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Specialty Chemistry Forums => Nuclear Chemistry and Radiochemistry Forum => Topic started by: jdurg on August 03, 2005, 07:00:21 PM

Title: Radiation Energies
Post by: jdurg on August 03, 2005, 07:00:21 PM
I have a quick question here.  Whenever I look at the data about radioisotopes, I always see the energy associated with the decay of said isotope.  (I.E. U-238 gives off 4.10 MeV in gamma rays, or x MeV alpha, etc. etc.).  My question is, on what scale is that energy associated with?  Is is per atom of the isotope?  Per gram?  Per mole?  NO place out there seems to indicate what the scale is.  Due to the number of decays per second, I find it hard to believe that those energies are per atom.  I just wish places would define the units they use.  It's like going to the supermarket and seeing the roast beef priced at $4.00.  Is it four bucks a pound, an ounce, a slab?
Title: Re:Radiation Energies
Post by: Mitch on August 03, 2005, 07:21:49 PM
It is per atom! Thus nuclear power is such an attractive energy source.
Title: Re:Radiation Energies
Post by: Grejak on August 03, 2005, 10:13:27 PM
I have a quick question here.  Whenever I look at the data about radioisotopes, I always see the energy associated with the decay of said isotope.  (I.E. U-238 gives off 4.10 MeV in gamma rays, or x MeV alpha, etc. etc.).  My question is, on what scale is that energy associated with?  Is is per atom of the isotope?  Per gram?  Per mole?  NO place out there seems to indicate what the scale is.  Due to the number of decays per second, I find it hard to believe that those energies are per atom.  I just wish places would define the units they use.  It's like going to the supermarket and seeing the roast beef priced at $4.00.  Is it four bucks a pound, an ounce, a slab?

Mitch is correct, it is per atom.  Or, more precisely, per event.  An atom can give off numerous gamma rays during a cascade down to ground state.  Each gamma ray would then be x MeV.
Title: Re:Radiation Energies
Post by: jdurg on August 03, 2005, 11:07:30 PM
Okay.  I just didn't realize how pathetically weak a MeV is in terms of energy.  (1 joule equals over 1 quadrillion MeV).
Title: Re:Radiation Energies
Post by: Mitch on August 04, 2005, 12:06:34 AM
A quadrillion seems small, until we start talking about moles of radioactive materials.
Title: Re:Radiation Energies
Post by: jdurg on August 04, 2005, 06:38:18 PM
If you want to cringe over some completely and utter nonsense, take a look at this thread over at the scienceforums.  Good god these people just don't know anything about nuclear decay.   :(

http://www.scienceforums.net/forums/showthread.php?t=12773 (http://www.scienceforums.net/forums/showthread.php?t=12773)
Title: Re:Radiation Energies
Post by: Borek on August 04, 2005, 07:24:09 PM
It is hopeless, some people just have to die stupid.
Title: Re:Radiation Energies
Post by: limpet chicken on August 04, 2005, 08:20:44 PM
It isn't so much that people have to die stupid, but it is the stupid people who need to die ;D