Atomic Energy for Military Purposes (The Smyth Report)
The Official Report on the Development of the Atomic Bomb Under the Auspices of the United States Government
By Henry De Wolf Smyth
CHAPTER III. ADMINISTRATIVE HISTORY UP TO DECEMBER 1941
INTEREST IN MILITARY POSSIBILITIES
3.1. The announcement of the hypothesis of fission and its experimental confirmation took place in January 1939, as has already been recounted in Chapter I. There was immediate interest in the possible military use of the large amounts of energy released in fission. At that time American-born nuclear physicists were so unaccustomed to the idea of using their science for military purposes that they hardly realized what needed to be done. Consequently the early efforts both at restricting publication and at getting government support were stimulated largely by a small group of foreign-born physicists centering on L. Szilard and including E. Wigner, E. Teller, V. F. Weisskopf, and E. Fermi.
RESTRICTION OF PUBLICATION
3.2. In the spring of 1939 the group mentioned above enlisted Niels Bohr's cooperation in an attempt to stop publication of further data by voluntary agreement. Leading American and British physicists agreed, but F. Joliot, France's foremost nuclear physicist, refused, apparently because of the publication of one letter in the Physical Review sent in before all Americans had been brought into the agreement. Consequently publication continued freely for about another year although a few, papers were withheld voluntarily by their authors.
3.3. At the April 1940 meeting of the Division of Physical Sciences of the National Research Council, G. Breit proposed formation of a censorship committee to control publication in all American scientific journals. Although the reason for this suggestion was primarily the desire to control publication of papers on uranium fission, the "Reference Committee" as finally set up a little later that spring (in the National Research Council) was a general one, and was organized to control publication policy in all fields of possible military interest, The chairman of the committee was L. P. Eisenhart; other members were G. Breit, W. M. Clark, H. Fletcher, E. B. Fred, G. B. Pegram, H. C. Urey, L. H. Weed, and E. G. Wever. Various subcommittees were appointed, the first one of which had to do with uranium fission G. Breit served as chairman of this subcommittee; its other members were J. W. Beams, L. J. Briggs, G. B. Pegram, H. C. Urey, and E. Wigner. In general, the procedure followed was to have the editors of various journals send copies of papers in this field, in cases where the advisability of publication was in doubt, either directly to Breit or indirectly to him through Eisenhart. Breit then usually circulated them to all members of the subcommittee for consideration as to whether or not they should be published, and informed the editors as to the outcome. This arrangement was very successful in preventing publication and was still nominally in effect, in modified form, in .June 1945 Actually the absorption of most physicists in this country into war work of one sort of another soon reduced the number of papers referred to the committee practically to the vanishing point, It is of interest to note that this whole arrangement was a purely voluntary one; the scientists of the country are to be congratulated on their complete cooperation. It is to be hoped that it will be possible after the war to publish these papers at least in part so that their authors may receive proper professional credit for their contributions.
INITIAL APPROACHES TO THE GOVERNMENT THE FIRST COMMITTEE
3.4. On the positive side-government interest and support of research in nuclear physics-the history is a much more complicated one. The first contact with the government was made by Pegram of Columbia in March 1939. Pegram telephoned to the Navy Department and arranged for a conference between representatives of the Navy Department and Fermi. The only outcome of this conference was that the Navy expressed interest and asked to be kept informed. The next attempt to interest the government was stimulated by Szilard and Wigner. In July 1939 they conferred with A. Einstein, and a little later Einstein, Wigner, and Szilard discussed the problem with Alexander Sachs of New York. In the fall Sachs, supported by a letter from Einstein, explained to President Roosevelt the desirability of encouraging work in this field. The President appointed a committee, known as the "Advisory Committee on Uranium" and consisting of Briggs (director of the Bureau of Standards) as chairman, Colonel K. F. Adamson of the Army Ordnance Department, and Commander G.C. Hoover of the Navy Bureau of Ordnance, and requested this committee to look into the problem. This was the only committee on uranium that had official status up to the time of organization of the National Defense Research Committee in June 1940. The committee met very informally and included various additional scientific representatives in its meetings.
