Radioactivity and Air Dose Rate

（2020）

ＱHow can radioactive Cs in a solid phase material such as soil be analyzed?

ＡWe analyzed the properties of radioactive Cs using instruments based on different principles, depending on the purpose.

Property	Geometry, elemental composition, and elemental distribution on the surface	Elemental distribution and isotopic composition on the extreme surface	Internal structure and elemental composition
Analytical instrument	Electron probe micro analyzer (EPMA)	Time-of-flight secondary-ion mass spectrometry (TOF-SIMS)	Transmission electron microscope (TEM)
Principle	An electron beam is applied on the surface of the sample to measure the ejected secondary electrons or transmitted X-ray. （Source：JEOL website）	An ion beam is irradiated on the sample to analyze the resulting mass of ions (secondary ions) ejected from the surface of the sample. (Source : ULVAC-PHI brochure）	An electron beam is irradiated on a thin-sliced sample to detect the transmitted electron beam. (Nanometer-scale objects can be observed.) （Source：JEOL website）
Example of analysis result	We examined the elemental composition and distribution of soil particles to which Cs was adhered. ¹⁾ From those analysis results, we identified the constituent elements of minerals coexisting with Cs at the same location on the soil particles.	We measured the isotopic abundance of Cs (e.g., ¹³³Cs, ¹³⁷Cs) in environmental samples containing Cs. ²⁾ From the results, we examined radioactive Cs in the environmental samples to determine whether they were derived from nuclear testing in the past or by accident at 1F; if the latter, which unit of 1F.	We observed soil particles and other objects collected at rivers to which Cs was strongly adhered. ³⁾ Based on the results, we confirmed that Cs was strongly adhered to both clay and weathered minerals.

Property

Geometry, elemental composition, and elemental distribution on the surface

Elemental distribution and isotopic composition on the extreme surface

Internal structure and elemental composition

Analytical instrument

Electron probe micro analyzer (EPMA)

Time-of-flight secondary-ion mass spectrometry (TOF-SIMS)

Transmission electron microscope (TEM)

Principle

An electron beam is applied on the surface of the sample to measure the ejected secondary electrons or transmitted X-ray.

（Source：JEOL website）

An ion beam is irradiated on the sample to analyze the resulting mass of ions (secondary ions) ejected from the surface of the sample.

(Source : ULVAC-PHI brochure）

An electron beam is irradiated on a thin-sliced sample to detect the transmitted electron beam. (Nanometer-scale objects can be observed.)

（Source：JEOL website）

Example of analysis result

We examined the elemental composition and distribution of soil particles to which Cs was adhered. ¹⁾

From those analysis results, we identified the constituent elements of minerals coexisting with Cs at the same location on the soil particles.

We measured the isotopic abundance of Cs (e.g., ¹³³Cs, ¹³⁷Cs) in environmental samples containing Cs. ²⁾

From the results, we examined radioactive Cs in the environmental samples to determine whether they were derived from nuclear testing in the past or by accident at 1F; if the latter, which unit of 1F.

We observed soil particles and other objects collected at rivers to which Cs was strongly adhered. ³⁾

Based on the results, we confirmed that Cs was strongly adhered to both clay and weathered minerals.

Radioactivity and Air Dose Rate

ＱHow can radioactive Cs in a solid phase material such as soil be analyzed?

ＡWe analyzed the properties of radioactive Cs using instruments based on different principles, depending on the purpose.

Related articles

Reference