A precise method to determine the activity of a weak neutron source using a germanium detector

Area of Science:

• Nuclear physics
• Radiation detection

Background:

• Neutron sources are crucial for various applications, including nuclear research and security.
• Accurate characterization of neutron sources, especially weak ones like americium-beryllium (AmBe), is essential for reliable measurements.
• Previous neutron activity data for this specific AmBe source was unavailable.

Purpose of the Study:

• To determine the previously unknown neutron activity of a weak americium-beryllium (AmBe) neutron source.
• To establish a reliable method for characterizing neutron sources using gamma-ray detection and Monte Carlo simulations.

Main Methods:

• Utilized a standard high purity germanium (HPGe) detector to measure gamma rays.
• Induced gamma rays via neutron interactions (n,n') and (n,γ) with aluminum and (n,γ) with hydrogen in acrylic disks.
• Developed a Monte Carlo simulation to model the detector system's efficiency due to the unconventional experimental setup.

Main Results:

• Successfully measured gamma rays resulting from neutron interactions with aluminum and acrylic.
• The Monte Carlo simulation provided an accurate model for the detector system's efficiency.
• The neutron activity of the AmBe source was determined to be 307.4±5.0n/s.

Conclusions:

• The determined neutron activity of 307.4±5.0n/s is consistent across different neutron-induced gamma rays.
• The methodology combining HPGe detection and Monte Carlo simulation is effective for characterizing weak neutron sources.
• This study provides essential data for the accurate use of this AmBe neutron source.