5 ms·

One her comments: 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

by ehmmm 11y ago

One her comments: 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. :)

grecy 11y ago
...and it was maxing out her meeter, which I think was showing 100 mSv/h, wasn't it?
- deleted 11y ago
  [deleted]
- joshvm 11y ago
  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.
  - grecy 11y ago
    ahhh, Thankyou. 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.
rdtsc 11y ago
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.
- nakedrobot2 11y ago
  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? what damage is being done by holding that grain?
  - moopling 11y ago
    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.
    - nnq 11y ago
      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 :) )
      - Retric 11y ago
        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. http://en.wikipedia.org/wiki/Anatoli_Bugorski http://en.wikipedia.org/wiki/Anatoli_Bugorski Note: You may want to avoid doing an image search though. 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.
caramel 11y ago
Then of course, if some speck of radioactive material gets lodged in your body the inverse square law works against you.

by ehmmm 11y ago

grecy 11y ago

...and it was maxing out her meeter, which I think was showing 100 mSv/h, wasn't it?

deleted 11y ago
[deleted]
joshvm 11y ago
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.
- grecy 11y ago
  ahhh, Thankyou. 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.

rdtsc 11y ago

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.

nakedrobot2 11y ago
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? what damage is being done by holding that grain?
- moopling 11y ago
  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.
  - nnq 11y ago
    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 :) )
    - Retric 11y ago
      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. http://en.wikipedia.org/wiki/Anatoli_Bugorski http://en.wikipedia.org/wiki/Anatoli_Bugorski Note: You may want to avoid doing an image search though. 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.

caramel 11y ago

Then of course, if some speck of radioactive material gets lodged in your body the inverse square law works against you.