Isegoria

It had begun to seem possible early in 1943, General Groves explains (in Now It Can Be Told: The Story of the Manhattan Project), that the Germans could have progressed to the point where they might be able to use atomic bombs against us, or, more likely, against England:

Although this possibility seemed extremely remote to me, a number of the senior scientists in the project disagreed. One even went so far as to urge that I should warn the American people in an official broadcast that the United States might be hit by an atomic bomb. Naturally, I was opposed to doing any such thing. What I thought more likely was that the Germans would use an ordinary explosive bomb containing radioactive material. If we were unable to neutralize the effects of such a weapon promptly, a major panic could easily sweep through the Allied countries.

However, as the plans for the invasion of Europe began to take form, we considered very seriously indeed the possibility that the Germans might lay down some kind of radioactive barrier along the invasion routes. We could not calculate with any certainty the likelihood of their doing this, for we were truly in the dark then about their progress in atomic development. It had always seemed to most of us that their best prospects lay in the use of plutonium, which would demand a much smaller industrial effort as well as considerably less in the way of time, critical equipment and materials than any other method—provided they were willing to ignore safety precautions. This I felt the Germans would do, for considering what we already knew of their treatment of their Jewish minority, we could only assume they would not hesitate to expose these same citizens to excessive radiation. Hitler and his ardent supporters, we felt, would consider this a proper use for an “inferior” group, quite apart from the saving in effort and materials and time. Moreover, we knew that in the course of developing the plutonium process the Germans were certain to discover that tremendous quantities of highly radioactive fission products would be produced in their reactors. It would be perfectly natural for them to think of using these to lay down a barrier through which ground troops could not pass without disastrous results.

At the request of the Military Policy Committee, a three-man group, Conant, Compton and Urey, assisted by other project members, had made a study of radioactive poisoning; and on the basis of their report we had ordered a supply of portable Geiger counters and were training a number of our personnel to use them.

[…]

The Chief Surgeon, Major General Paul R. Hawley, issued two cover orders designed to insure that GHQ would be promptly alerted if the Germans did resort to radioactive warfare, but worded in such a way as to disguise the real nature of the danger. One order said that trouble had been experienced with fogging (which always results when film is exposed to radiation) on certain photographic and X-ray films and that if any such trouble was noted by troops in the field, an immediate report should be made, citing lot numbers, so that defective film could be withdrawn from use.

General Groves explains (in Now It Can Be Told: The Story of the Manhattan Project), that in making his initial appraisal of the German atomic picture, Captain Horace K. Calvert knew it would take a combination of three requisite factors to make a bomb:

Those were: (1) a sufficient number of top nuclear scientists and technical assistants; (2) the basic fuel for a bomb—uranium, and possibly thorium, probably combined with uranium; and (3) laboratories to develop it and industrial means to make it.

He started working on the fuel problem first, for we were sure of Germany’s scientific and industrial ability to do the job. Thorium seemed out of the question, since it is mined chiefly in Brazil and India and, because of embargoes, Germany had been unable to import any since the war began, and had had only insignificant stocks on hand before the war. The basic fuel was thought to be uranium. Considering our own firsthand knowledge of the enormous industrial effort required to produce U-235, we were confident that we would have seen evidences of any such program had one existed. It seemed more likely that they would use plutonium. That they had enough to launch an atomic program seemed to be within the realm of possibility, for we knew there had been a large stockpile of refined uranium ore at Oolen, Belgium, a few miles outside Brussels, which originally had been the property of Union Miniere.

The only other possible supply of uranium was the mines at Joachimsthal, Czechoslovakia, which was not a particularly significant source. Most of this ore was shipped to a uranium plant outside Berlin, the Auer-Gesellschaft. British Intelligence kept in touch with the activities of these mines, and in July, 1944, Calvert’s group started periodic aerial surveillance over the entire mining area, studying the pictures in detail for new shafts and aboveground activity. Tailing piles from each mine were microscopically measured from one reconnaissance to the next. By knowing the general grade of the ore and measuring the piles, we could determine with some degree of accuracy the mine’s daily production. There were no signs of extraordinary activity.

