Tuesday, March 20, 2012

Japan, Radiation - buying and using a Geiger counter.

This Article needs help updating.  If you see any inconsistent information, please let me know in a comment.
If you are living in Japan and have wondered if you should buy a Geiger counter, here are a few things to consider.

1: The Japanese government is not testing all products.  The government is doing random tests of foods mostly from the Fukushima area, but some grown outside Fukushima as well. Information about the tests the government have done can be found at http://atmc.jp/food/. Plenty of food is going to market without ever being tested.

2: Just because a product has been tested and discovered to contain radioactive cesium or iodine, doesn't stop it from reaching the market.  Japan has specific levels of radiation allowed in the food that can be sold.

3: There is no such thing as a "safe" level of radiation.  Any radiation can cause cancer.  Generally, the less, the better.  Though radiation outside of your body is usually brief and when you move away from the radiation source you no longer are in danger.  Food you eat is a different story entirely.  The radiation in food can easily be stored and used by your body.  When this happens, the radioactive particles don't go away and continue to expose your internal organs to harmful radiation for the rest of your life.

4: The Japanese government is only testing for Cesium and Iodine.  They are not testing for uranium, strontium, plutonium or any other number of radioactive particles that are created by the three dai-ichi nuclear power plants that melted down; Even though radioactive Strontium has been found 250km away from fukushima in Yokohama. See this link for more information.

5. Many foods are not labeled as to where they come from and none of it is policed by any organization.  There are laws for some products but no enforcement for those laws.  For more information on food safety, please watch this excellent youtube video: Food safety in Japan.

6. Food is not the only consumer product that is contaminated with radiation.  Used cars are another recent danger.  Please see this link and this link. How many other products might have radiation contamination that you never would have considered?

7. Radiation "hot spots" can be found hundreds of kilometers from Fukushima.  These are areas you should avoid if you know about them.  There may be areas you frequently visit.  Have those areas been tested yet?

Buying and using a Geiger counter.

There are hundreds of Geiger counters on the market.  Some ranging in price from tens to thousands of dollars or thousands to hundreds of thousands of yen.  Even if you buy a Geiger counter, would you know how to use it?  How do you use a Geiger counter?  What is a Geiger counter?  Let me answer these questions for you.

What is a Geiger Counter?

The word Geiger comes from the use of a Geiger-Muller tube.  A Geiger-Muller tube is a metal tube containing a noble gas and electrical leads.  When radiation passes through the tube, it creates an electric charge or pulse.  The word counter means to simply count the amount of pulses over a specified amount of time. Geiger-counter.

You may know a Geiger Counter as a device that measures radiation.  But there are many devices and many names for the same thing.  Here is a list.

Geiger Counter
Survey meter

They all measure radiation in some way.   A geiger counter usually measures with a Geiger-Muller tube, and the others can use the Geiger-Muller tube or a scintillation detector. A scintillation detector is a much more sensitive detector.

Most Geiger-Counters are hand held units where you can't even see the tube.  They can be inexpensive, but are not very sensitive.  Meaning, you can use one to test radiation and find hot spots, but for checking food you won't get a very good reading.

For testing food, you need a survey meter, scaler, or ratemeter. Any of these will be a boxlike device with a handle and either an analog display or a digital numerical display.  They will have a cable and a probe detector that connects to them.  The probe can be a Geiger-Muller tube or a Scintillation detector.  These units can cost a few hundred to a few thousand dollars or ten thousand to a couple hundred thousand Yen. These units can be much more sensitive than the standard Geiger counter and are necessary for testing food.

Buying a Geiger counter, scaler, ratemeter or survey meter.

When buying one of these radiation detectors, the price can be a major stumbling block.  A $500 unit in the USA could run you double that in Japan.  I am not exactly sure why.  I decided to buy a Ludlum model 3, model 2241-2 or model 2221. (click the models to see their perspective pages.) I found the price at Ludlum's website for each of these units. But the pricing is domestic pricing (USA pricing) only.  They won't ship the item to you outside of the USA.  You must contact one of their licensed sellers in Japan.  The licensed sellers quoted prices 2.2x higher than the USA, even though the US dollar is so weak, and the Japanese Yen is so strong.  When asked why the price was so high I was given this response.

