well, if its over 100 mSv/h, then acute radiation sickness begins after ~2 hours (noticable reduced blood cell count from 200 mSv acute dose onward, though you'd only FEEL sick after another 3 or 4 hours). but yeah, as the inverse square law applies, there's nothing to fear with this particle. and yep, the spectrum was done by a HPGe, as usual. :)
Yes, but radiation sickness is caused by prolonged exposure - that is, 100mSv/h for two hours (dimensions are important here, dosage is in Sv). Additionally that's for a full body dose and she was mostly irradiating her fingers.
I thought it meant that if you're exposed to 100mSv/h, you'll get sick around 2 hours later... but what it means is a full body dose for 2 hours is enough to make you sick.
Therefore 5 minutes to the fingers is probably OK.
I think the key was if that was the dose to the total body area not just from a single grain in her hand. Imagine being covered in those grains for 1 hour that would be the equivalent.
And what happens if you "only" irradiate your hand? Presumably some of the alpha/beta particles can go into your blood and then to the rest of your body?
Alpha particles (high energy bare Helium nuclei actually) and beta particles (high energy electrons actually) don't "go into your blood", they are just absorbed by atoms in your skin and they break a few molecules those atoms were part of along the way. If they go deep enough they make break up some DNA in you skin cells. If they would get to the blood they would just be absorbed by the blood itself and break some molecules that float in the blood - which would be pretty harmless. If the dose is really big they may even turn some atoms in your skin's cell radioactive and yeah, these could then go around your body, but at such a dose you'd have burns on your skin already.
Her biggest problem from holding something like that radioactive grain in hand would be the gamma rays causing mutations in the cells in her hand that would then lead to cancer in the log term. Like I'd imagine she will be sick with some bone cancer or leukemia or a random sarcoma in like 10 - 15 years from now. Maybe even longer if she has inherited some good DNA-repair genes and anti-cancer-immunity genes. Or sooner if she wasn't so lucky at the genetic lottery and if she has other risk factors too...
And then there's the radioactive dust... I'd imagine she has inhaled quite a lot of it along her trips, and this is probably her biggest short term (think "less than 10 years") concern.
It's really only neutrons that can transmute other elements into radioactive ones. Charged particle or EM radiation might damage your body's chemicals but they won't harm your atoms.
Generally a whole body dose of 1 sievert will increase your odds of getting cancer by 10% over your life. I don't know how much she's been exposed to but while my guess is that while future cancer is a concern it really isn't a sure thing.
The gigacounter predicts the sieverts/h based on the local amount of radiation and by assuming that is the dosage all parts of your body are exposed to. If significantly less of your body is actually exposed to that level of radiation the actual dosage you receive will be less than predicted.
You're right but it's not about the dose only. If I blast a millimeter-sized piece of your finger with neutrons the body dose might be extremely small, but that piece of finger tissue might itself become radioactive and the newly-made-radioactive atoms in it will keep irradiating the cells around. Then some of them will get cancer mutations. Then some of them will go long enough along the path to cancer. Then some of them will metastasize...
The girl seems to have a good understanding of dose safety. But a poor understanding of biological effects, just like everyone else. Beta vs alpha vs gamma radiation have very different biological effects and sieverts, the measuring units that take some of these differences into account, are a gross over simplification. You can kill someone with a radiation dose well below the lethal one in Sv and you can survive a dose above the lethal one...
Biological systems have very complicated relationships with radiation in general, that's why even the health impact of non-ionizing radiation needs to be investigated (yeah, your cellphone is most likely safe ;) ...but you know that you have at least some cells in you body that respond even to non-ionizing EM radiation - they are in your eyes and thanks to them you can read this :) )
High Radiation doses to small areas are a really complicated issue. One example of a greater than lethal dose in 1978 to a person’s head where mostly it was just a question of direct tissue damage.
More generally in the short term it's fast growing tissue that's most at risk. So, exposure that is quickly lethal may not do a lot of damage to slow growing tissues. Long term you can often remove severely affected tissues so a person can often survive much higher doses to their arms and legs vs torso.
PS: Another issue relates to population sizes. A 0.1% risk to everyone in the US kills more than 300 thousand people and is a major issue. A 0.1% risk to one person may not seem that bad as that's around the default risk every month for a 55 year old male.
well, if its over 100 mSv/h, then acute radiation sickness begins after ~2 hours (noticable reduced blood cell count from 200 mSv acute dose onward, though you'd only FEEL sick after another 3 or 4 hours). but yeah, as the inverse square law applies, there's nothing to fear with this particle. and yep, the spectrum was done by a HPGe, as usual. :)