|Radiation Activity Fallout Measuremen|
AIST measures energy spectra of the ionizing radiations from fallout using a Germanium semiconductor detector.
The fallout sample is obtained by smearing on a vinyl sheet, which is the size of 1 m times 1.5 m and put on the ground at AIST.
The following figure shows the energy spectra of the ionizing radiation from the fallout sample (red) and background (blue).
We found radionuclides of Te-132, I-131, I-132, I-133, Cs-134, and Cs-137.
These radionuclides are expected to be released from the nuclear power plants
at Fukushima because these are not exist in the environment.
Photon energy spectra from the fallout sample smeared
on the vinyl sheet on the ground at NMIJ measured on
March 15, 2011 (red) and March 19, 2011 (green). The blue curve shows the background.|
The following data show the change of the radioactivity of these radionuclides.
(2) The measured values change slightly due to sampling conditions.
(3) The sampling time changes due to rain.
Change of the radioactivity of the detected radionuclides
Germanium semiconductor detector system at NMIJ