自考英语综合二下册课文 lesson 8

　　Lesson Eight

　　Text

　　How I Designed an A Bomb

　　in My Junior Year at Princeton John A . Phillips and David Michaelis

　　The first semester of my junior year at Princeton University is a disaster,

　　and my grades show it.

　　D's and F's predominate,and a note from the dean puts me on academic probation.

　　Flunk one more course,and I'm out.

　　Fortunately, as the new semester gets under way,

　　my courses begin to interest me.

　　Three hours a week,

　　I attend one called Nuclear Weapons Strategy and Arms Control.

　　One morning,Freeman Dyson,

　　an eminent physicist assisting Hal Feiveson in the course,

　　opens a discussion on the atomic bomb:

　　"Let me describe what occurs when a 20-kiloton bomb is exploded,

　　similar to the two dropped on Hiroshima and Nagasaki

　　First, the sky becomes illuminated by a brilliant white light.

　　Temperatures are so high around the point of explosion

　　that the atmosphere is actually made incandescent.

　　To an observer standing six miles away

　　the ball of fire appears brighter than a hundred suns.

　　"As the fireball begins to spread up and out into a mushroom shaped cloud,

　　temperatures spontaneously ignite all flammable materials for miles around.

　　Wood frame houses catch fire.

　　Clothing bursts into flame,

　　and people suffer intense third degree lash burns over their exposed flesh.

　　The very high temperatures also produce a shock wave

　　and a variety of nuclear radiation capable of penetrating 20 inches of concrete.

　　Silence falls over the roomas the titanic proportions of the destruction begin to sink in

　　"It takes only 15 pounds of plutonium to fabricate a crude atomic bomb,

　　"adds Hal Feiveson. "

　　If breeder reactors come into widespread use,

　　there will be sufficient plutonium shipped around the country each year

　　to fashion thousands of bombs.

　　Much of it could be vulnerable to theft or hijacking.

　　"The class discusses the possibility of terrorists

　　using a homemade atomic bomb to push their extravagant political demands.

　　"That's impossible," a student objects.

　　"Terrorists don't have the know how to build a bomb.

　　Besides, they don't have access to the knowledge.

　　"Impossible? Or is it?The question begins to haunt me.

　　I turn to reference books and find,according to a famous nuclear physicist,

　　that a terrorist group could easily steal plutonium

　　or uranium from a nuclear reactor

　　and then design a workable atomic bomb

　　with information available to the general public

　　are legally available at hardware stores and chemical supply houses.

　　Suddenly,an idea comes to mind.

　　Suppose an average or below average in my case physics student

　　could design a workable atomic bomb on paper?

　　If I could design a bomb, almost any intelligent person could.

　　But I would have to do it in less than three months

　　to turn it inas my junior independent project.

　　I decide to ask Freeman Dyson to be my adviser.

　　"You understand," said Dyson, "

　　my government security clearance will prevent me from giving you any more information

　　than that which can be found in physics libraries.

　　And that the law of'no comment' governing scientists

　　who have clearance to atomic research requires that,

　　if asked a question about the design of a bomb,

　　I can answer neither yes nor no?"

　　"Yes, sir," I reply."I understand.""Okay, then.

　　I'll give you a list of textbooks outlining the general principles

　　and I wish you luck."

　　]A few days later,Dyson hands me a short list of books on nuclear reactor technology

　　general nuclear physics and current atomic theory.

 

　　"That's all?" I ask incredulously, having expected a bit more direction.

　　At subsequent meetings Dyson explains only the basic principles of nuclear physics

　　If I ask about a particular design or figure,

　　he will glance over what I've done and change the subject.

　　At first, I think this is his way of telling me I am correct.

　　To make sure, I hand him an incorrect figure.

　　He reads it and changes the subject.

　　Over spring vacation,I go to Washington,D.C

　　to search for records of the Los Alamos Project

　　that were declassified between 1954 and 1964.

　　I discover a copy of the literature given to scientists

　　who joined the project in the spring of 1943.

　　This text carefully outlines all the details of atomic fissioning

　　known to the world's most advanced scientists in the early '40s.

　　A whole batch of copies costs me about $ 25.

　　I gather them together and go over to the bureaucrat at the front desk.

