Electron emission spectra from gold nanoparticles when irradiated with electrons and protons

Within the scope of a DFG-funded project, the electron emission spectra from gold nanoparticles (AuNP) were measured for various irradiation types. These spectra are important for estimating the dose‑enhancing effect of AuNP in theranostic applications. After completing the experiments with photons, the interaction of electrons and protons with gold nanoparticles of different diameters was investigated, and the double‑differential spectra of the emitted electrons were measured as a function of the emission angle and of the electron energy. To this end, the AuNP samples were previously deposited on a self‑supporting carbon foil with a thickness of 50 nm. The samples were then characterized as to their spatial distribution by scanning electron microscopy [1].

Figure 1 shows an example of the double‑differential electron emission spectra d²N/dEdΩ of AuNP for 100 keV protons compared to those of gold foil and carbon foil. The emission angle, which is defined in relation to the proton beam axis, was 30°. As demonstrated in Figure 1, below 50 eV, the electron emission spectra of AuNP considerably differ from those of gold foil and carbon foil. At energies higher than 50 eV, they exhibit a similar energy dependence.

Figure 1: Energy spectrum of the electrons released during bombardment with 100 keV protons for an emission angle of 30°.

Reference

[1]   P. Hepperle, W. Y. Baek, H. Nettelbeck, and H. Rabus, Part. Part. Syst. Charact. 2022, 2200136 

Contact

W. Y. Baek, Department 6.3, Working Group 6.36