Cyclorama

There were twenty-two cyclotrons completed or under construction in the United States in 1940. They came in four sizes, as indicated in table 6.5, which also contains information about their coming-to-be. As the table shows, the quantity of steel and copper in the magnet increases much more rapidly than the diameter of its poles, somewhere between the cube and the square. Since the

[95] Fleming to Cork, 22 Nov 1939 (MAT, 23/"cycl. letters").

[96] Tuve to Lawrence, 17 June 1939, quotes, and Lawrence to Fleming, 1 June 1939 (3/32); Tuve to Arthur Hemmingdinger, 20 Nov 1939, and Cooksey to Tuve, 10 June 1939 (MAT, 24/"cycl. reports").

[97] Fleming to C.C. Clark, ARMCO, 5 and 30 Sep 1939, Tuve to Dunning, 5 Oct 1939, and Fleming to Lawrence, 18 Oct 1939 (MAT, 23/"cycl.letters"); Fleming to Robert B. Nation, International Nickel, 26 Feb 1940 (MAT, 25/"cycl. letters"); A.B. Hendricks, Jr., GE, to R.W. Hickmann, 1 May 1940 (UAV, 691.60/3).

[98] Tuve to DuBridge, 17 Feb 1940 (MAT, 19/"Tuve letters").

magnet's metal was the single largest expense in the construction of a cyclotron, its unit cost became a matter of concern as prices rose owing to inflation in the worldwide buildup of arms. In 1935 mild steel boiler plate, which Cook and Henderson regarded as almost the equivalent of ARMCO iron, cost 1.6 cents a pound. With iron so cheap, Lawrence wrote, a good magnet could be made from scratch more cheaply than refurbishing an old navy arc, and he urged DuBridge to build bigger—the Rochester cyclotron initially was to have 14-inch poles—since the raw ingredients came for a song.^[99] In 1937 the prices of steel and copper were about twice what they had been in 1935, and in 1938 they increased another 150 percent. The implicit and symbolic competition between cyclotrons and armaments for strategic materials in the late 1930s became explicit and realistic in the early 1940s, when several incomplete machines secured high-priority allocations of iron and copper in the national interest.^[100] Only medicine could cope with the rapidly inflating capital requirements of cyclotroneers.

The second set of information in table 6.5 reveals that, with a few exceptions easily explained away, a baby cyclotron took about a year to build, a small cyclotron perhaps a year and a half, a medium one two years or a little more. The exceptions: Washington, a three-year birth in the baby class, was almost entirely the work of one man; Yale, two years acoming in the small class, also had a very small crew and assembled its own magnet; in the middle class, Columbia was delayed by navy bureaucracy and by its own innovativeness, while Purdue suffered from lack of resources, and both had the disadvantage of doing almost entirely without a man from Berkeley.^[101] But a physicist or two who knew what they were about, did not hanker after novelties, and had the help of a graduate student, a competent shop, and enough money for their project, could bring a 90-ton cyclotron from the drawing boards to first beam in two years or less. The record of Berkeley men in partibus may be read from table 6.5.

[99] Lawrence to Tuve, 12 Sep 1935 (3/32), to Livingston, 13 Aug 1935 (12/12), and to DuBridge, 12 Sep and 16 Oct 1935, and reply, 20 Sep 1935 (15/26).

[100] Lawrence to Hughes, 26 May 1938 (18/12); Livingston to Cooksey, 28 Jul 1938 (12/12); U.S. Steel to Lawrence, 2 Sep 1938 (14/38); J.A. Gray to Lawrence, 21 Nov 1938 (14/38).

[101] John D. Howe to Cooksey, 6 Jul 1937 (25/1), re Purdue.

