just forgotten about. These volumes probably could have been fully declassified at least as early as 1992, and probably would have, had the declassification effort not gotten shelved.

Still, it is important that they are finally released. Even a negative result is a result, and even an empty archive can tell us something positive. Knowing that the un-redacted transcripts contain nothing that would either exculpate, nor incriminate, J. Robert Oppenheimer is itself something to know. Secrecy does not just hide information: it creates a vacuum into which doubt, paranoia, fear, and fantasy are harbored. Removing the secrecy here has, at least, removed one last veil and source of uncertainty from the Oppenheimer affair.

Notes
  1. On Vista, see esp. Patrick McCray, "Project Vista, Caltech, and the dilemmas of Lee DuBridge," Historical Studies in the Physical and Biological Sciences 34, no. 2: 339-370. The Vista cover page image comes from a heavily redacted copy of the report that was given to me by Sam Schweber. []