Date of Award
Bachelor of Science
Physics and Astronomy
Pb, sample, figure, rbs, energy, alpha
A Rutherford Backscattering (RBS) analysis experiment was performed on several pyrrhotite samples in order to understand their lead (Pb) diffusive properties and determine the diffusion coefficients for Pb into the sample. The pyrrhotite samples were prepared at Rensselaer Polytechnic Institute and were subsequently annealed for one to several days at temperatures on the order of 500–800℃. A 1.1–MV Pelletron Accelerator in the Union College Ion Beam Analysis Laboratory was used to produce beams of 3.3–MeV alpha particles. The beam of alpha particles collided with the samples and the backscattered alpha particles’ energies were detected using a silicon surface barrier detector. The backscattered alpha particle energy spectra were then analyzed using SIMNRA to determine the diffusivity of Pb in the samples. The simulated layers of the sample (obtained using SIMNRA) were determined using the collected RBS spectra and known diffusion trends. Three RBS spectra on the Pb–pyrrhotite samples were collected, simulated and diffusion coefficients D= 3.4x〖10〗^(-22) m^2⁄s,5.6x〖10〗^(-21) m^2⁄s,and 1.1x〖10〗^(-20) m^2⁄s were determined. The activation energy can be described by the relation: D=1.0 exp(-56 kJ mol^(-1)⁄RT. These diffusion coefficients and activation energy were found to be consistent with prior results .
McCalmont, Andrew, "Direction of Lead Diffusion in Geological Samples using Rutherford Backscattering Sepctrometry" (2016). Honors Theses. 181.