Friday, October 14
Exploring the Effects of Copper on Composition and Charge Storage of Prussian Blue Analogue Pseudocapacitors
As energy usage has increased in recent years, there has been great demand for efficient, cost-effective, and earth-abundant materials to be used for energy storage. The ability to produce hexacyanoferrate (HCF) modified nickel film for use as a pseudocapacitor has already been demonstrated. This project focuses on the effects on the modification procedure and the resulting material of adding copper to the nickel metal film. A NiCu film was deposited onto a gold substrate with a controlled potential electrolysis experiment, then was modified and characterized with a cyclic voltammetry experiment. The composition was determined with a scanning electron microscope with energy dispersive x-ray spectroscopy before and after the modification process. Copper was selectively removed in some cases as a result of the modification. With increased levels of copper, the material can become structurally unsound and result in unintentional stripping of the material. Preliminary data suggests that as the pre-modification level of copper is increased, the resulting charge storage of the HCF film increases as well.
Scanning of the Intermodulation of Superconductor Resonators
At the resonant frequency, superconductor resonators produce intermodulation distortions, smaller signals near the resonant frequency. By inducing external microwave signals, it is possible to analyse the patterns of intermodulation distortions (IMD) in several different types of superconductor resonators. These measurements can be used to complement the main peak values like quality factor and frequency shift in order to understand nonlinearities present in the material of the superconductor. Once spatial distributions of IMD have been identified, they can be used to interpret IMD signals from unknown superconductors and identify various defects in the crystal structure. Using a probe outputting two combined tones into the resonator, it was possible to map the whole of a two-dimensional resonator, using the IMD as the z-direction. In order to best resolve the intermodulation distortions, two superconductors were imaged, a hairpin wide-line resonator and a thin, line resonator. A contour plot of the data was then generated, which displays the IMD of the given resonator.
Determining the Nuclear Structure of an Unstable 25O Isotope
One of the primary goals of nuclear physics research is to better understand the force that binds nucleons. This can be accomplished by studying the structure of neutron-rich isotopes. For this experiment, excited 25O nuclei were formed by a collision between a 101.3 MeV/u 27Ne ion beam and a liquid deuterium target at the National Superconducting Cyclotron Laboratory. One resulting reaction involved two-proton removal from 27Ne particles, which created excited 25O nuclei that decayed into three neutrons and an 22O fragment. The four-vectors for the neutrons and 22O fragments were determined, allowing the calculation of the decay energy for this process on an event-by-event basis. However, another reaction would also take place, in which an alpha particle was stripped from the beam, creating 23O nuclei that decayed into an 22O fragment and a single neutron. In order to distinguish between 22O fragments and neutrons from both 25O and 23O isotopes, members of the MoNA collaboration are conducting GEANT4 simulations of each decay process in order to uncover their distinguishing characteristics. By successfully correlating simulated decay processes to experimental data, the relative cross sections of the two decay processes will be determined, and their decay energies will reveal more about their nuclear structures.