Effects of Alpha Particle Irradiation on Graphene Oxide with Applications to MEMS Alpha Radiation Detectors
Advisor: Dr. Noble
Internship Location: UC Berkeley, Fine Lab
Onsite Mentor: Dr. Dragoslav Grbovic, Professor of Physics, Naval Post Graduate School
The goal of this project is to determine the effect of alpha radiation on Graphene Oxide in order to design a MEMS alpha radiation detector. Typically, the detection of high-energy particles and ionizing radiation has been carried out with detectors that contain gases as the detecting medium. These detectors tend to be quite bulky, expensive, and difficult to mass produce because the necessary glass tubes full of gas are delicate components. As a result, for many applications that require cheap, small, and disposal alpha radiation detectors, including environmental monitoring, biomedical technologies, and nuclear reactors, MEMS alpha radiation detectors with Graphene Oxide as the detecting medium would be more effective. This project will be conducted in two phases. The first step is to identify the effect different doses of alpha radiation have on Graphene Oxide samples, measuring the changes in the samples’ structural, chemical, and electromagnetic properties using various methods (Raman Spectroscopy, FT-IR, and XRD). The expected result based on previous research conducted is that alpha radiation will cause structural changes in Graphene Oxide, such as a reduction in the intensity of oxygen functional groups bonded to the carbon lattice or decreased d-spacing between layers. The second step of the project is to use this change in the properties of Graphene Oxide after exposure to alpha radiation to design a prototype of a MEMS alpha radiation detector. Similar MEMS detectors developed for gamma and neutron radiation have used carbon and boron-nitride nanotubes and novel printed-electronics techniques.
Project Blog
Week 1
Hello to all readers!
Sorry for getting to the party so late and only now making my first blog post. Circumstances around my project have been changing rapidly over the last two months in completely unpredictable ways that have precluded me from writing accurate updates about the progress of the project. In this blog post, I will summarize everything my project has been dealing with since late January, not only to explain some substantial changes to my project, but also to provide an inside perspective on what kind of obstacles you face working in research in 2025.
Those already familiar with my project know that my original goal was to study the effects of alpha radiation on Graphene Oxide with the eventual goal of using this research to develop a MEMS Alpha Radiation Detector. This work was to be done with the Naval Postgraduate School Physics Department working under Dr. Grbovic and Dr. Fabio. This lab happened to be a federal lab run by the Navy and the Department of Defense, which did not mean much to me when I was first starting my project many months ago, but those of you who are following the news can probably start to guess why my project ran into a lot of problems. Working at a federal lab in 2025, my project faced a variety of different setbacks over the last few months that neither my advisors nor I could have ever foreseen
As early as the second week of February, I began to realize that my project was running into some problems. The first step of the project was to create graphene oxide sheets that we could experiment on, which required a graphene oxide dispersion and silicon wafers. The lab did not have these supplies on hand, so Dr. Grbovic instructed me to find some materials supply companies from which we could purchase said supplies. The order request ended up being about 400 dollars, and Dr. Grbovic assured me there would be no problem, because in previous years, the process for securing funding for such a cheap project would be completely straightforward. For Small Expense Projects (in the range of several hundred to several thousand dollars), if my PI (Dr. Grbovic) approved the expense and the lab approved the expense, that would be enough to secure funding and place the order. However, in 2025, any federal research funding, no matter the size, now requires approval from the Department of Government Efficiency (DOGE), which meant my project was delayed indefinitely until this government agency nobody in the lab had ever worked with got back to us about funding my project.
We waited a few weeks for a response, but before we ever heard back about the funding for my project, the situation got a lot worse. One day in the first week of March, every professor, postdoc, graduate student, and intern at the Naval Postgraduate School Physics Department was notified that their lab’s credit cards were frozen indefinitely. The lab could not spend any money whatsoever. Not only could the lab not fund any new projects, like mine, but it could not pay for any expenses for ongoing existing projects. Every researcher began to scramble to find a way to somehow continue their work while spending nothing at all for the foreseeable future.
Just a few days later, the lab was notified that the federal government was headed toward a shutdown in mid-March. If this shutdown were to happen, not only would the researchers not be able to get into the lab (their IDs would just stop working), but they would lose access to their NPS emails and any work they had to access through their NPS emails (software licenses, shared coding projects, etc.). Every researcher began to scramble to find a way to continue their work if the federal government shut down for an indefinite amount of time.
