Complete Venus Equilateral (1976) SSC

by George O. Smith

  “I’ll put in my first oar by seeing the gadget. Wait till I find my pants, and I’ll go right along.”

  -

  Don inspected the installation and whistled. “Not half bad, sonny, not half bad.”

  “Except that we haven’t been able to make it work.”

  “Well, for one thing, you’ve been running on the wrong track. You need more power.”

  “Sure.” Walt grinned. “More power, he says. I don’t see how we can cram any more soup into this can. She’ll melt.”

  “Walt, what happens in a big gun?”

  “Powder burns; expanding products of combustion push—”

  “Functionally, what are you trying to accomplish? Take it on the basis of a solid shot, like they used to use back in the sailing-ship days.”

  “Well,” said Walt thoughtfully, “I’d say they were trying to heave something large enough to do damage.”

  “Precisely. Qualifying that statement a little, you might say that the projectile transmits the energy of the powder charge to its objective.”

  “Right,” agreed Walt.

  “And it is possible to transmit that energy mechanically. I think if we reason this idea out in analogy, we might be able to do it electrically. First, there is the method. There is nothing wrong with your idea, functionally. Electron guns are as old as radio. They—”

  The door opened and Arden entered. “Hi, fellows,” she said. “What’s cooking?”

  “Hi, Arden. Like marriage?” Walt asked.

  “How long do people have to be married before people stop asking that damn fool question?” asked Arden.

  “O.K., how about your question?”

  “I meant that. I ran into Warren, who told me that the brains were down here tinkering on something that was either a brilliant idea or an equally brilliant flop—he didn’t know which. What goes?”

  “Walt has turned Buck Rogers and is now about to invent a ray gun.”

  “No!”

  “Yes!”

  “Here’s where we open a psychopathic ward,” said Arden sadly. “So far, Venus Equilateral is the only community that hasn’t had a village idiot. But no longer are we unique. Seriously, Walt?”

  “Sure enough,” said Channing, “He’s got an idea here that may work, with a little tinkering.”

  “Brother Edison, we salute you,” said Arden. “How does it work?”

  “Poorly. Punk. Lousy.”

  “Well, sound recording has come a long way from the tin-foil cylinder that scratched out: ‘Mary had a little lamb!’ And transportation has come along swell from the days of sliding sledges. You may have the nucleus of an idea, Walt. But I meant its operation instead of its efficiency.”

  “We have an electron gun of super size,” Walt explained. “The cathode is a big affair six feet in diameter and capable of emitting a veritable storm of electrons. We accelerate them by means of properly spaced anodes of the proper voltage level, and we focus them into a nice bundle by means of electrostatic lenses—”

  “Whoa, Tillie, you’re talking like the venerable Buck Rogers himself. Say that in words of one cylinder, please,” Arden chuckled.

  “Well, any voltage gradient between electrodes of different voltage acts as a prism, sort of. When you have annular electrodes of the proper size, shape, and voltage difference, they act as a lens.”

  “In other words, the ring-shaped electrodes are electrostatic lenses?”

  “Nope. It is the space between them. With light or electrons, a convex lens will converge the light no matter which direction the light is coming from.”

  “Uh-huh. I see in a sort of vague manner. New, fellows, go on from there. What’s necessary to make this dingbat tick?”

  “I want to think out loud,” said Channing.

  “That’s nothing unusual,” said Arden. “Can’t we go into Joe’s? You can’t think without a tablecloth, either.”

  “What I’m thinking is this, Walt. You’ve been trying to squirt electrons like a fireman runs a hose. Walt, how long do you suppose a sixteen-inch rifle would last if the explosives were constantly replaced and the fire burned constantly?”

  “Not long,” admitted Walt.

  “A gun is an overloaded machine,” said Don. “Even a little one. The life of a gun barrel is measured in seconds; totaling up the time of transit of all the rounds from new gun to worn barrel gives a figure expressed in seconds. Your electron gun, Walt, whether it be fish, flesh, or fowl, must be overloaded for an instant.”