　　She looks at the titles and then looks up at me.

　　"Oh, you want to build a bomb, too?" she asks matter-of-factly.

　　I can't believe it.

　　Do people go in there for bomb-building information every day?

　　When I show the documents to Dyson, he is visibly shaken.

　　His reaction indicates to me that I actually stand a chance of coming up with a workable design

　　The material necessary to explode my bomb is plutonium-239.

　　Visualize an atomic bomb as a marble inside a grape fruit

　　inside a basketball inside a beach ball.

　　At the center of the bomb is the initiator,

　　a marble-size piece of metal.

　　Around the initiator is a grapefruit-size ball of plutonium-239.

　　Wrapped around the plutonium

　　is a threeinch reflector shield made of beryllium.

　　High explosives are placed symmetrically around the beryllium shield.

　　When these detonate,an imploding shock wave is set off,

　　compressing the grapefruit-size ball of plutonium to the size of a plum.

　　At this moment, the process of atoms fissioning or splitting apart begins.

　　There are many subtleties involved in the explosion of an atomic bomb

　　Most of them center on the actual detonation

　　of the explosives surrounding the beryllium shield.

　　The grouping of these explosives

　　is one of the most highly classified aspects of the atomic bomb,

　　As the next three weeks go by,

　　I stop going to classes altogether and work day and night.

　　I develop a terrible case of bloodshot eyes.

　　Sleep comes rarely.

　　I approach every problem from a terrorist's point of view.

　　The bomb must be inexpensive to construct,

　　simple in design and small enough to sit unnoticed in the trunk of a car.

　　As the days and nights flow by,

　　I scan government documents for gaps

　　indicating an area of knowledge that is still classified.

　　Essentially, I am putting together a huge jigsaw puzzle.

　　The edge pieces are in place and various areas are getting filled in,

　　but pieces are missing.

　　Whenever the outline of one shows up,

　　I sit down to devise the solution that will fill the gap.

　　With only two weeks left, the puzzle is nearly complete,

　　but two pieces are still missing:

　　which explosives to use,and how to arrange them around the plutonium.

　　Seven days before the design is due,

　　I'm still deadlocked I realize something drastic must be done,

　　and I start all over at the beginning.

　　Occasionally I find errors in my old calculations,and I correct them.

　　I lose sense of time.

　　With less than 24 hours to go,

　　I run through a series of new calculations,

　　mathematically figuring the arrangement of the explosives around the plutonium

　　If my equations are correct,

 

　　my bomb might be just as effective as the Hiroshima and Nagasaki bombs.

　　But I can't be sure until I know the exact nature of the explosives I will use

　　Next morning, with my paper due at 5 p.m.,

　　I call the Du Pont Company from a pay phone

　　and ask for the head of the chemical explosives division,

　　a man I'll call Mr.Graves."Hello, Mr. Graves.

　　My name is John Phillips,a student doing work on a physics project.

　　I'd like to get some advice, if that's possible."

　　"What can I do for you?"

　　"Well," I stammer,"

　　I'm doing research on the shaping of explosive products

　　that create a very high density in a spherically shaped metal.

　　Can you suggest a Du Pont product that would fit in this category?"

　　"Of course." he says,in a helpful manner.

　　"We sell the names of the product

　　to do the job in similar density problem situations

　　to the one you're talking about.

　　"Mr. Graves has given me just the information I need.

　　Now,if my calculations are correct with respect to the new information,

　　all I have to do is complete my paper by five.

　　Five minutes to five,I race over to the physics building and bound up the stairs

　　Inside the office,everybody stops talking and stares at me.

　　"I came to hand in my project," I explain.

　　A week later, I return to the office to pick up my project.

　　My paper is not there.

　　"Aren't you the boy who designed the atomic bomb?"

　　The secretary looks up, then freezes.

　　"Yes," I reply.She takes a deep breath.

　　"The question has been raised

　　by the department whether your paper should be classified by the U. S. government

　　"What! Classified?"She takes my limp hand shaking it vigorously.

　　"Congratulations," she says, all smiles.

　　"You've got one of the only A's in the department.

　　"For a second I don't say anything.

　　Here I have put on paper the plan for a device

　　capable of killing thousands of people,

　　and all I was worrying about was flunking out.