# How much radiation is there in a banana

## Banana can equivalent

I had already written that bananas emit a lot of radioactive radiation (at least more ionizing radiation than a cell phone), but so far I had completely concealed the fact that you can also measure radioactivity with bananas. Well, we are currently trying to build a banana detector in vain, but we can at least express the measured radioactivity in bananas, in so-called banana equivalent doses.

We have the problem that people can hardly imagine anything below a dose in (µ) Sievert and we admit that the explanation is not that simple either. The definition of a dose is based on the deposited energy, but statements can be made such as:

If 100 people don't get extra radiation, 30 of them will get cancer.

If 100 people get 1 extra Sievert, 35 of them will get cancer and of those 5 extra cancers from the extra radiation, 4 will be fatal.

This statement is extremely simplified and so imprecise that every scientist sets up his toenails. Nevertheless, hardly anyone can do anything with it, because 1 Sievert is much more than any of us will get in his life and then to oppose an abstract figure of “5% cancer risk extra” ... you can argue directly with bananas.

This would then work as follows: The banana contains about 0.4g of healthy potassium. All natural potassium consists of the radioactive potassium isotope K40 in a proportion of 0.01% and this ensures that our banana emits an activity of approx. 12 Becquerel (decays per second) of radioactive beta and gamma radiation. If I were to eat this banana and also incorporate the potassium into my body, I would get a dose of approx. 0.1 µSv per banana.

So if we were to assume that a banana (or short BED for banana equivalent dose) corresponds to 0.1µS, most people can do a lot more with it. That is a unit that can be dealt with. For example, on my bridge in the research reactor, I may not exceed 3µSv / h. In other words, if I got the maximum there, then I would get as much radiation as if I were to eat 30 bananas an hour.

It is also reported that during CASTOR transports there was increased radiation of 50 µSv / h in the area, which in turn would correspond to 500 bananas per hour. An immediately fatal dose would be 35 megabanana doses or 35,000,000 BED.

Admittedly, even in my most athletic times, I never tried to eat 30 bananas, but if my mother is afraid that I would get radiation, then I can say: “I received as much radiation a week as I did in 300 bananas stuck. "That 300 bananas is not normal, but still relatively harmless, reveals itself quite well to mMn. It also works the other way around, because if I had received an (impermissibly high) dose of 30mSv as a result of an accident, I would have to tell my mother: "I received as much radiation as there is in 300,000 bananas. I have to go to the hospital now." Even the biggest banana fan will have to admit that 300,000 bananas are unhealthy.

Well, the whole thing is not really correct, because if I eat a lot of bananas, then my body only absorbs the potassium up to a certain maximum and the rest is excreted again and if I were to pile up a pile of 300,000 bananas, Then it would be the bananas inside this pile are so far away from me that no radiation from them would reach me, even if I were to sleep on the mountain of bananas. But I think the principle is clear, even if it might give the poor bananas a bad name.

I had already written that bananas emit a lot of radioactive radiation (at least more ionizing radiation than a cell phone), but so far I had completely concealed the fact that you can also measure radioactivity with bananas ...