Program Information

A Simulation of X-Ray Emission with Gold Nanoparticle Irradiated by Energetic Proton Beam

M Newpower

M Newpower*, S Ahmad , Y Chen , University of Oklahoma Health Sciences Center, Oklahoma City, OK

Presentations

SU-E-J-247 Sunday 3:00PM - 6:00PM Room: Exhibit Hall

Purpose: To investigate the proton induced X-ray emissions in gold-water mixture materials.

Methods: In this study a Monte Carlo simulation was created using the GEANT4 toolkit (version 4.9.6). The geometry in this setup includes a 2 cm x 2 cm x 2 cm target, a scoring sphere (radius = 10 cm) and a 65 MeV planar proton source (2 cm x 2 cm). Four concentrations of a gold-water solution were irradiated with 5x10⁵incident protons at a distance of 0.5 cm perpendicular to the surface of the target. The solutions of gold-water mixture had 10%, 5%, 1% and 0.5% of gold by mass, respectively. The number of photon emitting for the target was counted in the scoring sphere for the energy range of 0-86.0 keV in 0.1 keV bins. For this study the reference physics list PhysListEmStandard was used together with the x-ray fluorescence, Auger electron and PIXE (particle induced x-ray emission) options enabled. The range cuts for photons and electrons were set at 0.5 mm and 1.0 mm, respectively.

Results: In the energy spectra of emitting X-ray fluorescence, peaks from gold K shell characteristic x-rays (68.8 and 66.9 keV) were observed. The number of counts under the peaks of Ka1 and Ka2 was found to increase with the increasing of the gold concentrations in the mixture materials. The X-ray yields (for both Ka1 and Ka2) when fitted with least-square method as a function of gold concentration demonstrate a linear dependency with R² > 0.96. The Ka1yield per incident proton was found to be 0.0016 for 10% gold-water mixture solutions.

Conclusion: This preliminary study with PIXE technique with gold nanoparticle has demonstrated potentials for its utilization in the development of range and dose verification methodology that is currently of great interest in the field of proton radiation therapy.



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