18F half-life measurement using a high-purity germanium detector.

Area of Science:

• Nuclear Physics
• Radiochemistry
• Metrology

Background:

• Accurate knowledge of radioisotope half-lives is crucial for various applications, including medical imaging and nuclear science.
• The radioisotope Fluorine-18 (18F) is widely used in Positron Emission Tomography (PET) imaging, necessitating precise decay data.
• Previous measurements of the 18F half-life have established a reference value, but ongoing verification is important for metrological standards.

Purpose of the Study:

• To perform an independent and precise measurement of the half-life of Fluorine-18 (18F).
• To investigate and quantify systematic uncertainties associated with measuring high-activity 18F sources.
• To compare the experimental result with the recommended value from metrology institutes like LNHB.

Main Methods:

• Utilized High-Purity Germanium (HPGe) detectors for gamma-ray spectroscopy.
• Employed a Cesium-137 (137Cs) reference source for calibration and cross-referencing.
• Applied a weighted least-square method to fit the counting ratio of 511 keV gamma-rays from 18F to 622 keV gamma-rays from 137Cs.

Main Results:

• The measured half-life of 18F was determined to be (109.72 ± 0.19) minutes.
• Detailed analysis of systematic effects related to high-activity 18F measurements was conducted.
• The experimental result shows good agreement with the recommended value of (109.728 ± 0.019) minutes.

Conclusions:

• The precise measurement confirms the established half-life of 18F, validating its use in critical applications.
• The study demonstrates the robustness of the experimental method for determining radioisotope half-lives.
• This work contributes to the ongoing effort of refining fundamental nuclear decay data for scientific and medical purposes.