Walking survey technique for ambient gamma dose rate measurement established in Fukushima Medical University

ABSTRACT

This study aimed to establish a walking survey technique for rapidly determining the distribution of the ambient gamma dose rate. The measurement system consists of a scintillation spectrometer and a Global Positioning System receiver, which are controlled using a laptop. In addition to locality information, the ambient gamma dose rates were measured continuously and corrected based on shielding by the measurer body. The measurement interval was optimized at 12 s based on the locality resolution and fluctuations of the measured dose rates. A comparison was also made between the dose rate distribution maps depicted by the walking survey technique and spot measurements at fixed points. Based on the measurement data selected for the comparison, it was found that the values of 80% of the data obtained using the walking survey technique deviated within ±20% relative to those obtained by spot measurements. Compared to the spot measurements, the time taken to depict the map was reduced to one-fifth, and the localized contamination points could be depicted.

KEYWORDS:

• Ambient dose equivalent rate
• gamma radiation
• nuclear power plant accident
• survey meter
• walking survey technique

Acknowledgments

The authors would like to thank the faculty of the Radiation Disaster Medical Center in Fukushima Medical University for arranging the use of the survey meters. This work was partly supported by JSPS KAKENHI Grant Number JP20H04318.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the JSPS [JP20H04318].