"Your price was US domestic price of Ludlum, here is Japan.

The cost is not only ludlums equipment, such as transportation, consumption
tax, insurance and remmitance charge, so about twice.
And instruction translation cost for Japanese peaple and some informations
such as attached pdf files are included."

But later, he said he would give me a discount of 10% and then said I would have to pay tax which he stated above was included in the earlier price he quoted me.

Ludlum is not willing to sell to me directly because they need an End-User agreement.  Some countries they are not allowed to sell their products to. The End-User agreement just says that they have made sure to the best of their ability that they are not selling a product that could get in the hands of, for instance, someone in North Korea.

One of the more important parts of buying a meter and detector new is calibration.  Calibration means to set the unit to be as sensitive as possible without error.  Calibration is not something the layman can do on their own.

If you don't mind buying a used meter or can find a unit that has been recently calibrated for the detector it comes with, you can save a lot of time and money.  If you buy a used unit for example on Ebay, and the seller is willing to ship it to you in Japan, then you can save more than 50% on the price. 

What Geiger counter should you buy?

If you just want to test areas for hotspots, any geiger counter should do. I would suggest the SOEKS Ecotester.  which is the unit at the bottom left of the picture.

If you want to test your garden soil, or the food you buy then you are going to need a much more sensitive unit.  for these measurements, you should get a survey meter of some sort, and a GM pancake detector.  An example is the top left unit in the picture.  That is a Johnson survey meter and pancake probe.  It could run you from $600 to $2000 used.

Another option is a survey meter and scintillation probe. Scintillation probes are often made of Sodium Iodide Crystals that are reactive and glow in the presence of radiation. They are very sensitive, but won't detect all radiation like the pancake probe, which is a problem since there are three kinds of radiation. The three kinds of radiation are Alpha, Beta and Gamma.  For more information on these, please come back for my next article.

How to use a Geiger counter?

Geiger counters give readings in the following:

CPM: Counts Per Minute, corresponding directly to the audible beeps or clicks per minute.  CPM is the standard unit of measurement for alpha and beta radiation, and is also commonly used to express background radiation in numerical terms.

mR/hr: milli-Roentgens per hour, or 1/1000 of a Roentgen per hour, a standard unit of measurement for radioactivity, popular in the United States and Israel.

µR/hr: micro-Roentgens per hour, or one millionth of a Roentgen per hour.

mSv/hr: milli-Sieverts per hour.

µSv/hr: micro-Sieverts per hour, a standard unit of measurement for radioactivity, popular in Canada and overseas.

Any one of these can be converted to the other fairly simply, but it is best to have a unit that measures using the unit of measurement you are most familiar with.

Each unit will have it's own special settings but here is an explanation of  how you should measure the radiation in food using a CDV-700 and standard GM pancake probe.

1. Set the unit where you will be testing the food before you put the food down for testing.

2. Test the ambient radiation for at least 5 minutes, or more for a better reading of ambient radiation.  Record that number

3. Add your food to the test.  Test again for at least 5 minutes.

4.Subtract your ambient radiation reading from the new reading.  Anything left over would be the radiation output of the food.

If you do this test many times and average the results, you will have a much more accurate account of the radiation content of the food.

Without a spectrometer, there is no way to know what radioactive elements might be in the food you test. A cheap spectrometer will run you $5,000 or more, and they won't be very accurate until you get into the tens of thousands. At least with this method you can test your food and throw anything away that shows a large increase in radiation measurement. Any radiation is bad, and it shouldn't be necessary to know exactly what radioactive elements you are dealing with.  Just throw anything that is radioactive in the trash.

You  can also use this same technique for measuring soil radiation.  Later, I will give a list of all the places and things you will most want to check for radiation.  Keep coming back for more!

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