PhD Thesis Proposal: Eldred Lee

Wednesday, January 8, 2020, 1:00–3:00pm

Rm 105, Cummings Hall

“Novel Light-Matter Interactions in Solar & X-ray Wavelength Regimes”

Abstract

Our everyday technologies are heavily influenced by light-matter interactions that are engineered to our advantage. Some excellent examples of these include solar energy and X-ray detection technologies. Today, affordable, efficient, and durable solar energy technologies, especially concentrated solar power systems (CSP) and photovoltaic (PV) technology, and advances in X-ray detection are attracting many as they both have a tremendous potential to be improved to make a considerable impact in our everyday life in various ways. However, the status of the available technologies pertaining to solar and X-ray wavelength regimes has significant problems and limitations that can lead to inefficiency, increased maintenance, and undesirable outcomes. This thesis proposes novel methods to address the known issues in CSP systems and X-ray detection technologies, which inevitably requires engineering light-matter interactions in solar and X-ray wavelength regimes.

In the solar wavelength regime, this thesis will focus on the development efforts of efficient and durable solar absorbers for CSP systems with Mn- and Fe-oxide nanoparticle-pigmented solar-selective absorber coatings and native oxide solar-selective absorbers of FeMnNiAlCr high entropy alloys (HEAs) that can complement and alleviate the current issues of PV technology that lacks the flexibility on long-term, low-cost energy storage by enhancing the output as CSP systems can enable extremely efficient solar energy harvesting and storage. These solar-selective absorbers demonstrated remarkably high solar absorptance while maintaining relatively low thermal emittance loss compared to the existing art, therefore leading to high thermal efficiency.

In the X-ray wavelength regime, this thesis will begin exploring the advancements of high-energy X-ray detection, namely the 10-100keV range, with Los Alamos National Laboratory for the United States Department of Energy Nuclear Security Administration (NNSA) to mitigate major limitations of state-of-the-art (SOA) high-energy X-ray detection technologies and their ineffectiveness in NNSA’s next-generation light source facilities. With this goal, a novel high-Z semiconductor-based two-layer high-energy X-ray detector design concept has been proposed with an underlying principle of photon energy down conversion, where high-energy X-ray photons are attenuated down to an X-ray spectral regime that can lead to enhanced electron generations with respect to the amount of incident X-ray photons. To understand the fundamentals of the proposed concept, to obtain preliminary data for feasibility studies, and to compare performance with existing art, Monte Carlo N-Particle software (MCNP6.2) has been used to simulate the detector design. MCNP6.2 simulation of the proposed two-layer design reports electron generations significantly exceeding those claimed by a leading class of research even at much higher incident X-ray photon energies. Furthermore, a considerable amount of gain in electron generation can be achieved with this design from the SOA Si direct detection method used in commercially-available products.

Thesis Committee

For more information, contact Daryl Laware at daryl.a.laware@dartmouth.edu.