Recent developments in ultra low-level gamma-ray spectrometry at IRMM

Area of Science:

• Nuclear physics and instrumentation
• Low-background radiation detection
• Applied metrology

Background:

• Ultra low-level gamma-ray spectrometry is crucial for sensitive measurements.
• The underground HADES laboratory offers a unique low-background environment.
• Previous detectors at IRMM had limitations in background characteristics.

Purpose of the Study:

• To introduce and characterize a new low-background coaxial HPGe detector.
• To evaluate the performance of the upgraded shielding for gamma-ray spectrometry.
• To demonstrate applications in nuclear safeguards and material selection.

Main Methods:

• Installation and operation of a third coaxial HPGe detector with 60% relative efficiency.
• Construction of a new shield using 14 cm of lead (210Pb specific activity 20 Bq kg-1) and 14 cm of electrolytic copper.
• Measurement of background count rate in the HADES underground laboratory.

Main Results:

• The new detector exhibits improved background characteristics compared to previous systems.
• The integrated background count rate from 40 to 2700 keV is 394 ± 2 counts per day.
• Detailed background spectra and shielding performance are presented.

Conclusions:

• The upgraded facility significantly enhances ultra low-level gamma-ray spectrometry capabilities.
• The new detector and shielding are suitable for sensitive applications in nuclear safeguards.
• The system facilitates precise material selection and characterization through advanced spectrometry.