Magnet Problems
THE SSC Design Group occupied temporary quarters in a large industrial park in De Soto, Texas, south of Dallas and north of the SSC campus site. The starkness of the building had been softened with paintings and potted plants, but it still had a temporary feel. Removable partitions divided the large open area of the hangar-like structure into small cubicles, each containing a programmer or designer.
Roger Hilton, temporary-hire physicist/programmer attached to the group, sat in his cubicle looking at magnetic field profiles that traced bright colors on the screen of his X-terminal. It was frustrating to have to use this ancient computer hardware. The small lapstation in his backpack had hundreds of times more computing capacity than the entire SSC computer complex here. But nevertheless, he was achieving his goal.
“How’s it going?” asked a soft female voice behind him.
He turned and smiled at Edwina Troy, his boss, and then turned a thumb downward. “I believe we have a serious problem here, Edwina,” he said. “The field of the LBL dipole design looks rather marginal to me. I think they cut a few too many corners to keep the cost down. Look at this multipole expansion of the field. See the red lines? There are big high-multipole components that simply shouldn’t be there. The injected beams are not going to stack properly in the ring.”
Edwina squinted at the screen and looked worried. “We had trouble like that with Energy Doubler dipoles at Fermilab, and we had to make correction magnets to fix the problem. But with a machine of the complexity of the SSC, I’m not sure we can get away with that kind of fix.”
Roger nodded. “I could try variations on the coil geometry, turn spacing and shim placement,” he said. “Those are supposed to have been optimized already, but perhaps it’s worth another go. But if that doesn’t work, the only remedy will be to go to a larger aperture. I think we need 5 centimeters instead of 4.”
Edwina winced. “I’ve already looked into enlarging the aperture,” she said. “You’re talking about a billion dollar design change, Roger. The magnets will get bigger, more expensive, and harder to cool. The field of each magnet will go down, so more magnets will be needed to bend the beam. But an increased number of magnets won’t fit into the tunnel as designed, so we will have to come up with a new tunnel design that’s miles longer, in order to accommodate the extra magnets. It’s much too expensive.”
“But at least the machine would work then,” said Roger.
She frowned. “There is that. See what can be done with layer and spacing modifications to the coil windings. And I’ll hope and pray that it works.”
“I’ll try,” said Roger.
“Try very, very hard, Roger,” said Edwina. “It will be my job to explain to the admiral that there’s been a slight design problem and that the SSC is going to cost a couple of billion dollars more than we had promised him it would. He’ll probably nail me to the mast as an example and make you guys walk the plank.” She turned and walked away, looking depressed.