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    Radiation monitoring post (the west for Hodogaya Ward France) (1m above the ground)  


1. Measurement contents

 In Yokohama-shi, we started the regular measurement of atmospheric γ (gamma) dose of radioactivity in 1m above the ground point in radiation monitoring post which we installed in west municipal ownership place for Hodogaya Ward France on March 29, 2012.
 In addition, as for the radiation doses such as authorization nursery school, private nursery school, elementary school, junior high school, park, please see page of "radiation related information". 

2. Measurement data

* We update data every about one hour, but update may be late by trouble of data transmission.
* Indication of "-" is time when we were not able to display measurements by maintenance. Measurements that we can restore display later.
* It is gray every hour [nGy/h]) nanoas for the unit of measurements. As can exchanging to 1 nano gray every hour in [nGy/h] = 0.001μSv/h [μSv/h], for example, in [nGy/h], it is in 0.050μSv/h [μSv/h] in 50 nano gray every hour.
* All data after March 29, 2012 click this, and please see. In addition, CSV data, please click this.
* Please read size of browser in middle size or less. We can switch from "size" in indication menu.

Graph plotted the maximum on the day. Past graph, please click this.

※We can read data in portable site




3. Measurement location, measuring instrument of Yokohama-shi

 (1) Measurement location
  1m above the ground point in municipal ownership place of west 21-1 for Hodogaya Ward France
 (2) Measuring instrument
  Model name                  MAR-22 type (product made in Hitachi Aloka Medical Corporation)
  Detector               NaI(Tl) scintillation detector DBM method
  Measurement lines class            γ (gamma) line
  Measurement unit            Nanogray every hour [nGy/h]
  Dose rate measurement is    1-10,000 nano gray every hour [nGy/h]

4. Conversion of gray and sievert

 [Gy/h] is credit indicating quantity of energy which radiation has in gray every hour. [Sv/h] is credit to express size of influence that radiation gives in the human body in sievert every hour.

[conversion table] When we assume 1 Gy = 1Sv

   Gy/h  Gray every hour    1  Sv/h   Sievert every hour
 1,000  mGy/h  Millimeters gray every hour    1,000  mSv/h  Millisievert every hour
 1 million  μGy/h  Microgray every hour    1 million  μSv/h  Microsievert every hour
 1 billion  nGy/h  Nanogray every hour    1 billion  nSv/h  Nanosievert every hour


5. Reference about measurements

 Environmental Planning Bureau Environment Administration Division monitoring center telephone 045-671-3507 (weekdays from 8:30 to 17:15)

City of Yokohama, Environmental Planning Bureau environment Maintenance Division Environment Administration Division - March 29, 2012 Making - August 8, 2013 Update
Opinion, inquiry - ks-kankyokanri@city.yokohama.jp - telephone: 045-671-2487, 2474 - FAX: 045-681-2790
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