Activity standardisation of ³²Si at IRA-METAS

Area of Science:

• Nuclear physics
• Geochronology
• Radiochemistry

Background:

• The SINCHRON project aims to improve geochronological dating by precisely measuring the half-life of silicon-32 (³²Si).
• Accurate standardization of ³²Si activity is crucial for reliable dating applications.
• Long-term stability studies of ³²Si solutions were conducted to determine optimal sample composition and vial types.

Purpose of the Study:

• To establish a primary activity standard for ³²Si.
• To precisely measure the half-life of ³²Si.
• To validate measurement techniques for ³²Si standardization.

Main Methods:

• Liquid scintillation counting (LSC) using the triple-to-double coincidence ratio (TDCR) technique.
• CIEMAT-NIST efficiency tracing (CNET) method for LSC standardization.
• 4πβ-γ coincidence counting with ⁶⁰Co as a tracer for complementary measurements.

Main Results:

• ³²Si solutions in hexafluorosilicic acid (H₂³²SiF₆) demonstrated adequate stability over extended periods.
• TDCR and CNET methods provided consistent results for ³²Si activity standardization.
• ⁶⁰Co coincidence tracing with a liquid scintillator corroborated the LSC results.
• Plastic scintillation proved unfeasible due to crystal formation issues during sample preparation.

Conclusions:

• The developed methods are suitable for the primary activity standardization of ³²Si.
• Precise half-life measurements of ³²Si are achievable, contributing to the SINCHRON project's goals.
• Liquid scintillation counting techniques are recommended for future ³²Si standardization efforts.