How many cyclotrons did the United States require? Of what sizes and capacities? In May 1938 Lawrence had an easy recipe: "There should be a cyclotron laboratory in every university center which will provide ammunition for unending work in nuclear physics and biology as well as in clinical medicine." Cooksey explained the situation to Karl Darrow, an industrial physicist and physics popularizer, who calculated that "the country may need a thousand cyclotrons." In October 1940 Urey judged that the country had as many as it needed, or could afford. "There are cyclotrons and Van de Graaff machines in most of the universities of the United States. . . . Some institutes have one or two of each."^[102] The natural limit to their reproduction might well have been sighted. Their costs were increasing as the square or cube of their size and their number perhaps linearly in time, while the national funding base showed no prospect of rapid enlargement. Indeed, there were signs of retrenchment: the National Advisory Cancer Council declined to distribute $100,000 for the capital improvement of cyclotrons, as Lawrence counselled in 1938 and 1939; the Research Corporation, with a reduced income, cut off support to leading cyclotron laboratories like Rochester in 1939 and 1940; the Rockefeller Foundation turned down Harvard and looked askance at all applications in support of new cyclotrons that did not go beyond the reach of Berkeley's 60-inch. The sovereign remedy for weak finances—"getting the phosphorus up in millicuries will bring you the [needed] backing, and support"—had, by repetition, made foundations resistant.^[103]

In this Malthusian situation, the American Institute of Physics and the cyclotroneers at Harvard and MIT called a conference on applied nuclear physics that met in Cambridge from October 28 to November 2, 1940. For it Livingston drew up the chart reproduced as table 6.6. Apart from the baby cyclotrons, installation costs, including labor, did increase with at least the square of the pole size, whereas the operating expense of small and medium

[102] Lawrence to A.L. Hughes, 26 May 1938 (18/12); Cooksey to Lawrence, re Darrow, 29 Apr 1938 (4/21); Urey to Hevesy, 25 Oct 1940 (Urey P, 2).

[103] For NACC and RF, supra, §5.1; for RC's cutback, DuBridge to Lawrence, 25 May 1939 (15/26A); Cooksey to Snell, 10 May 1939 (16/33).

cyclotrons came to about the same.^[104] The last represented a true gain in efficiency: the typical medium machine needed less tending than the smaller ones and consumed no more power. For a long time the price of power was the most worrisome part of

[104] Installation costs include replacement value of apparatus, cost of space, technical services, and directors' salaries; operating expenses include direct costs, salaries of crew, 4 percent interest on the installation price, 20 percent obsolescence for the apparatus, 10 percent depreciation of the building. Direct costs for the larger machines fell out considerably under Livingston's estimate for installation, e.g., $35,000 for the 42-inch cyclotron at Saint Louis (18/12).

Lawrence's budget: the 27-inch ate up around $1,500 a year in 1933/34 and 1934/35 and almost twice that in 1935/36; after its enlargement to 37 inches, it required as much as 50 kW for the magnet, and (for 100 µA of deuterons) around 40 kW for the oscillator, which, at the Laboratory's cost of 2 cents/kWh and at Livingston's figure of 2,400 operating hours a year, amounted to almost $4,500 per annum.^[105] The Harvard and MIT cyclotrons—made identical in size to "short circuit [covetousness]"—required only $1,500 a year for power, about a third that of the 37-inch. Their more compact magnets of ARMCO iron, transmission lines, and lower unit costs (around 1.5 cents/kWh) compassed the reduction.^[106]

The most significant figures in Livingston's table concern output. From the beam currents (numbers to the right of the slash are Livingston's estimates of the expected eventual performance of the Harvard and MIT machines), the assumed operation of seven hours a day, and the operating costs, the unit price of the common tracer P³² is readily deduced. The advantage of the medium machines leaps to the eye: when in stride, the Cambridge 42-inchers would produce P³² at about $1/mCi, very much cheaper than the Rochester cyclotron could do and not much more than the cost at the Crocker. (These figures must be taken as approximations; from operational data on the Berkeley machines, the Carnegie Institution deduced that a mCi would cost $6.50 at the 37-inch cyclotron and $2.25 at the 60-inch.)^[107] A similar story emerges from Livingston's figures on neutron production. From the neutron intensity in equivalents of Rn-Be follows the neutron effect in "n units" per minute at one meter from the cyclotron's

[105] Crew size: Lawrence to Hughes, 26 May 1938 (18/12), minimum of three; proposed budget of Harvard cyclotron laboratory, 24 May 1939 (UAV, 691.60/3), crew of five. Power costs: unsigned memo, 3 Dec 1934, and Leuschner to Lawrence, 16 Jan 1935 (25/1); Time, 30:2 (1 Nov 1937), 40 ($1.50/hr); Lawrence to J.A. Gray, 14 Feb 1938 (14/38), and to Oliphant, 2 Aug 1938 (14/6); "Operating costs," 14 Dec 1940 (22/3).