3.5. The first meeting of the Uranium Committee was on October 21, 1939 and included, besides the committee members, F. L. Mohler, Alexander Sachs, L. Szilard, E. Wigner, E. Teller, and R. B. Roberts. The result of this meeting was a report dated November 1, 1939, and transmitted to President Roosevelt by Briggs, Adamson, and Hoover. This report made eight recommendations, which need not be enumerated in detail. It is interesting, however, that it specifically mentions both atomic power and an atomic bomb as possibilities. It specifically recommended procurement of 4 tons of graphite and 50 tons of uranium oxide for measurements of the absorption cross section of carbon. Others of the recommendations either were of a general nature or were never carried out. Apparently a memorandum prepared by Szilard was more or less the basis of the discussion at this meeting.
3.6. The first transfer of funds ($6,000) from the Army and Navy to purchase materials in accordance with the recommendation of November 1 is reported in a memorandum from Briggs to General E. M. Watson (President Roosevelt's aide) on February 20, 1940. The next meeting of the "Advisory Committee on Uranium" was on April 28, 1940 and was attended by Sachs, Wigner, Pegram, Fermi, Szilard, Briggs, Admiral H. G. Bowen, Colonel Adamson, and Commander Hoover. By the time of this meeting two important new factors had come into the picture. First, it had been discovered that the uranium fission caused by neutrons of thermal velocities occurred in the U-235 isotope only. Second, it had been reported that a large section of the Kaiser Wilhelm Institute in Berlin had been set aside for research on uranium. Although the general tenor of the discussion at this meeting seems to have been that the work should be pushed more vigorously, no definite recommendations were made. It was pointed out that the critical measurements on carbon already under way at Columbia should soon give a result, and the implication was that definite recommendations should wait for such a result.
3 7. Within the next few weeks a number of people concerned, particularly Sachs, urged the importance of greater support and of better organization. Their hand was strengthened by the Columbia results (as reported, for example, in a letter from Sachs to General Watson on May 15, 1940) showing that the carbon absorption was appreciably lower than had been previously thought and that the probability of carbon being satisfactory as a moderator was therefore considerable. Sachs was also active in looking into the question of ore supply. On June 1,1940, Sachs, Briggs, and Urey met with Admiral Bowen to discuss approaching officials of the Union Miniere of the Belgian Congo. Such an approach was made shortly afterwards by Sachs.
3.8. The general status of the problem was discussed by a special advisory group called together by Briggs at the National Bureau of Standards on June 15,1940. This meeting was attended by Briggs, Urey, M. A. Tuve, Wigner, Breit, Fermi, Szilard, and Pegram. After full discussion, the recommendation of the group to the Uranium Committee was that funds should be sought to support research on the uranium-carbon experiment along two lines-
(A) further measurements of the nuclear constants involved in the proposed type of reaction;
(B) experiments with amounts of uranium and carbon equal to about one fifth to one quarter of the amount that could be estimated as the minimum in "which a chain reaction would sustain itself.
"It was estimated that about $40,000 would be necessary for further measurements of the fundamental constants and that approximately $100,000 worth of metallic uranium and pure graphite would be needed for the intermediate experiment." (Quotations from memorandum of Pegram to Briggs, dated August 14, 1940.)
THE COMMITTEE RECONSTITUTED UNDER NDRC
3.9 Before any decisions made at this meeting could be put into effect, the organization of the National Defense Research Committee was announced in June 1940, and President Roosevelt gave instructions that the Uranium Committee should he reconstituted as a subcommittee of the NDRC, reporting to Vannevar Bush (chairman, NDRC). The membership of this reconstituted Uranium Committee was as follows- Briggs, Chairman; Pegram, Urey, Beams, Tuve, R. Gunn and Breit. On authorization from Briggs, Breit consulted Wigner and Teller frequently although they were not members of the committee. From that time until the summer of 1941 this committee continued in control with approximately the same membership. Its recommendations were transmitted by Briggs to the NDRC, and suitable contracts were made between the NDRC and various research institutions. The funds, however, were first supplied by the Army and Navy, not from regular NDRC appropriations.
