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Old 12-25-2003, 05:50 PM
Ranchoth Ranchoth is offline
Join Date: Jul 1999
Location: The Brink
Posts: 11,235
How quickly can radiation poisoning kill someone? (Without just incinerating them?)

It's mostly all there in the title, aside from the requisite reference link to the illness in question. Said link mentions that exposure to 100,000+ Rads will cause "almost immediate unconsciousness and death within an hour."

But, what would the immediate cause of death be? Blood loss? Mass cell rupture?

If you got hit by 500,000 Rads, would you die within half an hour? Or would you just be vaporized?
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Old 12-25-2003, 06:09 PM
KP KP is offline
Join Date: Sep 1999
Well, short of incinerating you, it could literally cook you.

Extreme levels of ionizing radiation [high energy charged particles, cascades produced by high speed uncharged particles, high energy photons, etc.] can produce reactive chemicals and molecular fragments by ripping apart or damagine the molecules in your body. These reactive fragments (ions, free radicals, abnormal chemicals) can react with perfectly functional chemicals in your body, impairing them, and producing unexpected products. Also, most of the energy absorbed by you body will end up as heat in a matter of minutes.

The expected result? Toxic compounds, denatured proteins, scrambled DNA, and a fondness for Reality shows.

Death can be a blessing.
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Old 12-25-2003, 06:54 PM
yoyodyne yoyodyne is offline
Join Date: Dec 2002
High exposure results in something called Central Nervous System (CNS) Syndrome. It's not really well understood, but death results from respiratory failure and/or brain edema resulting from fluid leakage due to a combination of cellular and vascular damage.

500,000 rads would result in a temperature rise on the order of 1 degree C, so it would take a lot more than that to incinerate someone. Death would be pretty fast though.

Some more info
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Old 12-25-2003, 07:03 PM
bbeaty bbeaty is offline
Join Date: Aug 1999
They guy at Los Alamos on Manhatten Project, the one who yanked the plutonium masses apart and saved... wasn't the first symptom that his hand and arm swelled up to enormous size and turned black? Massive tissue swelling must screw up all sorts of body symptoms.

Dr. Louis Slotin 1946
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BILL BEATY _ _ _ _ _ _ _ _ billb, _ _ _ SCIENCE HOBBYIST
beaty, _ Seattle, WA USA
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Old 12-25-2003, 07:13 PM
bbeaty bbeaty is offline
Join Date: Aug 1999
Body SYSTEMS, not body symptoms.

And that's Manhatt*A*n project.

"Tickling the dragon"

And maybe I was thinking of Harry Daghlian, not Slotin
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Old 12-25-2003, 10:33 PM
raygirvan raygirvan is offline
Join Date: Dec 2002
This Movie Physics review of "Sum of All Fears" mentions the detail about Slotin's hand, though without crediting a source.
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Old 12-25-2003, 10:56 PM
KP KP is offline
Join Date: Sep 1999
500,000 rads would result in a temperature rise on the order of 1 degree C, so it would take a lot more than that to incinerate someone. Death would be pretty fast though.
Thank you. The first site I checked (University of California - San Francisco, Office of Environmental Health and Safety, Radiation Safety Training Manual) 1 rad = 10 J/kg. After reading your post, I double checked, and it was wrong.

The rad is no longer a SI unit, but is still widely used in the US, so the National Institute of Science and Technology still lists it. 100 rads = 1 Gray (the proper SI unit). 1 Gray is 1 J/kg so 1 rad = 0.01 J/kg (This fits the original definition: 1 rad = 100 ergs/g of absorber)

500,000 rads would be 5000 joules per kilogram of tissue.

I agree that this would only raise the bulk temperature of tissue by about 1 degree C. However, the energy of each 'capture' is initially converted to a far larger local thermal effect, and has a correspondingly larger effect in the locale of each photon absorption or shower.

I also erred in saying "in minutes" when I should have said "within a second". This gruesome error arose as I merged three sentences while editing and simplifying my post. Based on the incorrect equivalence cited above, I decided it would be needlessly complicated to explain both the nano and macro scales

Thank you for bringing my attention to this so I could clarify: absorption of radiation can cause local temperatures (on a molecular scale) to briefly increase by 10s, 100s or 1000s of C, with the microscopic effects you would expect from cooking meat at those temperatures. Within minutes, that heat would diffuse throughout the tissue, leaving you with much more (and more extreme) chemical changes than you would expect from the bulk increase of 1C
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