CHARACTERIZATION OF A THIN SILICON SENSOR FOR ACTIVE NEUTRON PERSONAL DOSEMETERS.

Area of Science:

• Nuclear instrumentation
• Radiation detection and measurement

Background:

• Active neutron personal dosemeters are crucial for monitoring radiation exposure in high-risk professions.
• Existing silicon sensors can suffer from the funneling effect, leading to inaccurate readings from cosmic protons and neutrons.

Purpose of the Study:

• To develop and characterize a thin silicon sensor for active neutron personal dosimetry.
• To overcome limitations of existing sensors, such as the funneling effect and gamma ray sensitivity.

Main Methods:

• Experimental determination of neutron response functions using monoenergy neutron beams (2.5 and 5 MeV) and a Californium-252 neutron source.
• Monte Carlo N-Particle (MCNP) transport code simulations utilizing a circular truncated cone energy deposition region.

Main Results:

• The thin silicon sensor demonstrates reduced sensitivity to gamma rays.
• An improved energy detection limit for neutrons down to 0.8 MeV was achieved.
• Enhanced sensitivity to fast neutrons was observed.
• Simulation results closely matched experimental data with the modified geometry.

Conclusions:

• The developed thin silicon sensor is a promising advancement for active neutron personal dosimetry.
• The sensor's design mitigates issues like the funneling effect and gamma ray interference.
• The findings support the use of MCNP simulations with specific geometric considerations for accurate dosimetry predictions.