SUPPORT OF RESEARCH
3.10 The first contract let under this new set-up was to Columbia University for the two lines of work recommended at the June 15 meeting as described above, The project was approved by the NDRC and the first NDRC contract (NDCrc-32) was signed November 8, 1940, being effective from November 1, 1940, to November 1, 1941. The amount of this contract was $40,000.
3.11. Only very small expenditures had been made before the contract went into effect. For example, about $3,200 had been spent on graphite and cadmium, this having been taken from the $6,000 allotted by the Army and Navy in February, 1940.
3.12. We shall not attempt to review in detail the other contracts that were arranged prior to December 1941. Their number and total amount grew gradually. Urey began to work on isotope separation by the centrifuge method under a Navy contract in the fall of 1940. Other contracts were granted to Columbia University, Princeton University, Standard Oil Development Company, Cornell University, Carnegie Institution of Washington, University of Minnesota, Iowa State College, Johns Hopkins University, National Bureau of Standards, University of Virginia, University of Chicago, and University of California in the course of the winter and spring of 1940-1941 until by November 1941 the total number of projects approved was sixteen, totaling about $300,000.
3.13. Scale of expenditure is at least a rough index of activity, It is therefore interesting to compare this figure with those in other branches of war research. By November 1941 the total budget approved by NDRC for the Radiation Laboratory at the Massachusetts Institute of Technology was several million dollars, Even a relatively small project like that of Section S of Division A of the NDRC had spent or been authorized to spend $136,000 on work that proved valuable but was obviously not potentially of comparable importance to the uranium work.
COMMITTEE REORGANIZED IN SUMMER OF 1941
3.14. The Uranium Committee as formed in the summer of 1940 continued substantially unchanged until the summer of 1941. At that time the main committee was somewhat enlarged and subcommittees formed on isotope separation, theoretical aspects, power production and heavy water.* It was thereafter called the Uranium Section or the S-1 Section of NDRC. Though not formally disbanded until the summer of 1942, this revised committee was largely superseded in December 1941 (see Chapter V).
THE NATIONAL ACADEMY REVIEWING COMMITTEE
3.15. In the spring of 1941, Briggs, feeling that an impartial review of the problem was desirable, requested Bush to appoint a reviewing committee. Bush then formally requested F. B. Jewett, president of the National Academy of Sciences, to appoint such a committee. Jewett complied, appointing A. H. Compton, chairman; W. D. Coolidge, E. 0. Lawrence, J. C. Slater, J. H. Van Vleck, and B. Gherardi. (Because of illness, Gherardi was unable to serve.) This committee was instructed to evaluate the military importance of the uranium problem and to recommend the level of expenditure at which the problem should be investigated.
3.16. This committee met in May and submitted a report. (This report and the subsequent ones will be summarized in the next chapter.) On the basis of this report and the oral exposition by Briggs before a meeting of the NDRC, an appropriation of $267,000 was approved by the NDRC at its meeting of July 18, 1941, and the probability that much larger expenditures would be necessary was indicated. Bush asked for a second report with emphasis on engineering aspects, and in order to meet this request 0. E. Buckley of the Bell Telephone Laboratories and L. W. Chubb of the Westinghouse Electrical and Manufacturing Company were added to the committee. (Compton was in South America during the summer and therefore did not participate in the summer meetings of the committee.) The second report was submitted by Coolidge. As a result of new measurements of the fission cross section of U-235 and of increasing conviction that isotope separation was possible, in September 1941, Compton and Lawrence suggested to J. B. Conant of NDRC, who was working closely with Bush, that a third report was desirable. Since Bush and Conant had learned during the summer of 1941 that the British also felt increasingly optimistic, the committee was asked to make another study of the whole subject. For this purpose the committee was enlarged by the addition of W. K. Lewis, R. S. Mulliken, and G. B. Kistiakowsky. This third report was submitted by Compton on November 6, 1941.
*Uranium Section: Brigg, chairman; Pegram, vice-chairman: S. K. Allison, Beams, Breit, E. U. Condon. H. D. Smyth, Urey.
