Neutron activation in interrupted neutron beams

Area of Science:

• Nuclear physics
• Radiation detection and measurement
• Medical physics

Background:

• Neutron activation analysis (NAA) is crucial for material characterization and quality assurance in Boron Neutron Capture Therapy (BNCT).
• Beam interruptions during NAA can lead to nuclear decay, complicating accurate quantification of activated atoms.
• Existing methods may require complex calculations or frequent experimental setup resets after interruptions.

Purpose of the Study:

• To develop a robust formalism for calculating activated atoms during neutron beam interruptions.
• To introduce simplified correction methods for nuclear decay during pauses in irradiation.
• To quantify the error associated with these simplifications and establish limits for interruption durations in BNCT quality assurance.

Main Methods:

• Derivation of a new formalism for neutron activation measurements with beam interruptions.
• Development and presentation of two simplified methods for correcting nuclear decay during pauses.
• Quantification of simplification errors using Manganese (Mn) and Gold (Au) activation targets under typical BNCT quality assurance conditions.
• Establishment of upper limits for interruption durations to maintain measurement accuracy.

Main Results:

• A simple and robust formalism for neutron activation analysis with beam interruptions was derived.
• Two simplified correction methods for nuclear decay during pauses were presented with associated equations.
• The error of these simplifications was quantified for Mn and Au targets, with established interruption duration limits to minimize uncertainty.
• The methods enable accurate quality assurance measurements in BNCT despite beam pauses, avoiding setup resets.

Conclusions:

• The developed methods allow for accurate neutron activation measurements even with beam interruptions, crucial for BNCT quality assurance.
• Simplified correction techniques effectively account for nuclear decay during pauses, within defined interruption time limits.
• These findings facilitate efficient and reliable quality assurance in BNCT by accommodating beam interruptions without compromising data integrity.