  “Is overload a necessary requirement?” asked Arden. “It seems to me that you might be able to bore a sixteen-inch gun for a twenty-two. What now, little man?”

  “By the time we get something big enough to do more than knock paint off, we’ll have something bigger than a twenty-two,” grinned Channing. “I was speaking in terms of available strength versus required punch. In the way that a girder will hold tremendous overloads for brief instants, a gun is overloaded for milliseconds. We’ll have a problem—”

  “O.K., aside from that, have you figured out why I haven’t been able to do more than warm anything larger than a house brick?”

  “Sure.” Channing laughed. “What happens in a multi-grid radio tube when the suppressor grid is hanging free?”

  “Charges negative and blocks the electron stream—Hey! That’s it!”

  “What?” Arden asked.

  “Sure,” said Walt. “We fire off a batch of electrons, and the first contingent that arrives charges the affair so that the rest of the beam sort of wriggles out of line.”

  “Your meteor is going to take on a charge of phenomenal negative value, and the rest of your beam is going to be deflected away, just as your electron lenses deflect the original beam,” said Channing. “And now another thing, old turnip. You’re squirting out a lot of electrons. That’s much amperage. Your voltage—velocity—is nothing to rave about even though it sounds high. Watts is what you want, to corn a phrase.”

  “Phew,” said Walt. “Corn, he says. Go on, prodigy, and make with the explanations. I agree, we should have more voltage and less quantity. But we’re running the stuff at plenty of voltage now. Nothing short of a Van de Graaff generator would work—and while we’ve got one up on the forty-ninth level, we couldn’t run a supply line down here without reaming a fifty-foot hole through the station, and then I don’t know how we’d get that kind of voltage down here without—That kind of stuff staggers the imagination. You can’t juggle a hundred million volts on a wire. She’d squirt off in all directions.”

  “Another thing, whilst I hold it in my mind,” said Channing thoughtfully. “You go flinging electrons off the station in basketful after basketful, and the next bird that drops a ship on the landing stage is going to spot-weld himself right to the south end of Venus Equilateral. It wouldn’t be long before the station would find itself being pulled into Sol because of the electrostatic stress—if we didn’t run out of electrons first!”

  “I hardly think that we’d run out—but we might have a tough time flinging them away after a bit. Could it be that we should blow out a fistful of protons at the same time?”

  “Might make up a concentric beam and wave positive ions at the target,” said Channing. “Might help.”

  “But this space-charge effect. How do we get around that?”

  “Same way we make the electron gun work. Fire it off at a devilish voltage. Run your electron velocity up near the speed of light; the electrons at that speed will acquire considerable mass, in accordance with Lorenz’s equation which shows that as the velocity of a mass reaches the speed of light, its mass becomes infinite. With a healthy mass built up by near-light velocities, the electrons will not be as easy to deflect. Then, too, we can do the damage we want before the charge can be built up that will deflect the stream. We ram ‘em with a bundle of electrons moving so fast that the charging effect cannot work; before the space charge can build up to the level required for self-nullification of our beam, the damage is done.�
��

  “And all we need is a couple of trillion volts. Two times ten to the twelfth power. Grrr.”

  “I can see that you’ll need a tablecloth,” said Arden. “You birds can think better over at Joe’s. Come along and feed the missus, Don.”

  Channing surveyed the instrument again, and then said: “Might as well, Walt the inner man must be fed, and we can wrangle at the same time. Argument assists the digestion—and vice versa.”

  “Now,” said Channing as the dishes were pushed aside, clearing a space on the table. “What are we going to do?”

  “That’s what I’ve been worrying about,” said Walt. “Let’s list the things that make our gun ineffective.”

  “That’s easy. It can’t dish out enough. It’s too dependent upon mobility. It’s fundamentally inefficient because it runs out of ammunition too quick, by which I mean that it is a sort of gun with antiseptic bullets. It cures its own damage.”

