Radiation dosage chart
Posted: Fri Aug 16, 2013 5:49 pm
I keep losing and finding this - and it's useful. From XKCD to give credit where due. Too many people don't understand all this (including some nuclear physicists). There have been many attempts to convert "counts" to physiological damage - some seem fairly well thought out, some not so much, none proven to my complete satisfaction. For example, you can be exposed to a lot of low energy X rays, and do little damage, or externally to almost infinite alpha rays (helium nuclei) with just about zero damage - the dead layer of skin you have on your body stops them all harmlessly. I might debate some of the number conversions used for neutrons - fast ones are supposedly worse than slow - but the slow ones are what activate (make radioactive) things in your body, that do you harm later on. While it should be obvious, I'll just (re) state that there's a big difference between things that get into you, versus things that you're exposed to externally - which might just pass on through without doing any damage, or be stopped harmlessly by your skin. That's why you can handle say, uranium ore with relative safety - but by golly, don't breathe the dust. Radon, for example, has a short half life and is a gas you can breathe in - but its decay products are themselves nasty - and solid and some are soluble - and hang around to kill you later.
This isn't simple stuff. Yet, we have a lot of potassium-40 in us - we are radioactive. I see about 120 cpm on 2" sq of geiger counter here, from cosmic rays and natural (and nuke test from the cold war years) - and you're a lot bigger than 2" sq, so you're getting more than that, and some of it's pretty nasty. Here's the chart:
As usual here, click the chart for a bigger, more readable version. I think many will be surprised at what they see here.
Now, when someone is trying to scare you, they play the units specsmanship game (I'd quote a guy calling himself George Washiington on zerohedge as one of these scare mongers). For example - he'd use Bequerels, which gives you huge numbers, rather than say sieverts, which measure actual damage a little better,
http://en.wikipedia.org/wiki/Sievert
But that's not all there are. There are rads, rems, and so on. This is a result of many attempts to find a unit that means something to humans.
http://en.wikipedia.org/wiki/Roentgen_equivalent_man
And then, to really scare you, the one that creates the biggest numbers, and the unit mostly used by scaremongers about fusors, Fukishima, and so forth.
http://en.wikipedia.org/wiki/Bequerel
Which is counts/second. While a single count *might* defeat the amazing DNA built in error-correction we all have, it's real doubtful, and you're getting quite a few anyway, being bigger than my geiger counter. Let's see, at my location (which is on the low side for background radiation, indoors, vented basement (no radon) and so on, assuming I look like about a square foot to the sky (more if I'm relaxing, less if I stand up), then I'm getting about 72 bq continuously....but there's one heck of a lot of atoms in my body to divide that among...
This isn't simple stuff. Yet, we have a lot of potassium-40 in us - we are radioactive. I see about 120 cpm on 2" sq of geiger counter here, from cosmic rays and natural (and nuke test from the cold war years) - and you're a lot bigger than 2" sq, so you're getting more than that, and some of it's pretty nasty. Here's the chart:
- Radiation dosage chart from XKCD
Now, when someone is trying to scare you, they play the units specsmanship game (I'd quote a guy calling himself George Washiington on zerohedge as one of these scare mongers). For example - he'd use Bequerels, which gives you huge numbers, rather than say sieverts, which measure actual damage a little better,
http://en.wikipedia.org/wiki/Sievert
But that's not all there are. There are rads, rems, and so on. This is a result of many attempts to find a unit that means something to humans.
http://en.wikipedia.org/wiki/Roentgen_equivalent_man
And then, to really scare you, the one that creates the biggest numbers, and the unit mostly used by scaremongers about fusors, Fukishima, and so forth.
http://en.wikipedia.org/wiki/Bequerel
Which is counts/second. While a single count *might* defeat the amazing DNA built in error-correction we all have, it's real doubtful, and you're getting quite a few anyway, being bigger than my geiger counter. Let's see, at my location (which is on the low side for background radiation, indoors, vented basement (no radon) and so on, assuming I look like about a square foot to the sky (more if I'm relaxing, less if I stand up), then I'm getting about 72 bq continuously....but there's one heck of a lot of atoms in my body to divide that among...