GOOGLE EARTH – Japan Levels - Constantly Updated










Radiation levels exceeding state-set limit found on grounds of five Chiba schools — The Japan Times

” Radiation levels exceeding the government-set safety limit of 0.23 microsieverts per hour have been detected on the grounds of five schools in the city of Kashiwa, Chiba Prefecture, the prefectural board of education said Monday.

Between late April and mid-May, the board officials detected radiation levels of up to 0.72 microsieverts per hour in certain areas of the schools, including Kashiwa High School and Kashiwa Chuo High School. The areas — including soil near a school swimming pool and drainage gutters — are not frequented by students, but the board closed them off and will work to quickly decontaminate them, the officials said.

Kashiwa has been one of the areas with high radiation readings since the 2011 nuclear disaster at Tokyo Electric Power Company Holdings Inc.’s Fukushima No. 1 power plant.

According to NHK, the board of education had been checking the soil on the school premises in Kashiwa after radiation levels beyond the state limit were detected in shrubbery near the city’s public gymnasium. The board will announce the results of radiation tests at other schools in the prefecture around the end of July, NHK reported. ”

by Kyodo, The Japan Times 



MEASUREMENTS : Units of Ionizing Radiation

This is an ongoing collection of conversion factors used to change a radiation reading into another type of measurement.

Picocuries per liter (pCi/L) multiply the amount by 0.037 to get becquerels per liter (Bq/L)

What is a Sievert?
What is a Gray?
What is a Rad?
What is a Curie?
What is a Becquerel?
What is a Roentgen?

What Is CPM in Radiation? - SOEKS

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What Are Counts Per Minute in Radioactivity?

When you get a Geiger counter and are learning how to use it, you’ll need to know about CPM, which is the counts per minute that you’ll see displayed on the analog meter in addition to the corresponding level of radiation. You might sometimes see counts per second, or CPS, instead, or you can easily convert from CPM to CPS if you’d like by dividing your CPM value by 60. So what is the CPM reading all about?

How Does CPM Work?

The counts per minute measurements are generally used to pick up the amount of particles around, which could include alpha or beta particles. A different level of measurement tends to be used for rays, including gamma rays and X-rays.

Instead of showing how much radiation something is giving off, the CPM radiation levels tell how many detection events the meter picks up. So the CPM amount doesn’t show you the amount or strength of the radiation. The device that you’re using to measure radiation can then also tell you the dose rate, although the conversion from CPM to dose rate will vary based on your specific device and some other factors, such as the kind of radiation. A Geiger meter uses energy compensation to create a reading of the dose.

While the measuring rate is “counts per minute,” the device often takes a sample from less time than the full minute and then determines what the total would be for the minute based on that sample.

What Does the CPM Value Mean?

Once you get your CPM reading from your device, you then need to figure out what that reading means. What are normal radiation levels CPM and what are dangerous ones? If you have your Geiger counter calibrated to Cs137, which most are, 1 milliRad per hour would equate to 1,200 CPM on your counter. At the same time, 1 microSievert per hour would equate to 120 CPM on the reading. These are more universal units of measurement that can help you better understand your radiation exposure.

A CPM reading of at least 100 is considered a warning level by the Radiation Network, although the length of time you’re exposed to the radiation is an important factor. If you’re concerned about staying within safe radiation levels, Ken Jorgustin explains on the Modern Survival Blog that it would take 432 days at a CPM of 100 to up your chance of getting cancer to odds of 1 in 1,000. At higher exposure rates, it would take less time. For instance, it would only take four days to increase your rate to those odds if you’re exposed to a level of 10,000 CPM.

When you use a Geiger Mueller detector, you’ll be able to easily see the counts per minute of radiation in a certain area. This can help you understand more about your environment and your exposure.

Units of Measurement (Radiation)

rad = 0.01 gray (Gy)
gray (Gy) = 100 rad

rem = 0.01 sievert (Sv)
sievert (Sv) = 100 rem

Rad and Gray are ‘absorbed dose’ units.
Rem and Sievert are ‘equivalent dose’ units.

Why a Rem and a Sievert?

They relate to biological damage done to human tissue and factor the differences between types of radiation. A multiplication factor is used that represents the ‘effective’ biological damage of a given type of radiation. This is the main reason for these units – to factor the differences in damage that is caused from one type of radiation to the next.

Radiation Factor (QF Quality Factor)
(1) Beta
(1) Gamma
(1) X-ray
(10) Nuetron
(20) Alpha

For example, the list above shows that a ‘rad’ or ‘gray’ unit of ‘Alpha’ energy that is absorbed by soft human tissue does 20 times more damage than a ‘rad’ or ‘gray’ of Gamma, X-ray or Beta radiation.

Radioactivity or the strength of radioactive source is measured in units of becquerel (Bq).

1 Bq = 1 event of radiation emission or disintegration per second.

One becquerel is an extremely small amount of radioactivity. Commonly used multiples of the Bq unit are kBq (kilobecquerel), MBq (megabecquerel), and GBq (gigabecquerel).

1 kBq = 1000 Bq, 1 MBq = 1000 kBq, 1 GBq = 1000 MBq.

An old and still popular unit of measuring radioactivity is the curie (Ci).

1 Ci = 37 GBq = 37000 MBq.

One curie is a large amount of radioactivity. Commonly used subunits are mCi (millicurie), µCi (microcurie), nCi (nanocurie), and pCi (picocurie).

1 Ci = 1000 mCi; 1 mCi = 1000 µCi; 1 µCi = 1000 nCi; 1 nCi = 1000 pCi.

Another useful conversion formula is:

1 Bq = 27 pCi.

Becquerel (Bq) or Curie (Ci) is a measure of the rate (not energy) of radiation emission from a source.


How much radiation is too much? – PBS



Videos from British Columbia :

Radiation From Fukushima Has Reached The BC Coast
April 2015


Videos from Japan :



“Im waking up, to ash and dust, I wipe my brow, and sweat my rust, I’m bringing in the chemicals..” Radioactive (Image Dragons)