My friend, Mike Kirk, is an executive at a Silicon Valley tech firm, and he recently returned from a business trip to Japan (less than 2 months after Fukushima).

One of his destinations was 50 miles from the crippled Fukushima Daiichi nuclear power plant. As a precaution, a colleague gave him a Geiger Counter so he could make sure it wasn’t getting dangerous as he approached the plant.

Maybe they assumed he would turn it on when he hit the ground… Instead, he logged the whole trip, and you can see the relative peaks of radioactivity.

The AFL-CIO has a nice primer on Cosmic and Solar Radiation: Facts for Flight Attendants, reminding us that higher altitudes and latitudes raise the exposure; radiation levels at the poles are ~2x those at the equator for example. So the shorter-hop flights might be lower altitude… and the night flight is better, but the long trans-Pacific flights look very different. I’ll add flight details in the notes above in case that helps as a clue.

I can hear it now…
Please turn off all electronic devices, anything with an on-off switch, especially Geiger counters, as the sound just makes us all a bit twitchy.

(PPT posted with permission. Do keep in mind that these are radiative exposures. Ingesting radioactive particles is a completely different risk and would not map on this chart)

54 responses to “Radiation in Japan”

  1. ok, posted simulaneously again:D

  2. Remembering that exposure to environmental radiation from flights, etc. is a very different animal from ingestion of radioactively decaying particles. There’s low enough radioactivity now at much of Chernobyl for limited tourism. But DON’T eat the grass. Or even mushrooms and wild boar from much of Eastern Europe. Cesium can bite you back.

  3. @Steve Jurvetson Sorry, this chart means absolutely nothing – the reference isotope is Cs137. Mike should have set it to show raw counts – the Sieverts conversion based on Cs137 alone is completely wrong. (From the manual p2: "The conversion from impulses per time into the dose rate is based on Cs-137").

  4. I asked about that and he replied: "I can go back to my friend’s device and see what calibration or scale setting there are on it. But my gut reaction is that anything like that would just reset set the vertical scale globally vs some non-linear correction (if you saw this thing you would be surprised if it had anysmarts at all). So I would claim that it still shows the relative difference to being on a plane vs SFO Vs 50 miles from the power plant.
    Let me check if there is something more complicated than that with the device."

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