Considerations for massic activity determination by Decay Energy Spectrometry (DES) using cryogenic Transition Edge...

Area of Science:

• Nuclear Physics
• Metrology
• Radiochemistry

Background:

• Decay Energy Spectrometry (DES) with cryogenic Transition Edge Sensors (TES) is a powerful technique for radionuclide activity standardization.
• Its 4π geometry, high efficiency, and resolution allow for precise quantification, including difficult-to-measure impurities, without chemical separation.

Purpose of the Study:

• To develop and validate new methods for DES sample preparation, TES chip design, and data analysis.
• To address challenges in accurate source deposition, pulse pileup, and pulse shape variability for primary standardization.
• To achieve relative combined standard uncertainties below 1% for DES measurements.

Main Methods:

• Development of novel DES sample preparation techniques for microgram source deposition.
• Implementation of advanced TES chip designs and data analysis algorithms.
• Inclusion of live-timing, dead time extension, and pileup exclusion for accurate counting.
• Correction of systematic errors specific to DES data acquisition.

Main Results:

• Accurate massic activity and isotopic ratio measurements for ²⁴³Am sources with ²⁴¹Am impurity.
• Demonstration of relative combined standard uncertainties below 1% after applying corrections.
• Excellent agreement between DES and liquid scintillation (LS) counting for ²⁴³Am massic activity (A_DES/A_LS=1.000±0.005).

Conclusions:

• The developed methods significantly improve the accuracy and reliability of Decay Energy Spectrometry.
• DES is validated as a primary standardization method capable of achieving high precision.
• The technique shows great potential for routine application in nuclear metrology and radiochemistry.