Radiation Specific FAQ

Some of the radiation-related questions we often get asked:

What kind of Geiger counter should I buy?

  • Short answer: Something by a “Googleable” brand name, that measures alpha, beta and gamma radiation.
  • Long answer: Radiation measurement is not as simple as measuring something like temperature. It’s important that any sensor you purchase actually gives you useful information. A rule of thumb is that any device that gives only “”red/green or “safe/unsafe” feedback may not be adequate – it’s important to know more details about the measurement. It’s also worth thinking about how you will actually intend to use it. If you want to measure radiation in the air and on surfaces near you, then a Geiger counter should meet your needs. If you want to measure food or water contamination or check to see if you or your family have been irradiated, a Geiger counter is not the right kind of equipment and will not help you. We also recommend that you stay away from any company that didn’t sell geiger counters before March, 2011.

    We recommend the SAFECAST bGeigie Nano, of course, which is our current workhorse design. It features GPS and data logging, and if you want to contribute radiation data to our online database then buying and building one of these kits is the easiest way.

  • One caveat: After the 3/11 Fukushima Daiichi event the global demand for Geiger counters skyrocketed. This resulted in both a significant backorder time from major and reputable manufactures that lasted over one year, and in an increase in the availability of less accurate or poorly constructed devices. Because of this it’s very important to make sure any device you buy is reliable.

What level of radiation is “Safe”?

  • Short answer: That’s hard to say.
  • Long answer: Unfortunately there is very little agreement within the health physics world about what is safe and what is unsafe. While there are some things that are generally agreed upon, that children and pregnant women are at greater risk for example, there is no clear level that is universally agreed to be the cut-off point between “safe” and “unsafe.” One school of thought believes that “any amount of radiation is unsafe,” while others say that while even small amounts of radiation exposure can cause damage to cells, and so to health, current guidelines adequately guard against all but the smallest risks (less than many risks people accept easily). What’s most important is being aware of what you and others are exposed to, and finding information that will help you decide if it is acceptable or not. It’s a fairly complex subject, because risk factors differ depending on age, existing health issues, exposure time, areas of exposure, etc.. Therefore risk is best gauged on an individual basis and not generalized for an entire population.
  • One caveat: Individual comfort levels should not be discounted, and different people will be more or less comfortable with various levels. One person’s “safe” could well be another’s “run away!”

Alpha, Beta, Gamma?

  • Short answer: Confusing isn’t it?
  • Long answer: These are the three kinds of radiation that are most commonly associated with nuclear plants. Gamma is very high energy and gamma particles can pass through walls, buildings, and people. A very high dose of gamma radiation can kill a person almost immediately. Alpha and Beta are lower energy, and can be blocked with a sheet of paper or thick clothing. Alpha and beta pose a greater risk if they are inhaled or ingested. The Cs137 that was released by Fukushima Daiichi is primarily a beta emitter which is why food contamination is such a concern.
  • One caveat: A lot of readings that are being published are gamma only, which Safecast doesn’t feel tells the full story.

How can I find out the radiation level near me?

  • Short answer: That’s why we’re here.
  • Long answer: The best bet from our perspective is to check out the maps we link to above. Hopefully some of these will give you useful information. If not, stay tuned or get in touch with us to see when we might be able to get data from your area.
  • One caveat: The world is a big place and until recently no one seemed to be concerned with mapping this kind of info, so it’s a big job. But we’re doing what we can.

Has SAFECAST found evidence of plutonium, iridium, or strontium?

  • Short answer: No
  • Long answer: Other organizations and research groups have documented the detection of these isotopes, generally in very small traces (often at levels equal to what existed before the accident), and occasionally at much higher levels. We feel confident in assuming that these isotopes could be detected in many places in Japan and elsewhere if adequately sensitive equipment were used. But to date no samples that SAFECAST has collected and examined have contained them.
  • One caveat: The SAFECAST team is highly competent and experienced, but we do not have a fully-stocked isotope lab. Because of this some kinds of analysis are beyond our capability, though we have established good relationships with large labs we can occasionally call on for assistance with particularly demanding technical tasks.