lesson24 How I Designed an A-Bomb in My Junior Year at Princeton

　　How I designed an A-Bomb in my junior year at Princeton

　　John A.Phillips and David Michaelis

　　1.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.

　　2.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.

　　3.“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 verrry high temperatures also produce a shock wave and a variety of nuclear radiation capable of penetrating 20 inches of concrete……”

　　4.Silence falls over the room as the titanic proportions of the destruction gegin to sink in.

　　5.“It takes only 15 pounds of plutonium to fabricate a crude atomic bomb,”added Hall Feiveson.“If breeder reactors come into widespread use,there will be sufficient plutonium shipped around the country each yearr to fashion thousands of bombs.Much of it could be vulnerable to theft or hijacking.”

　　6.The class discusses the possibility of terrorists' using a homemade atomic bomb to push their extravagant political demands.

　　7.“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.”

　　8.Impossible？ Or is it？ The question begins to haunt me.I turn to reference books and find,according to a famous nuclear physcist,that a terrorist group could easily steal plutonium or uranium from a nuclearr reactor and then design a workable atomic bomb with imformation available to the general public,and that all the ingredients——except plutonium——are legally avialable at hardware stores and chemical-supply houses.

　　9.Sudenly,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 in as my junior independent project.I decide to ask Freeman Dyson to be my adviser.

　　10.“You understand,”said Dyson,“my government security clearance with 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 niether yes or no.”

　　11.“Yes,sir,”I reply.“I understand.”

　　12.“Okay,then.I'll give you a list of textbooks outlining the general principles——and I wish you luck.”

　　13.Afew days later,Dyson hand 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.

　　14.At subsequent meetings Dyson explains only the bisic principles of nuclear physics.If I ask about the 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.

　　15.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 fissioining 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.

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

　　17.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.

　　18.The material necessary to explode my bomb is plutonium-239.Visualize an atomic bomb as a marble inside a grapefruit inside a basketball inside a beach ball.At the center of the bomb is the initiator,a marble-size of metal.Around the initiator is a grapefruit -size ball of plutonium-239.Wrapped around the plutonium is a three-inch reflector shield made of beryllium.High explosives are placed symmetrically around the beryllium shield.When these detonate,an implodinng shock wave is set off,compressing the grapefruit-size ball of plutomium to the size of a plum.At this moment,the process of atoms fissioning——or splitting apart begins.

　　19.There are many subtleties involved in the explosion of an atomic bomb.Most of them center onn the actual detonation of the explosives surrounding the  beryllium shield.The grouping of there explosives is one of the most highly classified aspects of the atomic bomb,and it poses the biggest problems for me as I begin to design my bomb.

　　20.As the next three weeks go by,I stop going to classes althogether and work day and night.I develop a terrible case of bloodshot eyes.Sleep cames rarely.

　　21.I approach every problem from a terrorist's point of view.The bomb must be inexpensive to construct,simple in disign,and small enough to sit unnoticed in the trunk of a car.

　　22.As the days and nights flow by,I scan government documents for gaps indicating an area of knowledge that is still classified.Essentially,I'm 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.

　　23.With only two weeks left,the puzzle is enarly complete,but two piece are still missing：which explosives to use,and how to arrange them around the plutonium.Seven days before the designis due,I'm still deadlocked.I realize something drastic must be done,and I start all over at the begining.Occasionally I find errors in my old calculation,and I correct them.I lose sense of time.

　　24.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 explosives I will use.

　　25.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.

　　26.“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.”

　　27.“What can I do for you？”

　　28.“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？”

　　29.“Of course,”he says,in a helpful manner.

　　30.“We sell [the names of the product] to do the job in similar density-problem situation to the one you're talking about.”

　　31.Mr Grave 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.

　　32.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 haven't shaved in over a week.

　　33.“I came to hand in my project.”I explain.

　　34.A week later,I return to the office to pick up my project.My paper is not there.

　　35.“Aren't you the boy who designed the atomic bomb？”the secretary looks up,then freezes.

　　36.“Yes,”I reply.

　　37.She takes a deep breath.“The question has been raised by the department whether your paper should be classified by the U.S.government.

　　38“What！ Classified？”

　　39.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.”

　　40.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 worring about was flunking out.