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The radiation dose measurement situation in school grounds of Yokohama city school

●Measurement contents
 It is elementary school about school grounds of city school: Surface of the earth 50cm, junior high school: We measure at position of surface of the earth 1m

The measurement situation

[all 491 Municipal Elementary Schools, junior high school radiation result of a measurement] (Portable Document Format, from June to September result of a measurement summary)

●Measuring instrument

(A)  Gauger         City of Yokohama, Fire Bureau

       Model name      RDS -30 (product made in million technology company)
       Detector       Energy compensation type GM pipe
       Measurement lines class    γ (gamma) line
       Measurement unit    μSv/h
       Dose rate measurement range 0.01μSv/h - 100mSv
             Or it is 1μrem/h - 10μrem/h

(B)  Gauger         Yokohama-shi school pharmacist society

       Model name      TCS-172B (product made in Hitachi Aloka Medical Corporation)
       Detector     Na I (TI) scintillation detector
       Measurement lines class    γ (gamma) line
       Measurement unit    μSv/h
       Dose rate measurement range 0.01μSv/h - 30mSv

      [we get cooperation of Yokohama-shi school pharmacist society after Friday, August 12 we add measuring instrument of (B) and measure.]


About difference of measuring instrument

Generally, measurements of GM counter (A) are paid in comparison with scintillation detector (B) highly.
This is difference of difference in mechanism of apparatus.
For example, scintillation detector is sensitive to radiation of constant direction, and measurements tend to appear highly because GM counter is sensitive to lateral radiation dose.

In addition, about difference in measurements by difference in kind of apparatus, we guide site of Tokyo security research center as reference.

Board of Education Secretariat Education Institution Section - April 02, 2012 making update
Opinion, inquiry - - Telephone: 045-671-3299 - FAX: 045-664-4743
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