As a result of these two events, Dr. Grbovic and I began to discuss possible ways for me to continue my research depending on how this situation resolved itself. We settled on a total of four cases:
Case A: If the federal government avoids a shutdown, the credit cards are unfrozen, and DOGE approves the funding request by mid-March, I will continue my work as usual. I order the graphene oxide and silicon wafers, and work on my project as initially envisioned, just on a slightly shortened timeline. This is the best-case scenario.
Case B: If the federal government avoids a shutdown, the credit cards are unfrozen, but DOGE doesn’t approve the funding request by mid-March, I continue working on my project but in a more theoretical way. I start by doing simulations of the MEMS Detector and performing calculations on how the energy from alpha radiation would change the chemical properties of Graphene Oxide. Then, when the funding request is eventually processed, I start my in-person lab work toward the end of the project, pivoting my project but not completely abandoning it.
Case C: If the federal government avoids a shutdown and the credit cards remain frozen, I stay at NPS but move to a different project completely.
Case D: If the federal government fails to reach a compromise on the budget and shuts down, my senior project is delayed substantially. I could try to wait out the shutdown and hope it only lasts briefly, or I could even try to move to a different lab that is not federally run and start on a new project. This is the worst-case scenario.
About ten days ago, the outcome became clear. The federal government had avoided a shutdown but the credit cards remained frozen (they remain frozen even now), so Dr. Grboic and I chose to go with Plan C. Completely abandoning my original project and the months of work I had already put into it, I moved to a different project. Still working under Dr. Fabio and Dr. Grbovic, I am now working on developing Directional Multi-Resonant MEMS Acoustic Sensors for Low-Frequency Detection.
When I first realized that I would have to move projects, I was deeply sad. I was disappointed to move on from a project I was so passionate about and had already invested so much time and effort into. However, in the time since making this tough decision, I have begun to appreciate how important this experience was. It made me learn at a younger age than most that external factors like funding and politics play a key role in the scientific research process. For someone like myself, whose goal it is to pursue a career in academia and scientific research, that realization was harsh but necessary.
Completely changing my project this late in the Senior Project journey has been hard. I have been forced to completely start from scratch, conducting a literature review and familiarizing myself with the basic science and engineering behind the technology of Acoustic Sensors. This is the phase most of my peers were in back in January, which has been both embarrassing and demoralizing. Nevertheless, I have tried my best to remain steady and work as hard as I can to make sure I have something cool to share with everyone at my Senior Project Presentation in May.
Check back in next week to read an update all about my new project and the progress I have made so far.
Thank You for reading!
Despite how long this update ended up being, I have so many more details to share about my journey, so please don’t hesitate to leave comment and ask a question!
Week 2
Hello readers!
Welcome back to my Senior Project blog. To those of you who are new here and didn't read my post from last week, I will give a quick update. As a result of various setbacks and obstacles I encountered over the last two months, I have abandoned my original project idea that involved working with graphene oxide and MEMS Alpha Radiation Detectors. I have moved on to a new project. I will dedicate this post to introducing my new project, outlining my role within this project, and explaining the overall mission of the project.
The goal of my project is to design a directional multi-resonant MEMS acoustic sensor for low-frequency sounds. Low-frequency sound detection is a key area of research in the development of acoustic sensors, with numerous applications in medicine, environmental monitoring, and defense. These devices are of such importance because low-frequency sounds are inaudible to the human ear. Despite the significance of these detectors, current prototypes are bulky, expensive, and difficult to mass-produce, as they rely on three separate components to achieve cosine-like directionality.
Under the guidance of my advisor, Dr. Grbovic, and MEMS acoustic sensor expert Dr. Fabio, I am working at NPS to develop a prototype MEMS chip that will be smaller, cheaper, and easier to mass-produce than existing directional acoustic low-frequency detectors, without sacrificing performance. My role in the engineering design process for this chip is focused on Analytical Modeling and Finite Element Modeling. Specifically, I am responsible for using these modeling techniques to experiment with the chip’s engineering parameters (such as geometry, materials, and orientation) to create a design that maximizes the usable frequency bandwidth and signal-to-noise ratio (SNR), while maintaining cosine-like directionality and adhering to design requirements. The final product of my work will, hopefully, be a complete three-dimensional prototype of the chip created in COMSOL Multiphysics.
Thank you for reading my blog post. See you all next week for my first update on the project's progress.
Week 3
Hello again dear readers!
It has been a few weeks since my last blog post, and I am happy to say that for the first time in the history of my Senior Project, the updates are almost completely positive. I have been working diligently on my new project (read my last blog post if you don’t remember in what ways my current project is “new”) and there has been only one minor setback that is not related to science or engineering or anything to do with the project itself.
