Interested in nuclear fission in my life

[derryck1234]

Hello, I have been really interested in nuclear fission in my life, however, have not studied anything solid in the field. I have, however, read a little about it.

Basically, I know that in order for fission to take place, a neurton needs to collide with a large, dense nucleus. What I do not know is, how do we fire a neutron?

If anyone can help me, it would be greatly appreciated.

PS: I am not a terrorist or anything of the sort, I just would like to understand the subject fully, so that I can ponder over it in my free time...

Thanks

Derryck

 

[mathman]

Fission bombs include a small amount of radioactive material which produces neutrons. The chain reaction then takes over.

 

[derryck1234]

okay,so basically all radioactive materials emit neutrons. I have also heard that only slow moving neutrons are effective for fission. Is this true?

I have also heard that lead is the heaviest non-radioactive element. Does this mean that the heavier an element is, the more likely it is to be radio-active? More over, basically anything heavier than lead has to be radioactive?

Thanks

Derryck

 

[Bob S]

okay,so basically all radioactive materials emit neutrons. I have also heard that only slow moving neutrons are effective for fission. Is this true?

Actually not. Radioactive sources usually emit only betas (electrons), positrons, gammas, X-rays, and alpha particles (plus neutrinos). Mixing an alpha particle source, e.g., polonium or plutonium, with beryllium will produce neutrons.

It is true that slow ("thermal") neutrons are best for most fission reactions.

Bob S

 

[mathman]

okay,so basically all radioactive materials emit neutrons. I have also heard that only slow moving neutrons are effective for fission. Is this true?

I have also heard that lead is the heaviest non-radioactive element. Does this mean that the heavier an element is, the more likely it is to be radio-active? More over, basically anything heavier than lead has to be radioactive?

Thanks

Derryck

For bombs there is not enough time for the neutrons to slow down, so they rely on fast neutron fission. In reactors, the neutrons are slowed down by the moderator, typically water.

Radioactivity is a nuclide property, not an element property. It is true that lead is the element with the highest atomic number that has non-radioactive isotopes.
Until fairly recently it was thought that bismuth had a non-radioactive isotope.
"Bi-209 has been known as stable nuclide. But, alpha decay of Bi-209 with a half life of 2*10^19 years was found, recently."

 

[derryck1234]

Ok, thanks. So basically, we discovered that mixing an alpha particle with beryllium creates a reaction which emits neutrons?

Firstly, what is an alpha particle? Secondly, why beryllium?

PS: I would like to read up on the history of the atomic bomb, or rather, fission. Could you suggest any good texts?

Thanks

Derryck

 

[inflector]

Derryck,

If you are really interested in neutrons and fission, it might be cliche to say but, Google is your friend.

Try googling: "alpha particle" for instance and you'll quickly find out what it is. The first entry is currently:

http://en.wikipedia.org/wiki/Alpha_particle

which does a reasonable job explaining what an alpha particle is.

You can ask questions here and someone might be kind enough to answer, but you'll be wasting their time if it is a common question you could have answered in 1 minute of googling. If you haven't read these:

http://www.gerv.net/hacking/how-to-ask-good-questions/
http://www.catb.org/~esr/faqs/smart-questions.html

you will find them helpful.

There are lots of good resources on the net that you should be aware of. Wikipedia is a good starting point, but the best place for learning basics is:

http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

 

[terryphi]

Well, the best way to 'fire' a neutron is to get your hands on a fancy research reactor. These things are designed to get neutrons out of them. Take a look at the SNS in Oakridge; that's the biggest one.Now if you don't have a multi million dollar you can use a low Z material bombarded by an alpha emitter (eg AmBe). This process knocks neotrons free.