EPR/alanine pellets with low Gd content for neutron dosimetry

Area of Science:

• Materials Science
• Radiation Dosimetry
• Nuclear Physics

Background:

• Electron paramagnetic resonance (EPR) dosimetry offers a method for detecting radiation exposure.
• Improving the sensitivity of EPR dosimeters to specific radiation types, like thermal neutrons, is crucial for accurate dose assessment.
• Tissue equivalence is a key property for dosimeters used in medical and biological applications.

Purpose of the Study:

• To investigate the effect of gadolinium oxide doping on the thermal neutron sensitivity of alanine-based EPR dosimeters.
• To compare the performance of gadolinium-doped alanine with boric acid-doped alanine for neutron dosimetry.
• To validate experimental findings with Monte Carlo (MC) simulations.

Main Methods:

• Electron paramagnetic resonance (EPR) measurements were performed on alanine samples doped with gadolinium oxide.
• Comparative studies included alanine doped with boric acid (natural isotopic composition).
• Monte Carlo (MC) simulations were employed to model and understand the experimental results.

Main Results:

• Gadolinium oxide doping (5% by weight) increased thermal neutron sensitivity by over an order of magnitude compared to undoped alanine.
• The gadolinium addition showed a greater influence on neutron sensitivity than boric acid addition (50% by weight).
• The fading characteristics of the EPR signal induced by neutrons remained largely unchanged with the addition of these dopants.

Conclusions:

• Low-content gadolinium oxide doping is an effective method to significantly enhance the thermal neutron sensitivity of alanine EPR dosimeters.
• Gadolinium-doped alanine presents a promising, low-cost alternative for neutron dosimetry, maintaining essential tissue-equivalent properties.
• Monte Carlo simulations successfully corroborated the experimental results for gadolinium-doped samples, supporting the proposed mechanism.