The Bramble Bush Read online

corridor. We'll haveto dig 'em out. I called 'em both on the phone. They're all right, butthey're trapped."

  "Did you call Base?"

  "Yes. They haven't got a ship. They sent three moon-cats, though. Theyought to be here by morning."

  De Hooch looked up at the chronometer on the wall. Oh one twelve,Greenwich time. "Morning" meant any time between eight and noon; theposition of the sun up on the surface had nothing to do with Lunar time.As a matter of fact, there was a full Earth shining at the moment, whichmeant that it wouldn't be dawn on the surface for a week yet.

  "If the cats from Base get here by noon, we'll be O.K., won't we?" deHooch asked.

  "Look at the instruments," Willows said.

  De Hooch ran a practiced eye over the console and swallowed. "What werethey running?"

  "Mercury 203," Willows said. "Half-life forty-six point five days. Betaand gamma emitter. Converts to Thallium 203, stable."

  "What did they want with a kilogram of the stuff?"

  "Special order. Shipment to Earth for some reason."

  "Have you checked the end-point? She's building up fast."

  "No. No. I haven't." He wet his lips with the tip of his tongue.

  "Check it," said de Hooch. "Do any of the controls work?"

  "I don't know. I didn't want to fiddle with them."

  "You start giving them a rundown. I'm going to get into a suit and gopull those two out of there--if they're still alive." He opened thelocker and took his radiation-proof suit out. He checked it overcarefully and began shucking his vac suit.

  * * * * *

  A few minutes delay in getting to the men in the reactor's anteroomdidn't matter much. If they hadn't been killed outright, and were stillalive, they would probably live a good deal longer. The shells of theradiation suits didn't look damaged, and the instruments indicated verylittle radiation in the room. Whatever it was that had exploded had donemost of its damage at the other end of the reactor. Evidently, a fissurehad been opened to the surface, forty feet above--a fissure big enoughto let all the air out of A and B corridors, and activate the automaticbulkheads to seal off the airless section.

  What troubled him was Willows. If he hadn't known the man so well, deHooch would have verbally blasted him where he stood.

  His reaction to trouble had been typical. De Hooch had already seenWillows in trouble three times, and each time, the reaction had been thesame: near panic. Every time, his first thought had been to scream forhelp rather than to do anything himself. Almost anyone else would havemade one call and then climbed into a radiation suit to get Ferguson andMetty out of the anteroom. There was certainly no apparent immediatedanger. But all that Willows had done was yell for someone to come anddo his thinking and acting for him. He had called Base; he had called deHooch; he had called Quillan and Laynard. But he hadn't done anythingelse.

  Now he had to be handled with kid gloves. If de Hooch didn't act calm,if he didn't go about things just right, Willows might very likely goover the line into total panic. As long as he had someone to depend on,he'd be all right, and de Hooch didn't want to lose the only help he hadright now.

  "Fermium 256," said Willows in a tight, flat voice.

  "What?" de Hooch asked calmly.

  "Fermium 256," Willows repeated. "That's what the stuff is going tostart building towards. Spontaneous fission. Half-life of three hours."He took a deep breath. "The reactor won't be able to contain it. Wehaven't got that kind of bleed-off control."

  "No," de Hooch agreed. "I suggest we stop it."

  "The freezer control isn't functioning," Willows said. "I guess that'swhat they went in there to correct."

  "I doubt it," de Hooch said carefully. "They wouldn't have needed suitsfor that. They must have had something else bothering them. I'd bewilling to bet they went in to pull a sample and something went wrong."

  "Why? What makes you think so?"

  "If there'd been trouble, they'd have called for someone to stay hereat the console. Both of them wouldn't have gone in if there was anytrouble."

  "Yeah. Yeah, I guess you're right." He looked visibly relieved. "What doyou suppose went wrong?"

  "Look at your meters. Four of 'em aren't registering."

  Willows looked. "I hadn't noticed. I thought they were just registeringlow. You're right, though. Yeah. You're right. The surface bleed-off.Hydrogen loss. Blew a valve, is all. Yeah." He grinned a little."Must've been quite a volcano for a second or two."

