How the Neut Came to Be

"It's sort of a mini-hydrogen bomb," says Weapons Analyst Samuel T. Cohen of the so-called neutron bomb. Cohen should know. In the late 1950s, as a Rand Corp. consultant to the Air Force, he was the first to draw the military's attention to the possibility of making a new type of nuclear weapon. It would do the bulk of its damage not by heat or concussive force, but by a flood of high-energy subatomic particles called neutrons. Cohen, who has no academic credentials beyond a bachelor's degree from U.C.L.A., wanted to create a relatively "clean weapon" that produced a minimum of radioactive fallout, blast and heat.

In retrospect, it is easy to see why Cohen and his colleagues were fascinated by such a device. At the time, there was a growing revulsion against contamination by radioactive debris from extremely "dirty" nuclear tests in the atmosphere. Also, a low-yield bomb fitted in neatly with the limited-war concepts that were then being explored by the Eisenhower Administration. Some Pentagon strategists wanted to include in their nuclear arsenal a relatively small weapon that could be used tactically by troops in the field against a potential aggressor without causing incalculable havoc among civilian populations.

All nuclear weapons, of course, kill by heat, concussive force and radiation. But when their yield is reduced, as in the neutron bomb, the balance changes. In the words of Herbert Scoville Jr., a former weapons specialist for the Pentagon and CIA: "The instantaneous nuclear radiation, first gamma rays, then neutrons, become predominant, and the blast thermal effects become less and less important." As a result, if a typical bomb of this sort is exploded 500 ft. above the target, the blast and heat effects extend only about 400 yds. from ground zero, but the high-energy neutrons, hurtling in all directions and penetrating even the thick armor of tanks and other vehicles, can kill at distances of up to a mile. Victims of radiation sickness suffer from vomiting, fever, hemorrhaging and convulsions. Yet proponents of the bomb argue that because the radiation is short-lived and there is little lingering fallout, much of the battle zone remains fit for habitation and even people who live relatively close by should be safe if they have taken cover.

The construction details of the "neut" remain a guarded secret, but the principles are well known to physicists. Neutron bombs are essentially small thermonuclear devices, or H-bombs, the explosive equivalent of about 1,000 tons of TNT. Unlike the earliest A-bombs, which involved the fission--or splitting--of such radioactive materials as uranium and plutonium, H-bombs work by fusing isotopes of the simplest and lightest element, hydrogen, into slightly heavier atoms of helium, although they still require a small fission "trigger" to reach the sunlike temperatures (tens of millions of degrees) required for fusion.

Edward Teller and his colleagues at the Government's Lawrence Radiation Laboratory in Livermore, Calif., had shown as early as the 1950s that a miniature H-bomb was scientifically feasible. However, the actual detonation of a neutron device did not take place until 1963 at the old Atomic Energy Commission's Nevada proving grounds. Though the test was successful, the neutron bomb did not win ready acceptance in Washington. Intent on building up a stockpile of conventional weapons in Western Europe, the Kennedy Administration shelved the N-bomb. The concept was revived in 1969 for an entirely different purpose: the U.S. wanted to develop a defense against incoming Soviet missiles by exploding nuclear bombs at high altitudes. Since such blasts might take place over American territory, low-yield neutron bombs seemed ideal. But once more, neutron bombs were ruled out of the strategic thinking, this time because the U.S. scrubbed plans to build the costly and complex antiballistic missile defense system.

In 1975 Defense Secretary James Schlesinger became convinced that NATO's conventional nuclear weapons were losing their effectiveness as a deterrent, and he persuaded President Ford to authorize funds for production of at least two neutron devices, at a cost of about $1 million apiece (twice the cost of conventional nuclear warheads). They were to be designed as warheads for either the new Lance missiles or 8-in. artillery shells. But the move created such a clamor that President Carter has now held up production and deployment of the weapons.

Carter's concern reflects not only the political fears that neutron bombs have raised but also the doubts of many scientists about their actual effectiveness. Despite the assurances of proponents that there will be minimal damage to civilians from the weapons, researchers can still only guess at some of the long-term consequences of even relatively mild doses of neutron bombardment, a form of radiation extremely lethal to living tissue. What is more, there is no assurance that an adversary will not adjust his tactics to minimize the damage to his own forces--say, by spreading his tanks so far apart that it will take dozens of neutron bombs to knock them out. Because of insufficient tests, there is no certainty how much radiation would penetrate an invading tank or how long it would take radiation sickness to kill enemy troops. Claims IBM Physicist Richard Garwin, a longtime Government defense consultant: "The neutron bomb is less effective than either the weapons we have now or the weapons the Russians have now." That is a minority view, to be sure, but it illustrates the scientific and military complexities of the N-bomb decision.

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