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Radioactivity and Air Dose Rate

（2015）

ＱHow were the reliabilities of the environmental measurements verified?

ＡWe verified the reliabilities of the measurements in three ways:
(1) calibrating the measurement instruments using a standard radiation source with a known accurate intensity
(2) obtaining comparative measurements using multiple measurement instruments
(3) having external experts check the obtained results.

◆ Performance verification of KURAMA-Ⅱsystem

The capability of obtaining measurements at the precision specified by the criteria in the JIS standard was verified using a standard radiation source.

Calibration system with a standard radiation source

Fig.1　Calibration system with a standard radiation source

  • Fluctuations of measured values by direction of incidence

    Fig.2　Fluctuations of measured values by direction of incidence

  • Fluctuations of measured values by energy

    Fig.3　Fluctuations of measured values by energy
    （Tsuda et al, 139: 260-265 (2015)）

In addition to checking the measurement systems and methods by calibrating and comparing the measurement instruments, the validity of the measurement results was verified by a committee of external experts.

◆ Comparison of in situ measurements using a portable Ge semiconductor detector

  • Scene showing comparison of results

    Fig.4　Scene showing comparison of results

  • Results of comparison

    Fig.5　Results of comparison

    Similar inventory values were checked to ensure that they had been measured at the same position.
    (Mikami et al., Jpn J Health Phys, 50: 182-188 (2015))

◆ Comparison of soil sample measurements using a stationary Ge semiconductor detector

  • Scene showing sample comparison

    Fig.6　Scene showing sample comparison

  • Results of comparison

    Fig.7　Results of comparison

    Similar nuclide concentration values were checked to ensure that they had been measured on a common sample.
    (Report on Preparation of Distribution Map of Radiation Doses, etc. (Part 1))

Related articles

References

  1. Tsuda, S., Yoshida, T., Tsutsumi, M. and Saito, K. (2015): Characteristics and verification of a car-borne system for dose rate in air: KURAMA-II, Journal of Environmental Radioactivity, vol. 139, 260-265. https://doi.org/10.1016/j.jenvrad.2014.02.028
  2. Mikami, S., Sato, S., Hoshide, Y., Sakamoto, R., Okuda, N. and Saito, K. (2015): In situ gamma spectrometry intercomparison in Fukushima, Japan, Japanese Journal of Health Physics, vol. 50, no. 3, 182-188. https://doi.org/10.5453/jhps.50.182