Separation Subsection: Urey, chairman; Beams
Power Production Subsection: Pegram, chairman; Allison, Fermi, Smyth, Szilard.
Heavy Water Subsection: Urey, chairman; T. H. Chilton. Theoretical Aspects Subsection: Fermi, chairman: Breit, C. H. Eckart, Smyth, Szilard, J. A. Wheeler.
INFORMATION RECEIVED FROM THE BRITISH
3.17. Beginning in 1940 there was some interchange of information with the British and during the summer of 1941 Bush learned that they had been reviewing the whole subject in the period from April to July. They too had been interested in the possibility of using plutonium; in fact, a suggestion as to the advisability of investigating plutonium was contained in a letter from J. D. Cockcroft to R. H. Fowler dated December 28, 1940. Fowler, who was at that time acting as British scientific liaison officer in Washington, passed Cockcroft's letter on to Lawrence . The British never pursued the plutonium possibility, since they felt their limited manpower should concentrate on U-235. Chadwick, at least, was convinced that a U-235 bomb of great destructive power could be made, and the whole British group felt that the separation ofU-235 by diffusion was probably feasible.
3.18. Accounts of British opinion, including the first draft of the British report reviewing the subject, were made available to Bush and Conant informally during the summer of1941, although the official British report of July 15 was first transmitted to Conant by G. P. Thomson on October 3. Since, however, the British review was not made available to the committee of the National Academy of Sciences, the reports by the Academy committee and the British reports constituted independent evaluations of the prospects of producing atomic bombs.
3.19. Besides the official and semi-official conferences, there were many less formal discussions held, one of these being stimulated by M. L. E. Oliphant of England during his visit to this country in the summer of 1941. As an example of such informal discussion we might mention talks among Conant, Compton, and Lawrence at the University of Chicago semicentennial celebration in September 1941. The general conclusion was that the program should be pushed; and this conclusion in various forms was communicated to Bush by a number of persons.
3.20. In the fall of 1941 Urey and Pegram were sent to England to get first-hand information on what was being done there. This was the first time that any Americans had been to England specifically in connection with the uranium problem. The report prepared by Urey and Pegram confirmed and extended the information that had been received previously.
DECISION TO ENLARGE AND REORGANIZE
3.21. As a result of the reports prepared by the National Academy committee, by the British, and by Urey and Pegram, and of the general urging by a number of physicists, Bush, as Director of the Office of Scientific Research and Development (of which NDRC is a part), decided that the uranium work should be pushed more aggressively.
3.22. Before the National Academy issued its third report and before Pegram and Urey visited England, Bush had taken up the whole uranium question with President Roosevelt and Vice-President Wallace. He summarized for them the British views, which were on the whole optimistic, and pointed out the uncertainties of the predictions. The President agreed that it was desirable to broaden the program, to provide a different organization, to provide funds from a special source, and to effect complete interchange of information with the British. It was agreed to confine discussions of general policy to the following group: The President, Vice-President, Secretary of War, Chief of Staff, Bush, and Conant. This group was often referred to as the Top Policy Group.
3.23. By the time of submission of the National Academy's third report and the return of Urey and Pegram from England, the general plan of the reorganization was beginning to emerge. The Academy's report was more conservative than the British report, as Bush pointed out in his letter of November 27, 1941, to President Roosevelt. It was, however, sufficiently optimistic to give additional support to the plan of enlarging the work. The proposed reorganization was announced at a meeting of the Uranium Section just before the Pearl Harbor attack and will be described in Chapter V.
3.24. In March 1939, only a few weeks after the discovery of uranium fission, the possible military importance of fission was called to the attention of the government. In the autumn of 1939 the first government committee on uranium was created. In the spring of 1940 a mechanism was set up for restricting publication of significant articles in this field. When the NDRC was set up in June 1940, the Uranium Committee was reconstituted under the NDRC. However, up to the autumn of 1941 total expenditures were relatively small. In December 1941, after receipt of the National Academy report and information from the British, the decision was made to enlarge and reorganize the program.