Fast Neutron Measurement System Using Prompt Gamma Neutron Activation Solid Converter: Monte Carlo Study

Area of Science:

• Nuclear Physics
• Radiation Detection and Measurement

Background:

• Accurate measurement of fast neutron emissions is vital for environmental monitoring and radiation safety.
• Existing hydrogen-recoil proportional-counters have a detection threshold of 2 MeV, limiting the detection of lower-energy fast neutrons.
• Prompt Gamma Neutron Activation (PGNA) converters offer a method for detecting fast neutrons via prompt gamma emissions.

Purpose of the Study:

• To expand the capability of PGNA converters based on potassium chloride (KCl) for detecting fast neutron energies from 0.02 MeV to 3 MeV.
• To improve the detection performance of PGNA converters for fast neutron emissions.
• To investigate methods for optimizing KCl-based converters for enhanced fast neutron detection.

Main Methods:

• Utilized MCNP simulations to model a counting system with various PGNA converters based on KCl.
• Employed a previously established counting system comprising a large KCl converter and a NaI(Tl) gamma radiation spectrometer.
• Investigated the efficiency of KCl converters for fast neutron prompt gamma emission, noting the advantage of naturally occurring potassium radioisotope gamma rays for stable background detection.

Main Results:

• KCl mixtures combined with other elements as PGNA converters demonstrated improved detection performance for fast neutron emissions.
• The study successfully explicated methods for adding materials to KCl to create effective converters for fast neutrons.
• The enhanced PGNA converters show potential for detecting neutron energies in the range of 0.02 MeV to 3 MeV.

Conclusions:

• Optimized KCl-based PGNA converters can effectively detect fast neutrons in the lower energy range (0.02-3 MeV).
• The integration of specific materials into KCl converters significantly enhances their detection capabilities for fast neutron emissions.
• This advancement is critical for improving radiation safety and environmental monitoring protocols around particle accelerators.