  “Prevents,” Arden corrected.

  “All right, it acts as its own shield, electrostatically.”

  “About this mobility,” said Walt. “I do not quite agree with that.”

  “You can’t whirl a hunk of tube the size and weight of a good-sized telescope around fast enough to shoot holes in a racing spaceship,” said Channing. “Especially one that is trying to dodge. We’ve got to rely upon something that can do the trick better. Your tube did all right following a meteor that runs in a course that can be predicted, because you can set up your meteor spotter to correct for the mechanical lag. But in a spaceship that is trying to duck your shot, you’ll need something that works with the speed of light. And, since we’re going to be forced into something heavy and hardhitting, its inertia will be even more so.”

  “Heavy and hardhitting means exactly what?”

  “Cyclotron, betatron, or synchrotron. One of those dinguses that whirls nucleons around like a stone on a string until the string breaks and sends the stone out at terrific speed. We need a velocity that sounds like a congressional figure.”

  “We’ve got a cyclotron.”

  “Yeah,” drawled Channing. “A wheezy old heap that cries out in anguish every time the magnets are charged. I doubt that we could move the thing without it falling apart. The betatron is the ticket.”

  “But the cyclotron gives out with a lot more soup.”

  “If I had to increase the output of either one, I could do it a lot quicker with the betatron,” said Channing. “In a cyclotron, the revolution of the ions in their acceleration period is controlled by an oscillator, the voltage output of which is impressed on the D chambers. In order to speed up the ion stream, you’d have to do two things. One: build a new oscillator that will dish out more power. Two: increase the strength of the magnets. “But in the betatron, the thing is run differently. The magnet is built for A.C. and the electron gun runs off the same. As your current starts up from zero, the electron gun squirts a bouquet of electrons into a chamber built like a pair of angel-food-cake tins set rim to rim. The magnet’s field begins to build up at the same time, and the resulting increase in field strength accelerates the electrons, and at the same time its increasing field keeps the little devils running in the same orbit. Shoot it with two-hundred-cycle current, and in the half-cycle your electrons are made to run around the center a few million times. That builds up a terrific velocity—measured in six figures, believe it or not. Then the current begins to level off at the top of the sine wave, and the magnet loses its increasing phase. The electrons, still in acceleration, begin to whirl outward. The current levels off for sure and begins to slide down—and the electrons roll off at a tangent to their course. This stream can be collected and used. In fact, we have a two-hundred-cycle beam of electrons at a couple of billion volts. That, brother, ain’t hay!”

  “Is that enough?”

  “Nope.”

  “Then, how do you hope to increase this velocity?”

  Walt asked. “If it is easier to run this up than it would be the cyclotron, how do we go about it?”

  Channing smiled and began to draw diagrams on the tablecloth. Joe looked over with a worried frown, and then shrugged his shoulders. Diagrams or not, this was an emergency—and besides, he thought, he needed another lesson in high-powered gadgetry.

  “The nice thing about this betatron,” said Channing, “is the fact that it can and does run both ends on the same supply. The current and voltage phases are correct so that we do not require two supplies which operate in a carefully balanced condition. The cyclotron is one of the other kinds; though the one supply is strictly D.C., the strength of the field must be controlled separately from the supply to the oscillator that runs the D plates. You’re sitting on a fence, juggling knobs and stuff all the time you are bombarding with a eye.

  “Now let us inspect the supply of the betatron. It is sinusoidal. There is the catch. There is the thing that makes it possible. That single fact makes it easy to step the power up to terrific quantities. Since the thing is fixed by nature so that the output is proportional—electron gun initial velocity versus magnetic field strength—if we increase the input voltage, the output voltage goes up without having to resort to manipulistic gymnastics on the part of the operator.”

  “Go on, Professor Maxwell.”

  “Don’t make fun of a great man’s name,” said Arden. “If it wasn’t for Clerk Maxwell, we’d still be yelling out of the window at one another instead of squirting radio beams all over the Solar System.”

