Making sense of radiation doses

[TimberWolf]

A lot of ways of expressing doses are being used that span different periods of time amongst other things, and as it's not easy gauging the radiological effect at the best of times (e.g eating or breathing the stuff is really bad), here's a comparisons list I made. The most common unit currently being used for the radiological effect on humans in the media is the sievert.

Sievert (Sv) "equivalent dose" (old measure was rem). 1 Sv = 1 J/kg = 1 m^2/s^2 = 100 rem

Prefixes
m = milli = 1*10^-3
μ = micro = 1*10^-6
n = nano = 1*10^-9
p = pico = 1*10^-12
Watch out for milli and micro as they are easily confused, especially their respective prefix symbols, and to top it all when copying μ, it pastes here as an m! Hope I caught them all. Maybe μ still displays here as an m in your browser.

Single dose
0.1 μSv = Banana
185 μSv = Flight from Tokyo to London & back
0.04 mSv = Chest x-ray = 2 to 3 years of background radiation
1-3 Sv = Recovery probable but not assured
3-6 Sv = Death probable if not treated
10+ Sv = Incapacitation and death

Per hour
6 μSv / hour = Aircraft flight
1 Sv / hour = Nausea
2.5 Sv / hour = Hair loss and possible death

Per year
0.4 mSv / year = Radioactivity of a human
1 mSv / year = Max recommended exposure for public from human sources
2 mSv / year = Natural background (up to 50 mSv in some countries) = 270×10^-6 Gy ?
13 mSv / year = Smoking 30 a day for a year
20 mSv / year = Max recommended for radiation workers
100 mSv / year = Rate above which cancer rates seen to increase

[ 1mSv = 0.001Sv or 1×10^-3 Sv, 1μSv=0.000001Sv or 1×10^-6 Sv ]

Banana equivalent dose =3520pCi/kg = 130Bq/kg. Or 520pCi / banana = 5.2×10^-10Ci = 19 Bq/banana. 365 bananas = 36uSv

Brazil nuts = 444 Bq/kg


Hopefully we will not have a need to reference a whole seivert.

Additions or corrections welcome.



Other units:
Becquerel (Bq) decays/second. 1 Bq = 2.7×10^−11 Ci. See curie

curie (Ci), a unit of radioactivity
1 Ci = 3.7×10^10 decays/second = 3.7×10^10 Becquerel (Bq) ~ 1 gram of radium
A radiotherapy machine may contain 1000Ci of radioisotope such as caesium-137 or Cobalt-60 = serious health effects after a few minutes exposure. Human body contains ~ 0.1 μCi of naturally occurring potassium-40 (1 μCi = 3.7×10^4 disintegrations/second)

Gray (Gy) "absorbed dose". J/kg (as with the Sv). 1Gy = 100 RAD
Not a good biological measure. For electron & photon radiation 1 Gy = 1 Sv
Its non-SI unit was the RAD.
Badly vented house can give 6μGy / hour
Maximum level allowed in working environment = 20μGy / hour

RAD = 0.01 Gy. see Gray

rem = 0.01 Sv. See Sievert


Here's a chart that shows dosages in a slightly different way:

[Churchill]

Per hour
6 μSv / hour = Aircraft flight
1 Sv / hour = Nausea
2.5 Sv / hour = Hair loss and possible death

What is the above supposed to represent?

Ok, 1 Sv/hour gives you nausea, 2.5 SV/hour gives you hair loss and possible death.

And 6 μSv / hour gives you a free flight?

[TimberWolf]

What is the above supposed to represent?

Ok, 1 Sv/hour gives you nausea, 2.5 SV/hour gives you hair loss and possible death.

And 6 μSv / hour gives you a free flight?

That's the dose you get per hour on a flight on average. Cosmic rays and stuff.

[Churchill]

That's the dose you get per hour on a flight on average. Cosmic rays and stuff.

I guessed that. It's just the grouping with the symptoms, nonsensical.

[EternalOptimist]

What is the above supposed to represent?

Ok, 1 Sv/hour gives you nausea, 2.5 SV/hour gives you hair loss and possible death.

And 6 μSv / hour gives you a free flight?

taller people are closer to the sun, and get radiation poisoning much easier than smaller folks, or people who wear a biscuit tin on their head.
If you are very tall, one of the recommended solutions is to spend an hour a day watching television upside down on the couch

[Churchill]

taller people are closer to the sun, and get radiation poisoning much easier than smaller folks, or people who wear a biscuit tin on their head.
If you are very tall, one of the recommended solutions is to spend an hour a day watching television upside down on the couch

With a biscuit tin on me nads?

[TimberWolf]

I guessed that. It's just the grouping with the symptoms, nonsensical.

There are no symptoms for the average flier, symptoms start at around 100mSv / year, after many years exposure. It's useful a comparison. I would have included background radiation too, again as a reference, but didn't find a source for that, except per year and which is quite variable anyway.

[OwlHoot]

Basically, avoid Cornwall & Aberdeen.

I was once on a geology field trip on the Isle of Arran, and near the cliffs South of Lamlish bay there was a large boulder, presumably dropped by a glacier at some time.

When the lecturer moved his Geiger counter near it, the thing went from silent to clicking like mad, almost buzzing! One night sleeping near that rock, or under it, and I imagine your risk of getting cancer would significantly increase.

[TimberWolf]

I was once on a geology field trip on the Isle of Arran, and near the cliffs South of Lamlish bay there was a large boulder, presumably dropped by a glacier at some time.

When the lecturer moved his Geiger counter near it, the thing went from silent to clicking like mad, almost buzzing! One night sleeping near that rock, or under it, and I imagine your risk of getting cancer would significantly increase.

Would a Geiger counter pick up human radiation (not infra red, but beta particles)? That would be cool to see.

Potassium-40 is the largest source of natural radioactivity in animals and people. An adult human body contains about 160 grams of potassium, of which a small fraction is potassium-40. From the isotope abundance and half-life it can be calculated that this produces, within our bodies, about 300,000 disintegrations per minute, 24 hours a day, all our lives.
Potassium-40 - Wikipedia, the free encyclopedia

If not, there's an app for that.

[BlasterBates]

In Iran there's a town where the background radiation is of the order of about 100 mSv, and apparently the life expectancy is higher than average.