It would have been imperative for Hitler to enlist the aid of all his top scientists. Allied Intelligence had established that many of them were working on the “V” weapon; particularly at Peenemiinde, but to our knowledge no nuclear physicists had been reported there. Calvert started a search for some fifty German nuclear scientists. He knew that there must be many young scientists who had come up since Hitler’s rise to power of whom we had no knowledge; however, if we could locate a few of the top people, they should lead us to the rest. All the present and back issues of the German physics journals were scrutinized. Foreign-born nuclear scientists in the United States, like Enrico Fermi, O. R. Frisch and Niels Bohr, as well as anti-Nazi professors and scientists in Switzerland, Sweden and other neutral countries, were questioned in detail to obtain any past or present information they might have on the whereabouts of the German scientists. The names of all German scientists were placed on watch lists with American and British intelligence agencies which were daily scanning German newspapers that had been smuggled out. Before long we had recent addresses for a majority of the scientists in whom we were interested.

The third main category of pre-D-Day investigation, laboratories and industrial plants, was studied in much the same way. Lists were compiled of all of the precious metal refineries, the physics laboratories, the handlers of uranium and thorium, manufacturers of centrifugal and reciprocating pumps, power plants and other such installations as were known to exist in the Axis countries. These were placed on a master list from which they were not removed until we had positive information that they were not engaged in, or supplying, an atomic program. All plants where work of an unknown nature was being conducted were checked through aerial reconnaissance, the underground, OSS and all the numerous intelligence agencies.

We did not make any appreciable effort during the war, General Groves explains (in Now It Can Be Told: The Story of the Manhattan Project), to secure information on atomic developments in Japan:

First, and most important, there was not even the remotest possibility that Japan had enough uranium or uranium ore to produce the necessary materials for a nuclear weapon. Also the industrial effort that would be required far exceeded what Japan was capable of. Then, too, discussions with our atomic physicists at Berkeley, who knew the leading Japanese atomic physicists personally, led us to the conclusion that their qualified people were altogether too few in number for them to produce an effective weapon in the foreseeable future. Finally, it would have been extremely difficult for us to secure and to get out of Japan any information of the type we needed.

[…]

Positive support for our reasoning that the Germans were vitally interested in atomic energy had come from Norway, where before the war, in the town of Rjukan, about seventy-five miles west of Oslo, the Norwegians had constructed a complex of hydroelectric and electrochemical plants. When the Nazis occupied the country in 1940, they had required the operators of the Rjukan works to enter into contracts to produce heavy water which was to be shipped to Berlin for experimental use in the development of atomic energy. In September of 1942 we had estimated that approximately 120 kilograms of heavy water were being delivered to the Nazis each month under the terms of this contract.

[…]

The first attempt to put these works out of commission involved the use of guerrilla forces. Some five months after my request, three Norwegians, especially trained in sabotage techniques, and wearing British uniforms, parachuted into Norway, where they were met by local guerrillas. After nearly a week of hard cross-country skiing, they arrived at Rjukan and attacked the factories there on February 27, 1943.

The first reports on this action were most encouraging. A news dispatch from Oslo, which was relayed to Stockholm, stated that damage was “not extensive except at the place where the attempt was made and there the devastation was total.” Subsequent reports from Sweden were even more encouraging, calling this “one of the most important and successful undertakings the Allied saboteurs have carried out as yet during the war.”

These same Swedish newspapers caused me some headaches when they went on to speculate at considerable length about the importance of heavy water, pointing out that “many scientists have pinned their hopes of producing the ‘secret weapon’ upon heavy water, namely an explosive of hitherto unheard-of-violence.” These items were picked up by the London papers and finally, on April 4, 1943, New York readers were greeted by such headlines as “Nazi ‘Heavy Water’ Looms as Weapon.” Immediately, Dr. Harold Urey, who had discovered heavy water, was deluged with calls from reporters wanting more information. He neatly sidestepped all such inquiries with the statement that “So far as I know, heavy water’s uses are confined solely to experimental biology. I have never heard of an industrial application for heavy water, and know of no way it can be used for explosives.”

Meanwhile, the British were hard at work assessing the damage done to the Rjukan works in the February raid. Their first estimates indicated that heavy-water production had been set back by about two years. We had different information, but our suspicions were not confirmed until we learned definitely that the plant had resumed partial operations in April. Yet doubt can be contagious and, under our gentle prodding, Sir John Dill soon felt himself compelled to inform General Marshall that a more realistic appraisal of the damage indicated that the plant could be completely restored in about twelve months. After some discussion of launching another commando raid—a full-scale one this time—General Marshall, at my behest, proposed to Sir John Dill that, instead, the plants be made a first priority bombing objective. This proposal led ultimately to a massive air attack on Rjukan in November of 1943. Although this mission in itself was not particularly destructive, it apparently led the Germans to believe that more attacks would follow. This belief, together with the problem of constant sabotage by workers in the plants, and probably a lack of appreciation at high government levels of the possible value of the product, caused the Nazis to give up their attempts to repair the damage done by the saboteurs in February. All apparatus, catalyzers and concentrates used in the production of heavy water were ordered shipped to Berlin. Norwegian guerrillas interfered with every step of the transfer, successfully destroying much valuable equipment and even going so far as to sink the ferry which carried a large part of the heavy water.