  “Then make him quit calling me Tom Swift.”

  “Go on, Don. Walt and I will finish this argument after we finish Hellion Murdoch.”

  “May I?” asked Channing with a smile. He did not mind the interruption; he was used to it in the first place and he had been busy with his pencil in the second place. “Now look, Walt, what happens when you smack a charged condenser across an inductance?”

  “You generate a damped cycle of the amplitude of the charge on the condenser, and of frequency equal to the L, C constants of the condenser and inductance. The amplitude decays according to the factor Q, following the equation for decrement—”

  “Never mind, I’ve got it here on my whiteboard,” smiled Channing, pointing to the tablecloth. “You are right. And the purity of the wave?”

  “Sinusoidal—Hey! That’s it!” Walt jumped to his feet and went to the telephone.

  “What’s ‘it’?” asked Arden.

  “The betatron we have runs off a five-hundred-volt supply,” Channing chuckled. “We can crank that up ten to one without running into any difficulty at all. Five-hundred-volt insulation is peanuts, and the stuff they put on wires nowadays is always good for ten times that just because it wouldn’t be economical to try to thin the installation down so that it only protects five hundred. I’ll bet that he could crank the input up to fifty thousand volts without too much sputtering—though I wouldn’t know where to lay my lunch hooks on a fifty-thousand-volt condenser of any appreciable capacity. Well, stepping up the rig ten to one will dish us out just shy of a couple of thousand million volts, which, as Brother Franks says, is not hay!”

  Walt returned after a minute and said: “Warren’s measuring the inductance of the betatron magnet. He will then calculate the value of C required to tune the thing to the right frequency and start to achieve that capacity by mazing up whatever high-voltage condensers we have on the station. Now, Don, let’s calculate how we’re going to make the thing mobile.”

  “That’s a horse of a different color. We’ll have to use electromagnetic deflection. From the constants of the electron stream out of our souped-up Suzy, we’ll have to compute the necessary field to deflect such a beam. That’ll be terrific, because the electrons are hitting it up at a velocity approaching that of light—maybe a hundred and seventy thousand miles per—and their mass will be something fierce. That again will help to murder Murdoch; increasing mass will help to keep the electrons from being deflected, since it takes more to turn a heavy mass—et cetera; see New
ton’s law of inertia for complete statement. Have ‘em jerk the D plates out of the eye and bring the magnet frame down here—to the turret, I mean—and set ‘em up on the vertical. We’ll use that to run the beam up and down; we can’t possibly get one-hundred-and-eighty-degree deflection, of course, but we can run the deflection over considerable range. It should be enough to catch a spaceship that is circling the station. For the horizontal deflection, what have we got?”

  “Nothing. But the eye magnet is a double pole affair. We could break the frame at the D plates and set one winding sidewise to the other and use half on each direction.”

  “Sure. Have one of Warren’s gang fit the busted pole pieces up with a return-magnetic frame so that the field will be complete. He can weld some girders on and around in an hour. That gives us complete deflection properties up and down; left and right. We should be able to cover a ninety-degree cone from your turret.”

  “That’ll cover all of Murdoch’s ships,” said Walt.

  “Too bad we haven’t got some U-235 to use. I’d like to plate up one of his ships with some positive ions of U-235 and then change the beam to slow neutrons. That might deter him from his life of crime.”

  “Variations, he wants,” said Arden. “You’re going to impale one ship on a beam of electrons; one ship on a beam of U-235 ions; and what will you have on the third?”

  “I‘ll think of something,” said Channing. “A couple of hundred pounds of U-235 should make things hum, though.”

  “More like making them disappear,” said Franks. “Swoosh! No ship. Just an incandescent mass falling into the Sun. I’m glad we haven’t any purified U-235 or Plutonium in any quantity out here. We catch a few slow neutrons now and then, and I wouldn’t be able to sleep nights. The things just sort of wander right through the station as though it weren’t here at all; they stop just long enough to register on the counter upstairs and then they’re gone.”