In order to work collaboratively on the design of the chip with other members of the team, I needed a COMSOL license. COMSOL licenses are paid software and thus need to be assigned to a specific user’s email account. Usually, the Naval Postgraduate School only gives out these licenses to nps.edu emails, but because of new policies from the federal government, the process for assigning federal emails to interns and staff was more complicated than it used to be. The solution to this problem was quite simple, since the license could just be assigned to my personal email, but this was out of the norm and thus caused a slight delay in the process of receiving my COMSOL license.
Aside from this short holdup, the majority of my project has, for the first time, been fairly smooth sailing. In fact, the project has been going so well that Dr. Grbovic and Dr. Fabio decided that I could probably expand the scope of my project by a little bit and still finish in time for the Senior Project presentations. A functioning acoustic sensor of this type, regardless of the wavelength it is designed to operate at, has three components: a detector of cosine-like directionality, a detector of sine-like directionality, and an Omni. The math of how these three components interact to unambiguously determine the DOA (Direction of Arrival) is quite interesting but I will explain that more thoroughly another time. As I stated in my last blog post, my original goal for this project involved designing only the cosine aligned detector, which represented only one half of the chip. However, now my goal now has expanded to include designing both sides of the chip, the sine-like and cosine-like detectors (or “rocker” and “bender” as these components have been nicknamed by Dr. Grbovic). The Omni is by far the easiest part of the MEMS chip to design and it does not affect the simulations in any way, so my step of the modeling and design process mostly ignores it.
The highlight of my research so far has been getting to go into the lab to meet the other people working on the design of this MEMS device. It has been not only an incredibly fun experience, but also an incredibly educational experience as well. Touring the lab and listening to the professors discuss the science behind the project has easily taught me more about how to approach the design of the chip than all the papers I read combined. Considering that just a month ago I thought I would not get a single chance to actually go in-person into the lab over the course of my Senior Project journey, I feel so blessed to have these opportunities.
Thank You for reading my blog post! I am so glad to finally have my research moving along smoothly and for my project to be showing real progress, and I am equally happy to get to share this victory with all of you, supporting my work and rooting for me!
Week 4
Hello Dear Readers! I am back to give a quick update about the state of my project. As of this moment, I am about 95% of the way to having a final model that will be ready to present on May 17th. In this blog, I will explain what I have done and what is left to do to get my model presentation-ready.
My Finite Element Model of the Directional Acoustic Sensor consists of two separate models, each simulating the performance of their own component. The two components have been nicknamed the rocker and the bender.
As of this moment, the model of the bender is fully complete. It resonates in the correct frequency band (750-850 Hz) and the parametric sweep from -180 to 180 degrees shows that the amplitude of oscillation of the bender is proportional to the cosine of the angle at which the sound reaches the bender from the DOA.
As of this moment, the model of the rocker is not fully complete. I started my investigation by checking out the two parameters Dr. Grbovic suggested (substrate thickness and Gap 2). After only a few days of study, I concluded that neither of these parameters would in any way help make the directionality of the rocker sine-aligned. From here, my work became a lot tougher.
I would not have time to experiment with every parameter, because the investigation of a single parameter would require multiple simulations testing the performance of the model while plugging in different values for that parameter. A single one of these performance tests requires running two different simulations. The first is a test of the natural resonant frequency of the chip with the new parameter, which takes about twenty minutes on average (less or more depending on how much the mesh is compressed or loosened by the given change to the parameter). The second simulation is a parametric sweep from -180 to 180 degrees at the frequency the first test outputs, which takes about thirty minutes on average (again less or more depending on how much the mesh is compressed or loosened).
My solution to this time constraint would be to be more strategic with which parameters I chose to play around with. Modeling the rocker as a damped spring, you can easily build an Analytical Model of the system and solve a simple differential equation to determine the amplitude, frequency, phase shift, and every other factor of oscillation in the rocker system. Doing this quick math would not tell me how a specific change to the parameter would affect the system it would only give me a general idea of if any change to a parameter in the rocker system would affect the oscillation of the system. This saved me a bunch of time by helping me know in advance which parameters were completely irrelevant to the oscillation of the system and would not affect the directionality of the rocker in any way.
Once I used this method to narrow down which parameters I had to test, I began the brute force portion of the research process. I would plug in various values for every parameter, making sure to change only one independent variable at a time so I would know for certain once the simulations were complete how a given parameter affected the directionality and frequency band of the rocker.