General Groves was advised, he explains (in Now It Can Be Told: The Story of the Manhattan Project), that he could improve his working relationship with the Los Alamos scientists if he appointed a committee to review their work:

[Dr. James B. Conant] pointed out that these people were accustomed to making their views known to similar committees appointed by their university administrations, and that our adoption of this system would meet with their approbation. A further advantage which we both recognized was that a review committee, with its fresh outlook, might be able to make a suggestion that would be eagerly seized upon, whereas if the same suggestion came from me, it might be regarded as interference.

Personally, I never found the idea of a committee particularly obnoxious so long as I recalled the opinion of a very wise and successful Chief of Engineers, General Jadwin. When some of his subordinates intimated to him that there was no need to appoint a board of consultants on the Mississippi River, since its members would have neither the knowledge nor the background in this field possessed by many officers of the Corps of Engineers, Jadwin replied: “I have no objection to committees as long as I appoint them.”

[…]

Out of the Review Committee’s work came one important technical contribution when Rose pointed out, in connection with the Thin Man, that the durability of the gun was quite immaterial to success, since it would be destroyed in the explosion anyway. Self-evident as this seemed once it was mentioned, it had not previously occurred to us. Now we could make drastic reductions in our estimates of the Thin Man’s size and weight. Because the gun-type bomb thus became militarily practical at an early date, work on it could go ahead on an orderly and not too hurried basis.

William S. Parsons was the first Navy officer to be assigned to Los Alamos, General Groves explains (in Now It Can Be Told: The Story of the Manhattan Project), and he appeared at the gate wearing his Navy summer uniform:

His arrival was announced by a frantic guard, who telephoned his sergeant: “Sergeant, we’ve really caught a spy! A guy is down here trying to get in, and his uniform is as phony as a three dollar bill. He’s wearing the eagles of a colonel, and claims that he’s a captain.”

As the work got under way, General Groves explains (in Now It Can Be Told: The Story of the Manhattan Project), some amazing rumors began to circulate through Santa Fe, some thirty miles away:

Typical of these was that old stand-by that we were building a home for pregnant WAC’s.

[…]

After a number of Navy officers had been assigned to the project, and were seen on the streets of Santa Fe, rumors burgeoned about the new type of submarine that was being perfected on the Hill, as Los Alamos came to be known locally. Although the nearest navigable body of water was many hundreds of miles away, this rumor sounded entirely plausible to a number of people.

[…]

Colonel G. R. Tyler, the military commander at Los Alamos, once boarded a train at the railway stop nearest Santa Fe, and in the club car sat next to a man in civilian clothes who had gotten on at the same station. The stranger at once began a one-sided, rapid-fire conversation. It was obvious that he had failed to note the fact that Tyler had boarded the train at the same time that he had for, finally, he lowered his voice and said, “If we can find a secluded spot, I can tell you something which, I think, will interest you.”

Both men walked to the vestibule of the car, and stood while the man related his story. “You’d never believe the strange things that are happening on a certain mountain about fifty miles from Santa Fe. They’re doing some work that is very secret and the place is surrounded by belts of tall wire fencing. In order to keep intruders out, between these belts of fences they keep ferocious packs of wild African dogs. Besides, there are thousands of heavily armed soldier guards, and I can tell you that a number of people have been killed by the guards, or torn to pieces by the animals. It’s a frightful thing! However, I suppose that in wartime these things have to be.” He then told of other strange happenings on the Hill, none of which were true, and concluded with, “Of course, I happen to be one of the very few residents of Santa Fe who know what they are doing up there, but I do hope that you won’t ask me any questions. You see, I’ve given my word of honor that I will not divulge their secrets.”

By this time the train was approaching Tyler’s station, and as the stranger followed him to the platform he said, “Colonel, I forgot to ask you, but where are you stationed, and what sort of an assignment have you?” The officer replied, “I am stationed at Los Alamos, and I command the military personnel there.” The horrified and now extremely red-faced stranger said, “I hope that you’ll forget everything that I’ve told you. I don’t really know what’s going on at the Hill. I merely repeated some of the things that I’ve heard.”