  De Hooch grinned back at him. "Yeah. Must've. Give me a hand with theseclamps."

  Willows began fastening the clamps on the heavy suit. "D'you thinkFerguson and Metty are O.K., Guz?" he asked.

  De Hooch noticed it was the first time he had used the names of the twomen. Now that there was a chance that they were alive, at least in hisown mind, he was willing to admit that they were men he knew. Willowsdidn't want to think that anyone he knew had done such a terrible thingas die. It hit too close to home.

  The man wasn't thinking. He was willing to grasp at anything thatoffered him a chance--dream straws. The idea was to keep him busy, keephis mind on trivia, keep him from thinking about what was going oninside that reactor.

  He should have known automatically that it was building toward Fermium256. It was the most logical, easiest, and simplest way for a D-Hreactor to go off the deep end.

  A Ditmars-Horst reactor took advantage of the fact that any number canbe expressed as the sum of powers of two--and the number of nucleons inan atomic nucleus was no exception to that mathematical rule.

  Building atoms by adding nucleons wasn't as simple as putting marbles ina bag because of the energy differential, but the energy derived fromthe fusion of the elements lighter than Iron 56 could be compensated forby using it to pack the nuclei heavier than that. The trick was to finda chain of reactions that gave the least necessary energy transfer. Themethod by which the reactions were carried out might have driven amid-Twentieth Century physicist a trifle ga-ga, but most of thereactions themselves would have been recognizable.

  There were several possible reactions which Ferguson and Metty couldhave used to produce Hg-203, but de Hooch was fairly sure he knew whichone it was. The five-branch, double-alpha-addition scheme was the onethat was easiest to use--and it was the only one that started thedamnable doubling chain reaction, where the nuclear weights went upexponentially under the influence of the peculiar conditions within thereactor. 2-4-8-16-32-64-128-256 ... Hydrogen 2 and Helium 4 were stable.So were Oxygen 16 and Sulfur 32. The reaction encountered a sticky spotat Beryllium 8, which is highly unstable, with a half life of ten tothe minus sixteenth seconds, spontaneously fissioning back into twoHelium 4 nuclei. Past Sulfur 32, there was a lot of positron emission asthe nuclei fought to increase the number of neutrons to maintain astable balance. Germanium 64 is not at all stable, and neither isNeodymium 128, but the instability can be corrected by positive betaemission. When two nuclei of the resulting Xenon 128 are forcedtogether, the positron emission begins long before the coalescence iscomplete, resulting in Fermium 256.

  But not even a Ditmars-Horst reactor can stand the next step, becausematter itself won't stand it--not even in a D-H reactor. The trouble isthat a D-H reactor _tries_. Mathematically, it was assumed that theresulting nucleus did exist--for an infinitesimal instant of time.Literally, mathematically, infinitesimal--so close to zero that it wouldbe utterly impossible to measure it. Someone had dubbed the hypotheticalstuff Instantanium 512.

  Whether Instantanium 512 had any real existence is an argument forphilosophers only. The results, in any case, were catastrophic. Thewhole conglomeration came apart in a grand splatter of neutrons,protons, negatrons, positrons, electrons, neutrinos--a whole slew ofGreek-lettered mesons of various charges and masses, and a finecollection of strange and ultrastrange particles. Energy? Just oodlesand gobs.

  Peter de Hooch had heard about the results. He had no desire toexperience them first hand. Fortunately, the reaction that led up tothem took time. It
could be stopped at any time up to the Fm-256 stage.According to the instruments, that wouldn't be for another six hoursyet, so there was nothing at all to worry about. Even after that itcould be stopped, provided one had a way to get rid of the violentlyfissioning fermium.

  "Connections O.K.?" Willows asked. His voice came over the earphonesinside the ponderous helmet of the radiation suit.

  "Fine," said de Hooch. He adjusted the double periscope so that hisvision was clear. "Perfect."

  He tested the controls, moving his arms and legs to see if the suitresponded.