[B-Chan]

If neutron radiation was detected, I share your concern. Ordinary radioactive materials (uranium, plutonium, etc.) in ordinary amounts are generally fairly neutron-cool; they emit alpha and gamma radiation to one degree or another, but their neutron emission rates are low -- that is, until you get enough of the stuff together in a small space. Then, neutron emissions from some of the atoms cause the nuclei of other nearby atoms to fission (split), releasing more neutrons, which causes still further fission -- the famous "chain reaction". Every time a nucleus splits, a small portion of its mass is converted to energy in the form of electromagnetic radiation, and thus (when the radiation interacts with matter) to heat, according to Einstein' famous formula E=MC^2 (energy equals mass times the speed of light squared). If this fission chain reaction occurs gradually, the energy will released at a controlled rate, and the reaction becomes "critical" (self-sustaining), producing heat; this is how nuclear power plants generate steam. However, if the fission chain reaction occurs quickly enough, and within nuclear materials that are smaller that a given volume (the "critical mass"), then an uncontrolled, runaway chain reaction occurs, releasing all the fission energy at once: E=MC^2. Boom. This is the principle behind an atomic bomb

Neutron radiation also has the effect of rendering surrounding materials radioactive over time. The stray neutrons from the radioactive material shoot out of their nuclei and slam into the nuclei of other atoms nearby, knocking out nuclear particles from them and changing their composition; certain of the resulting changed nuclei become unstable as a result, emitting electromagnetic radiation on their own. (These "changed" atoms are called radioisotopes.) By converting the atoms in nearby materials to radioisotopes over time, neutron-emitting material can cause non-radioactive materials to become radioactive. Thus, even if the ship in question has no nuclear or radioactive comb on board now, the presence of radiation might indicate that such a bomb was located on the ship at some time before. By analyzing the rate at which this induced radiation dissapates (its "rate of decay"), scientists might be able to tell how long ago it was irradiated and, thus, when the nuclear materials were onboard.

The presence of detectable neutron radiation onboard this ship would be a serious indication that a critical mass of radioactive material is or was on board. That would not bode well.

[seeker41]

The Liberian-flagged M/V Palermo Senator was ordered back to sea by the Coast Guard Wednesday after traces of radioactivity were found in the hold during a routine inspection at the Port of Newark.

From Fox.com

[EternalHope]

By converting the atoms in nearby materials to radioisotopes over time, neutron-emitting material can cause non-radioactive materials to become radioactive.

Good post.

One addition: American nukes emit low enough levels of neutrons that it would take quite awhile to make the surrounding materials noticeably radioactive. A crude enough device might emit a lot more, but the very nature of the beast limits the amount of neutrons released.

The plutonium (or U-235) must be kept separated enough to avoid starting a chain reaction. Furthermore, the amounts used are not likely to be dramatically more than critical mass. The bad guys of the world would make more bombs rather than use up their supply of fissile material all in one place.

[piasa]

If that's the case then we definitely want to know who was responsible for the thing. Given this ship's itinerary from the far east it makes for some interesting possibilities beyond just al Qaeda, don't you think?

[spunkets]

"neutron emissions from some of the atoms

There are no neutron emmisions from any of these heavier elements. The neutrons come from the splitting reactions. The only elements that release neutrons are light ones like lithium and carbon that are really loaded up with extra neutrons from a reaction source. They are extremely short lived and would be gone before anyone could collect them.

All this says is that if their are neutrons detected there is a quantity of fissionable material. More neutrons mean the mix contains a higher quantity of isotope, or an isotope with a shorter lifetime.

[Jennifer in Florida]

Great post, thanks for the explanation. I guess the big question now is whether it was neutron radiation. I've had Fox News on in the background all day, and it seems a little strange to me that they are not dwelling on this issue with the "Fox News Alerts" every five minutes like they usually do. They have been relatively quiet about this ship.

[Peach]

A lot of information to digest, but I thank you for writing it.

[Madame Dufarge]

What a great "Radiation for Dummies" explanation.

Thanks!

[Grampa Dave]

B-Chan, thanks for this great essay on Radiation for dummies, as Madame Dufarge labeled it.

This is why I had rather come to Free Republic when a story is breaking, we great essays for dummies, walks down memory lane re vanilla cokes, jokes and find out more about was or didn't happen than watching tv for an hour or all day!

My wife jokes that I had rather go to Free Republic for the news instead of Fox News, and most of the time she is right.