The general principles governing control of information were simple, General Groves explains (in Now It Can Be Told: The Story of the Manhattan Project):

First, nothing should be published that would in any way disclose vital information. Second, nothing should be published that might attract attention to any phase of the project. Third, it was particularly important to keep such matters out of any magazine or newspaper that was likely to be read by an enemy agent or by anyone whose knowledge of scientific progress would enable him to guess what was going on.

[…]

We were only too aware that the piecing together of bits of published information is a prime source of knowledge to every intelligence organization.

It was in order to prevent speculative articles as well as the publicizing of any of our efforts that the press and radio had been asked to avoid the use of certain words, such as “atomic energy.” Certain decoy words, such as “yttrium,” were included in the list to camouflage its real purpose. This was a step we did not want to take, for it automatically pointed out to the press that the government was interested. However, Howard insisted that we simply had to do it if press security was to be maintained. Most reluctantly we agreed. As it turned out, it was a very wise move and an absolutely essential one.

We wished, too, to avoid any widespread mention of such places as Hanford or Oak Ridge and all mention of Los Alamos, as well as any reference to the MED. We also did not want any mention of my name that might arouse the interest of a foreign agent in my activities. Yet to have banned all reference in the near-by papers to Oak Ridge or Hanford would have been neither practical nor desirable, for it would only have tended to attract attention locally. We did try to keep Los Alamos entirely out of the news, but the Knoxville papers were permitted to carry items—mostly in the nature of social notes—about employees and events at Oak Ridge, though nothing, of course, that would help the average reader determine the purpose of the project or its importance. The same leeway was given to the papers close to Hanford.

We did have several unfortunate security breaks, but none of them, so far as we could ever find out, attracted any particular interest. The one with the worst potential for damage was a radio program that discussed the possibilities of an atomic explosion. The script for this had been prepared for the regular news reporter on a network program; he himself had had nothing to do with writing it. Unfortunately, in order to meet his travel schedule, he delivered it from a small affiliated station, where apparently it had not been reviewed to make certain that it did not violate press censorship rules.

From all that we could ever discover, there had been no deliberate breach of security. The information on which the talk was based came from a scientist who was not connected with the project in any way but who evidently had an inkling of what was going on, gleaned, we thought, from some of the project’s scientists at the large laboratory in his city. The actual text was written for the reporter by a friend of the scientist. There was never any question in my mind but that the reporter delivered it in good faith. The failure of the radio station to stop it was attributable to plain carelessness.

Another incident that concerned us greatly was the appearance in a national magazine of an article hinting at the theory of implosion. While it did not violate any rules, it was most disturbing. A thorough investigation indicated that it resulted from the work of an alert and inquisitive reporter in another country.

There was one unfortunate happening not too long before the bombing, when a Congressman, in discussing an appropriations bill, commented on the importance of the Hanford Project. This item was picked out of the Congressional Record and was republished in a newspaper without any comment. I could never disabuse myself of the feeling that this newspaper did it with the deliberate intent of letting me know that our security prohibitions were not so effective as we thought.

Never once, General Groves notes (in Now It Can Be Told: The Story of the Manhattan Project), was any definite country named as the one against which major security effort should be aimed:

At first it seemed logical to direct it toward the Axis Powers, with particular emphasis on Germany. She was our only enemy with the capacity to take advantage of any information she might gain from us.

Japan did not in our opinion have the industrial capacity, the scientific manpower or the essential raw material. Italy was in the same position, with the further disadvantage that any large plants would be exposed to Allied bombing attacks. We did not feel that information secured by Japan would reach Germany accurately or promptly, and we suspected that the Italian-German intelligence channels were not too smooth either.

I had learned within a week or two after my assignment that the only known espionage was that conducted by the Russians against the Berkeley laboratory, using American Communist sympathizers.

[…]

When I was first placed in charge of the MED I found that a number of people in the project had not as yet received proper security clearances, though some of them had been engaged in the work for months.

Any question of the trustworthiness of any one of these people was troublesome, for he would already be in possession of valuable information. To remove him would create only a greater hazard, particularly if he thought our suspicion of him unjustified. (I remembered that Benedict Arnold’s treason had been sparked by his feeling that he had been unfairly treated.) Moreover, if we were to dismiss a person without publicizing the proof, which we would not want to do, the understandable resentment of his friends and associates in the project might seriously interfere with their work.

