Physics students observe evolution of Rutherford back-scattering

Equipment at the University of Northern Texas
By Taylor Morris
Staff Writer
Valentine’s Day weekend is usually a time for rest and relaxation with loved ones, but for four students in the Sewanee Physics Department, the weekend was an adventure filled with hard work and scientific discovery. As part of the department’s Advanced Laboratory course, Joel Stewart (C’15), Charlie Morrow (C’16), Taylor Morris (C’16) and Daniel Rosales Giron (C’17) traveled to Denton, Texas with Professor Randolph Peterson to work with particle accelerators at the University of Northern Texas (UNT).
The Texas trip is an annual event for the lab class, and is one of the highlights of the Sewanee physics curriculum. Under the supervision of Professors Gary Glass and Duncan Weathers, the two major types of experiments the students performed this year while at UNT involved Rutherford back-scattering (RBS) and particle-induced x-ray emission (PIXE). Both of these methods involve shooting a high-power beam of particles toward a small sample and measuring the energies of the particles that are scattered and emitted from the interaction. PIXE methods were studied, and before long the students were able to identify unknown samples of materials by their elemental composition. The most interesting results came from RBS on a 2 metal alloy. The students were able to observe a complex evolution of the RBS spectrum from this material as it was heated by the particle beam, and then slowly cooled. One of the metals was observed migrating toward the top of the sample, but then become less structured as the beam cooled. RBS has never (to the knowledge of anyone at UNT) been formed on this particular alloy, so these results could be particularly useful to science.
The results from the experiments are to be presented by the students on the night of February 25, as part of the department’s weekly seminar series. The talk begins at 7 pm, with pizza to be served afterwards. For more information on the research or other Physics Department events, contact Society of Physics Students President Taylor Morris at