This is the phase of research I am in currently, finishing up this brute force testing of every relevant parameter. I will be done with this step tonight, and I will have a notebook filled with collected data on how every single relevant parameter affects the performance of the rocker. Tomorrow, I will go into the lab one final time to present my findings to Dr. Grbovic and Dr. Fabio and hear their feedback. Maybe they will have some out-of-the-box ideas about what I could try to play around with, such as using multiple materials or something else out of the norm.
I will make another blog post on Thursday explaining what happened in the lab and what the final results of my project are.
Thank you for reading and see you next time.
Week 5
Hello dear readers! Welcome back to the penultimate blog post of my Senior Project. This blog will be a quick rundown of my last time going into the lab this past Wednesday and the crazy changes to the results of my project that followed.
This was an especially important meeting with my advisors, because it was my opportunity to present all my findings from the last few weeks of research to Dr. Fabio and Dr. Grbovic and receive their feedback. As I mentioned in my last blog post, my hope was that their experience with MEMS Acoustic Detectors would allow them to see something I had missed and help me finally get the rocker to work.
As I presented my spreadsheet of data, which included tables depicting how changing every single parameter would affect the resonant frequency band and directionality, Dr. Grbovic and Dr. Fabio came to the same conclusion I did. The rocker as an engineering design could not work as a sine-aligned acoustic sensor. The consistent asymmetry present across every single directionality study was proof of this fact. Even my out-of-the-box ideas, like using multiple materials or creating an asymmetric rocker with two halves that have legs of differing dimensions, did not succeed in making the directionality graphs symmetric.
This result was somewhat disappointing. I had spent two months of my life and hundreds of hours of work developing this piece of technology, only to eventually determine after lots of testing that it could not work in its current form.
However, in that moment of disappointment, Dr. Fabio noticed something interesting about my directionality graphs. Within the rocker’s directionality graphs, there was a range between -50 degrees and 100 degrees of continuous unambiguous growth of amplitude. Although this was irrelevant to the effectiveness of the coupled bender-rocker acoustic sensor I had been working on, this was a beneficial result to the development of a directional acoustic sensor that could be used for other applications that did not require 360 degrees of range, such as the development of hearing aids.
This was a surprising result to not only me but also my advisors, and they urged me to look over all my data to work towards a new goal. Instead of trying to create sine-like directionality, my goal was now the opposite: to maximize the asymmetry of the rocker’s directionality instead of minimizing it. After getting home from the lab, I analyzed all my data and, using everything I had learned about every parameter from my research, I ran a simulation that showed a whopping 165 degree range of effectiveness.
This was a noteworthy achievement that left me surprised. I do not yet know how my findings will be used by Dr. Grbovic and Dr. Fabio, but it is entirely possible that my findings could be used to send a line of rocker-inspired MEMS Directional Acoustic Detector chips into production.
Thank You for reading this blog post! Come back and read my last blog post, which I will write later today, that will explain everything I learned about research from my project and my general takeaways from this experience.
Week 6
Hello Dear Readers! Welcome to my last blog post of my Senior Project!
This blog post will be a bit of a change of pace, taking a moment to look back on my time during my Senior Project and reflecting on what I have learned.
The first two months of working on my Senior Project taught me a great deal about the nature of research. As my advisor, Dr. Noble, reminded me every chance we met, this was an important lesson to learn. That lesson being that research is impacted by so many factors outside of the science itself. Politics and funding disputes and dozens of other annoyances that have nothing to do with research will always pop up and try to slow you down from reaching your goals. Battling with these factors and eventually having to make the hard choice to scrap my original project all together made me learn this lesson sooner than most. Looking back on that experience, now that I am a bit further removed from it and less emotional about it, I can see how I am better off having lived through and learned the lessons I learned.
The final results of my project also taught me a great deal about scientific research. Realizing that the months of work I put into the development of the Rocker component was all to achieve a negative result was definitely a blow at first. However, the calmness that Dr. Grbovic and Dr. Fabio showed in response to the realization, contrasted with my own disappointment, made me realize that this is a frequent occurrence in research. Although negative results are not as fun or exciting as positive ones, they are equally as important and helpful in the research process.
Additionally, seeing how Dr. Fabio was able to transform my failure in making the Rocker sine-like into a positive, by proposing an alternative chip design that capitalized on the asymmetry of the Rocker also taught me a great deal about research. I realized that scientific research is not a linear path, and getting the result you “want” is not always for the best. Sometimes, setbacks offer opportunities to change course and take your research in a new direction.
All of these realizations have made transformed me into a significantly better researcher. I am very grateful to have had the opportunity to conduct my Senior Project and work at the Naval Postgraduate School. Thank You everyone for reading my blog and supporting me on my Senior Project journey! Hopefully, I will see you at my presentation!