Almost all our original scientific workers came from academic surroundings. Most of them had been in universities as students or young teachers during the depression years, when there was more than the usual amount of sympathy for Communist and similar doctrines. Almost all of them at one time or another had been exposed to Communist propaganda and had had friends who were secret or even semi-open Communists.

I realized what the temper of the times had been, even though I never had any sympathy for the philosophy or for the educated Americans who adopted it. Discussions with others experienced in this area led me to the belief that among those whose employment would be to the advantage of the United States a reasonable distinction could be made between individuals whose use might be dangerous and individuals whose use would probably not be.

We gave a great deal of weight to how closely the person had followed the party line and for how long. We were particularly interested in how closely he had followed the twists and turns of Soviet relations with Germany. In most doubtful instances this was a deciding factor.

Our problem was made much more difficult by the very limited number of qualified atomic scientists available in this country. We could not afford not to use everyone possible.

The most disastrous break in security was that resulting from the treasonable actions of the English scientist, Klaus Fuchs. Fuchs was born in Germany and had fled to England, where he completed his education. The British authorities had been informed by the Germans prior to the war that he was a Communist. For some reason they ignored this and did not even record the information where they would find it. After the outbreak of the war he was interned as an enemy alien, first in the British Isles and then in a prisoner of war camp in Canada. After some time there he was released and returned to work in England on atomic research. After his return he was made a British citizen.

Our acceptance of Fuchs into the project was a mistake. But I am at a loss when I try to determine just how we could have avoided that mistake without insulting our principal war ally, Great Britain, by insisting on controlling their security measures.

[…]

Since the disclosure of Fuchs’ record, I have never believed that the British made any investigation at all. Certainly, if they had, and had given me the slightest inkling of his background, which they did not, Fuchs would not have been permitted any access to the project. Furthermore, I am sure the responsible British authorities would have withdrawn his name of their own volition, before giving me his history.

If Dr. Chadwick had been in charge of the British mission at that time, as he was later, I am sure that no such deception would have been attempted. Chadwick was always most punctilious in informing me of the slightest question of background, including that of German blood. Unfortunately for the free world, Chadwick did not take over until a few weeks later.

[…]

I have always felt that the basic reason for this was the attitude then prevalent in all British officialdom that for an Englishman treason was impossible, and that when a foreigner was granted citizenship he automatically became fully endowed with the qualities of a native-born Englishman. With the uncloaking in recent years of Fuchs, May, Maclean and Burgess, as well as others, I doubt if this feeling still prevails.

The first uranium separation process General Groves looked into, as he explains in Now It Can Be Told: The Story of the Manhattan Project, involved liquid thermal diffusion:

The basic apparatus is a column. It consists of a long, vertical, externally cooled tube with a hot concentric cylinder inside. What makes this an effective separation method is the fact that one isotope tends to concentrate near the hotter of two surfaces, and then moves upward.

From a practical standpoint, thermal diffusion was not suitable as an independent process because of the incredibly large amount of steam required. The production costs would have been staggering. A minimum rough estimate was two billion dollars, and I would not have considered this a safe figure, but would have raised it to at least three billion if I had thought the work would have to be undertaken.

[…]

However, in June of 1944, Oppenheimer suggested to me that it might be well to consider using the thermal diffusion process as a first step aimed at only a slight enrichment, and employing its product as a feed material for our other plants. As far as I ever knew, he was the first to realize the advantages of such a move, and I at once decided that the idea was well worth investigating.

Just why no one had thought of it at least a year earlier I cannot explain, but not one of us had. Probably it was because at the time the thermal diffusion process was studied by the MED we were thinking of a single process that would produce the final product. No one was considering combining processes.

[…]

To expedite the design and construction, I ordered that, insofar as possible, all process features of our plant, particularly the basic column assemblies, should be Chinese copies of those at the Philadelphia pilot plant. A great deal of time was also saved by frequently using field engineering sketches instead of the customary more formal drawings.

[…]

The basic piece of equipment was the isotope separation column, 102 of which were arranged to form an operating unit which we termed a “rack.” The column was a vertical pipe, forty-eight feet long, of nickel pipe surrounded by a copper pipe. The copper pipe was encased in a water jacket contained in a four-inch galvanized-iron pipe. The copper pipe was cooled with water at a moderate temperature. The columns were arranged in three groups, each of seven racks, making a total of 2,142 columns.

[…]

Sixty-nine days after the start of construction, one-third of the plant was complete, and preliminary operation began.

A Chinese copy, by the way, is an exact imitation or duplicate that includes defects as well as desired qualities. The term goes back to 1844.