Doctor of Philosophy, The Ohio State University, 2023, Electrical and Computer Engineering

High-energy physics (HEP) experiments such as the Large Hadron Collider (LHC) facilitate unveiling the mysteries inside the atom's nucleus and lead to a better understanding of the universe. They also enrich the capabilities of humanity by extending the limits of existing technologies and encourage the need for new technologies. An accurate measurement of the amplitude and time of arrival of high-energy particles or ionizing radiation is a recurrent requirement in HEP experiments and other applications such as the positron emission tomography (PET), Light Detection and Ranging (LiDAR), and X-ray imaging. Recent technology advancement requires improved amplitude and timing measurement precision. This research investigates the fundamental measurement limitations, targeting a complete system design, prototype fabrication, and experimental measurements. Furthermore, the fabricated electronics along with the radiation sensor is being integrated in one module to be used by the European organization for nuclear research (CERN) in the next LHC run. The system consists of a radiation hardened frontend readout integrated circuit (ROIC) and a backend scalable analog to digital converter (ADC). The ROIC contains a low noise preamplifier with second stage differential variable gain amplifier, followed by a Constant Fraction Discriminator (CFD). The CFD is used to provide a timing edge, while eliminating the influence of signal intensity on the measured timing (time walk). A new design methodology for the CFD is proposed to improve both time walk and jitter performance, incorporating an all-pass filter delay line to reduce the extra jitter, typically added by the CFD, and an optimum slew rate comparator to eliminate the time walk. The ROIC is designed in 65 nm CMOS technology. Three design, fabrication, and measurement iterations were completed to improve system reliability and to qualify the ROIC for deployment at CERN. A record low time walk of ±6 ps across a 30 dB signal d (open full item for complete abstract)

Master of Science (M.S.), University of Dayton, 2021, Electro-Optics

Ultrafast optical spectroscopy is the branch of optical science that involves the use of a femto/pico/nanosecond pump as an excitation source, with a broadband probe (either white light or a supercontinuum source) that captures the spectral signatures of dynamic events as a function of frequency/wavelength. In these methods, while the pump pulse is responsible for a physical or chemical change of the sample, the delay between the pump and the probe allows for reconstruction of the time dynamics of the ultrafast process. By sending multiple pump-probe pairs with a successive (small) delays between them, the dynamics in either the transmission or reflection spectrum can be reconstructed; however, the observed sample has to be excited multiple times with pump pulse corresponding to the time-stamp determined by the delay. Repetitive excitation of a sample can result in damaging effects for a reversible process. On the other hand, the starting conditions will not be same each time pump-probe pair hits the material or sample under study for an irreversible process where different spots on a material or different specimen are used per pulse delay. This thesis offers a new, rather simple way of achieving dynamic transmission/reflection spectral characterization using state-of-the art electronics and parallel detection on commercial detector arrays. Rather than sending single pump-single probe signals for each time stamp, a single pump multiple probe technique is proposed: In this method, we excite a sample only once and read out transmission/reflection spectrum multiple times during the window in which the physical transformation under study occurs. To achieve this, an advanced light detection and pulse shaping techniques is required to achieve the requisite detection speed for this real-time detection. In this thesis, I present the starting blocks for a complete ultrafast real-time spectrometer, with focus on the electronic subsystem, which was the main challenge dur (open full item for complete abstract)

Doctor of Philosophy, Miami University, 2019, Educational Leadership

Research reveals that there is often a major disconnect between leaders and workers in organizational settings, especially when it comes to decision-making. Consequently, organizational decisions are often misunderstood by the employees who must implement top-down directives, which can lead to growing distrust, frustration, and needless resistance toward change initiatives. This kind of disconnect, resulting confusion, and resistance is also found in schools between principals and teachers. Having worked as a teacher and then as an administrator in three separate school districts, I have become overwhelmed by the bureaucratic nature of school committees. In my experience, school committees tend to be exclusive, administrator-driven, and lack authentic, rich discussion. This study seeks to narrow the focus of research on school committees by exploring how teachers experience the decision-making process for change initiatives in a school committee setting when inclusive deliberation (ID) is used as a framework for school committee design. Also, the study explores the impact of school committee design and operation on teacher resistance and feelings of morale. The methodology of this study is a single instrument, action research case study, expressed in a narrative. The case exists at the high school where I work as an assistant principal. During the second semester of the 2018-2019 school year, a committee known as the Building Leadership Team (BLT) altered its design and operation, using the framework of inclusive deliberation (ID). Teachers' experience with the BLT, along with other phenomena that took place during the case study with additional members of the staff, were collected as data. Data was collected through observational field notes, journaling of daily interactions, participant reflection prompts, staff surveys, a focus group reflection, and individual interviews. Inductive analysis was used to triangulate the data to understand the phenomena being resear (open full item for complete abstract)

Master of Science in Engineering (MSEgr), Wright State University, 2012, Electrical Engineering

Carbon nanotubes (CNTs) are widely studied by the researchers in recent years, as they have small size, large strength, highly electrical and thermal conductivity. The single-walled CNT (SWNT) is readily changed in electrical resistance when exposed to gas, and has significant use in environmental monitoring, agriculture and fishing industry, chemical industry and even security. A read-out integrated circuit (ROIC) is required to detect the resistive change. In this thesis, an ultra-low power, wide dynamic detecting range and small size CMOS ROIC design is presented. This ROIC can interface wide dynamic range signal up to more than two orders (100pA-60nA) from deployable sensors using automatic gain control (AGC) unit. A novel technology of sub-threshold technique is applied in this design, which can save up to 96% (from 25.2mW to 0.89mW) power consumption comparing to the circuit operating in super-threshold. To improve the accuracy of calibrated readout current, compensation factor derived from the analysis of simulation results is finally added. The proposed circuit also has the capability to output 8 bit digital signal that can be transmitted wirelessly to the data center for further signal processing.