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Roppongi Hills

April 29, 2011 in Uncategorized

Radiation reading taken directly on top of the pavement under the spider statue at Roppongi Hills, April 28, 2011. Reading is 87microRads/Hr (0.87microSv/Hr).
Background radiation in the subway is 8-9microRads/Hr and going up the esculator is 13microRads/Hr.
This is the 4.6cm diameter pancake Geiger tube which is sensitive to Alpha, Beta and Gamma radiation. The readings take a few minutes to stabilize due to an averaging algorithm with a time constant of 2-3 minutes.
When I located the counter on the soil the display began to drop off and there was very little clicking, so there is clearly no elevated levels there only on the concrete paving surfaces.

1 response to Roppongi Hills

  1. After it rains would be interesting to test again, see if it is higher or washed away.

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