Because liquid hydrogen is dangerously explosive, the cryogenics room is explosion-proof and equipped with a fast ventilating system. The roof off the experimental hall is also designed for rapid ventilation to minimize the hazards of spilled hydrogen.
Standing about on the floor of the hall are a number of large bending magnets, created to deflect the beam toward targets, as it comes from the accelerator itself. Adjacent to the hall is a huge machine shop, enabling technicians to turn out special fittings on the spot.
Everywhere there is color. The huge concrete shielding blocks are green, purple, and gray. Pipes are blue, nitrogen tanks a vivid yellow, heavily insulated cables are red, and black. Overhead ventilation ducts are fire red. The personnel of the C.E.A. are oblivious to the gaudy, nursery school quality of their surroundings. "It's better than just having everything gray," said a technician, "but I don't suppose it really matters much. You get used to the color, whatever it is."
Scattered about the experimental hall are sober reminders of the potential danger in the work being conducted here. Three-pronged "Radiation" signs are all about; flashing lights warn of special dangers. Above the door which leads into the accelerator tunnel is an illuminated, blood-red notice, "Hazard to Life Machine On."
"It's no joke," one scientist commented. "Inside the ring, there is tremendous leakage of energy in the form of high-frequency radiation. A person caught in there when the machine is running would receive a fatal does in a small fraction of a second." Eight feet of concrete and lead are used to shield the experimental hall personnel from the ring's radiation.
Elaborate safeguards have been devised to insure that no one is ever caught inside the heavily shielded circular tunnel when the accelerator is in operation. Before the machine is started up, a crew walks the length of the tunnel, checking to see that all personnel are out of the danger area, and locking the doors to the ring as they go. When they finish, a gong sounds at five second intervals. Later, red lights flash warning, and a still more insistent gong begins to sound. When the flashers and gong cease, anyone caught inside has one minute to hit any of a dozen crash buttons located inside the tunnel. Pushing the button immediately shuts down the machine.
Scientists are not disturbed by the dangers inherent in their work. "Some scientists have to be careful with explosives, or poisons. We have to be careful with radiation. It's not really very different," said one. Technicians at the accelerator need not wear dosage clips, but no job is without its peculiarities. At the C.E.A., nobody wears a wristwatch-the powerful magnets in the ring will quickly ruin a watch.
The staff of Harvard and M.I.T. people have been careful to emphasize the joint nature of the project, even down to the smallest details. In the conference rooms, for instance, Harvard and M.I.T. alumni chairs are carefully alternated. Every sign, every press release includes the name of both institutions. More importantly, the executive committee of the C.E.A., the policy-making body, is composed of five members (three scientists, two administrators) from each of the two universities.
The third party in the undertaking the Atomic Energy Commission, provided the funds. Proponents of federal aid to education point to the C.E.A. as an ideal case of government supported research with no strings attached. Although over 12 million dollars have already been spent on the project, none of the work is classified, and the federal agency has chosen to take an unobtrusive role. Were it not for an occasional "U.S. Government Property" stencilled on equipment, the causal observer might never guess the government was involved at all.
When planning for the accelerator begain in 1954, the 11 million dollar anticipated outlay by the AEC was unusually large. It is worth nothing, however, that last spring, just as Cambridge accelerator started operations, the government approved an expenditure of 114 million to build the two-mile Linear Accelerator near Stanford University in Palo Alto, California.
This accelerator will overcome the most serious objection to a circular machine: the tremendous quantity of energy that is radiated as the electron revolves around the track. For a fixed orbit radius, the radiation losses increase with the fourth power of the particle energy. Eventually, the point is reached where most of the accelerating energy is lost immediately as radiation.
For example, most of the energy radiated in the C.E.A. occurs while the particles are increasing in energy from 5 to 6 bev. At 6 Bev, the electrons are losing 4.5 mev per turn. But should the energy of the particles be increased by only one-sixth, to 7 Bev, this energy loss would nearly double. As a result, power requirements for the accelerator would double-and in some systems quadruple.
The Stanford Accelerator will avoid this problem by building a straight line course two miles long, along down which the electrons will travel. The major problem here will be to construct a level track for such a great distance. If accomplished, it will be an engineering feat without parallel. The Stanford machine will be considerably more powerful than the C.E.A.: it is designed to operate at 25 Bev, and eventually reach as much as 45 Bev. But, it will concentrate on the same problems the C.E.A. is currently attacking