[106] Evans to Cooksey and Lawrence, 28 May 1938 (12/40), quote; Livingston, Buck, and Evans, PR, 55 (1939), 1110; budget of 24 May 1939, attached to Hickman to Evans, 23 Jan 1940, and R.B. Johnson to Hickman, 19 Nov 1940 (UAV, 691.60/3).

[107] Fleming to Bush, 9 Sep 1940 (MAT, 25/"biophys."). The figures for the 37-inch appear quite reasonable.

beryllium target; and from the n units and the hypothesis that energy delivered by neutrons to living tissue is four times as destructive as the same quantity of energy delivered by x or gamma rays, Livingston arrived at the penultimate line of his chart. The bottom line, the cost of therapy per 100 roentgens/minute, shows that price did not limit the effective treatment of cancer by neutrons.^[108]

To bring out clearly the relative excellence of the cyclotron as a factory for radioisotopes and therapeutic neutrons, Livingston rated the electrostatic generators of 1940 as shown in table 6.7. A comparison of the three classes of generators with the largest classes of cyclotrons (table 6.6) shows that although the cyclotrons cost more than the corresponding Van de Graaffs in both capital investment and operating expenses, they enjoyed so great an advantage in beam and energy that they manufactured radioisotopes and neutron doses at much lower unit prices. The standard moderate cyclotron made—or could make, after improvement—a millicurie of radiophosphorus in six minutes for less than a dollar; the top-of-the-line generator, Tuve's 19-foot pressurized Van de Graaff, also after perfection, would need about twenty hours—and $166—to do the same. It was not that Van de Graaff and his associates had been idle or ill-financed. Between 1936 and 1940 both the cyclotron and the generator increased their effective beam energies by a factor of four and beam currents by a factor of ten or more: from 4 to 16 MeV and 20 to 200 µA at Berkeley, from 0.9 to 3.5 MeV at the Carnegie Institution, and from the Carnegie's 10 µA to MIT's 100 µA and more.^[109] But an electrostatic generator that could hold 3.5 MV was a technological freak—Westinghouse was trying for 5 MV but could scarcely reach 3—and MIT's Van de Graaff represented the effective energy limit in 1940 if a respectable current were desired.^[110] Clinical doses of radioisotopes lay beyond its capabilities.

[108] For definition of the n unit and the comparative biological effects of x and neutron rays see infra, §8.3.

[109] Supra, table 6.7; Hafstad and Tuve, PR, 48 (15 Aug 1935), 306–8; Elsasser to Joliot, 13 Sep 1936 (JP, F28); Livingston to Lawrence, 5 Feb 1939 (12/12).

[110] Amaldi, Viaggi, 6 (1940), 9, reporting that after two years the Westinghouse engineers had got only 2.9 of their hoped-for 5 MV.

It is not easy to state the goals of the leaders of cyclotron laboratories in 1940. On the one hand, their instruments had opened up vast fields of biological and medical research, held promise of discoveries in nuclear chemistry and physics, and constantly challenged and enticed Homo faber . Theirs was an exciting and progressive line of work. On the other hand, the cyclotron brought slavery to physicians and to the chase for money, regimentation of laboratory work, and no long-range research project.

It was a tool constantly in need of improvement lest it condemn itself and its attendants to routine manufacture in the service of others. After consulting with Lawrence and Conant, Karl Compton summed up the situation: "To maintain an active program and a well rounded staff has required more aggressive salesmanship than the scientific profession relishes. . . . , an abnormal competitive element which is unfortunate."^[111] The cyclotroneers escaped the logic of their situation—an increasingly competitive struggle for large sums in an increasingly inelastic market, a growing disparity between builder-physicists and operator-technicians, a tightening tension between service to others and science for oneself—by going off to war.

[111] Compton to M.C. Winternitz, 24 Nov 1941 (4/12). Lawrence approved Compton's assessment as "excellent in every way;" Lawrence to Compton, 29 Nov 1941 (4/12).